Quad driver troubles

[StuMpy77]

Hello, I'm new to the forum first of all. I have a 1989 Buick Lesabre Custom 3.8L(vin C), which is used primarily for rural mail delivery. I live in WI but the car came from Florida a few years back(no rear window defrost is a tell tale, and pain during the winter lol). The car has approx 135k miles. I've been messing with a trouble code for awhile now and can't find the information I need on it anywhere(could prob buy ALLDATA but can't afford it atm).

I keep getting diagnostic code 26 and yesterday a code 65 was causing cel to come on and go off when you put the car in drive or reverse and started moving. I have a spare engine/trans w 90k I saved out of a car I junked out due to the frame rotting out so I swapped EGR valves(had a gasket leftover from intake job too so free to try). In less than 24hrs the code 26(quad-driver module "A" error) was back, no sign of the egr code yet but i'm still waiting. My reasoning for swapping the egr was to rule out part failure vs ECM failure, if the egr code 65 came back right away everything I've found on this issue points to the ECM being bad(multiple codes at once). Before I suck it up and drop $100 on an ECM I want to check each of the circuits controlled by QDM circuit 1 or A for issues. My problem is finding the information, does anyone have a flow chart or troubleshooting guide that lists what it all controls so I know what to test? Judging from a blurry distorted(not legible) flow chart I found for a Bonneville I believe it controls the torque converter clutch(TCC), the low speed radiator fan circuit, the coolant temp warning light on the dash and something else(possibly canister purge? I don't know). I believe the 3 other quad drivers control egr function, and shift solenoids but that's less concern to me as I'm not getting codes for them...yet haha. The ECM ground underneath the coil packs is clean and good, going to get the car up in the air this weekend to check for any/other grounds condition(first place to start according to logic). I'm not one to diagnose a problem by just throwing parts at it, that isn't called being a mechanic and I'm no longer a parts salesman haha. I can jump the data link for codes but don't own a scanner capable of live data for obd1. Is there an easy test for the TCC? My data link in the car doesn't have the pin for the TCC, only the test terminal(B), ground terminal(A) and serial data terminal(M). I disconnected the battery when I swapped EGR valves as I also had to repair a cracked coolant reservoir(fun times!) and like I said the EGR(code 65) hasn't returned so far which leads me to believe I had a bad EGR solenoid outta 3 on the old one. Coincidental timing? I am however concerned about burning up the QDM circuit in the ECM just leaving it as it is, the car runs just fine and cooling fan comes on like it should. I want to fix the root problem so if I do end up changing the ECM it doesn't just come back right away or damage the new ECM. The fact the warning light is one of them also has me a bit worried, if it overheats and the light doesn't come on I'm cookin head gaskets at minimum right? Off topic is there any good pre-existing location to mount an aftermarket mechanical temp gauge? I don't trust only a light, but that's the way I am and have a new gauge that never made it into my old Trans Am before I sold it(another "free" piece of mind so to speak).

Thanks for any input or thoughts, have been kind of lost on this one and the lack of information online has me stumped. Call me a cheap ass but I can't see replacing a computer plus swapping PROM chips just to see if it MAY fix my issue. I swear the automotive industry has, for lack of better words, abandoned OBD1. Yeah I know the information it can provide is limited, but it's still information 🙂

 

[journeyforce]

I think you have isolated the problem with the Quad Driver. Most of the time it is ECM related. Where are you getting this $100 for an ECM from? Don't you have a self service junk yard in your area? Get a used ECM from the same year Lesebre and switch over your PROM chip to the new computer. If you can see if you can find one that says GM REMAN because that means the original was replaced and got a more up to date ECM

You can mount the gauge anywhere it will fit. Did you get the analog electric gauge( has wires and a sending unit) or is one with a tube that the hot coolant runs through(has clear hose)

You can pick up a good used copy of a GM factory service manual for not a lot of coin

Good luck

 

[StuMpy77]

First of all thank you for your comment! The $100 was a reman w/LLT warranty +core charge added.(lifetime warranty because I have the spare drivetrain for it and know the ECM's weren't the most reliable parts of the older GMs, wishful long term planning). If it ended up not being the problem I would keep the OEM one and eat the core charge of $26, my opinion is OE is "usually" better than aftermarket. I've just heard something as simple and stupid as a burned out temp warning light bulb is enough to produce the code 26. Most often it seems the code has something to do with the module not being able to "hold" ground, or otherwise it's a bad component. Yes I do have salvage yards around me, just don't trust used parts too much. Have had bad experiences in the past and I'll leave it at that haha. Just got a call the car was down on power/sluggish now and the CEL is blinkin away again. When it gets home I'll pull codes again and check that "hey stupid bulb" for peace of mind.

The temp gauge I have to use is a tube type old school one with a probe on the end, I looked the engine over pretty well and was hoping to find a threaded plug which led to the water jacket not being used for something. Was also hoping there was something I missed that's buried under parts on the heads somewhere. I know you can't just replace the coolant temp sensor or sending unit for the fan(too easy anyway lol) with the probe. Do they make a modified/stock water neck for any of the 3.8Ls down the line I could swap for and gain a threaded hole I could adapt to for the temp probe(say a GTP/SSE etc)?

I'll probably end up getting pricing on a junkyard ECM anyway, it's a bit of a pain to get to but if I go that route I can always get a reman one down the road I suppose. Cheers on reminding me about factory service manuals, last one I got was for the 78 T/A and I got raped at a car show for that one($45) even though it looks brand new lol. I'd be willing to bet they aren't that desirable for the Lesabre ie cheaper. Thanks again for the thoughts journeyforce and the heads up on the GM reman sticker to look out for, wouldn't have thought of that!

 

[journeyforce]

Well the coolant temp sensor (CTS) that the computer relies on to monitor coolant temps and to switch on and off and the sending unit for the temperature dummy light or gauge are two different creatures and exist separate from themselves. For instance if you were to unplug the sending unit that controls the turning on and off of the bulb the fans would still get turned on by the computer at a preset temp.

You are able to remove the temp sensor for the bulb and put the sending unit for the gauge in its place. However i would suggest if you are going that route that you spend the money for a electric analog temp gauge(looks just like your one but uses a electric sending unit instead of a hose. That is safer because those hoses are very fragile. The electric one at a parts store is about $25 or $30

When I got my 1989 Century, it had the base model instrument cluster with the dummy light for the temp gauge. The optional cluster had the temp gauge. I went to the junk yard and discovered clusters were the same. and all I needed to do was to buy the temp/fuel gauge combo(on the dummy light cluster the fuel gauge is stand alone) and the 4 metal clips(that attach the gauge rear terminals to the cluster), the black plastic divider that covers the gauges and sits under the glass and buy a brand new $12 GM temp sending unit for the gauge(the units are not the same) from the dealer and I got a working temp gauge for less then $25. I did not have to change the speedo or odometer.


But I digress on this. Did you bulb check the temp light? take your ignition key and turn it to run(the point before you start the car) and look, all the lights should come on. Some stay on until the car is started and some come on quick and shut off. If the temp light does not come on at all then check the bulb.

As for the junk yard computer, If you can find one cheap then get it and see if it works. If it works just keep it in and don't worry about it. A lot of people think the pre OBDII GM computers were really bad and problematic but by the end of the 1980's and up to the end of the OBD I era were reliable. While the late 1970's and early 1980's computers failed a lot, the ones from the late 1980's to end of the OBD I era were robust reliable. The reason a lot of them were replaced in the late 1980's was because a bad sensor mimicked a failing computer and some parts changer simply tossed parts at the problem(Parts changer is a term for a tech that rather then diagnose and issue throws parts at the issue till it fixes it)

In my 1989 I replaced the computer with one from a junk yard(I caused the original one in my Century to get broken by my clumsiness.) and I had this junk yard in the car for 6 years and it worked fine. I gave the car away a family friend and it is still driving around VA as I write this(so that means it has been using that junk yard computer for over 10 years now)
Good luck

 

[HotZ28]

I hope this helps you with troubleshooting. This came from an early 90's VIN-L FSM, but I don't think the QDM's circuits changed any, if at all. In addition, notice the footnote (*) on page 3-3.

The 1989 VIN-C PCM was known as "QDM" in which Quad driver modules (QDM) temporarily shut down, sets a fault code, and then resets if a device or its circuit shorts.

 

[StuMpy77]

Sorry for the delay in response, been pretty busy getting ready to rebuild an axode and wouldn't ya know it just about everyone I know is having some kind of vehicle problem to slow me down even more. If only I had a hoist and 220V in the garage, could almost make a full time business happen. Oh and a tire changer/balancer, welder, a press, etc etc....someday they'd all be nice lol.

I didn't look for the temp light while testing the CEL the first time(was locked into "code stare" I suppose haha). It does stay on when you have the diagnostic terminal grounded, the low speed fan circuit also runs while testing for codes. My EGR fault code 65 was back again with the known good EGR valve so I went ahead and ordered the reman computer, have 5 days before it arrives so after a quick Town Car window switch job and Subaru exhaust "adjustment" I should have some time to go over the Buick a little closer. Plan on visually inspecting all fuses, testing relays, and checking connectors. I'll just give the core back(after pulling PROM of course), will only be about $70 said and done for the reman with warranty. Local yards were looking for $30-35 & funny thing was I had more than one guy finish the price quote with "If there's a car out there with one yet". Must be a large population of "Parts Changers" in my area, not a good sign either way lol! I rebuilt basically the whole front end of it recently so whats another $70 in the long run...I guess. Just hurting from the front end parts yet but that's my own damn fault for leaving the struts bad for as long as I did and waiting for a half shaft to start clicking before giving it attention. It needs an oil pan gasket pretty bad too, that's an easy one though and $12 I can't complain 🙂

So I'm not going to make the QDM gods unhappy if I just pull the sender for the coolant light eh? I'd like the added accuracy of an aftermarket gauge...but you've got me adding another thing to the list of stuff to look for at the junkyard with that factory temp set up. That's a good one and I like it alot. Delivering mail you drive from the middle and was having added trouble with a location for the gauge that wouldn't catch knee's in either driving position(normal/mail). Suppose I could always save the tube gauge for a transmission temp set up in the crusty plow truck, wouldn't care if the tubing leaked in that pos. Regardless I've been putting off a trip to the junkyard and it's time to go wander around for a few hours, what can I say? It's like Fleet Farm, I just can't help myself.

HotZ28 that's exactly the document I found but was unable to read, thank you very much sir! I have an all models Chilton manual I get by with most of the time that cover's 1988-1992 but its pretty vague and missing diagrams. Autozone's website had the standard wiring diagrams(after you create an account and give them your info of course) but none of the QDMs were labeled so I could guess but that was about it. I didn't know the brake switch was part of this mess, that's easy enough to check though. Just for giggle's I might pull the temp sender, I assume you can test that with a heat source and multi meter, like a CTS?

I can't thank you guys enough for your time and ideas, much appreciated! Armed with some new ammo I'm gonna keep pluggin away at it, like I said I'll be pretty busy the next day or two but will report back with what I find. Cheers!

 

[StuMpy77]

Now I'm really lost! Well the ECM came in yesterday and they didnt call me so I picked it up today. I checked the fuses with a DMM, all passed. The ground pin on the data link was at 3.6 ohms, the canister purge solenoid seemed a little high at 25 ohms(I say this because the ECM that was in the car was a reman already, a sticker on it says to "test circuits with ohm meter, should not exceed 20ohms or warranty void"). Both the high and low cooling fan relays clicked away when voltage was applied, not the ideal test but they functioned. Relays were all at 75 ohms, pin 85 to 87(can't remember which pins for sure, the ones that give you a resistance value haha). It should be mentioned the old ECM was not properly fastened in and loose when I removed it. Vibration issue? Either way I went ahead with putting in the new computer.

I disconnected the battery before I started pulling the ECM out of course, was a fairly easy job albeit on my back on the floor of the car(don't lay on the trim screws after you take them out, they hurt a little stuck in your back). I swapped the PROM and cover over to the "new reman" unit, made sure it was clipped in all the way and secure by the tabs on the end of it. Had them next to each other oriented the same way to make sure I didn't do a 180 with the PROM chip. Only snag really was catching a tan or possibly tan w/white stripe wire on a fuse box down there on install, I stressed it a little but didn't try cramming the ECM in there so I think it's okay. Didn't seem loose when it was plugged in so I didn't pull the connector back out and check the end. The schematics I have say it goes to the MAT sensor, but then again they are from Autozone and they couldn't find me axle seals for a 93 Taurus. The eye candy they hired a few months back told me to try the dealership, for a regular stock item I know they have probably a half dozen of. I'm off topic, sorry it's been a bad day.

I did a DLC jump test as per the reman ECM instructions provided with the unit before attempting to start it. It gave me the start/end code (12), seemed to hiccup or stutter, and then gave me the code 12 again. I thought okay, a little weird but lets see. It really seems like the high speed fan circuit is now running with the DLC test where it was the low speed fan running with the old ECM. I'm about 98% sure it's running full speed now. There was some clicking from under the hood the first time I ran the test, seemed normal enough. After that test the alternator was humming/buzzing while the key was in the on position, I know it didn't do that before for sure. I never tried to start the car because I decided to run the check engine light again at this point. The light was staying on with the key turned to run so I figured what the hell, "scan" it again. This time it was like a meltdown! Started off normally with the start code 3 times, then gave me a code 41(3x) followed by a code 42(3x). After it finished the code 42 the light(it looked like it was shorting out, had a diminishing flicker so to speak) and a bunch of stuff under the hood went nuts(very rapid erratic clicking from several locations), couldn't pin point it as I turned the key off and pulled the paper clip from the data link. I was trying to keep damage to a minimum if possible because it was pretty obvious something wasn't right. There was a lot of sounds goin on but I swear I heard a sizzle type sound and got concerned. The car still hasn't been started at this point.

Code 41=Cam sensor signal was not received by PCM for the last 2 seconds while engine was running.

Code 42=The EST signal did not change when the ECM applied bypass voltage to the ignition module.

The first one(41), how can I be getting this if the engine hasn't been started in this ECM's life? Are the codes even valid considering the light tweaked out during the process? What did I do? I have heard of flickering check engine lights but I can't remember what caused it. Do I need to trailer it to the dealership to have it "flashed" now even though I transferred PROMs, though that was the whole reasoning behind transfering it? The car isn't going to attempt a "relearn" procedure without the car actually running is it? Almost what it seemed like but doesn't make sense to me logically, what is there to learn without the car running? I have a buddy who just bought a shiny new obd1/2 tester, think I'll get him over to see what there is to learn that way. Anything I should be looking for specifically with the scanner? Have never used an actual scan tool on anything obd1 personally lol.

Ma needs this thing for work, and what seemed like an easy job has gone awry. Any and all input is as always much appreciated. I have all afternoon to fiddle with it but it needs to get sorted out because in the mean time the Town Car is doing mail route duty and that ain't good 🙂 Looks like the oil pan gasket will have to wait yet again....

 

[HotZ28]

After it finished the code 42 the light(it looked like it was shorting out, had a diminishing flicker so to speak) and a bunch of stuff under the hood went nuts(very rapid erratic clicking from several locations), couldn't pin point it as I turned the key off and pulled the paper clip from the data link.

Have you checked battery voltage?

Do I need to trailer it to the dealership to have it "flashed" now even though I transferred PROMs, though that was the whole reasoning behind transfering it?

There is no flash procedure required on the OBDI PCM. All engine operating parameters are contained within the prom. The relearn begins after the car is driven, not before it starts.

 

[StuMpy77]

Battery voltage is 12.71 @ the battery terminals after sitting disconnected over night. Was curious about that too after the alternator started making noise with the key on, have seen low/failed batteries cause a buzzing alternator before myself. I pulled the ECM plugs back out and checked for loose pins to no avail.

I was wrong about the sticker on the old ECM, it states any circuit or solenoid reading UNDER 20 Ohms will damage the unit. So at 26 ohms the canister purge should be okay yet. Am I worried about a normal thing that happens with an ECM replacement? I mean I guess I would expect a code(41) stating it didn't have a sensor signal during the last run cycle because there are no previous run cycles. I'm going to put the old ECM back in and see what happens with that, just killing time til the scanner shows up more or less. Maybe I can drive it awhile before he gets here with the old ECM and trip the original codes again...then scan it.

I talked to the local Buick dealership, they claimed the ECM couldn't be "reflashed" out of the car but they could do it in the vehicle, and only in the vehicle...they were more than happy to have me drag it in there so they could charge me $90 an hour to quote "reflash" the computer. I worked a lube rack in the late 90s at a GM dealership and swear I couldn't remember hearing the earlier ECMs needed reprogramming so thank you for confirming that HotZ28. They fed me a line of bs is what it seems to amount to so they could get the car in and start adding up diagnosis time.

I'm sure I will eventually get mad enough to throw caution to the wind and just try starting it with the new ECM, it doesn't seem right but I can talk myself into it if I try long enough haha. Would the voltage regulator hum if the ECM hasn't gotten the running signal due to the car not being started yet? I rebuilt starters for over 3 years but never got the cross training to alternators, that was always "in the works". It is an internally regulated alternator from what I can see though. Have a spare good one of those too but I don't think the alternator is the problem as it worked just fine before, I mean the battery is sitting at just over a full charge so that has to say something. I'll see if it does the same thing when I transfer the previous unit back it, that should tell me if it just needs to be started I would like to think?

PS-Are my code definitions correct? I got them from troublecodes.net specifically listed for the
88-90 3.8L VIN C. I've seen variations which list code 41 as ECM failure, why I'm curious. The
instruction sheet with the ECM say's it will throw a 51(bad or loose PROM) or 52(bad or loose CALPAC)
I guess the PROM is also referred to as MEM-CAL in my application. I suppose after I try the old unit
again my next step would be to see if it wigs out again with the new one, then maybe see what
happens with the key on, no data link jumper attached?

 

[HotZ28]

Your terminology for code 41 is correct.

 

[journeyforce]

I am surprised that the axle seals on your taurus are bad. Usually it is the front pump seal on the 86-95 Taurus/Sable (My folks swear by Tauruses and replaced their old 1993(bought new in 1993) with a 2009 (also bought new) and also have a 2003 Sable(which I am tired of fixing) )

But I digress

So at this point you have not tried to start the car? Did you pull the battery cables off the battery while installing the ECU to both protect it and to clean everything? Try pulling them again just in case the computer got a bit wonky initially. The PROM chip only can fit one way into the computer so there is no worry about how to install it. The correct way will cause the tabs that hold the prom to latch to the PROM. There is only one way to program the OBDI computer and that is to replace the PROM, so you are correct the stealership was feeding you a bunch of bull.

I wonder if the computer was wrong for that model? (they all look the same)

This is mine from my 1989 Century(with the PROM cover off it)

It looks the same as yours, Verify that they sent you the right ECU.

I am wondering if it is the PROM that is the problem?

If the only thing you are worrying about is the temp light then that should not be affected by the QDM. The temp sensor for the dash is simply a probe/sensor screwed into the block with a wire plugged into it. inside there is something that monitors the resistance(when cold the resistance is more then when hot) and that wire is connected to the dash.The light is kicked on when there is little to no resistance at the sensor because this tells the sensor the car is really hot.

Now the car also has a Coolant Temp Sensor (CTS) which goes through the computer and tells it what the temp is to adjust the RPM and fuel mixture

Have you checked all your grounds? That mention of all sorts of stuff going crazy under the hood makes it seem like it is ether voltage related or a ground is not there or is having issues.

If you can spare it, I suggest you get a factory service manual. When I had my century it was one of the best things I bought

Good luck

 

[HotZ28]

The latest revision of the PCM for an '89 LeSabre VIN-C should be ACDELCO Part # 88999198 {#1228253} and replaces the earlier version, which was #16198264. The original should be labeled with #1228253

 

[StuMpy77]

Where to begin, the axle seals in the taurus would've been fine but I have the transmission out and sitting on a table waiting for the shift kit before it goes back in so figure'd the time was right. Funny you mentioned the front pump seal which is actually leaking, Ford dealerships are currently holding all of the seals with the part number I need for a recall lol! I can try giving them my vin and roll the dice. Parts guy there is just amazing though, know's his stuff and willing to go above and beyond everytime.

It would have been REALLY nice if the previous mechanic wrote down the numbers off the OEM ECM, all the spaces for information were blank on the used reman unit. I can only speculate what the original ECM part number was unfortunately. The BWD "new" reman carries the 8253 part of the Delco part #, as does the reman unit which was in there before. My ECM does look like the one you posted a picture of Journeyforce, the harness plug on the right side is orange on mine but otherwise the same.

I put the previous ECM back in the car, did the paperclip test and got code 12. I checked right away with the key on and the alternator wasn't making any noise at all now again(like it should with the engine off key on). Started right up, no problems. The idle changed a little here and there for the first minute or so, more what I'm used to expecting from a relearn procedure. I took it for a 30 minute drive watching the CEL like a hawk, it never came on. I varied from 30-65 mph, and a mix of normal in town driving. I got on a particularly long on-ramp...twice, easy to moderate acceleration the first time and then at 3/4 throttle. Nothing happened, converter seemed to lock up around 50ish mph but could probably use a second opinion on it because I wasn't certain(no tach, goin by butt sensor).

Here's were it gets weird again, buddy came over with his new Innova obd1/2 scanner. I said "Well I don't think we'll find anything, I just put the old ecm back in." It came up with 15 codes! The check engine light still is not on at this point, hasn't since the ecm was reconnected(yes it still works, paperclip test still giving me all 12s). The scanner gave me codes: 21-26, 31-35, 41, 46, and finally 56. This is with no check engine light illuminated on the dash mind you. The car runs the same as it always has, not bad at all but I wouldn't compare it to a swiss watch 🙂 One or more of the motor/trans mounts are getting loose too, that keeps getting pushed back with the oil pan though.

That many different systems(32,33,35 and 56 I need to look harder for a definition on, didn't write it down from the scanner and I should have even though it gave multiples on some codes) sounds like it qualifies as a bad ECM to me, but why don't they show up with the clip test, any of them? I'm sure the check engine light will blink again, haven't actually fixed anything so very likely indeed. I'm going to run errands with it tomorrow on the old ecm, see if anything driveability wise or CEL comes up. I finally came up with a tech line number for BWD, the company who sells the the reman unit I purchased(my "cheapassness" will probably come back to bite me here, not going with Delco parts). Will contact them tomorrow with VIN number handy to make sure I got the correct one. I was looking in the access panel for the PROM and the main circuit boards didn't match up, chips in different locations but more or less the same I guess. I assume with different updates and so forth this maybe just a part of that. Will see what they say though. The BWD reman had a sticker with part#8253 on it, with another sticker saying #8253S over the top of it. Probably nothing but I don't like it anyway, grr change hehe.

I never found a coolant temp sender for the gauge, there is a threaded plug directly under the coolant temp sensor in the intake manifold driver side but it is fairly small say a 1/4in pipe thread. Would have to say stock location for a sending unit perhaps. My understanding is the gauge set up used the sending unit, the light used the CTS signal via the ECM, explaining why I have no coolant temp sending unit? Maybe should have tested that too. You can do it with an analog multi meter and a heat source aka Bic lighter, a digital gauge will work as well but it's harder to see "blips". That has to wait, I'm behind on the 97 Taurus intake/valve cover/timing cover and oil pan gasket job thats been waiting since yesterday to begin.

I never did try to start it with the "new" reman ECM, my pin connectors are all very clean not a spot of corrosion anywhere under the dash for that matter. Hope I didn't just pay $70 for a pin cleaning tool that's no longer in the car lol! I already plugged it in so I own it regardless. Dumb as it sounds I'm really hoping SOMETHING shows up tomorrow driving around to parts stores for unrelated projects, finger's crossed! Maybe I will find out I have the wrong part for my application, O'Reilly's website I've found does have some quirks to it. The turn signal switch(in the column, holds the cancelling cam springs) that they list isn't even close. Too many options on these cars in this era that affect the design of the switch and it sucks. Finally found the right one and the "vendor is out of stock". One of these days I'll knock on the door of the "vendor", they are located in my home town 🙂

Will try and check back in tomorrow as well, hopefully have some news one way or another. I found a dead thread on some other forum, guy was having similar problems and never posted results after he figured it out. Thanks pal! That's not going to happen here, what ever happens I'm posting results. Thanks for the help and reading my lengthy posts, this forum rocks!

 

[HotZ28]

Here's were it gets weird again, buddy came over with his new Innova obd1/2 scanner. I said "Well I don't think we'll find anything, I just put the old ecm back in." It came up with 15 codes! The check engine light still is not on at this point, hasn't since the ecm was reconnected(yes it still works, paperclip test still giving me all 12s). The scanner gave me codes: 21-26, 31-35, 41, 46, and finally 56. This is with no check engine light illuminated on the dash mind you. The car runs the same as it always has, not bad at all but I wouldn't compare it to a swiss watch

More than likely, the codes reveled with the scanner were stored/history codes. All those should have been cleared while the scanner was connected, otherwise they will remain as history. There is a selection in most scanners, that ask if you want to "Erase all codes". Once you select Erase, some scanners will ask if you want erase current codes & history/stored codes, if so press ENTER. I am not sure what the particular scanner you were using suggest, but it should erase all codes, both current & history. Some of the stored/history codes my be erroneous codes set during troubleshooting and may not indicate anything wrong. It is better to erase everything and start from fresh and see what comes back, if anything.

 

[StuMpy77]

That makes sense. I looked for an erase codes function on the scanner but couldn't find anything, it's not top of the line and wouldn't give any live data at all either. It will erase OBD2 codes no problem, the on screen options are severely limited for GM OBD1. Think he said it was about $150 at Fleet Farm, so it's no where near a Tech 2. If I had enough for a Tech 2 I'd rather buy a whole car with it lol! I thought disconnecting the battery would clear all codes, current or history/freeze data as well? I do know someone with an older Snap-on brick scanner i can try, maybe able to erase stored codes or be able to test the TCC with it. Still nothing to report driving it, all seems fine. No CEL so far. Haven't made the call to BWD support yet either, I'm a slacker haha. Nah not really, just takin my lunch now 🙂 Still plan on just playing the waiting game with the car, I need more feedback from it and it's as simple as that. I had a revelation yesterday, I thought back farther into the history of the car. The leaky coolant reservoir sits right above 2 wire looms which run along the body and ac lines. One is a power wire back to the isolated battery source on the firewall, under the cover. The other set of wire loom goes back to the passenger side bulkhead connector(the smaller one of the two). The leak is fixed but I'm wondering what state the wires are in now, IDK how I never made this connection before. The timing on the two issues could certainly coincide, I need to pull that tank out again and pull some loom apart to check for breaks/shorts or gelled/liquid coolant built up in there. Me hope's I'm on to something....

 

[StuMpy77]

I found out the buzzing/humming alternator was the fields being supplied full battery voltage, the "new" reman ECM is junk. If I would have attempted to start the car with it I would have more than likely cooked the alternator, glad i didn't now. It ran and drove just fine with no issues all day today. It didn't want to start the first time I cranked it over, let off the key and it fired up right away the next time and every start afterwards. It does that very occasionally say every 2-3 weeks, always has. I don't think it likes the aftermarket cam magnet or thrust button it got awhile back, figure i'll finally find the old one when I change the oil pan gasket. Who knows, maybe it fell out again.

 

[HotZ28]

I don't think it likes the aftermarket cam magnet or thrust button it got awhile back, figure i'll finally find the old one when I change the oil pan gasket. Who knows, maybe it fell out again.

The cam interrupt/magnet signal is not used during starting. You have another problem, maybe in the ignition switch.

 

[journeyforce]

Maybe the IAC is getting lazy and giving a false reading to the computer causing the computer to think that the engine is already running or something? Have you cleaned out your IAC? or you might have a leaking fuel pressure regulator? the regulator is on the fuel rail and looks like a round valve(well it is a round valve 😀) there should be a vacuum line attached to it. Pull it off with the engine off and see if fuel comes out or there is a presence of fuel. Fuel should not be there. The diaphragm is bad.

 

[StuMpy77]

Well it's been a couple of crappy weeks, still no problems with the original ECM since it was removed and ultimately reinstalled. I wish I had a good answer for everyone but I can only speculate it was either a vibration issue from the computer not being properly secured(she delivers mail with it so constantly dropping that side of the car on to the gravel shoulder?) or I managed to wiggle or change position of loose wiring...somewhere. I can't get them to do a defective return on the reman ECM so it looks like I'm stuck with it, and it is defective which is just a kick in the nuts. They will swap it with a "new" one but what am I going to do with another one which may or may not work? Not to mention the one in it now is working as it should. If anything ever does end up happening with it again I'll post whatever it is and where I go from there. I need to pick up a fuel pressure gauge, just keeps coming up where I need one so figure it's about time. The fuel pump as far as I know hasn't been done in this one yet so it wouldn't surprise me it's getting weak.

Thanks for all the help everyone, I will attempt to return the favor when and where I can.

 

[Cadillac_AL]

Tell us which parts store doesn't stand behind their crappy ECM's so we can avoid them.