2002 Lesabre randomly shuts off while driving - no codes (to cause this)

[BuickGirlFromMars]

My next part replacement, which I'v had here in the basement for a few months will be the ICM. Looking back thru the thead I've changed almost every sensor.
I have't gone over my grounds but unless one has come loose? I've added extra ground to a few vehicles in the past just cause it can't hurt but may help.

Now that I've replaced the MAF again, tried to go thru the relearn provedure that says unplug it, crank car, let idle a few minutes, turn off car, reconnect MAF sensor, clear code, crank car and drive as normal.....problem is it will not idle with the MAF sensor unpluged so I did everything else.
Just sitting in my drive it is running smooth as butter.

I probably will not test drive or do anything else "such as replacing the ICM" for a few days, and I'm gonna drive it until it acts up berfore replacing the ICM. I do wish I had a more expensive tester.

It was kinda funny I never got a dash light saying my gas cap is loose when driving home with it in the trunk. I used to get that occasionally way bck when it ran perfect. Does the gas tank pressure sensor trigger that? I'll look into it. (found this - Over time a faulty fuel tank pressure sensor will cause low fuel efficiency, trouble starting the vehicle and/or stalling, and eventually keep the vehicle from starting.) - No code?

Not gonna give up. I wish I had an answer for anyone that may have a similar issue, but their is probably not a 1 thing fix all for what I've tried to describe my car is doing.

I may take the time to put in chronological order what I've done and why I did it in one post.

if it cant idle without the MAF, your MAP sensor, 5v ref, pcm grounding, internal pcm circuitry, or vacuum system is not working properly. Also, technically, an improperly installed IAC and dirty or worn IAC and blocked passages probably could cause an issue here

Based on what I just said. lets look at what the car is doing when it stalls
Completely normal, stall?
Wind down? sputtering? coughing? jerking? Surging? choking out? Hissing? spitting? on throttle change? On coast? on tip ins? WOT?

Think about that, it helps guide your approach. A stall with NO discernable reason other than possibly a change in load but otherwise pretty much instant and random, is almost always going to be Crank sensor or ICM and associated wiring.

If it sputters out or starts getting choppy and stuff, id say we are looking at something pulling the 5v or grounding or something in the bang juice arena. etc.

ANYWAY, can you show me your engine from the top, so we can see your vacuum harness and your sensors and stuff

 

[dadymurano]

If I'm at a stop, and have the feeling it's gonna stall when I give it gas. It stalls. No hiccup or anything. Will throw it in neutral, crank it back up rev it just alittle, put in drive and take off.

Sometimes when I 1st start it after sitting overnight or a few days I'll let it run a munit or two and it will just die. No sputtering or anything.

If I'm crusing down the road at say 25-65mph it will feel like I let off the gas, then pick back up. (this was the very 1st symptom that started my diagnostic endevors to fix my car)

I am curious about it not idling with the MAF unplugged. This model car also has a MAP sensor.

 

[dadymurano]

if it cant idle without the MAF, your MAP sensor, 5v ref, pcm grounding, internal pcm circuitry, or vacuum system is not working properly. Also, technically, an improperly installed IAC and dirty or worn IAC and blocked passages probably could cause an issue here

Think about that, it helps guide your approach. A stall with NO discernable reason other than possibly a change in load but otherwise pretty much instant and random, is almost always going to be Crank sensor or ICM and associated wiring.

Well I changed the crank and cam sensors with quality sensors that had no discernable effect on the issue. Purchased a new ICM that's still in the box.

 

[Mad_Coachman]

Now that I've replaced the MAF again, tried to go thru the relearn provedure that says unplug it, crank car, let idle a few minutes, turn off car, reconnect MAF sensor, clear code, crank car and drive as normal.....problem is it will not idle with the MAF sensor unpluged so I did everything else.
Just sitting in my drive it is running smooth as butter.

Considering what the MAF does and how it does it I don't think there is a "re-learn" needed. MAFs are "plug and play". What code did you have to clear?

 

[dadymurano]

Considering what the MAF does and how it does it I don't think there is a "re-learn" needed. MAFs are "plug and play". What code did you have to clear?

" po102 " 1st time I've gotten that with the wires connected to it.

 

[Mad_Coachman]

" po102 " 1st time I've gotten that with the wires connected to it.

Was the MAF new?

 

[Mad_Coachman]

Looking at your vacuum setup I wonder what your fuel trims are. Can you list STFT and LTFT at idle?
Oh well...guess you're done for the night.

 

[dadymurano]

Was the MAF new?

no

At idle after a few minutes
STFT 1.5
LTFT -13.3
RPM 780
MAP 8.0
Spark adv 24
MAF .579
TP % -0

Goodnight.

 

[dadymurano]

Looking at your vacuum setup...

The hose from the throttle body to the solinoid and the regulator don't look good but they don't leak. I do have a new/used hose setup I got at the pulapart, but like i said i'm confident there is no leak in the vaccum hose.

 

[Mad_Coachman]

MAF should be closer to .380. LTFT is pretty lean. Your STFT looks good but your LTFT is a concern. If you haven't tried a new HITACHI that might be the next step. 🙂

 

[BuickGirlFromMars]

I have many concerns with the vehicle and engine. Is that airbox normal for lesabre? seems different but maybe im just seeing things
but your air duct isnt sealed, as it seams, on the throttle body or the air box. Your airbox also appears ot have had something crack the part that connects it, maybe someone leaned on it. not sure if that is a big deal at that point
your sensors are concerning, I see at least 3 important sensors with hthe wiring yanked very tightly. Your IAC, your MAF which i actually am curious, it looks partially unplugged?? did you replace the o ring when setting it in, is the screen still intact and not bent up? your air duct is off, you could have things contaminate the maf or the screen is hit with stuff. I dont see security torx on stuff, so Was IAC Depressed to the proper length and a reset on its position performed?

also, what year is this engine from? you appear to have a W body engine from the late 90s?

I said some misunderstood things earlier in this above.. but not much. forget that w body comment, your manifolds seem interesting. Also, your fuel line has tape on it.... and doesnt appear securely connected on the back.. your FPR has no retainer holding it together securely, your MAP sensor seems shady, did you do the pcv valve and not forget the spring and the o rings? There is a kit for it. ever touch the alternator? The wiring plug looks yanked. that can definitely affect things. your TPS, did you "properly align" it on the throttle shaft?
You have vacuum lines that absolutely can be called into question. you need to buy the harness new its not that much on amazon.

YOUR intake air temp senosr is yanked, so is your ECT sensor, i think, it looks strange. Your ignition wires are inspring confidence but I am not going to say they are definitely problematic i woul d just say verify the connections. Wires are cheap these days and you can ruin a wire easily trying to install first time.
also out of coolant

hows the alt charge wire doing has it been Yanked it appears to have a clean spot near the grommet

 

[Mad_Coachman]

The airbox is correct. A lot of other stuff there looks "sketchy" though. 😳

 

[dadymurano]

Early on I checked for vaccume leakes with (dangerous i know) starting fluid. Found no leakes. I just removed the entire throttle body and used a can of MAF cleaner. It was in ver clean condition. The computer sits in the bottom of the air box. Why its so big. I've checked the wires from my ICM to the cam and crank sensor.
I replaced the intake manifold when i 1st got the car and changed the water elbows. The water level while a bit low hasn't dropped down from when i winterized it last year. I've seen some people wiggle wires until they damage them. The plugs to my sensors on the throttle body all have good O rings.
-air duct isnt sealed- hmmm yes I need to rotate the airbox to throttle body rubber a bit, but it is sealed, not sure where you see that... - I took off the throttle body and it was getting dark as I put it all back together.

As far as the LTFT goes would a rich condition cause that reading at idle? and what would be a good reading? I always though as close to zero was the target when not under load just idling. I took those readings with the car not up to temp as I saw your post and went outside but only sat long enough to make sure I was in closed loop. I think the IAT showed 71 degrees which is about what the outside temp was around dark last night. (also about as cheap a meter as can be purchased.

OK gotta run. Took off today.
Guy coming by to drop off the title to a suburban he traded me for a residential cam job. Also have the interior in a mess on my Murano. The sunroof drain tube came unplugged from the passenger side firewall and drivers side was full of s--t, gonna tear it up enough to check the rear drains also. (i will never buy a convertable or a car with a sunroof) i guess with proper maint and a garage/basement to park em in you'd be OK.
I've gotta get rid of a vehicle or two. The Muramo would bring the best price......probably.
Befor i cleaned it. Was hoping it was very dirty.

 

[dadymurano]

I had to check. It's seald up. That's the air box as it goes thru to the front for fresh air.

 

[dadymurano]

I guess I'll charge the battery on the old laptop and just leave it connected while I drive. I may be able to figure out how to record the live data. I don't see anything wrong at all, even with the LTFT at -13.3 the STFT at 1.6 brings the total to 11.7 or pretty close to in range.

Not gonna give up but gonna have to move to other fires than need putting out.

Thanks for the help and input. I'll definitely post any changes or what may have corrected the problem.

 

[BuickGirlFromMars]

View attachment 34897View attachment 34897
I had to check. It's seald up. That's the air box as it goes thru to the front for fresh air.

I meant the rubber flex thing its not properly set on the TB and its also not on the airbox squarely according to your older photo. whats it look like now?

 

[dadymurano]

I meant the rubber flex thing its not properly set on the TB and its also not on the airbox squarely according to your older photo. whats it look like now?

It's twisted to the correct position. There is a tab that interlocks on the air box. It puts the ait more on top than in my pic.
I've been driving it and it's no longer shutting off. I put a new pressure sensor on the top of the fuel pump. (i had replaced the gas cap long ago, but wondered if I'd get a "gas cap is loose" indication if I drove it with the cap in the trunk. Never got the error code I used to get all the time, so I replaced it. Still no cap is loose indication ----but lets move to some other things.
I am now getting a po101 sometimes. I'm starting to get a po306 sometimes.

Looking at my fuel trims in real time crusing down the freeway one seems to really try to compensate for something. I havent looked tonight at which one. It was LTFT on one of the banks....

Gettin to late to think about anything but eat and bed.

Car is doing better. No longer stalls. Got MAF and fuel trim issues. Starting to think about changing injector on cyl #6. also i need to throw away a few MAF's that are iffy.

 

[dadymurano]

Still got the block off plate under the EGR Valve also....

 

[John Canon]

Well I changed the crank and cam sensors with quality sensors that had no discernable effect on the issue. Purchased a new ICM that's still in the box.View attachment 34867View attachment 34870View attachment 34870View attachment 34867

I hope the stalling is gone for good. The ICM needs real thermal paste between it and the bracket. Engine block temperature of 195F is better that 300F inside the electronics. I have seen high temps cause erratic spark control.

 

[dadymurano]

I hope the stalling is gone for good. The ICM needs real thermal paste between it and the bracket. Engine block temperature of 195F is better that 300F inside the electronics. I have seen high temps cause erratic spark control.

I have not put the new ICM on yet. I really wanted to replace 1 thing at a time so if it corrected everything I'd feel confident what the problem part was.