2008 Buick Allure

[Smith1000]

Your very advanced on your testing abilities. On the 3.8's I have had, I had very few issues. Below are the issues I encountered.

MAF sensor failure-one time. Was difficult to diagnose
Crank and camshaft positions sensors-just replaced them due to known problems with them
Bad wire between ECM and ignition module-one time
EGR valve issues-3 or 4 times
Pack rats chewed injector wiring--multiple times
Bad grounds to body/frame-Cleaned grounds periodically
Bad plug wire-cylinder #6--maybe 2-3 times
Fuel pressure regulator valve-1 time

 

[Gibbyman]

Your very advanced on your testing abilities. On the 3.8's I have had, I had very few issues. Below are the issues I encountered.

MAF sensor failure-one time. Was difficult to diagnose
Crank and camshaft positions sensors-just replaced them due to known problems with them
Bad wire between ECM and ignition module-one time
EGR valve issues-3 or 4 times
Pack rats chewed injector wiring--multiple times
Bad grounds to body/frame-Cleaned grounds periodically
Bad plug wire-cylinder #6--maybe 2-3 times
Fuel pressure regulator valve-1 time

im fairly certain it’s the ICM I’ve got 12v in and out to sensors but no ground pulse to coils and they have the constant 12v as or well and injectors aren’t firing either which on start ICM deals with. I wish I had a bit more time today but I spent quite a bit of time making out a troubleshoot list of all fuses and relay contacts and coils involved and pretty much everything tested fine but just as my toes and fingers were about to fall off from combo rainy mist snowy Brrrrrr I was just getting to CMP and CKP sensors I’m pretty sure I don’t have the signal from either but I did last time. But wait it gets better…… when I crank it with my trusty piece of wire in crank relay slot and spray it with start fluid it almost starts so tell please where that spark Is coming from because it’s baffling me!!!! and I have new wires and plugs and doesn’t matter where I check spark sat at coil or end of wire or pull a plug or use an HEI spark tester or regular spark tester or screwdriver driver I get NO SPARK!!!!

 

[Gibbyman]

Your very advanced on your testing abilities. On the 3.8's I have had, I had very few issues. Below are the issues I encountered.

MAF sensor failure-one time. Was difficult to diagnose
Crank and camshaft positions sensors-just replaced them due to known problems with them
Bad wire between ECM and ignition module-one time
EGR valve issues-3 or 4 times
Pack rats chewed injector wiring--multiple times
Bad grounds to body/frame-Cleaned grounds periodically
Bad plug wire-cylinder #6--maybe 2-3 times
Fuel pressure regulator valve-1 time

Well I fell into an electrical apprenticeship right out of grade 12 and that was 37 going on 38 years ago so have a wee bit of knowledge on how it works and have worked on all my own vehicles and lots of “Friends” all my life and actually wanted to be a mechanic so I have a pretty big basket of skills I guess🤓

 

[Smith1000]

You must be getting an intermittent spark for it to run.

 

[Gibbyman]

You must be getting an intermittent spark for it to run.

Just wondering if there’s a chance that the ICM is pooched and somehow the ECM is somehow throwing out some king of coil pulse with no injector pulse before 400RPM. not sure if it tells just the injectors to pulse and sends the 12v ground path to coils after 400RPM or just the injectors and ICM just continues doing spark which I’m guessing it will. Sounds crazy. But this no spark but some fantom spark monster that likes to huff ether shows up when i spray is messing with my head!!!! o guess o have a bit more digging to do. I’m not sure if our auto parts places test ICM‘s or not I believe you are in the states correct? We have NAPAs and Car Choice and privately owned ones lots to choose from just drawing a blank on big names/chains at the moment. But think I should take it in unless they aren’t too expensive (just before Christmas of course) I’ll just buy a new one. Just don’t like putting in electronics without really knowing the problem and smoking it cuz nobody will take electronics back that have been installed. Sorry about all the long winded replys I’m a wee bit of a talker and like to get the info out and possibly back occasionally 😎

 

[Gibbyman]

Your very advanced on your testing abilities. On the 3.8's I have had, I had very few issues. Below are the issues I encountered.

MAF sensor failure-one time. Was difficult to diagnose
Crank and camshaft positions sensors-just replaced them due to known problems with them
Bad wire between ECM and ignition module-one time
EGR valve issues-3 or 4 times
Pack rats chewed injector wiring--multiple times
Bad grounds to body/frame-Cleaned grounds periodically
Bad plug wire-cylinder #6--maybe 2-3 times
Fuel pressure regulator valve-1 time

I won the battle she’s purring like a kitten!!!! I order a new ICM because mine had powdery white aluminum oxide and lots of pitting on it and I’ve read that if it’s not bad it more THan likely on its way so I’m not sure it was bad but I have a nice new one. I was going through all the troubleshooting tests of it and i accidentally blew a fuse which I didn’t realize until next day when I tried to crank it and nothing I went through all fuses and fuse for IGN1 was blown which controls power to crank relay and PCM fuse and ECM common fuse so I changed fuse and I heard the fuel pump relay kick in and out a few times fast so I pushed and wiggled the PCM relay and fuel pump relay was going crazy. Terminals in fuse box that the PCM relay stab into had dropped a bit and were relaxed from all the on off cycles and from the load on soft metals.
changed it took it apart and pushed all terminals back up while holding relays ( kinda tricky with a flashlight and screwdriver in one hand and holding relay in place with the other hand 😝) I snapped everything shut reached in hit the key and away she went!!!! No cranking at all it fired instantly YEEEEEEEEEHAAAAAAAA!!! I guess I could put old ICM back in and see if it works which i think it wasn’t the problem at all but at least it’s running and I have a new ignition module!!! Thanks for all the help

 

[Smith1000]

Your persistence paid off. Glad to hear it is running well. I learned quite a bit from this thread.

 

[Gibbyman]

Your persistence paid off. Glad to hear it is running well. I learned quite a bit from this thread.

Your persistence paid off. Glad to hear it is running well. I learned quite a bit from this thread.

Well I do have one more issue. When I was first into The stages of trouble shooting I removed a spark plug #5 it was no to check spark it had a very large gap and didn’t look the greatest so I bought new AC Delco plugs. When I removed # 3,and#5 plugs all in the front of engine bay 3 & 5 both broke off and left the threaded part in the cylinder head!!! In the past I’ve had that happen once and I dug up a 1/2” twist drill and with big gob of grease on it drilled just until I was past the taper fit (thinking that’s where it tightens against) of what was left of the plug and went in with small standard screwdriver caught the hooked part then unthreaded very easily. #3 wasn’t too bad to drill but #1 I had to removed fans and barely got my little cordless drill i. So moral of my long as usual story I haven’t changed rear plugs and am scared to do so because if they break I’ll have to pull head off or pull engine. Possibly with a right angle drill I can acces if needed. Any ideas possibly when engine is hot? It’s running great as is now all my misfire on acceleration is gone it’s smooth sailing. Leave it alone? They are NGK’s and front Are new Delcos

 

[Smith1000]

I would leave it alone, for now, if running smooth and deal with it if and when the plugs start causing a misfire. I have had the ceramic break off, but never the base of ta plug, leaving only the threads in the head. I believe it does help to remove them when the engine has been run for a period of time, similar to removing an O2 sensor.

 

[oldschool]

I also would leave it as long as it's running good. No point in causing grief if not needed.

 

[Gibbyman]

I would leave it alone, for now, if running smooth and deal with it if and when the plugs start causing a misfire. I have had the ceramic break off, but never the base of ta plug, leaving only the threads in the head. I believe it does help to remove them when the engine has been run for a period of time, similar to removing an O2 sensor.

Thanks. And also I didn’t mention my traction control light was on as well as my ABS and since I fixed the bad connections on base of IGN1 Relay they are both gone and had a service eng code po455 evap leak which I erased last night and did my roundtrip to work of 75KM and hasn’t came back on yet but maybe not enough Km’s time will tell. But smooth sailing and great acceleration she’s running great!!!’