What if the cpas isn't my issue? Then what?

Voymom

Original poster
Member
Feb 3, 2012
2,523
So I haven't put the new cpas in just yet. Mat works long hours on night shift and im just not secure enough to attempt it on my own yet. I have been racking my brain over the trucks stuttering and stalling issue for a while now, it has officially died on me while driving down the highway, and that was pretty unnerving to say the least. Anyways I have noticed that the stalling and stuttering happens when there is a lot of moisture in the air, rain, humidity etc...I just have this gut feeling that it isn't the cpas but since im still learning mechanics I cant put my finger on it. If putting the new cpas in does not clear up my problem, where do I go from there with my diagnostics?
 

Voymom

Original poster
Member
Feb 3, 2012
2,523
CaptainXL said:
Have you replaced the ignition switch yet?

No we haven't. Haven't had any other "ignition switch" antics so it honestly never crossed my mind. I have no codes to go off of either. I was basically told that if the cpas did not cure the symptoms "good luck" finding out what it is as long as no codes are being thrown im pretty much screwed in diagnostics. Im going to buy me a cheap wannabe tech 2 after Christmas to see if it can point me in some direction. I know this probably wouldnt worry most owners, but I need to think about my kids' safety.

If it stalls on icy roads, the way people drive around here I will be in deep doo doo.
 

CaptainXL

Member
Dec 4, 2011
2,445
The factory ignition switch is known to cause similar problems in these vehicles. It's pretty much become a "once every five years" preventative maintenance task. It can cause a whole host of electrical gremilins. Think of it this way. What parts wear out in a vehicle? The ones that move. I would not buy a tech2. Your going to spend a lot more money on that than if you just shotgunned all the sensors on the vehicle.

Besides the total combined knowledge of all of us is infinitely more than a tech 2.
 

gmcman

Member
Dec 12, 2011
4,656
Voymom said:
Anyways I have noticed that the stalling and stuttering happens when there is a lot of moisture in the air, rain, humidity etc.

Reminds me of the days of the worn distributor caps.

Are you sure that #4 is staying dry down near the plug? If that were mine the first thing I would do is pull the #4 coil and ensure it's dry, maybe even pull all of them but specifically #4.

I would also take some electronics cleaner and spray each of the 6 connectors for the coil packs, removing the connector to do this naturally.

When you changed the plugs did you use the dielectric grease to the contact area of the plug and the coil pack spring? Sometimes this may cause a problem but not 100% on it.

I don't recall when you cleaned your TB last, didn't go back and look at your posts.


I also love me some BG44K. ANYTIME..... I have a fuel related or any other driveability issue with regards to hesitation, rough idle, the first thing I do is run a can through then assess my options later.

I would then suspect the MAP sensor and like Capt XL stated the ignition switch. The ign switch is just one of those items that will very likely fail and is something that can remove alot of variables from your troubleshooting.
 

Voymom

Original poster
Member
Feb 3, 2012
2,523
CaptainXL said:
The factory ignition switch is known to cause similar problems in these vehicles. It's pretty much become a "once every five years" preventative maintenance task. It can cause a whole host of electrical gremilins. Think of it this way. What parts wear out in a vehicle? The ones that move. I would not buy a tech2. Your going to spend a lot more money on that than if you just shotgunned all the sensors on the vehicle.

Besides the total combined knowledge of all of us is infinitely more than a tech 2.

I wont get a tech 2 but maybe something similar. My dad said a buddy of his bought his scanner for $30 on amazon and I thought that was a pretty decent price. And your absolutely right about the forum having infinite amount of knowledge and diagnosing skills.


gmcman said:
Reminds me of the days of the worn distributor caps.

Are you sure that #4 is staying dry down near the plug? If that were mine the first thing I would do is pull the #4 coil and ensure it's dry, maybe even pull all of them but specifically #4.

I would also take some electronics cleaner and spray each of the 6 connectors for the coil packs, removing the connector to do this naturally.

When you changed the plugs did you use the dielectric grease to the contact area of the plug and the coil pack spring? Sometimes this may cause a problem but not 100% on it.

I don't recall when you cleaned your TB last, didn't go back and look at your posts.


I also love me some BG44K. ANYTIME..... I have a fuel related or any other driveability issue with regards to hesitation, rough idle, the first thing I do is run a can through then assess my options later.

I would then suspect the MAP sensor and like Capt XL stated the ignition switch. The ign switch is just one of those items that will very likely fail and is something that can remove alot of variables from your troubleshooting.


Yes #4 was dry, they all were and they all shown normal wear at the connector. I can pull #4 and take a peek if replacing the cpas doesn't fix the problem. I did have the issue and code with the failing cpas when Mat put the engine restore in, but he is pretty adament that the stuttering and stalling symptoms were going on before hand. I know the truck didnt act like this when I brought it home last January nor did it have these symptoms when test driving it. I think the issues started after the engine restore but thats just a futile battle with my husband lol. March was about the time it all started going on. I do have a failing fan clutch and I believe it is on its last leg, I haven't changed it because im wanting to do an e-fan kit when I get my tune.

I did have the blower motor fixed at the dealership the day after I brought it home but can't be sure if thats when it all started or not. I may end up taking it to my local trusted mechanic and leaving the truck over night on an expected wet day and go from there. Its only $35 for him to diagnose it. Im just not sure he will be able to find the issue either. If I can convince Mat to let me put a new ignition switch in if the cpas doesn't work then I will start from there to help eliminate a bunch of other possibilities.

As far as my TB being clean, it looks like 24k gold lol I check it every oil change or when working in that area.
 

Ed H

Member
Oct 18, 2012
167
I 2nd the possibility of a bad MAP sensor. I had the same problems in a different GM vehicle. No codes either...

Any basic scanner (not mine, which just pulls codes) can display the MAP output. Watch the output and mash the gas. If it doesn't respond, you found your culprit. I don't know how much they cost for a I6, but mine was cheap ($40, maybe).

Any good mechanic should do this for free - if you specifically ask about the MAP. Mine did. They I bought some oil, etc from him... I should have just handed him a $20...

Good luck. Keep us posted.
 

Voymom

Original poster
Member
Feb 3, 2012
2,523
Ed H said:
I 2nd the possibility of a bad MAP sensor. I had the same problems in a different GM vehicle. No codes either...

Any basic scanner (not mine, which just pulls codes) can display the MAP output. Watch the output and mash the gas. If it doesn't respond, you found your culprit. I don't know how much they cost for a I6, but mine was cheap ($40, maybe).

Any good mechanic should do this for free - if you specifically ask about the MAP. Mine did. They I bought some oil, etc from him... I should have just handed him a $20...

Good luck. Keep us posted.

Wouldn't a failing or failed MAF sensor throw a P0172 code? I don't have any codes, and sometimes I feel like the truck has a mind of his own and is trying to make me go crazy lol. I wonder if I can call around and see if someone is willing to take a look with a scanner for me to test the MAF and MAP to rule it out or rule it in, for a decent price. $35 is okay at the local mechanic, but I don't want to leave my truck in the hands of someone I don't know very well. I don't like sharing the truck, or having anyone else drive it for that matter, so leaving it over night just doesnt sit well with me. The dealership is out of the question. Do you know if auto part stores rent scanners out like they do with specialty tools?
 

CaptainXL

Member
Dec 4, 2011
2,445
If its the map sensor you can test it by unplugging it and then starting the truck. It will throw a code but if your performance is the same as when it was connected then you know its the sensor. I highly doubt it though. It would definitely throw a code if its out of range just as when you disconnect it.
 

Forum Statistics

Threads
23,392
Posts
638,779
Members
18,601
Latest member
Chris Moore

Members Online