A Challenge For The Veterans

[windrunner408]

Actually what should the line pressure be at??

 

[SIX_OHH]

Ok. After thinking.
I am guessing because i cant drive to feel it, so to be safe, have you ever had any tranny work done? Filters replaced, fluid, anything at all. Wonder if it is grinding itself causing this. Has your truck been in the extremes? (temps Truck and ambient.) This is my first course of action as I don't like buying tranny parts. Recommend changing filters blowing out lines change fluid. Fully service and flush the transmission. Its bout that time anyway. To me its an important thing to do to keep everything running top notch and keep my mind at ease.

If it is not that drink a beer.


How to tell if its the vgt solenoid. Just a guess. When the problem series of events occur, pay attention to the sequence of events. If the turbo changes THEN the engine is affected, the solenoid or turbo could be at fault. If the engine affects the turbo then rule that out.

Get that much figured out.

 

[wetnsloppy4x]

I'm no expert but here are my initial thoughts/questions..

All this is assuming the trans is OK.

1. Like Sixohh first eluded to, what is the VGT solenoid doing? Perhaps it's spazzing out sending the truck into an overboost situation causing the PCM to limp. With boost only raising a few psi, I have doubt about this being the culprit.

2. What is your ICP doing when it acts up? Perhaps an intermittent fault here or with the IPR?

3. What is FICM voltage doing when it acts up?

4. What is your EOT/ECT delta when this problem pops up. The PCM may be seeing too big of a difference and going limp.

Does the truck recover on it's own? Does it require a shut down and restart to straighten out?

One last note/question, I've been under the impression for some time that the EBV was disabled some time ago in newer strategies???? I'm I all wet?

 

[windrunner408]

Ok. After thinking.
I am guessing because i cant drive to feel it, so to be safe, have you ever had any tranny work done? Filters replaced, fluid, anything at all. Wonder if it is grinding itself causing this. Has your truck been in the extremes? (temps Truck and ambient.) This is my first course of action as I don't like buying tranny parts. Recommend changing filters blowing out lines change fluid. Fully service and flush the transmission. Its bout that time anyway. To me its an important thing to do to keep everything running top notch and keep my mind at ease.

If it is not that drink a beer.

How to tell if its the vgt solenoid. Just a guess. When the problem series of events occur, pay attention to the sequence of events. If the turbo changes THEN the engine is affected, the solenoid or turbo could be at fault. If the engine affects the turbo then rule that out.

Get that much figured out.

Ok the truck has not been in any extremes. It has been a while since my transmission fluid was changed. Like 50k miles since I changed it last. Nevertheless like I stated earlier, the transmission shifts great and I dont notice any flares of shifting ever even when this boosting condition exists. I also agree that I need to change the fluid and filters ASAP and WILL do in about two weeks when I get paid again. FYI the trans temp usually hangs out at 130*F (by my CTS) when it is cold out and up around 160-170*F when it is 80-90*F.


I also will watch VGT duty cycle when this happens and see if it is turbo or engine that changes first. I want to say that it is engine that goes first but not 100% certain.

Now I do know that VGT duty cycle goes to 48% or so while this condition does exist.

I'm no expert but here are my initial thoughts/questions..

All this is assuming the trans is OK.

1. Like Sixohh first eluded to, what is the VGT solenoid doing? Perhaps it's spazzing out sending the truck into an overboost situation causing the PCM to limp. With boost only raising a few psi, I have doubt about this being the culprit.

2. What is your ICP doing when it acts up? Perhaps an intermittent fault here or with the IPR?

3. What is FICM voltage doing when it acts up?

4. What is your EOT/ECT delta when this problem pops up. The PCM may be seeing too big of a difference and going limp.

Does the truck recover on it's own? Does it require a shut down and restart to straighten out?

One last note/question, I've been under the impression for some time that the EBV was disabled some time ago in newer strategies???? I'm I all wet?

I havent monitored ICP and I wouldnt know if it would help until I go drive the truck with the stock tune on it as if it is tuned the ICP wont be accurate anyways. Nevertheless I could watch for the change in ICP.

FICM Voltage stays constant between 48.0-49.0v regardless.

EOT/ECT delta is about 10-18*F always. I have an oil cooler delete and my oil temp at the sensor fluctuates between 200-208F and ECT is about 190F all the time. Now I have thought about this as well if this was the case, then the truck would do this even in the cold and at least for right now it doesnt seem to do this when it is cold outside.

No the truck does not recover on its own. The only way for the truck to recover is to shut it down and let it cool off. Then when you restart it and everything heats back up again, it will do the same thing.

I do not know if the EBP sensor has been disabled with my strategy or not. I have the VXCF4HB ECM strategy. I have also removed and cleaned the EBP sensor and tube.

 

[wetnsloppy4x]

I havent monitored ICP and I wouldnt know if it would help until I go drive the truck with the stock tune on it as if it is tuned the ICP wont be accurate anyways. Nevertheless I could watch for the change in ICP.

I may be barking up the wrong tree here, but it would be interesting to see what commanded and actual ICP is when it acts up. Even if the ICP sensor itself isn't the issue, that would give you an idea if the PCM was limping. If the PCM pulls ICP all of a sudden it may point to some other sort of electrical fault.

I can't quite wrap my head around a correlation between your 48% VGT duty cycle and an ICP issue though.

 

[windrunner408]

How do i see what commanded ICP is? I can see what actual is but dont think the CTS does the commanded option. However, I did note ICP voltage was 1.7v while cruising and .8v at idle. Not sure if that helps.

 

[wetnsloppy4x]

How do i see what commanded ICP is? I can see what actual is but dont think the CTS does the commanded option. However, I did note ICP voltage was 1.7v while cruising and .8v at idle. Not sure if that helps.

With the CTS I'm not sure you can look at commanded. Sorry, I was under the impression you were using AE.

The voltages sound right though IIRC, so yeah that does help. Have you gotten a voltage from the ICP when it acts up? That may not be all that relevant not knowing what commanded ICP is, but would be handy info for elimination purposes.

Have you happened to look and see if you're getting a CKP and CPS signal while it's acting up? Without a CKP signal, IPR duty cycle will default to 14% or 300 psi. I'm wondering if the CKP signal is crapping out once the sensor gets warm. My other thought is that the two signals may be unsyncing, although I don't personally know what happens in that case while you're cruising down the road. I DO know that will cause a hard/no start.

I apologize if I seem all over the place on this. I'm hoping the process of elimination will help here though as the problem doesn't seem to be anything obvious. Hopefully some more experienced eyes can use this to narrow it down further.

 

[windrunner408]

With the CTS I'm not sure you can look at commanded. Sorry, I was under the impression you were using AE.

The voltages sound right though IIRC, so yeah that does help. Have you gotten a voltage from the ICP when it acts up? That may not be all that relevant not knowing what commanded ICP is, but would be handy info for elimination purposes.

Have you happened to look and see if you're getting a CKP and CPS signal while it's acting up? Without a CKP signal, IPR duty cycle will default to 14% or 300 psi. I'm wondering if the CKP signal is crapping out once the sensor gets warm. My other thought is that the two signals may be unsyncing, although I don't personally know what happens in that case while you're cruising down the road. I DO know that will cause a hard/no start.

I apologize if I seem all over the place on this. I'm hoping the process of elimination will help here though as the problem doesn't seem to be anything obvious.

Oh no worries man. I am just thankful for the discussion and I dont mind going through the process and I like getting input on guys think it may be. I am probably just going to have to either take it to this tech at the dealer I have been recommended to.

I cant seem to be able to monitor CKP or CMP with the CTS so I cant say if one or the other is going out on me. However, I dont think it is the CKP sensor as I still have a rpm signal but maybe the CMP is going out IDK. I did have a no start the other day for no reason whatsoever, I had to take the wife's car to work that day and when I came home and tried starting it again it fired up. I just didnt think the two issues would be related.

Oh yea on the ICP voltage, that was the voltage while it was acting up. I also went out again and tried it to day and couldnt get it to do it in the 20 miles I was driving it. IAT was 60-62F the whole time and OAT (on my dash) was 64-68F. Transmission temp was 137F and shifted fine.

 

[wetnsloppy4x]

Are you able to monitor all three air temp sensors? It sounds like your monitoring the OAT (ambient air located at front of engine compartment) and IAT (located in the MAF).

Can you pull input for the other air temp sensor on the intake? It might be called either MAT or IAT2. I've seen it referred to as either but my diagram calls it MAT.

My thought here is that the truck is maybe limping for not seeing a temp differential between the two or perhaps the value is totally fubared as far as the PCM is concerned. It's a long shot and I'm sort of thinking out loud here......

edit: Your ICP voltage tells me it's not pulling fuel. Anyone more knowledgable than me on the subject please don't hesitate to correct.
edit#2: Without further investigation into the CKP, this possibility can't be eliminated yet. I can see the CKP causing all your issues including being able to start out of the blue.

 

[SIX_OHH]

Sounds like the egr is taking a dump lol

 

[windrunner408]

Are you able to monitor all three air temp sensors? It sounds like your monitoring the OAT (ambient air located at front of engine compartment) and IAT (located in the MAF).

Can you pull input for the other air temp sensor on the intake? It might be called either MAT or IAT2. I've seen it referred to as either but my diagram calls it MAT.

My thought here is that the truck is maybe limping for not seeing a temp differential between the two or perhaps the value is totally fubared as far as the PCM is concerned. It's a long shot and I'm sort of thinking out loud here......

edit: Your ICP voltage tells me it's not pulling fuel. Anyone more knowledgable than me on the subject please don't hesitate to correct.
edit#2: Without further investigation into the CKP, this possibility can't be eliminated yet. I can see the CKP causing all your issues including being able to start out of the blue.

Yea I can't monitor the second IAT sensor with my CTS. I have thought about replacing both the CKP and CMP sensors and might just do that next week.

Sounds like the egr is taking a dump lol

Not sure what you mean by this but the egr is totally deleted and I dont even have the valve plugged in and I have the egr valve disabled with the SCT tuner.

On a side note guys, what I have noticed before was the MAF (IAT1) sensor would be displaying IAT and it would trend at 2-4*F below OAT (I should note that IAT changes in 2*F increments) for about 10 miles or so while the truck as at normal operating temperature and then it would just jump to like 6-10*F above OAT. I am not sure what the deal is on why the IAT would do that but perhaps the MAF sensor is damaged from all the times I have removed my intake from the turbo and somehow interupts the signal to the ECM and sends it into limp mode. I am not saying this IS the case but am just throwing out a suggestion. I however could not get the IAT to jump yesterday when it raised the boost level.

 

[Johnboy3]

Is the wrench light coming on when this happens? Have you ever tried pulling a code with your Edge before you shut it off when it is in the limp mode?

 

[windrunner408]

I have. No codes and no CELs. I am sure at least one code is probably being thrown but not a hard code so no CEL. If I had an AE I am sure I could pull the soft/history codes and see which ones might correlate to this.

 

[SIX_OHH]

I know its not the egr i was just saying the symptoms seem the same.

 

[windrunner408]

Got ya. I am about 99% confident that it is a sensor that is affected by the heat or when the heat gets high enough the sensor reaches some sort of max range and then the ECM cuts fuel to protect the engine or the VGT solenoid is messed up when the heat gets that high.

 

[Wright337]

Not sure on the fix for the problem, but havent we all decided that even with the egr delete that the valve still needs to be plugged in and layed on top of the intake to let the fan circuit read rite? Im not saying this will fix anything but I think it runs in a loop with the fan.

 

[SIX_OHH]

Got ya. I am about 99% confident that it is a sensor that is affected by the heat or when the heat gets high enough the sensor reaches some sort of max range and then the ECM cuts fuel to protect the engine or the VGT solenoid is messed up when the heat gets that high.

How hot have you gotten the engine? Does it do it everytime no matter what? I guess this thing must not be your DD?

Not sure on the fix for the problem, but havent we all decided that even with the egr delete that the valve still needs to be plugged in and layed on top of the intake to let the fan circuit read rite? Im not saying this will fix anything but I think it runs in a loop with the fan.

I dont think its getting hot enough to matter from what i understand,.

 

[wetnsloppy4x]

EOT/ECT delta is about 10-18*F always. I have an oil cooler delete and my oil temp at the sensor fluctuates between 200-208F and ECT is about 190F all the time.

Considering this info, it doesn't sound like an overheating issue.

Windrunner, it might be time to get your truck on a more robust scanner. Any soft codes your CTS isn't able to pull up might be a big clue.

The IAT issue is interesting though. I could see it being a few degrees cooler than ambient but the jump is a little concerning.

 

[yeehaw]

the EGR valve has to be plugged in for the VGT to cycle properly IIRC

 

[windrunner408]

Thanks guys so much for the input and help. I have to say that I think I am in agreement with wetnsloppy4x on needing a more robust scanner.

This truck is my DD and I have only gotten the oil as high as 208*F (it flucuates between 200 and 208F with my thermostat that I have installed in my oil cooler delete system). Even on a WOT run from 10-70mph it wont exceed 208F

ECT is usually right around the 190F mark, with it being as low as 188 and as high as 192F.

I dont know if the EGR valve has anything to do with this issue or not but I can tell you that I just completed an 800 mile road trip yesterday and OAT/IAT was below 40*F the whole time and it never did this. I could run constantly at 70-75 mph and boost stayed between 7-9 psi while on flat ground the whole time.

Some parameters: TFT - 137-142*F, ECT - 188-190*F, EOT - 198-208*F, IAT - 3-4*F below OAT, and EGTs - 580-700*F (depended on the grade of hill).

Whereas like I mentioned when I was in 70*F or higher OATs, the boost would be at these levels for about 15 miles and then it would just jump to like 12-14psi under the same driving conditions and I would see EGTs drop by like 50-75*F (hence less fuel and MORE air).