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Thread: ---Car dies when warm---Scan to pin point.

  1. #1
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    ---Car dies when warm---Scan to pin point.

    Sorry for the 3rd post in a few days for starters. I bought the car knowing it had issues. One of them was a random stalling out issue when approaching a stop (idle).

    Some how I actually got a scan of it. I was just idling setting up histograms and had the scanner recording. All of a sudden the car just shuts off.

    In the scan the MAP sensor just sky rockets all of a sudden and that's when the car dies. But so doesn't the 02 sensor a bit before. But the sensor is brand new and is relocated to the crossover. The car did this when it was in the factory location when my friend owned it.

    My initial thought was the crank sensor but I don't see the rpms just cutting out. Maybe it's the ign module?
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    Last edited by PWNED; 11-14-2013 at 08:36 PM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  2. #2
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    I have an ignition module on the way but I figured I would post up 3 more scans. The car stalled out at idle 3 times back to back. Hope fully once I get this resolved the scans would be help to someone else.
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    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  3. #3
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    My money is on that crank sensor. Do you have another MAF you can try just to rule it out as well? These dam v6's man, I tell you.... Ive seen a ton of the 3400 and 3800 have crank sensor issues like this, but have seen a MAF do this as well all while never throwing a dam code for any of it! It sucks man, I know exactly how you feel on this one. I chased the same problem for three years until finally changing crank sensor and fixed the problem.
    2000 Trans Am WS6

  4. #4
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    Quote Originally Posted by MMGT1 View Post
    My money is on that crank sensor. Do you have another MAF you can try just to rule it out as well? These dam v6's man, I tell you.... Ive seen a ton of the 3400 and 3800 have crank sensor issues like this, but have seen a MAF do this as well all while never throwing a dam code for any of it! It sucks man, I know exactly how you feel on this one. I chased the same problem for three years until finally changing crank sensor and fixed the problem.
    Well a new crank sensor did not fix it unfortunately. At 221k I too would have thought it would.

    My thought is something is getting hot due to lack of air flow.

    The day after I put in a new/used ignition module. I have yet to have the car act up yet. Today I put in a new maf as well just for safe measure. (it must be one of these)

    The scan almost seems to say that the ignition is getting unstable just about the time the car stalls. But why does the MAP sky rocket?
    Last edited by PWNED; 11-24-2013 at 09:48 PM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  5. #5
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    Your IAT's are looking very high. You should check that sensor/harness.... something up there I think
    2000 Trans Am WS6

  6. #6
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    Quote Originally Posted by MMGT1 View Post
    Your IAT's are looking very high. You should check that sensor/harness.... something up there I think
    The high iat's are due to idling for a few too many minutes in one spot. Driving they are very close to ambient. I did the wiggle and tap test and the car wont act up by that method.

    Today for the first time in a few weeks it decided to act up again while idling in a parking spot.

    I forgot to mention that the previous owner installed knockoff ebay 255 walboro fuel pump years ago. The car runs perfectly fine under wot. I may end up swapping a used/stock unit in at some point. Perhaps the pump gets hot and is not being cooled by fuel at idle? I never though to check how much gas I have when this happens. But today I was at 1/2. I could put a fuel pressure gauge on it to see if the pressure drops but its hard to tell if/when the car will act up.

    If anyone has shut off their fuel pump via hpt just for fun it basically exhibits the same symptom it feels like. I have even made a new ground at the fuel pump with no change.
    Last edited by PWNED; 12-11-2013 at 08:47 PM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  7. #7
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    I made a scan this morning of me commanding the fuel pump off. The car does the exact same thing when it does it on its own. But why does the map just shoot up?

    Also is the iac valve working correctly when the car stalls? It sky rockets when the problem happens. I have no idle concerns in general. Safe to rule that part out?
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    Last edited by PWNED; 12-12-2013 at 07:09 AM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  8. #8
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    I want you to try something for me. Put your stoich fuel rating back to stock. I tried to do that with my V-6 and it would not take it. I put mine back to stock, tuned it with a wideband and never saw the problem again. Have a feeling the V6 does not like this change for some reason. Anyway, just give it a try and see....
    2000 Trans Am WS6

  9. #9
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    afr.JPG
    Quote Originally Posted by MMGT1 View Post
    I want you to try something for me. Put your stoich fuel rating back to stock. I tried to do that with my V-6 and it would not take it. I put mine back to stock, tuned it with a wideband and never saw the problem again. Have a feeling the V6 does not like this change for some reason. Anyway, just give it a try and see....
    Under which table? I am pretty sure the last owner tuned by maf that is why it is choppy in the higher maf hz. Is this what your talking about?
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  10. #10
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    Yes, that would be close to what stoich would be for E10, but put it to stock and try it out.

    14.70020, you have 14.15xxx

    I made no other change to my v6 at all and when I tried to change stoich for E10 it fell on its face. No idea why, but mine would not do it
    Last edited by MMGT1; 12-12-2013 at 05:07 PM.
    2000 Trans Am WS6

  11. #11
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    Quote Originally Posted by MMGT1 View Post
    Yes, that would be close to what stoich would be for E10, but put it to stock and try it out.

    14.70020, you have 14.15xxx

    I made no other change to my v6 at all and when I tried to change stoich for E10 it fell on its face. No idea why, but mine would not do it
    So why would he have put that number in? I am just trying to learn. When will this value be applied in general? Will it mess with wot at all? Or is it just idle cruise?
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  12. #12
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    That is stoich for E10, well close to it anyway. Have you seen the sticker at the pump that says; "May contain up to 10% Ethanol"? He may have been trying to compensate for that, as I tried with mine but like I said, when I tried that with my v6 it stalled, would not start, then when it did it fell on its' face. I put it back to stock and it stopped stalling. Just try setting it to 14.70020 and see if it clears up. Now, for myself, the only time I would change stoich is when building your wideband PID in Lambda. You do need to have the stoich value of the fuel you are running to properly map Lambda against VE or MAF. When using Lambda to tune you are looking for the % error against the fuels stoich measurement. Having incorrect data on your fuel when tuning with a wideband is going to result in an error against stoich, the same error you programmed into your PID to do so. Make sense? Still i have no idea why my v6 went insane when I changed stoich to account for E in the fuel, and I only went to 14.3 as I was not sure how much was actually in the fuel. Well, I was thinking something between the two extremes would be a good thing, at least I was trying. It did not like it one bit and I went back to the factory stoich rating in the tune.
    Last edited by MMGT1; 12-13-2013 at 05:02 PM.
    2000 Trans Am WS6

  13. #13
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    Quote Originally Posted by MMGT1 View Post
    That is stoich for E10, well close to it anyway. Have you seen the sticker at the pump that says; "May contain up to 10% Ethanol"? He may have been trying to compensate for that, as I tried with mine but like I said, when I tried that with my v6 it stalled, would not start, then when it did it fell on its' face. I put it back to stock and it stopped stalling. Just try setting it to 14.70020 and see if it clears up. Now, for myself, the only time I would change stoich is when building your wideband PID in Lambda. You do need to have the stoich value of the fuel you are running to properly map Lambda against VE or MAF. When using Lambda to tune you are looking for the % error against the fuels stoich measurement. Having incorrect data on your fuel when tuning with a wideband is going to result in an error against stoich, the same error you programmed into your PID to do so. Make sense? Still i have no idea why my v6 went insane when I changed stoich to account for E in the fuel, and I only went to 14.3 as I was not sure how much was actually in the fuel. Well, I was thinking something between the two extremes would be a good thing, at least I was trying. It did not like it one bit and I went back to the factory stoich rating in the tune.
    Should I do a temporary maf change like add 2% of fuel to the entire file due to me making everything leaner? 14.1 to 14.7?

    Side note if I am sticking with the 3.4 pully can't I install a stock maf and get rid of the lq4? Maybe even put the stock injectors back in later down the road once I get the wideband on it? In general I will get 200 miles to a tank of gas. (warming the car up in the mornings and maybe wot twice a week)
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  14. #14
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    I'd run the stock MAF and TB, you don't have enough flow into the motor to be running a larger throttle body and MAF sensor. Same with the injectors, you shouldnt max them untill you're in the 3.2 pulley range (250+ WHP.)
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  15. #15
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    Update.......

    Putting the Stoich back to 14.7 as well as the VE table table to stock did not fix a thing. While trying to get my wideband to connect the car died at least 5 times in 5 minutes. In general yes the wideband works. Initial 2nd gear hit/pull stays right around 10.3-10.7 at wot with no other change than stock ve/stock afr from the last tune.

    The wideband itself does read on the laptop well sometimes.. When put into the histogram table the number 20 is displayed plotted against the maf table. I tripple checked everything vs a PID from a last car and I don't see why this is not displaying actual afr. I don't know what I did but when selected now it just displays a blank pid as if it needs to be setup.

    After the first 2 times the car died I pulled back the carpet to listen. You can hear the fuel pump make a high pitch noise when its going to die. When this happened I gave it some gas and it just made it worse. The car did not want to start right back up. I had to prime the pump a few times. In doing so I had the hood open during all of this and I heard the fuel rail finally prime with 3 or so cycles of the key (even though you could hear the pump make different noises each time/almost a hollow noise at first and then as if it has filled up the space). I wiggled all wires back there as well as thumping the pcm around and massaging the harness around the iac and that general area. I am going to swap this ebay pump out for a stocker I have.
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    Last edited by PWNED; 12-22-2013 at 10:28 AM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  16. #16
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    Edit for the above post...I have the wideband working now through hpt but I will be making a separate thread for my results/questions.

    Also I now have a stock fuel pump in and have been tuning for 2hrs. The car has yet the act up yet but we shall see.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq

  17. #17
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    bet you got it with that pump
    2000 Trans Am WS6