Havoch
Proven Member
- 48
- 5
- Apr 15, 2019
-
Mission,
BC_Canada
So my car is supposed to go to the dyno next week but all of a sudden it begins to have starting/idle issues, which is nothing new really. I've had to deal with idle surge plenty of times but there are a few other things going on that make me want to ask some questions even if they seem dumb "cause i think I'm getting stupider by the minute here.
First I have to give you the low down, so bear with me while i spin a tale of woh and despair, a story of villains and heros with dramatic twists and turns...... well, you get the idea.. Bwhahaha.....
So anyways, with FIAV removed, cold weather is not my friend. Car began to die right after cranking unless i opened the throttle plate to compensate during cold weather starting. Once warmed up, Venom ran smooth, idled (a bit high) at 1000 RPM all day long but would still die immediately unless i cracked the throttle plate again, although, when warm i had no need to continue to keep it open as it would now begin to idle just fine again.
Not having a huge amount of time right now, i did some testing and detecting and found a few possible issues related to the situation. I use TunerPro RT to tune and log on this car so if anyone has any insights regarding that program specifically it would be appreciated.
First thing was to reset base timing and base idle, found something strange regarding this but i will bring that up in another thread. I now tweaked the maps a bit since i was tuning cruise and WOT anyhow but didn't seem to be making much headway based on the fact that it takes a long time to test changes to the maps in regards to a cold start being that you have to wait 'till the motor is cold again to if the results are positive. Checked IAC, black version, Ohmed out at 39 on all four channels so swapped in a tan version, from another car that idled perfect, which read 29 Ohms on all four channels, and idle did "seem" a bit better but no difference on cold start. Anyhow, I eventually ended up altering the COLD COMP map (idle speed vs. temp.) to raise the initial idle speed at the lower temperatures, as i have been told that this will cause the ISC to open further, netting more airflow and thus increasing idle speed and this did help the cold start and increased the idle speed but what ALSO happened was that the idle speed stayed high (like 1500 RPM) even when the engine was at operating temp. An interesting side effect of this was that it made shifting between gears quite a bit different, might end up utilizing this at the track!
I noticed the idle postion switch wasn't always registering as closed, so that had to be dealt with. TPS appeared to be fine. Checked for vacuum leaks via BLT which indicated nothing of any consequence. Decided to check IAC again..... now, i'm not positive on where it needs to be during idle but my log told me 120 on start and slowly dropping to 0. Also, not 100% on how the ISC relearn works..... but anyhow, it appeared that the ISC motor had somehow broken ( the pintle could be easily rotated around and around but was jammed from being able to go in and out. AHA! I said, proceeding to replace the ISC yet again, and wouldn't you know it, she idled like a champ!
Fast forward to the next day and a test run to see how things go.....
Trip1 = excellent trip, steady cruise, hard pulls, good solid boost control, steady idle, etc...
Trip2 = (hotstart test)Also a good trip, i believe there were a couple small oscillations at idle but smoothed out rapidly
Trip3 = Strange, idle has begun to sit high again, and would actually increase and sit steady at upwards of 2500 RPM, Just not my day i guess.
Did a cold start today and have got constant idle surge AGAIN!!!!, ISC appears to have dropped to 0 immediately after start but as of yet i haven't looked at my logs (company came over and got me distracted)
Planning on a new ISC again but also considering the fact that the ECU may be compromised and is actually killing the ISC when i request a higher RPM via TunerPro. It would explain some parts of this but not sure. Well, back to the drawing board. I won't have a chance to do anymore testing until the weekend unfortunately.
I will post logs as well if i can.
Thank you in advance
First I have to give you the low down, so bear with me while i spin a tale of woh and despair, a story of villains and heros with dramatic twists and turns...... well, you get the idea.. Bwhahaha.....
So anyways, with FIAV removed, cold weather is not my friend. Car began to die right after cranking unless i opened the throttle plate to compensate during cold weather starting. Once warmed up, Venom ran smooth, idled (a bit high) at 1000 RPM all day long but would still die immediately unless i cracked the throttle plate again, although, when warm i had no need to continue to keep it open as it would now begin to idle just fine again.
Not having a huge amount of time right now, i did some testing and detecting and found a few possible issues related to the situation. I use TunerPro RT to tune and log on this car so if anyone has any insights regarding that program specifically it would be appreciated.
First thing was to reset base timing and base idle, found something strange regarding this but i will bring that up in another thread. I now tweaked the maps a bit since i was tuning cruise and WOT anyhow but didn't seem to be making much headway based on the fact that it takes a long time to test changes to the maps in regards to a cold start being that you have to wait 'till the motor is cold again to if the results are positive. Checked IAC, black version, Ohmed out at 39 on all four channels so swapped in a tan version, from another car that idled perfect, which read 29 Ohms on all four channels, and idle did "seem" a bit better but no difference on cold start. Anyhow, I eventually ended up altering the COLD COMP map (idle speed vs. temp.) to raise the initial idle speed at the lower temperatures, as i have been told that this will cause the ISC to open further, netting more airflow and thus increasing idle speed and this did help the cold start and increased the idle speed but what ALSO happened was that the idle speed stayed high (like 1500 RPM) even when the engine was at operating temp. An interesting side effect of this was that it made shifting between gears quite a bit different, might end up utilizing this at the track!
I noticed the idle postion switch wasn't always registering as closed, so that had to be dealt with. TPS appeared to be fine. Checked for vacuum leaks via BLT which indicated nothing of any consequence. Decided to check IAC again..... now, i'm not positive on where it needs to be during idle but my log told me 120 on start and slowly dropping to 0. Also, not 100% on how the ISC relearn works..... but anyhow, it appeared that the ISC motor had somehow broken ( the pintle could be easily rotated around and around but was jammed from being able to go in and out. AHA! I said, proceeding to replace the ISC yet again, and wouldn't you know it, she idled like a champ!
Fast forward to the next day and a test run to see how things go.....
Trip1 = excellent trip, steady cruise, hard pulls, good solid boost control, steady idle, etc...
Trip2 = (hotstart test)Also a good trip, i believe there were a couple small oscillations at idle but smoothed out rapidly
Trip3 = Strange, idle has begun to sit high again, and would actually increase and sit steady at upwards of 2500 RPM, Just not my day i guess.
Did a cold start today and have got constant idle surge AGAIN!!!!, ISC appears to have dropped to 0 immediately after start but as of yet i haven't looked at my logs (company came over and got me distracted)
Planning on a new ISC again but also considering the fact that the ECU may be compromised and is actually killing the ISC when i request a higher RPM via TunerPro. It would explain some parts of this but not sure. Well, back to the drawing board. I won't have a chance to do anymore testing until the weekend unfortunately.
I will post logs as well if i can.
Thank you in advance
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