Help with warm start issue - Whipple

[TX-Ripper]

Your tuned by Pbd t

I have looked for a vacuum leak, but haven't been able to find anything.

If I had a vacuum leak, wouldn't I lean out during WOT as well?

You might need a professional to smoke test it.

If you look at your log, what are the signs that it’s leaning out? (Wot or otherwise)

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[khsonic03]

Your tuned by Pbd t


You might need a professional to smoke test it.

If you look at your log, what are the signs that it’s leaning out? (Wot or otherwise)

I'm not sure, which is why I'm asking for help here. I'm not experienced with tuning, which is why I posted the log asking for someone who is to help out.

I can only go based off what I have researched and what the tuner is telling me. Tuner is saying logs at WOT look perfect.

I dont see knock and I don't see lambda going over 1. Its always .8ish or in that area.

Can you tell me what else I should be looking for?

Happy to post a WOT log if that helps.

 

[TX-Ripper]

Your short term fuel trims should read 0 + or - 5%.

yours read in the 20% range, that tells me your car is running lean and adding 20% fuel.

Wild guess, you have a vacuum leak.

 

[khsonic03]

Your short term fuel trims should read 0 + or - 5%.

yours read in the 20% range, that tells me your car is running lean and adding 20% fuel.

Wild guess, you have a vacuum leak.

Got it. I do know that when I first told the tuner about this they said sometimes it needs more "air" at startup, so that's what they did. Not sure if that means that he's opening up the tb more or what.

Could that be an alternative reason its running lean an startup?

 

[TX-Ripper]

You can not tune out a mechanical problem.

 

[khsonic03]

You can not tune out a mechanical problem.

I get that. What does adding more air mean to you as someone who is familiar with tuning?

 

[Jackson1320]

Your short term fuel trims are out of control. Vacuum leak, throttlebody, tps sensor, maf sensor. And you need a new battery. Any codes?
Your mass airflow sensor doesn’t know what to do it’s all over the place like you have a vacuum leak or a misfire or both. I know your problem is at warm starts but you really should get a log with some driving also. Something might show up that helps

 

[khsonic03]

Your short term fuel trims are out of control. Vacuum leak, throttlebody, tps sensor, maf sensor. And you need a new battery. Any codes?
Your mass airflow sensor doesn’t know what to do it’s all over the place like you have a vacuum leak or a misfire or both. I know your problem is at warm starts but you really should get a log with some driving also. Something might show up that helps

Thanks. No codes - never had any misfires. I'll see what I can find.

I appreciate the response and will post some other logs.

 

[Jackson1320]

Any chance you know what your cranking spark is set to.
it doesn’t look like you have enough

 

[khsonic03]

Any chance you know what your cranking spark is set to.
it doesn’t look like you have enough

No, I'm not sure. Assuming the tuner would need to provide that info to me right?

I've tried a few more things too:

• propane test for vacuum leaks everywhere - no change in idle
• plugged off the ports for the brake booster and purge valve to eliminate those as potential vacuum leaks- no change
• filled up with 93, no boostane - no change
• charged my battery to 100% with a charger - no change (and still dropping to 9ish volts for a split second during startup, but read that's not out of the ordinary)
• cleaned MAF sensor - no change
• Replaced the PCV for laughs - no change

I have a MAF sensor on order to rule that out and a smoke machine. Planning on smoke testing it this weekend.

Also have educated myself more on STFT and LTFT.

Additionally - something I forgot to mention up front - that log is with the AC on during startup, as it makes the issue worse. When I turn off the AC, the STFT are closer to 10% during idle. While holding a steady speed w/cruise control, STFT are closer to 5-6% and sometimes lower.

Can it be that it's not getting enough fuel at startup? I have 1050x injectors - are they harder to tune for idle?

Still have not done a crank relearn yet.

 

[Jackson1320]

What are your LTFT and STFT at the same time. They need to = +/-5 combined

 

[Jackson1320]

The load is high for idling 38% like the maf is scaled wrong or just bad. If it is it will start good cold but take a log time warm because it’s flooding the engine with fuel

 

[khsonic03]

The load is high for idling 38% like the maf is scaled wrong or just bad. If it is it will start good cold but take a log time warm because it’s flooding the engine with fuel

Thanks. Ill add the LTFT to the logs and grab one tomorrow.

When you say the MAF is scaled wrong, is that something that is set via the tune tables, or is it a hardware issue?

 

[khsonic03]

Smoke tested the car today. Found one leak at the TB set screw (see video: ). Got excited and thought I had figured it out. Sealed that set screw with some tape and no change. There are absolutely no other leaks. Pumped a ton of smoke in there.

LTFT's are 0 during startup and idle.

Did a step test log and fuel trims are within 2-3% most of the time. Its just startup and idle that is a disaster.

New MAF is due in tomorrow. Also going to try swapping the TB circuit board with the factory one. Will probably have to recalibrate the TPS setting again. That will eliminate MAF and TPS sensor as an issue.

This is getting old. Lol

 

[Burkey]

This might sound stupid but you’re using an aftermarket IAT sensor right? Eg. Not the one supplied by Whipple.
Without throwing anyone under a bus, one of those ”big two” tuned a mates car and failed to notice that he was still using the Whipple sensor. Your issues sound very much like what he was seeing.

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