Warm/Hot Start Intermittent Idle Issue?
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Joined: Sep 2015
Posts: 66
Likes: 1
From: CT
Warm/Hot Start Intermittent Idle Issue?
Hello all,
I have a 2002 Z06. The car is not stock, and is occasionally giving me an issue upon restarting. The issue occurs after driving a short distance, turning off and then restarting the car after 5-30 minutes. It most frequently happens to me after re-fueling as that is typically the only time the car will sit for a short period of time before being re-started. As soon as the car is driven for even a tenth of a mile, the idle returns to normal.
I bought the car at the end of summer 2015, and it has done this maybe 6 times total. The PO of the car said it's happened to him a few times as well, but never bothered him because it never fails to go away. My issue is that I plan to take the car to a few cruises and shows this summer, and don't want to be worrying about my car stalling out a few times after making a few stops on a longer cruise.
I have no codes at all, I just checked.
The car is tuned by Slowhawk Performance literally to this date (March 26) 2 years ago, and has a Comp Cams 228/232 112LSA cam, Vararam intake, headers-back exhaust, a 25% UD pulley, and McLeod clutch.
Can anyone direct me where to look first? Is this most likely to be a mechanical issue or a tuning issue?
I have a 2002 Z06. The car is not stock, and is occasionally giving me an issue upon restarting. The issue occurs after driving a short distance, turning off and then restarting the car after 5-30 minutes. It most frequently happens to me after re-fueling as that is typically the only time the car will sit for a short period of time before being re-started. As soon as the car is driven for even a tenth of a mile, the idle returns to normal.
I bought the car at the end of summer 2015, and it has done this maybe 6 times total. The PO of the car said it's happened to him a few times as well, but never bothered him because it never fails to go away. My issue is that I plan to take the car to a few cruises and shows this summer, and don't want to be worrying about my car stalling out a few times after making a few stops on a longer cruise.
I have no codes at all, I just checked.
The car is tuned by Slowhawk Performance literally to this date (March 26) 2 years ago, and has a Comp Cams 228/232 112LSA cam, Vararam intake, headers-back exhaust, a 25% UD pulley, and McLeod clutch.
Can anyone direct me where to look first? Is this most likely to be a mechanical issue or a tuning issue?
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
I'd check the basics first. Plugs and wires OK? No vacuum leaks? All air intake tubes seated well and tight? PCV system OK? MAF sensor clean? Throttle position sensor OK? Fuel pressure high enough and steady? Some of these are driveway checks and some may require special tools or a better mechanic than most home wrench-turners.
Once you get beyond that, I'd suggest that your tune may not be spot on and may need tweaking a little.
Once you get beyond that, I'd suggest that your tune may not be spot on and may need tweaking a little.
Thread Starter
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Joined: Sep 2015
Posts: 66
Likes: 1
From: CT
I have not pulled a plug yet, but the plugs and wires were both swapped out at the time of the dyno tune.
The intake tubes is seated well and the silicon connectors are not cracked. I just installed a new Vararam tube to replace the factory one. Everything is very tight. The air filter was cleaned as well.
Not sure about the PCV system, what should I check there?
There is a catch can installed. I emptied that, put teflon tape on the brass fittings, and added clamps to the hoses associated with the catch can.
MAF was cleaned when the intake tube was installed as it was swapped onto the new unit. It did not appear to be too dirty.
How do I check the TPS and potentially reset it?
How do I check the fuel pressure? I was thinking that it could potentially be a fuel filter?
How do I check my vacuum? I was thinking it may be a cracked hose somewhere?
The intake tubes is seated well and the silicon connectors are not cracked. I just installed a new Vararam tube to replace the factory one. Everything is very tight. The air filter was cleaned as well.
Not sure about the PCV system, what should I check there?
There is a catch can installed. I emptied that, put teflon tape on the brass fittings, and added clamps to the hoses associated with the catch can.
MAF was cleaned when the intake tube was installed as it was swapped onto the new unit. It did not appear to be too dirty.
How do I check the TPS and potentially reset it?
How do I check the fuel pressure? I was thinking that it could potentially be a fuel filter?
How do I check my vacuum? I was thinking it may be a cracked hose somewhere?
Last edited by RideRed0331; Mar 27, 2016 at 11:31 AM.
Thread Starter
Advanced
Joined: Sep 2015
Posts: 66
Likes: 1
From: CT
Mine will do the same essentially.
My air cleaner was very dirty, I have a Vararam installed and I think that even though the MAF appeared clean it may have been a bit dirty. Everything I read as far as dirty/faulty MAF symptoms almost hits my issue on the head.
I ordered the Halltech honeycomb insert, and am relocating it to directly in front of the TB. I bought some specific MAF cleaner too. Hopefully this solves it.
Regardless, I'm installing a FAST 92mm intake and larger injectors, so the car will be tuned and I will mention it to my tuner
My air cleaner was very dirty, I have a Vararam installed and I think that even though the MAF appeared clean it may have been a bit dirty. Everything I read as far as dirty/faulty MAF symptoms almost hits my issue on the head.
I ordered the Halltech honeycomb insert, and am relocating it to directly in front of the TB. I bought some specific MAF cleaner too. Hopefully this solves it.
Regardless, I'm installing a FAST 92mm intake and larger injectors, so the car will be tuned and I will mention it to my tuner
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
When your engine is started cold it is running in what they call "open loop mode" When the coolant reaches 140* it will switch to normal mode or "closed loop" After the engine is beyond 140* the trigger switches to a timer--usually about 20-30 seconds after starting before it goes into closed loop---I would try and see if the problem occurs when the coolant is below 140* or if it is before the 30 second timer after it's warmed
The most common issue with LT headers and cams is the fueling when the engine is in Open Loop----This would tell the tuner that an adjustment would be required in the "open loop" fueling table--The only way to fix this would be with tuning----
If the problem occurs after the engine is beyond 140* and after 30 seconds when warm-- then the problem would point to something else---Those issues are mostly caused by----
An air intake tube leak
A vacuum leak
A dirty or fouled MAF
Clogged fuel filter
Failing or slow front 02 sensors
( this is assuming you have no misfire issues due to plugs /wires )
The most common issue with LT headers and cams is the fueling when the engine is in Open Loop----This would tell the tuner that an adjustment would be required in the "open loop" fueling table--The only way to fix this would be with tuning----
If the problem occurs after the engine is beyond 140* and after 30 seconds when warm-- then the problem would point to something else---Those issues are mostly caused by----
An air intake tube leak
A vacuum leak
A dirty or fouled MAF
Clogged fuel filter
Failing or slow front 02 sensors
( this is assuming you have no misfire issues due to plugs /wires )
Melting Slicks
Joined: Jun 2005
Posts: 2,396
Likes: 52
From: Sicamous BC
Thread Starter
Advanced
Joined: Sep 2015
Posts: 66
Likes: 1
From: CT
The injectors are due to my current cam. I plan to add heads in a short while. I figure I'd be at max or close to it for a stock injector.
Not sure about tuning yet, I've been in contact with Don. I hear SMG tuning is reputable as well
Not sure about tuning yet, I've been in contact with Don. I hear SMG tuning is reputable as well
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