Idle problem - URGENT
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Joined: Jul 2009
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From: Bahrain
Idle problem - URGENT I put the engine back together, car fired up with some encouragement of a little bit of throttle and would idle at 750 because I had flashed the PCM back to the stock tune. It loped and shook like there was no tomorrow. I think I also have a collapsed lifter as I can hear it ticking inside the intake towards the passenger side. My oil pressure in at 60psi cold, 30psi hot.
I flashed the PCM back to the tune I was using before storing the car for 6 months, it won't idle unless I hold down the throttle. I datalogged and watched the parameters, and on both stock and power tune, the right hand O2 is reading between 700mV and 950mV, sometimes 1V while the left never read more than 400mV. Could I be putting out unburned fuel into the passenger side header due to a collapsed lifter?
I was still in open loop as I could not get the car warm enough to go into closed loop (exhaust was loud and its parked in a back street so I didn't want to disturb anyone).
I had a knock count of up to 65K, and the IAC is always reading 160. I need 5% throttle to keep it idling at 850.
My ignition wires are new Taylors, I don't understand how I don't face this problem with the stock tune. I have no fault codes popping up either. The ignition coil is a brand new AC Delco replacement.
I use TTS DataMaster.
I have yet to drive it due to the lifter tick.
I flashed the PCM back to the tune I was using before storing the car for 6 months, it won't idle unless I hold down the throttle. I datalogged and watched the parameters, and on both stock and power tune, the right hand O2 is reading between 700mV and 950mV, sometimes 1V while the left never read more than 400mV. Could I be putting out unburned fuel into the passenger side header due to a collapsed lifter?
I was still in open loop as I could not get the car warm enough to go into closed loop (exhaust was loud and its parked in a back street so I didn't want to disturb anyone).
I had a knock count of up to 65K, and the IAC is always reading 160. I need 5% throttle to keep it idling at 850.
My ignition wires are new Taylors, I don't understand how I don't face this problem with the stock tune. I have no fault codes popping up either. The ignition coil is a brand new AC Delco replacement.
I use TTS DataMaster.
I have yet to drive it due to the lifter tick.
Last edited by ADM; Jun 9, 2010 at 05:20 AM.
well first, investigate the ticking.. take a valve cover off and see whats up, also you havn't told up your mods. so just because you have a stock tune doesnt mean the car is going to run the way it should if you have mods, Basic bolt-ons sure it should run but if you have some internal motor work, that could account for something.
Thread Starter
TECH Resident
Joined: Jul 2009
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From: Bahrain
well first, investigate the ticking.. take a valve cover off and see whats up, also you havn't told up your mods. so just because you have a stock tune doesnt mean the car is going to run the way it should if you have mods, Basic bolt-ons sure it should run but if you have some internal motor work, that could account for something.
I know it won't run the same on the stock tune, but I am amazing how it will hold idle on the stock tune yet won't on a proper tune for the mods. In closed loop it runs like a charm and smooth power and idle throughout.
I am running a CC503, long tubes, 1.6 rocker arms, and Hooker Aerochamber muffler round the back.
Paul Bell, the wires were installed correctly and I will check them again, I might have crossed one (silly mistakes can happen). Yes they are Taylors, and are brand new. Its the first time I ever fired up the engine with them.
you could be getting raw fuel in the driver side header, but the o2's dont read raw fuel, just the fumes, but the o2's could be reading off because of 2 much air, not enough fuel, or the other way around, and telling the computer to richen or lean it up... pull that driver's side valve cover and watch the valve's with it running and you will be able to judge the lifter situation, and if that lifter is fudged up, check that pushrod as well, might get warped
Last edited by 95_TA_USMC; Jun 9, 2010 at 11:26 PM. Reason: left comment out
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for your high idle i just had this problem and fixed it. i had a aftermarket TB which was 52mm BBK i turned the blade screw out to my iac count went to do around 20-40 and adjusted the tsp sensor to around .50-.67 and fixed my idle problem.
for your knock count are you running open headers or full exhaust right now because that can be throwing off your o2's
for your knock count are you running open headers or full exhaust right now because that can be throwing off your o2's
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Verdad Gallardo Thread Starter
TECH Resident
Joined: Jul 2009
Posts: 772
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From: Bahrain
for your high idle i just had this problem and fixed it. i had a aftermarket TB which was 52mm BBK i turned the blade screw out to my iac count went to do around 20-40 and adjusted the tsp sensor to around .50-.67 and fixed my idle problem.
for your knock count are you running open headers or full exhaust right now because that can be throwing off your o2's
for your knock count are you running open headers or full exhaust right now because that can be throwing off your o2's
I will pull the valve cover and see whats going on inside. The pushrod would be loose if the lifter had collapsed wouldn't it?
A colleague of mine who runs a speed shop and specializes in LS motors told me most likely my tune is very rich at start up and thats why the IAC is maxed out at idle. I have not shown him the tune yet or the logs as the opportunity has yet to come.
