Won't stay running
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Teching In
Joined: Nov 2008
Posts: 23
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From: San Diego, Ca. For now!
Won't stay running I just installed a BBK SSI intake, BBK 85mm throttle body with adapter plate and both gaskets, SLP preformance MAF sensor, SLP CAI, SLP lid, and SLP smooth bellows. Now when I start it it revs to about 2000 rpms and then drops and wants to stall out. I can keep it running by feathering the gas and eventually it will stay running long enough for me to get out and feather the accelerator from under the hood. It sounds like there is a back fire from inside the intake when it starts to stall and I try to rev it back up. I have HP tuner PRO and I hooked it up and the only thing I noticed was the MAF was around .31 lb/min at lowest and 4.17 lb/min at highest. The column all the way at the right has a low of 60 and a high of 125. I'm assuming those are what normal readings should fall between. I''ve checked for air leaks and vacuum leaks but have found none. Also I noticed that the exhaust was glowing orange. I was thinking that was because of the upgrades and the fact that I'm running while sitting in the garage with no airflow to cool it. Can anyone help me figure this out? With all these upgrades do I need to get it tuned or anything?
Thread Starter
Teching In
Joined: Nov 2008
Posts: 23
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From: San Diego, Ca. For now!
Update: Just took it out for a run to see what the drivability was. Had to keep my foot feathering the throttle at stops, rpms were up and down while idling and slow speeds to about 30 mph. New development though...When the engine reached op temp (210 F) it started reving to 3000 at which point I would have to engage the clutch, slow down, and pop the clutch to slow the revs or let the tranny slow the car until the revs dropped to a more normal range. Then when I touched the throttle it would increase back to 3000. I couldn't blip the throttle to bring it down it would just take it to 3000 rpms. Also the temp, at one point started to rise (about 230 F) but the glowing exhaust went away. Again, assuming that is because I had airflow around the pipes.
sound kinda like a vac leak? start the car get it to stay running, slowly spray starting fluid around the area of all the parts you unbolted. when it starts to rev up, theirs your vac leak.
Have you tried a vacuum gauge? What is you vac at idle and snap throttle? Does the needle stay steady or jump all over the place? Does the vac respond on snap and then drop off when you snap back shut. The suggestion to use a spray to find a leak(hose, gasket) is a good place to start. How do your LTFTs and STFTs look?
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I have the same intake just put my car together after changing that and the cam. I had the same prob. it was a vacuum leak. It came off the little black plastic piece that goes right into the side next to the throttle body on the driver side unplug it and see it u put ur finger on it if thats teh prob thats what mine was.
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Verdad Gallardo Thread Starter
Teching In
Joined: Nov 2008
Posts: 23
Likes: 0
From: San Diego, Ca. For now!
Have you tried a vacuum gauge? What is you vac at idle and snap throttle? Does the needle stay steady or jump all over the place? Does the vac respond on snap and then drop off when you snap back shut. The suggestion to use a spray to find a leak(hose, gasket) is a good place to start. How do your LTFTs and STFTs look?
To most of all the rest, thanks for the help. I'm going to try these sugestions. I'll keep you posted.
You need a scan tool to look at fuel trims. If you have a vacuum leak the ecm will add fuel driving you RICH trying to compensate for the extra air. This is adaptive strategy. You might hear a large leak, but not a small one. You can see it on the scan tool if you're unusually RICH. Try the spray method. It's used on Fords all the time as they have hoses that crack. The vacuum gauge should be steady. When you snap the throttle vacuum temporarily builds. When you release the throttle it should drop off and then stabilize again and be steady. This is an old school test, but if you have a basic problem you look for simple solutions. It doesn't have to be something complex all the time even on computer controlled engines.
