NEED HELP engine cutting out
Alright, so I've searched around on here and the other less important forums, but haven't found too much. So I'll start with what I have done to it. It's a 1990 still with the 1.6 in it. Engine is bored .020" over, with an older Begi kit bolted up to it with a brand new Garret GT2560R, all coming out to a 3" straight pipe from the downpipe back. Everything held together with some ARP studs. Only at 5 lbs of boost, stock ecu (I know, I know), rising rate fuel pressure regulator, Walbro 255 fuel pump. Exedy clutch, Fidanze flywheel, 1.8 driveshaft and axles, with a Torsen Type II 4.3 LSD.
I've had it on this set up for the last 5-6,000 miles. Now last week the engine just started cutting in and out under normal driving. When it first happened I thought it was just because I was a little low on fuel at the time, but even after I put gas in it it still does it, but it only does it when it is under half a tank of gas. Basically you feel the engine cut out, then it stays like that for however long it feels like it, normally between 5-20 seconds, and then it'll go back to normal. First thought was it being a fuel issue. I bought the Walbro 255 fuel pump brand new when I did the build, so I turned my attention to the fuel filter, figuring I just picked up some garbage off the bottom of the tank when the gas was low. I replaced the fuel filter, which did turn out to be pretty filthy, but that didn't solve my issue. Any help here would be great! |
What's your ignition setup?
Too bad about the ECU. Data logging really helps with issues like these. |
Originally Posted by hornetball
(Post 1047806)
What's your ignition setup?
Too bad about the ECU. Data logging really helps with issues like these. |
What's the wideband say?
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Originally Posted by Savington
(Post 1047827)
What's the wideband say?
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Anyone have any ideas?
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The wideband should not have a "mind of its own" at the operating conditions where you are having issues. Even with an exhaust leak, you are simply pushing exhaust out of the leak, not drawing air in. Can you log the wideband readings? Keep in mind that once you start misfiring, the wideband will necessarilly read lean (O2 present) even if the cause of the misfire was not leaning out.
Are you able to monitor fuel pressure while running? |
Originally Posted by hornetball
(Post 1047981)
The wideband should not have a "mind of its own" at the operating conditions where you are having issues. Even with an exhaust leak, you are simply pushing exhaust out of the leak, not drawing air in. Can you log the wideband readings? Keep in mind that once you start misfiring, the wideband will necessarilly read lean (O2 present) even if the cause of the misfire was not leaning out.
Are you able to monitor fuel pressure while running? |
Why don't you fix your obvious problems (boost leak and exhaust leak) before you worry about gas tank pressure.
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Originally Posted by thenuge26
(Post 1048418)
Why don't you fix your obvious problems (boost leak and exhaust leak) before you worry about gas tank pressure.
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You are still using the AFM, so a boost leak means your engine is not getting the amount of air the ECU thinks, and the exhaust leak means your wideband readings are useless.
Fix your known issues, then worry about what else might be wrong. |
GIGO.
What do you want from us? You know that several key things that could be culprits or present impediments to proper diagnosis exist and yet want us to guess the problem without you expending any effort to rectify them. Have you even read the spark plugs? |
Originally Posted by vinohare
(Post 1047831)
Forgot to mention that part. I have a small boost leak and a pretty significant exhaust leak from my manifold gasket. That being said, my wideband has a mind of it own. Before that, my afr's were normal for idle, in boost, and cruising.
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I know I know. My reason for posting wasn't to hear you rant on how I should fix the obvious issues. Rather merely to see if anyone else had a similar issue that was possibly unrelated to my known issues. That way, if its something I can do in the meantime I can do that, or if its something easier to take care of while the engine is out I'll do that then.
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We are not going to be able to help you until you clear up the obvious problems - it's simply not possible. You have too many variables for us to even come close to answering this.
Here's an algabraic rendering of what you're asking us to do. Can someone help me solve for B given these 3 equations?? (A+35/.4C-2^Y)-6/B=X A=14.3*-Z(Pi+G^2) D=0 |
P.S. - If your AFR is reading 17 under load, and you do it more than once, you're a moron.
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