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Fuel issues, stumbling misfiring, 320hp Omni
Whats up guys,
Haven't posted here in awhile, so my apologies. My '86 Omni GLH has developed some misfiring issues within the past week and I'm trying to get it fixed before my parents travel up here for vacation. My dad has never had a ride in the Omni since I got it back from Cindy's and got it street legal(brakes tires and etc.). What it's doing is stumbling and misfiring under acceleration, idles just fine at 1000rpm (not sure how to lower it, but I have the F4 cam installed), and when I go to WOT the car runs just fine and plants you in the seat.
Engine Specs- 2.2L SOHC, bored .040, 2 piece int, ported polished int/exh, walbro 255, +40's, FWD billet fuel rail, AccuFab adjustable fuel rate regulator, hybrid s57 T3/T4, FWD-F4 camshaft, Venoila forged pistons, eagle H-Beams, forged crank, non common block, wideband AFR, etc
The first week when it started doing this I could drive easy with no problems and WOT with no problems, it was the intermittent acceleration that started the stumbling. whenever it stumbled, my AFR would jump to around 17 on the gauge or to "- - -" which means theres no fuel at all im assuming. Whenever I saw that I got out of the throttle. Whenever I go WOT though, it would be at 10.8 to 11.2. On my way to work one day I started smelling gasoline and thought it was just unburned gas in the exhaust since I run a wide open exhaust cutout. On my way back home though it smelled as if I was at the gas station smelling right from the nozzle! When I pulled up to my house I popped the hood and discovered there was a pool of gas between the intake and head in that little valley under the fuel rail. I stuck my finger into the pool to see how deep it was and it went up to my first little bend on my index finger.
I called my friend over later to see if he could help me find the leak, which we suspected to be a foul O-ring on one of the injectors. Turns out that the little screw on the very end of the billet fuel rail from FWD had come loose a little bit and it was leaking from there. I thought that was why it was stumbling and I was going lean was because gas wasn't being delivered properly. So I took an allen head and teflon tape and tightened that sucker down. I started the car and watched the spot and it didn't leak any more. Gave it some revs and still no leak, took it around the block and checked it, no leaks. I went to a back road and got on it a little bit, and now it stumbles and misfires, with the same 17 or "- - -" on the AFR, when you accelerate or go WOT. I'm at a loss.
No codes other than 55.
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Re: Fuel issues, stumbling misfiring, 320hp Omni
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Did you use white or yellow teflon tape? Yellow is for fuel/petroleum.
Check your voltage at your pump while driving/boosting. Check your fuel pressure while driving/boosting. Make sure you're getting a true 1:1 rise in fuel pressure with boost.
http://www.turbo-mopar.com/forums/sh...cal&highlight=
A problem I ran into was I had a restriction in my return line at the tank. It was causing my fuel pressure needle to flutter, bad. I removed the restriction and open the line up to 3/8" (cutting off the 1/4" ends making my return line 5/16" wasn't enough) and the fluttering went away.
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Did you Check the oring on the fuel pressure regulator that mounts to fuel rail?
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Re: Fuel issues, stumbling misfiring, 320hp Omni
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Check your spark plugs, how do they look?
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Quote:
Originally Posted by
A.J.
Did you use white or yellow teflon tape? Yellow is for fuel/petroleum.
Check your voltage at your pump while driving/boosting. Check your fuel pressure while driving/boosting. Make sure you're getting a true 1:1 rise in fuel pressure with boost.
http://www.turbo-mopar.com/forums/sh...cal&highlight=
A problem I ran into was I had a restriction in my return line at the tank. It was causing my fuel pressure needle to flutter, bad. I removed the restriction and open the line up to 3/8" (cutting off the 1/4" ends making my return line 5/16" wasn't enough) and the fluttering went away.
White Teflon, I got it from the manager at O'Reilly's who said it would work fine. Guess I need to go to Autozone, huh? lol. I gave it around 6 turns and it seems to be sealing but I will go get some yellow to fix that. Also, fuel rail doesn't have a shrader valve to connect a fuel pressure line to
Quote:
Originally Posted by
GLHT_yeah_baby!
Did you Check the oring on the fuel pressure regulator that mounts to fuel rail?
Solid, no leaks
Quote:
Originally Posted by
karlak
You still at Robins?
Yes I am:thumb:
Quote:
Originally Posted by
glhs727
Check your spark plugs, how do they look?
Cindy! They looked awful. They were flaking a bit and brown on some of them. One of the plugs had cracked porcelain on top and they were oily on the threads. I will post a pic below. Replaced them with NGK BR8ES, part number 5422.
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Re: Fuel issues, stumbling misfiring, 320hp Omni
An update from what happened yesterday during the chase of the cars problems. Pulled the spark plugs and found that they were flaking and brown with oil on the threads. One of the porcelain tops on the chamber closest to the pass side fender had cracked. Replaced all four spark plugs with NGK BR8ES plugs with non projected tips. Car would still stumble and now does not go to WOT or above 3K rpm without breaking up. Car still idles just fine.
Next step was to replace the fuel filter. Pulled the old one off and checked it and it was full of some brown muck, like dirty water you'd find at a bog or something. Changed it out and went to drive it, still stumbles and misfires, won't go above 3K before breaking up. Still idles just fine.
Next step was to replace the coil since it was the stock black one and covered in grime. Went to Advance Auto and got a replacement stock coil and put it in. Went to drive it, still sputtered, stumbled, misfired etc. Car still idles just fine if not a little better. Finally thought that maybe the fuel pump was on its way out.
Started to drive the car home to base as it was going on 8pm. Didn't even make it out of the neighborhood of my buddies place before the car died while running.
Tried to start it and the car starts for about a second and then dies. Start it, idles for a second, then dies. Start it again, idles for a second, then dies while trying to flutter the throttle. So I think we've confirmed through that little episode that the pump finally gave out and I'm gonna need to order a new one. I ended up running back to base, getting my truck and towing it back to base.. needless to say the Security Forces guys all know my car as the "little red turbo sleeper" and were cracking jokes as I towed it through the gate for I.D. check. "About time that thing died!"
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Re: Fuel issues, stumbling misfiring, 320hp Omni
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Quote:
Originally Posted by
BoostedDrummer
Next step was to replace the fuel filter. Pulled the old one off and checked it and it was full of some brown muck, like dirty water you'd find at a bog or something.
http://www.turbo-mopar.com/forums/sh...ure&highlight=
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Re: Fuel issues, stumbling misfiring, 320hp Omni
So I ended up buying a new fuel pump, a Walbro 255, from Cindy. I got it yesterday in the mail and installed it once I got off work. Got everything back together and took it for a spin. As soon as the boost climbs to 0, the car starts to buck and misfire. Letting off the gas and cruising it will run fine. So I was turning around about a mile from my house and then it just died on me. When I went to start it, it would start for a second and then die. It would do this over and over again. If I feathered the gas I could barely keep the engine running. On occasion, I could get the engine to rev past 1500 where it would still stumble. If I kept doing it and the engine would keep up, I could rev it to nearly 5500rpm. After I did that, the engine would idle just fine. But as soon as I start rolling the engine would die. Also, when I turn the key on, my radio flickers off and on and makes a clicking noise. I checked the battery for security and it's good. Had to tow it home again. What else could it be?? Its starting to activate me that every time im about to see my parents, it starts acting up, and my dad has never ridden in it since we made it street legal and I really want him to. I'm starting to think TPS or something like the auto shut down relay
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Battery Cables, terminals and Grounds.
I just fought a similar problem, my car died on me and it ended up being a broken wire to the HEP, but after fixing it I was experiencing similar problems (misfires under load, random cut out) but I did not want to believe it could be the cables because the car started fine and idled fine. Once I dug into it I found all my ground wires were very questionable and the terminals on the battery were actually cracked. One of the critical Grounds is the one to the fuel rail with out that the computer will go crazy.
I did brand new battery cables (not just a new terminal) and made a couple new grounds between the block and frame. Runs great now.
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Not going past vacuum sounds like MAP to me, but I'm not sure or it could be baro-read. I know when I disconnected my baro read solenoid without a cal for that, it would stumble just as you stated and not make boost at all. Codes or CEL? I didn't read the entire thread or post, so sorry if this was already stated.
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Re: Fuel issues, stumbling misfiring, 320hp Omni
I will check the engine grounds and battery cables when I get off work. Where is the ground for the fuel rail, is it connected to the firewall?
To minigts: it sometimes gets up to 3 or 4psi, but not before it starts misfiring and all that. Only codes I got were 12 and 55.
Another thing I forgot to mention, when I was driving it and it was about to die, the wideband read "- - -" on the guage and it just bogged down until it died and I coasted unto a stop. This was regular driving, no boost at all. Aside from grounds, what should I check for MAP and Baro wise? I'm running '87 electronics with a PM and LM
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Well I know bigbrudda and Cordes had issues with this, very similar. Bigbrudda had a bad or leaking baro solenoid, Cordes I don't think ever found out for sure. But obviously, check for vacuum leaks to the those solenoids, check voltage (at all and then record if you are getting some), disconnect both one at a time and see what changes if anything. Right now it's hard to know for sure, not there, but the cut out could be that or HEP or in Cordes' case, his alternator was failing intermittently (another cutout issue, so two for him). But his was that it would drive fine for a bit and then do it, so that doesn't sound like you. The low boost cut out SOUNDS like the baro solenoid problem, but maybe troubleshoot that area? Just some ideas, I really don't know how to solve others' problems, just mine. :D And even THAT'S not terribly accurate. haha
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Similar thing happened to me when I had my Spirit R/T, it was the O2 sensor wires that had melted on the turbo and was shorting out.
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Re: Fuel issues, stumbling misfiring, 320hp Omni
Quote:
Originally Posted by
rx2mazda
Similar thing happened to me when I had my Spirit R/T, it was the O2 sensor wires that had melted on the turbo and was shorting out.
http://i1.kym-cdn.com/entries/icons/.../skeptical.jpg
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Re: Fuel issues, stumbling misfiring, 320hp Omni
I recorded a video and am going to post it. This time around, my Power Loss light was illuminated and I got codes 13 and 55. Gimme a few minutes to get the video posted
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Re: Fuel issues, stumbling misfiring, 320hp Omni
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Re: Fuel issues, stumbling misfiring, 320hp Omni