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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Fri Feb 17, 2012 8:03 am Post subject: Fueling issues |
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I've been battling an extreme rich cold start-up. Only happens when the car is first started after sitting for 8 or so more hours. Pegs my wideband at 10:1 and slowly climbs to about 13.5ish:1 until it reaches closed loop then jumps to 14.7-15:1 and stays there. I plugged in the laptop and all of the sensors were still reading what they normally do. I was thinking it might be bad injectors
Now on top of the rich cold start, it runs lean closed loop. Jumping around 15-16:1 hovering mostly around 15.6:1. I hadn't made any changes to the car or tune around the time this started happening. I haven't had a chance to look at the data yet but this seems like the o2 sensor might be dirty/shot skewing the feedback to the ecm. Anybody run into this? I haven't had any issues like this yet. |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Fri Feb 17, 2012 7:24 pm Post subject: |
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So I put most of a can of seafoam in the fuel and I'll run the last little bit down the intake tomorrow. I also got some MAF cleaner and I went ahead and bought an oxygen sensor since I don't know how old it is. Hopefully it all makes a difference. |
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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Fri Feb 17, 2012 7:29 pm Post subject: |
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I'm confused, when its warmed up, is it lean or is it stoich? You said both. How are you verifying the AFR, it could be that your sensor isn't warmed up when first start the car?
If you are scanning it, what is the BLM reading, is it making large adjustments to the fueling, or just minor ones? |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Fri Feb 17, 2012 7:34 pm Post subject: |
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It's currently super rich cold, and 15.5-16:1 lean warmed up. I haven't yet scanned it I have to find my aldl cable. The only indication I have is some hesitation on cruising and part throttle acceleration and consistent lean readings on my WB o2 gauge, I think it uses a bosch sensor. |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Sat Feb 18, 2012 6:44 pm Post subject: |
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Got the sensor installed. I can't tell if it made any improvement because the threads came out with the old one. I had to unplug the WB sensor and move it there for now. Now the ignition coil is sparking over to itself, hopefully some dielectric grease will fix that. I also found a fairly long list of things about the Firebird that piss me off. Hopefully I'll be able to get something else to drive after I start work. If I don't this car is going to be melted down and made into pots and pans. |
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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Sat Feb 18, 2012 7:37 pm Post subject: |
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If you are misfiring a cyl, it will read leaner than normal on your o2 sensor. If you spark is not solid, that might account for the lean closed loop readings. |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Sat Feb 18, 2012 7:54 pm Post subject: |
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I hope so. I need to have a new bung welded on as I am still using a single wire sensor and it's further downstream than I'd like. Tomorrow I'll mess with it. I found the aldl cable so I'll see what the computer is up to. If it was arcing before it got worse, because it now kills the engine about once every 30 seconds. Was an interesting ride home from the garage today.
I found out the reason I've been losing oil is the trick flow heads I got are longer than my valve covers are so they are making metal to metal contact, not allowing the gasket to seal.
Also, my driver side axle isn't being retained properly. I had to make spacers to make up for the difference in thickness on the ls1 brakes. It looks like I need to make a thicker spacer. |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Sat Feb 18, 2012 9:24 pm Post subject: |
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Well I got anxious and got some dielectric grease and put it on, and then I found an embarrassing mistake I made while putting the 700r4 in. The car runs much better. If I had the WB o2 in I'm sure the stupid mistake I fixed will have the AFR back to normal. It isn't surging at idle anymore like it pretty much always had been since getting this engine so it appears the cleaning and new sensor did help.
I don't know if my start-ups are still ridiculously rich but at least it drives pretty normal.
Now I need to fix the rear axle. |
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Alphius Peanut
Joined: 05 Sep 2006 Posts: 2429 Location: Grand Mound
1984 Chevrolet Camaro Z/28
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Posted: Sat Feb 18, 2012 10:28 pm Post subject: |
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Come on man, you gotta tell us the embarrassing fix. _________________ 84 Camaro Z28 - LS1/T56
85 Silverado - Low and Slow |
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chevymad Master B
Joined: 11 Jan 2004 Posts: 5474
1987 Pontiac Formula
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Posted: Sat Feb 18, 2012 10:41 pm Post subject: |
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Spark snapping at the coil.. plug wire in wrong place or not connected.. |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Sat Feb 18, 2012 11:41 pm Post subject: |
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chevymad wrote: | Spark snapping at the coil.. plug wire in wrong place or not connected.. |
Bingo
One of the driver's side plug wires was off the dizzy from then I rerouted them to snake the TV cable underneath. I stupidly put the distributor cover back on the plenum without reattaching it. I forgot I even had it off. So when that cyl came around the spark had nowhere to go and was arcing off the coil. I made a real f**k out of myself with this one. |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Sat Feb 18, 2012 11:43 pm Post subject: |
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Thanks to Dewey for leading me to it. Who knows how long I would have overlooked the obvious. |
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Alphius Peanut
Joined: 05 Sep 2006 Posts: 2429 Location: Grand Mound
1984 Chevrolet Camaro Z/28
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Posted: Sun Feb 19, 2012 12:28 am Post subject: |
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It happens to all of us. Good find. I'm glad it's running better now. _________________ 84 Camaro Z28 - LS1/T56
85 Silverado - Low and Slow |
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Leejo2005 Member
Joined: 12 Jul 2009 Posts: 466 Location: Kennewick
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Posted: Sun Feb 19, 2012 12:55 am Post subject: |
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I'll be much happier when this isn't my driver anymore so I can get some stuff done. The drivetrain is more or less pretty good but the car feels too cobbled together. I've had to add in wiring so it seems like I have 6 wiring harnesses on top of each other...because I do. My expensive valve covers don't fit my expensive heads so they leak oil on everything. The trans cooling lines are flex lines. They are installed well but I still don't like it. The headers bang on the frame due to their...crappiness, and probably the crappy motor mounts. Exhaust is 2 different sizes...I could go on. The car is going to be 30 years old next year. I cannot really rationalize spending the time or money to fix all those things but I'm sure I will anyways because I'm irrational.
*Edited to include leaking valve covers. Not because it is important to know, but because it really pisses me off. |
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RSFreak The other "John"
Joined: 23 Jan 2004 Posts: 2946 Location: Renton
1989 Chevrolet Camaro RS
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Posted: Wed Feb 22, 2012 9:26 am Post subject: |
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Don't feel bad, I ran on the dyno with only seven wires last year. _________________ '86 Trans Am - 5.0L TPI - LT1 cam - 700R4 - WS6
'85 Camaro Berlinetta - IROC clone
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