I just wanted to say how much I've enjoyed this forum. All you guys seem to know your stuff about f-bodies. Most of the other forums is all about LS-1. Don't get me wrong, I like the engine, but I am a big fan of TPI. That leads me to my qustion. I have a '85 I-ROC that is runing lean, very lean. I spun a rod bearing almost two years ago. The car sat for 8 months before I rebuilt it back to stock. I have had this problem since January of this year. I have tried and talked to everyone I know. I can't find any vacum leaks. Every sensor is new. I have no emissions instaled on the car and it has a new fuel pump. The fuel pressure is also within specs. There is no evidence of a exhaust leak. The only thing I can think of is dirty injectors. Any suggestions would be very helpful.
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Do you mind if I ask how you know it's running lean (I know it sounds like I'm unsulting your intelligence, but I'm just curious)?
It sounds to me like an injector problem, too. I know there is a way to take the injectors out of the manifold, but still installed on the fuel rail and check for leaking injectors, but I'm not sure if you can check for dirty injectors, unless it's safe to start the car and watch the spray pattern, I'm unsure. You may want to try some fuel injector cleaner, sometimes it actually works. Have you checked your fuel pressure regulator at all? The diaphram (<spelling?) may have a tear or rip in it.
Sorry I'm not of much help, I'm a TBI guy
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1991 Chevy Camaro RS (Is it plum or purple?)
Engine: 305 TBI (L03)
Trans: TH700R4
Mods: Some
CarDomain Site -
Those manifold runners can be hard to seal to the heads & plenum. You could try some propane around the joints and see if the revs come up. Are you lean at idle, part throttle, or WOT ?Comment
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I know that it runs lean due to the fact that the check engine light comes on. Upon scanning it i find code 44, lean exhaust mixture. It runs lean at all rpm's, but the worst at idle. It aldo misses at WOT, but I dismiss that due to the leaning out. I have spraying carnb cleaner around runner tubes, but can't find a vacum leak. The fuel pressue is withen specs, so I assumed that the diaphram was ok. If the diaphram had a hole or tear would the fuel pressure still be withen spec? Please keep posting ideas, I do not think any of you are trying to dicredit my intelingence, I will take all ideas in stride!!!!!
Thanks for all of you ideas.Comment
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You cannot always go by codes. For example, if there is a leak in the exhaust prior to the oxygen sensor, the extra oxygen present will be interpreted as lean. Then the computer tries to add fuel to compensate and it ends up running rich even though the computer reads lean. Fouled injectors can make it run lean, bad PCV, fouled EGR, along with a host of internal leaks including perhaps a power master brake cylinder booster leak. Anthing hooked up to a vacuum source could be a factor.
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Originally posted by Joe 1320
Yes, what do the plugs look like?96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there
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I tried that once and almost blew myself up.Originally posted by Benm109, unless it's safe to start the car and watch the spray pattern, it.
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Biiiig Fireball! Im much more careful now.
96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there )
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Go outside and look where your o2 sensor is on 87 L98, the only place it could have a exhaust leak is the manifold to the head, and I have looked and listened, with no such leak found. I can also also diconect all of the vacum acseossies and reset the ecm and it it still runs lean. The plugs are fouled so I replaced them. And to my surprise it ran........ LEAN!!!!! It also has no EGR valve or any other emission part on the car. Could this maybe be the problem. Or is it time to save for some new injector. SLP sells LS1 injector take offs for 99 dollars. They are rated at 25 lbs. Do you think these are to big for stock 305?Comment
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