87 that running extremely rich
Thread Starter
5th Gear
Joined: Jul 2021
Posts: 5
Likes: 0
87 that running extremely rich
All right I'm at my wit's end with my 1987 Corvette 5.7 TPI. It is running extremely rich heavy black soot smoke is on my back bumper strong smell that burns your eyes. The car is running extremely rich somewhere I changed all the injectors it has a new idle air control valve a new throttle position sensor new plugs new fuel injectors new EGR valve I've reset the computer several times by unplugging it and letting it set for a while and then plugging it back in. When I do that the car will run at a slightly high idle but I will still have a richness in the exhaust and then after about 5 minutes of running the idle goes down and the car starts bogging down loss of power smoke coming out the exhaust tips so strong that it burns your eyes. I thought I had bad injectors because when I put my finger on the driver side Bank I can fill to the injectors clicking two others weren't so I changed all the injectors brand new and the same position injectors I'm still having a week pulse to the injector I did put a pulse light on it and I do have a light that will flash but it's not as bright and strong as the others. The next thing I'm thinking is to change the ECM and prom will that cause my car to be doing what it's doing I don't know what else to do I need help.
Thread Starter
5th Gear
Joined: Jul 2021
Posts: 5
Likes: 0
All right I'm at my wit's end with my 1987 Corvette 5.7 TPI. It is running extremely rich heavy black soot smoke is on my back bumper strong smell that burns your eyes. The car is running extremely rich somewhere I changed all the injectors it has a new idle air control valve a new throttle position sensor new plugs new fuel injectors new EGR valve I've reset the computer several times by unplugging it and letting it set for a while and then plugging it back in. When I do that the car will run at a slightly high idle but I will still have a richness in the exhaust and then after about 5 minutes of running the idle goes down and the car starts bogging down loss of power smoke coming out the exhaust tips so strong that it burns your eyes. I thought I had bad injectors because when I put my finger on the driver side Bank I can fill to the injectors clicking two others weren't so I changed all the injectors brand new and the same position injectors I'm still having a week pulse to the injector I did put a pulse light on it and I do have a light that will flash but it's not as bright and strong as the others. The next thing I'm thinking is to change the ECM and prom will that cause my car to be doing what it's doing I don't know what else to do I need help.
Drifting
Joined: Aug 2019
Posts: 1,339
Likes: 225
Have you hooked up a scan tool to monitor sensor input? Have to done a fuel pressure check to make sure the injectors are not leaking?
You really need to get a scan tool to see what the computer is doing. The 87 also uses a cold start injector. If it's leaking ,or not shutting off that's another source of unwanted fuel.
You really need to get a scan tool to see what the computer is doing. The 87 also uses a cold start injector. If it's leaking ,or not shutting off that's another source of unwanted fuel.
Thread Starter
5th Gear
Joined: Jul 2021
Posts: 5
Likes: 0
Have you hooked up a scan tool to monitor sensor input? Have to done a fuel pressure check to make sure the injectors are not leaking?
You really need to get a scan tool to see what the computer is doing. The 87 also uses a cold start injector. If it's leaking ,or not shutting off that's another source of unwanted fuel.
You really need to get a scan tool to see what the computer is doing. The 87 also uses a cold start injector. If it's leaking ,or not shutting off that's another source of unwanted fuel.
4th Gear
Joined: Jun 2020
Posts: 4
Likes: 1
From: Sussex, WI
87 that running extremely rich
I had the exact same problem with my '88. Didn't matter if it was cold (open loop) or warmed up (closed loop).
Eventually it threw a light for running rich (duh). Checked everything but the ECM. Finally gave up and sold it.
Looking back it probably was the ECM.
Eventually it threw a light for running rich (duh). Checked everything but the ECM. Finally gave up and sold it.
Looking back it probably was the ECM.
Drifting
Joined: Aug 2019
Posts: 1,339
Likes: 225
With all due respect to your mechanic. there's not many things that affect air/fuel ratio that would not stand out on a scan tool. I don't want to get into a fuel delivery class, cause I'm not sure of your experience, but before you shell out any more money, I would get someone who knows how to read a scan tool. Heck. you can even post a snap shot of the data, and we can pick it apart.
Thread Starter
5th Gear
Joined: Jul 2021
Posts: 5
Likes: 0
With all due respect to your mechanic. there's not many things that affect air/fuel ratio that would not stand out on a scan tool. I don't want to get into a fuel delivery class, cause I'm not sure of your experience, but before you shell out any more money, I would get someone who knows how to read a scan tool. Heck. you can even post a snap shot of the data, and we can pick it apart.
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Pro
Joined: Feb 2009
Posts: 655
Likes: 164
From: Vancouver Washington
Ohm your coolant temp sensor. The one in front of the intake manifold that goes to the computer.
A scanner is a wonderful tool when T/S computer regulated cars. Very difficult to find your issue otherwise.
You mentioned changing quite a few parts but not the fuel pressure regulator. Do you have fuel in the vacuum hose running from the fuel pressure regulator?
What about fuel pressure? Maybe your return line is clogged.
And, as mentioned earlier...the ninth injector could be at fault. Cap it, not really needed unless you are in the great white north.
A scanner is a wonderful tool when T/S computer regulated cars. Very difficult to find your issue otherwise.
You mentioned changing quite a few parts but not the fuel pressure regulator. Do you have fuel in the vacuum hose running from the fuel pressure regulator?
What about fuel pressure? Maybe your return line is clogged.
And, as mentioned earlier...the ninth injector could be at fault. Cap it, not really needed unless you are in the great white north.
Thread Starter
5th Gear
Joined: Jul 2021
Posts: 5
Likes: 0
Ohm your coolant temp sensor. The one in front of the intake manifold that goes to the computer.
A scanner is a wonderful tool when T/S computer regulated cars. Very difficult to find your issue otherwise.
You mentioned changing quite a few parts but not the fuel pressure regulator. Do you have fuel in the vacuum hose running from the fuel pressure regulator?
What about fuel pressure? Maybe your return line is clogged.
And, as mentioned earlier...the ninth injector could be at fault. Cap it, not really needed unless you are in the great white north.
A scanner is a wonderful tool when T/S computer regulated cars. Very difficult to find your issue otherwise.
You mentioned changing quite a few parts but not the fuel pressure regulator. Do you have fuel in the vacuum hose running from the fuel pressure regulator?
What about fuel pressure? Maybe your return line is clogged.
And, as mentioned earlier...the ninth injector could be at fault. Cap it, not really needed unless you are in the great white north.
Oil Producer
Joined: Apr 2014
Posts: 9,372
Likes: 2,736
Like I said before all four injectors seem to be pulsing very good on the passenger Bank but on the driver side Bank to the injectors are ticking very lightly not like the other two and that is the same problem that I had with the original injectors in the same exact position and plug into the exact same pigtails for the injectors why would two of them be working fine in the other two when I listen to them through a stethoscope it's a very light ticking
I had an injector harness plug with one pin backed out and the inj was not firing. they get pulled out when bubba pulls on the wires to remove them from the injectors. carefullyinspect for damage to the pin connection or wires under the boot.
your O2 is on the driverside. If you have an injector not firing, it will see a lean condition and add fuel to both banks to compensate, resulting in a rich condition.
If you suspect maf, unplug it and start the engine. the car will run without it, and should run different (better) than if it was under the influence of a pooched maf.
Last edited by VikingTrad3r; Jul 14, 2021 at 02:05 PM.