85 C4 Running really rich
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 39
Likes: 0
85 C4 Running really rich
My 1985 corvette is running really rich for some reason im not to sure why. Ive already replacted the ETS and CTS and that didnt work, cause im getting long cranking starts and smoke out the mufflers. and when i start it and walk to the rear of the car smells like straight fuel. Please help!!
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Check fuel pressure to be sure that you don't have leaking injectors.
Check O2 sensor. IF bad it could be sending more fuel than needed and running very rich.
You might try unplugging the 9th injector. If that is bad it could also be pumping in additional fuel.
Have you checked the plugs to see if they are wet from fuel?
Spark to all cylinders?
Check O2 sensor. IF bad it could be sending more fuel than needed and running very rich.
You might try unplugging the 9th injector. If that is bad it could also be pumping in additional fuel.
Have you checked the plugs to see if they are wet from fuel?
Spark to all cylinders?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Which CTS did you replace? The one on the front of the intake manifold under the throttle body is the one used by the ECM. If the ECM thinks the engine is cold it will richen the mixture.
Did you check for error codes?
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Did you check for error codes?
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 39
Likes: 0
Which CTS did you replace? The one on the front of the intake manifold under the throttle body is the one used by the ECM. If the ECM thinks the engine is cold it will richen the mixture.
Did you check for error codes?
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Did you check for error codes?
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 39
Likes: 0
Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 276
From: Melbourne, Victoria, Australia
My 1985 corvette is running really rich for some reason im not to sure why. Ive already replacted the ETS and CTS and that didnt work, cause im getting long cranking starts and smoke out the mufflers. and when i start it and walk to the rear of the car smells like straight fuel. Please help!!
If the TPS voltage is good you will need to check the injectors if they are leaking, the normal fuel pressure on an 85 is 30psi.
You can do a leak down test on the injectors, disconnect the injector wiring connectors.
Fit a fuel pressure gauge and turn ignition on, connect 12 volts to one side of the injector and a ground to the other for just a few seconds and note the pressure drop over time.
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Thread Starter
Intermediate
Joined: Jan 2013
Posts: 39
Likes: 0
hooked a fuel pressure gauge up to it today. I turned the key on with out starting it, it went to 40 PSI and i left the key on and within 20 seconds it dropped to 0 PSI. So now i know i have a leaky injector somewhere but what one? Is there a way i can test the injectors to find out what one it is? if so how do I do so? with the car running im getting 35 PSI at idle.
Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 276
From: Melbourne, Victoria, Australia
hooked a fuel pressure gauge up to it today. I turned the key on with out starting it, it went to 40 PSI and i left the key on and within 20 seconds it dropped to 0 PSI. So now i know i have a leaky injector somewhere but what one? Is there a way i can test the injectors to find out what one it is? if so how do I do so? with the car running im getting 35 PSI at idle.
The cold start injector is between cyl 3 and 5 on the TPI inlet low down on the manifold
You can get the injectors tested also.
Good luck
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
hooked a fuel pressure gauge up to it today. I turned the key on with out starting it, it went to 40 PSI and i left the key on and within 20 seconds it dropped to 0 PSI. So now i know i have a leaky injector somewhere but what one? Is there a way i can test the injectors to find out what one it is? if so how do I do so? with the car running im getting 35 PSI at idle.
I'd say you need to crimp off the return line and see if the pressure holds.
Either way, I'd dump the old injectors and get FIC to sell you a good set.