Fuel delivery problems
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Fuel delivery problems
My 87' corvette is having some fuel delivery problems. When I start the car the idle is rough and It will not take the gas when reved. I have posted this problem before up here in the tech and performance forum. I was given some great advice. Thanks too everybody who tried to help me out, but as you can see the problem is still at large. After many hours of trouble shooting the problem i think I've found my problem. I disconnected two of my injectors and the problem seemed to gotten better. I could rev the car up and the idle smooth out, with a slight miss of couse. The only thing is, when I reconnect the pig tails on thoose two injectors and disconnect two other pig tails the car run fine again. My question is, are the fuel injectors the cause of my problem or is it the fuel regulator. All I know the car run like it has a dominator on top when I'm trying to idle it. Is it possible that all my injectors are leaking fuel at idle, causing a super rich condition? Thank you for any input you my have in advance.
purplehayes
purplehayes
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From: Citrus Heights California
My 87' corvette is having some fuel delivery problems. When I start the car the idle is rough and It will not take the gas when reved. I have posted this problem before up here in the tech and performance forum. I was given some great advice. Thanks too everybody who tried to help me out, but as you can see the problem is still at large. After many hours of trouble shooting the problem i think I've found my problem. I disconnected two of my injectors and the problem seemed to gotten better. I could rev the car up and the idle smooth out, with a slight miss of couse. The only thing is, when I reconnect the pig tails on thoose two injectors and disconnect two other pig tails the car run fine again. My question is, are the fuel injectors the cause of my problem or is it the fuel regulator. All I know the car run like it has a dominator on top when I'm trying to idle it. Is it possible that all my injectors are leaking fuel at idle, causing a super rich condition? Thank you for any input you my have in advance.
purplehayes
purplehayes
You should also rebuild your fuel pressure regulator at the same time.
Last edited by Kool88vette; Jul 4, 2008 at 02:11 PM.
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"TPIS mini ram. this intake does not have the cold start injector application. The fuel pressure at idle is 43lbs and it will hold that pressure for 10 to 15 mins after shut down. The drop fairly slow".
purplehayes
I would recommend futher fuel pressure checks to Isolate the drop.. Could be Injectors, reg or fuel pump at this point. The cold start injector is already out, so that is not a concern
Melting Slicks
Joined: Jan 2008
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From: Jasper Texas
To the OP, how fast of a pressure drop are we talking about here? My faulty injectors were causing me to go from 38psi to 0psi in 21 minutes.
Are your fuel injectors still stock? If not, what kind are they?
Here's a guide to tracking fuel problems coutesy of Agent 86:
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
There are some slight differences in the guide compared to performing the test on a mini ram, but they are easy to figure out.
Here's a link to my thread that may help:
http://forums.corvetteforum.com/show....php?t=2059679
Are your fuel injectors still stock? If not, what kind are they?
Here's a guide to tracking fuel problems coutesy of Agent 86:
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
There are some slight differences in the guide compared to performing the test on a mini ram, but they are easy to figure out.
Here's a link to my thread that may help:
http://forums.corvetteforum.com/show....php?t=2059679
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My fuel pressure is fine I think. One of the guys at tpis told me how to check my regulator. He informed me to pull the vacum line off while the car is running, you should see a change in your fuel pressure reading. I done the test and the f/p reading did change. He said that would rule out faulty regulator. I did notice something about my injectors, the pigtail connectors are hot on both sides. I has always assumed that one wire was a hot wire and the other was a ground. It seems strange to me that both wire are read hot when tested.
My next question, my mass air flow meter has no power going to the plug when the switch is on. Out five wire going to the plug I would think at least on of them would be hot. Do anybody know more on this.
My next question, my mass air flow meter has no power going to the plug when the switch is on. Out five wire going to the plug I would think at least on of them would be hot. Do anybody know more on this.
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Are pairs of batch fired injectors wired in series?
Melting Slicks
Joined: Jan 2008
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From: Jasper Texas
purplehayes, out of curiosity, did you find out a price for a fuel pressure regulator from tpis that fits the mini ram? I'd like to replace mine after I do the injectors as a precautionary measure.
Le Mans Master
Joined: Sep 2006
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From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
fuel
I have taken a harness apart, and checked it out with the wiring diagram. The injectors are hot, fused through the ignition switch, and grounded at the computer.
You can go here http:http://www.cis.udel.edu/davis/z28/EC...165v8tpi-2.jpg
alter the 2.jpg to 3.jpg or 4.jpg etc. to get all the pages. This is the 86 corvette injection sytem, but is applicable to 87-88 as well.
I think it was a college student's term paper or something. I forget how I got it. anyway, print all the pages, It looks like the GM diagrams.
It even gives the computer pinouts. The wire colors may not in every instance match your car, but it's the real deal.
Chris
You can go here http:http://www.cis.udel.edu/davis/z28/EC...165v8tpi-2.jpg
alter the 2.jpg to 3.jpg or 4.jpg etc. to get all the pages. This is the 86 corvette injection sytem, but is applicable to 87-88 as well.
I think it was a college student's term paper or something. I forget how I got it. anyway, print all the pages, It looks like the GM diagrams.
It even gives the computer pinouts. The wire colors may not in every instance match your car, but it's the real deal.
Chris
Last edited by coupeguy2001; Jul 5, 2008 at 06:13 PM.
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Tpis f/p regulator cost around 150.00. Guys I found my problem. I was having a grounding issue, but the problem was coming from my alternator. When I disconnected the ground cable on the battery and check the ground teminal of the battrey with a test light, the test read hot on the gound side!! So I unplugged the alternator and cranked the car. The car ranned great while the alternator was unplugged, but as soon as I replugged up the alternator the car start running like crap again. I replace the alernator and now all my troubles are gone!! Thanks again guys from all your help and inputs.
purplehayes
purplehayes