fuel pump relay
 

Hey all,
I have a 96 chevy s10 4.3 with about 75k, I am not sure what the problem is but this is what is going on!!

1) When I am driving down the road minding my own business, the fuel pump relay will click (sometimes once sometimes it will sound like a machine gun it clicks so much) after the click(s) the break light and the antilock break light will light after this occures the idle will stay around 1500 rpm in drive, and around 2k in netural/park, (I can power break in my driveway with out pushing the gas). When this happens (most of the time) if I shut it of, count to 10 and restart it will run fine and other times I am not so lucky.

2) On occation I will try to start the truck and it will rev up to about 1000 rpm and shut right off, I have noticed that if I play with the acclerator I can keep it running but it runs very rough, and I have also noticed that the exaust will have a brownish tint to it (ya know when there is a car infront of you and they put the petal to the metal to pass someone and you see that brownish exaust.) It will usually take me a couple times starting and shutting off to get it to run right.

I have been serching for about 8 months now and I am having no luck, also it has been in several garages and they either cannot get it to do it or if it dose it they are not sure what is going on.

Thanks in advance!!!

RE: fuel pump relay
 

You may have an electrical issue.

RE: fuel pump relay
 

Do you think it would be worth attempting to fix, or should I just push the truck into the lake, lmao. If so where do you think I should start? I am an ok back yard mechanic, however electrical is not my forte. I have replaced/checked most of the sensors and the egr. I am guessing that it would be between the Ignition and the fuel pump relay?? computer?? What do you think?
Thank you

RE: fuel pump relay
 

The reason I say it's electrical the brake and ABS lights come on also the relay is chattering when the problem shows up which almost sounds like something is glitching the computer...it's going to be a process trying to find the culprit.

You might try the wiring under the hood first. Check all the ground points for good clean secure contact ... especially the engine ones. Then check all the connectors for loose or corroded connections and make your way back to the ECU.

With the engine running try flexing the wiring harnesses to see if you can also duplicate the problem.

Good luck.

RE: fuel pump relay
 

I have tried many times to flex the harnesses while the engine is running and have had no luck duplicating the problem. I have done this with all the wires under the hood, and I have had the drivers side dash half way apart to do the same.
One of the guys at one of the garages that I have been to said "if the dash lights come on, that is caused by the ignition". I have had the truck running and flexed the ignition wires under the stearing columb and this did not cause any disturbance.
Is it possiable for a sensor to malfunction without throwing a code?? I have been thinking that possiably my MAP sensor may be causing the rich startups, When I tested the voltage it was correct, but it was not acting up at the time. I am wondering if it may be a little sticky inside and not working properly???

Thanks again!!

RE: fuel pump relay
 

The coolant temp sensor would also contribute to rich running fuel mix.

btw... do all the dash lights come on or just the ones mentioned ??

RE: fuel pump relay
 

I have replaced the coolant temp sensor already.

There may be one or two more lights that come on, but not all dash lights come on.

Thanks

RE: fuel pump relay
 

Are the battery and alternator connections solid and clean ?

RE: fuel pump relay
 

Yup, battery connections are clean, and I put a new alternator in it.

RE: fuel pump relay
 

I failed to mention......Im not sure if this might help pinpoint the issues any better or not but over the winter we had a cold (in the teens)February/March and it ran fine, once it started to warm up a little (above freezing) I noticed it starting to act up once in a while. Now that summer is here it has its good days and its bad days!!

Thanks