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i have a 1998 s-10 blazer my question is how do i know if the fuel pump is bad or some thing else i started having problems starting it especialy when cold then nothing i replaced the pressure regulator witch was a job since i had to remove the t-b cover ( oh its a csefi system)now i just got a pressure gague and when i first turn on the pressure goes to about 42psi as the pump wines then i here the relay click and the pressure drops to 0 as i turn off the key it again will go up to 35pai and then drop to 0 since i dont have the ideal location to drop a gas tank and the shop wants $700-850 to put one in i want to see if there is anything else i should check thank you for your support
bob
p.s. sensors previousally replaced t-p /crank/pressure regulator/map / maf (wow)
Answer -
Hi Bob,
Sounds like your pump is working correctly. It should, however, stay at the 35 to 45 PSI reading if you are cranking the engine over, or if it is running.
But as soon as the engine quits rotating, it will shut the fuel pump off.
If your pump doesn't continue running, it could be the crank sensor, which signals the ECM that the engine is probably running, and keeps the fuel pump relay engaged.
The crank sensor also effects the injector control.
Have you checked for power to the injectors, and then check por pulses at the injectors while cranking.
You may need to get a "noid" light.
But I wouldn't be dropping the tank according to what you tell me. I would look for spark, and injector operating.
Van
van;
should it hold somekind of pressure this buggy does not start and i thought the pressure was supposed to go to 60 psi and hold somewhere in the same location
thanks again bob
AnswerYou are right, Bob,
The pressure is supposed to be higher. 55 to 64 my book shows.
I must apologize, I didn't look it up last night.
To the best of my knowledge, all the systems drain off the pressure, but this is a system I have no experience with.
Before dropping the tank, I think I would find the return hose, and block it, either by squeezing or unhooking and plugging, and just see what the pump will put out.
Better yet, block it off before it gets to the manifold, in case there is a leak inside there that you can't see.
If the pump can't produce the correct pressure, there is no way it will run. But you do need to make sure the gas isn't just passing through unrestricted.
You would sure hate to go to the effort to replace the pump, only to find the new one act the same way.
Wish I knew more about that system, and sorry for the sorry answer.
Here is a link to a GM forum where you can get answers from other people, some of them service managers, some mechanics.
www.chevytalk.org/
You will need to sign up, and log in, but it is totally free, and you will love the place.
Van
