OK well this is about my cousins 1989 rs t-top. this motor is from a 95 chevy 1500 4x4.well here the problems im facing. well he bought it about 2 months ago ran fine had a new fuel pump put in before he purchased it. well he went to start it about a 2 weeks ago and no fuel was spraying out of the injectors
so i figured it was the hose on the fuel pump drop the tank wasnt it. changed fuel filter had everything hooked back up and started and would die instantly. so today had him buy a TPS sensor and tried again did the same thing.. going to check fuel pressure tomarrow and check the relay and fuse next to the battery.


ANYBODY KNOW WHAT GOING ON, Any similar problems

 

Injectors have a specific fuse or fuses.

Oil pressure needs to be adequate as well. Maybe that switch needs to be looked at?

Auto Zone has a tester to borrow (a noid light) that confirms signal at injector.

 

check those there good, But i talked to an friend of my uncles and he said he had a jimmy that that so he got the rebuild kit a i ran just fine..
so next thing is probably hit the junk yards get another throttle body a see if that works.

Thanks for the reply

 

There are two primary reason why fuel would not spray from injectors:

1) Fuel pump is not delivering fuel. You can check this with a fuel pressure gauge during cranking - you should see 9 to 13 PSI in a stock setup.

2) ECM is not commanding injectors to spray fuel. You can check this with a NOID light or test light between ECM side of injector plugs (it should be blinking during cranking ) and ground. Make sure that hot side of injector circuit (red wire) has +12 volts during cranking! A bad ignition key cylinder may be the culprit. Do you know if this car has VATS key system??

//RF

 

Don't know but i don't think it has one.. it sprays fuel but when it statrs idels on the gas shot in the cylinder and dies.. i think it has a weak fuel pump.. ill check the fuel pressure and see if that that's it

 

So let me get this straight.

1) The engine will start
2) It idles on its own
3) The moment you give it a little bit of gas it dies?

You have not checked fuel pressure to rule out fuel pump
The CEL is not lit when engine is running

//RF

 

no it starts and runs on the gas shot in the cylinder when turning the ignition and starts then dies it only runs like a second... but i dosn't always shoot gas into the intake sometime i have to put starting fluid in the intake and once it start it will spray fuel but will still only run for a second...

So its
1) engine starts sometimes
2) dosn't spray fuel all the time when turning the ignition trying to start it
3) runs a second and will die
4) wont stay running unless you apply the pedal to get it to say running

could this be from having a wrong fuel filter or is it just a weak fuel pump?

Hopefully This gives you a idea of the prob i having.. Thanks

 

Ok..replaced fuel pump and its still doing it and check fuses,replaced fuel filter, injectors. i think i has to be the idle air control valve.. Its the only thing i haven't replaced..lol

would make Since somtimes is dosnt let gas spray.

Any other ideas guys

 

IAC has nothing with injectors not spraying - you are wasting money.

 

If you know anyone with another car or truck that is TBI, swap the distributor and try that. The sensor in the distributor is what is used to fire the injectors. I've seen a bad distributor cause the injectors to not fire.

 

There is no sensor in the distributor per se. The reluctor coil generates a zero crossing pulse signal when rotor shaft rotates. These pulses are converted and amplified by the ICM to control ignition coil and sent as distributor reference pulse (DRP) to ECM. Under 400 RPM ICM timing is not controlled by ECM. However, once ECM sees DRP signal it energizes fuel pump relay and begins to fire injectors. Once engine fires - up (>400 RPM) ECM begins to control timing advance.

Things that do go wrong sometimes:

1) Injectors are not firing, there is no fuel pressure, and there no spark
2) Injectors are not firing and there is no fuel pressure, and there is spark
3) Injectors are firing, but there NO is fuel pressure, and there is spark
4) Injectors are NOT firing and there is fuel pressure

Quick check list
1) ICM, reluctor coil are bad or there is no +12 volt at coil during cranking.
2) Check harness, and dizzy connector between dizzy and ECM, check EFI fuses, check 12 volts at injectors, verify that ECM is pulsing injectors, bad injector coils or injector harness.
3) Bad FP relay, or socket, bad FP relay coil driver circuit inside ECM. Verify that fuel pump is functional by applying +12V to terminal G of ALDL (if wired).
4) Check fuses, check harness, bad injector, bad injector driver circuit in ECM.

//RF

 

checked all these they all work....

 

how would i check this stuff if could give me an idea

 

so whats your fuel pressure at?? i think for 28 bucks you can get one on ebay with the schrader valve attachment. i bought one. i left the schrader valve attached to the inlet side of the fuel filter so i can check it periodically. its been about 8 months now no probs. 9-13psi and your good. my car went down to 1 after 10 minutes idling. so check that first

 

I haven't seen anybody rule out the VATS