My fuel pump isnt pumping...Car wont start without spraying starter fluid in the plenum, once it does start it dies (once the starter fluid is burned), got no gas going through the fuel pipes to the injector rails and no priming sound from the pump (plenty of gas in the take by the way)

I hooked ALCL terminal G up to 12V+ and the pump turns on, so that works....So i was guessing the pump relay, I switched the pump relay with the MAF relay next to it, still no pump. I suppose it may still be the relay but....Would my car have been running at all if the MAF relay was bad??? Unless they're BOTH bad, i dont know because i switched them and still no pump.

I checked all the fusible links i can find, all are good. Any advice on what to check here? What voltage does the pump run off of? Can i just jump the orange E terminal to the brown A terminal on the relay, and see if the pump kicks on? If it did, then it'd have to be a bad relay i guess...

When you put 12 V to terminal G on the ALCL does it run straight to the pump through the relay, or is the relay bridging when it gets the voltage? May the relay isnt getting power from the battery, although i cant imagine why not, i test continuity....

 

Have you checked the 20 amp fuse that goes from the fuel pump relay to the ecm to see if it has blown. This will keep the fuel pump from operating if it is bad.

The Trickster!!!!!!!!!!!!!

 

errr....20 amp fuse between the relay and the ECM??? Your not talking about the FP fuse in the normal fuse panel are ya? Or the 20 amp fuse right near the battery in the front? I checked both of those as well as another fusible link i saw and they're fine.

 

i was thinking the same thing...its a 20 amp fuse that is the fuse for your pump...you remove this to cause your pump to turn off so you can burn all the fuel out of the lines when you do a fuel filter change.....

 

On re-reading your post, you mentioned switching the maf relay with the fuel pump relay. What you possibly did was switch the maf relay with the maf burn-off relay. The fuel pump relay connector is totally different than the maf relay connector, at least on my car which is an 1989 Iroc with the 350 tpi engine.

The Trickster!!!!!!!!!!!!!!!!!

 

*sob*
Allright you were right about the wrong relay...I got the right relay now, and went out and bought a new one. Problem is still no pump

I run 12V to terminal G, pump kicks on....Also, if i bridge A and E on the relay the pump kicks on as well, Sooooo... i'm getting 12V power to the relay, the wire to the pump is in tact, the pump works. Yet, when i turn the key "on" i get no priming, and the car wont start because it's getting no fuel....

So far as i can tell, it gets power from either the ECM directly, the ECM through the relay, or the oil pressure switch. I tested the relay coil wires for continuity to the ECM connector and i test OK. I have a solid ground on the relay as well. All fuses are A-Ok.

This sucks....I'm starting to think my ECM is bad. Everything else checks out OK. BTW i noticed now that with my key "on" my SES light does not come on, and in test mode theres no flashing....I'm gonna see if i can figgure out whats wrong with the SES..Then i'm gonna hotwire the fuel pump and try to start the car like that. Once it's running, my oil pressure switch should keep the pump on, right? So it'll keep running even if the ECM isnt sending the signal? .....On a side note, does the pump have any sensors for pressure or anything? I know i probably need a new fuel filter....But right now i dont really care unless it's going to help me get this thing started. Would a really really really clogged fuel filter (or something else) be seen by the ECM so that the computer doesnt turn the pump on by itself?

 

Oh good lord my car is screwed up. I dunno to be happy or just plain scared.....

I was gonna change the SES light to see if the bulb was burnt out. I was about to take the faceplate off and i turn the key "on" one more time to make sure i'm grabbing the right lights (planned on pulling the bulb out of the "brake" or something) and what do you know? SES light comes ON AND i hear my fuel pump prime. WTF? Ok....turn the key......cranks, fires right up. Car is running.....I didnt do anything......

Heh well...I guess this is good....Maybe if i cant find the problem it just wont come back.....

 

Ok Big j,

well heck, here I spend all this time typing my poor little fingers to the bone and getting eyestrain trying to see what I'm typing and while I'm doing this , you post that your problem is solved. Now if that isn't gratitude for you. (just kidding BIGJ, glad to see that you're up and running again. it probably was the fuel pump relay.)

Kindly disregard the information posted below unless you need it for future reference.

Try this, disconnect your battery and use a multimeter to check the continuity of these wires.

1. pin A of the fuel pump relay connector (tan/white) to pin B2 of ecm connector (fuel pump control).

2. pin B of fuel pump relay connector (black/white) to engine ground.

3. pin C of fuel pump relay connector (dk green/white) to pin A1 & then pin C1 of ecm connector(fuel pump relay and fan control output)

4. pin D of fuel pump relay connector (red/black) to pin G of ALDL.

5. pin E of fuel pump relay (orange) to pin B1, then pin C2, and then pin C16 of the ecmconnector. (battery, air diverter valve, and battery)

If you have good continuity in all these wires, then it is back to the drawing board. But now at least you know that the fuel pump is not bad.

The Trickster!!!!!!!!!!!!!

 

Try moving your steering column up and down, try starting the car with it fully up and with it fully down.
Since you were going to pull the instrument face plate/lens, you probably pulled your tilt wheel all the way down (assuming you have tilt) to get the face plate out. You may have some flakey wiring under dash or on the column that you moved and got to make contact.

 

Thank the maker this has happened to someone else, but please tell me this isn't the whole story!! My car coughed up the EXACT SAME thing yesterday. I just got her all back together and running and the 1st time on the road THIS happens. No joy from the fuel pump and no SES lite. Was there anymore found to this?? Where exactly is this relay to ECM fuse?? I hear a click from relay central (driver's side firewall) when I turn the key but that means nothing of course. Chilton's & I are about to have a session so's I can try the suggestions above. Making sure I don't make a(nother) dumb assumption - in the checks listed above - that IS talking about THE emc connector INSIDE the car, correct?? Gonna need some loooong leads 4 that! Anyone else have this happen??

 

Since no one else has said to check your oil pressure sending unit you might check that. The fuel pump will not work if it is bad.

 

I'm sorry armac, but I will have to disagree with you on your post. The oil pressure sending unit, in addition to operating the oil pressure indicator in the instrument panel, acts as a backup to the fuel pump relay only if the ECM receives a code 54 (fuel pump relay failure), it will then turn the fuel pump on when oil pressure reaches 4 psi. The fuel pump will work regardless of whether the oil pressure switch works or not as long as the fuel pump relay works.

The Trickster!!!!!!!!!!!!!!

 

Neither is correct, the oil pressure SWITCH is the "back up" for the relay, sending unit merely sends a signal to the guage.

 

Morley, If you go back and check your manual, you will find that the oil pressure switch serves two purposes.

1. to act as a sending unit to the oil pressure gage in the instrument panel and 2. to act as a back-up to the fuel pump relay in the event that the ECM gets a code 54 (fuel pump relay failure).

Please go back and re-read my post and you will see that what you are saying is the same thing that I posted with exception of your stating that the oil pressure switch and sending unit are two completely different units.

The Trickster!!!!!!!!!!!

 

And they are.

 

Switch

 

Sender. Just above and to the left of the sender (large "bell" shaped object) is also the oil switch.

 

Okay Morley,

I'll compromise with you, we are both right in a way. On the 2.8l engines, they had two units mounted one above the other. one was the oil pressure sensor and the other was the fuel pump/oil pressure switch. On the 5.0l and the 5.7l engines, there was only one unit and it was the fuel pump/oil pressure switch. this unit served the dual purpose of oil pressure sensor and fuel pump/oil pressure switch. Okay!

The Trickster!!!!!!!!!!!!!

 

No, actually the V8's also had/have 2 seperate components, a switch and a sender. That is how my car was/is set up, a "log" with a threaded fitting going into the block back by the dist, a switch threaded into it sitting vertically and a sender threaded into it at about a 45* angle.

 

In my previous post, I should have mentioned that it depended upon the year and model car. There was a rather interesting (and heated at one point) post last month I believe, where someone had gone to a parts store to get a unit for his car and they sold him the wrong one. but, anyway, mine is a 1989 Iroc with the 5.7l and it only has the one unit. The 2.8l have the two units similar to yours but the design has changed a little. I don't know what year they decided to go with just one unit instead of two. However, this is how my car is and that's how it is in my GM service manual. So can we agree that we are both right in a sense. The earlier models had two units and the older models had just one unit in their 5.0 and 5.7l engines.
Truce!!!!!!!!!!!!!

The Trickster!!!!!!!!

 

Ok, so my 89 rs 305 holly carb, wont start. when I turn the key it clicks and trys to start the engine, but it does not run... What does it sound like when the fuel pump primes, and where is the fuel pump located???.... Also there was a fuse mentioned, a 20amp fuse.. Where is this fuse located?? I was thinking that it might be the distributor, or the coil, or perhaps the module. HELP ASAP???? Does anyone have any Ideas at all???

 

When the fuel pump primes, you will hear a faint humming noise for about two seconds. If your car cranks and tries to run, it is not a problem with the 20 amp fuse. Are you getting spark to your plugs? If no spark, I would check the ignition module and the coil.

The Trickster

 

is there anything else that might cause the car not to start, like a clog in the fuel lines, clogged up fuel filter, and whats the best way to tell if the plugs are getting a spark. I replaced the module today and still no worky.. To change the coil I have to take out the whole distributor correct? and take off some gear or something?? Thanks for the help, does anyone know how much a coil will set me back? Thanks,

mace87:hail:

 

No, you don't have to remove the distributor to replace the coil. There are two types of coils, the external coil which sits to the side of the distributor and the internal coil which is mounted in the top of the distributor cap.

The Trickster!!!!!!!!!!!!

 

BIGJ'sTA

You mentioned your SES light is not coming on and that you are beginning to suspect your ECM. I agree with that part.

Get that ECM blinking some codes, so you know it works! If the bulb worked prior to the problem, then I would be really-really suspicous of the ECM or its wiring.

I drove myself nuts diagnosing an intermittent failure in my ECM once.

- joe