FUEL PUMP.

Ok, here's the story.
The car has been sitting since July of this year only running it in the driveway for about ten minutes every so often. When we took it off the road in July it only had a few gallons of fuel in it.

The car has always started right up with no problems at all. We drove it 2 weeks ago for about a total of 15 minutes with no real problems and parked it again.

I went out there today to try and start it and the battery was too low for it to fire over. Went to Walmart and bought a battery charger and charged the battery to 100%. I hopped in the car and it still won't fire over.

I did not hear the fuel pump on the intitial 2 second prime like it supposed to do when you put the key in start mode but not run.

I swapped the (what I think) is the fuel relay on the passenger side by the a/c with the two relays on the drivers side and still no prime.

Is my fuel pump kaput?
Do they just fail without warning?
I've read some old posts about this problem, and everything seems to point to a faulity fuel pump.

Has anyone had this replaced at a garage? If so what can I expect to pay?

I don't have the tools or the patience to even begin tackling this pain in the A** job.

I've also checked for codes and everything is fine. Only shows a code 12.

Any info would be greatly appreciated.
Thanks in advance.

 

I wouldnt just automatically assume that it would be the fuel pump. Those things are a bear to change (time consuming), so I would start looking elsewhere and checking to make sure, first of all, that you are getting spark. Pull a plug wire off one of the plugs and insert another spark plug, have someone crank it over while you watch it, and look for a spark. If it is firing, then I would check the fuel pressure before attempting (or paying someone) to swap the pump. I would think that you could buy (or even loan) a fuel pressure gauge from Autozone or the likes.

 

Yeah, I'm getting spark.

I sprinkled a little fuel into the TBI and it fires right up until the little bit of fuel in there burns up.
It's just not getting any fuel at all to either injector and the pump won't prime. So it's definately something to do with the fuel.

I think that from the car sitting up so long the fuel in the tank might have jelled or something and causing the fuel pump to burn up when we drove it a few weeks ago.

I had my girlfriend turn the car over while I looked at the injectors, and there is no fuel spitting out of either one of those bad boys.

Thanks for the reply though!

 

Well, first of all, from the description of the relay locations you gave. It looks like you actually changed out the MAF burn-off relay, the MAF sensor relay, and the fan control relay. They are all the same relay, the fuel pump relay is a rectangual shape and is mounted next to the MAF sensor relay and the MAF burn-off relay. The fan relay is on the passenger side near the battery. When you say it won't fire over, do you mean that it won't crank or that it cranks but won't start? If it won't crank and you don't hear the fuel pump prime, it could be that the 20 amp fuel pump relay/ecm that is located near the battery could be blown. This kills every thing to the ecm if it blows. Also check your injector fuses under the dash,

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

 

Thanks for the info Trickster.
And you're right! I did change the MAF relays after hearing you say it.

I checked in my 1000 page 1991 Chevy Camaro Service Manual and it says everything is located on the passenger sidefor the fuel pump relay. So go figure?
You're saying the Fuel Pump Relay is on the Drivers side??

I checked the 20A fuse on the passenger side fender wall and it is fine. The two injector fuses was one of the first things I checked when I started troubleshooting.

(EDIT#2) Taken picture off

(edit)
Just thought of something else that might be helpful.

Many many months ago..... I was just watching how the TBI injectors worked and noticed they kinda did a spray/sputter thing and a few large drops of fuel came out while the car is running. I was thinking that this looked kinda odd.

I thought they would spray more of a fine mist or something.

Could this have been my sign of a failing fuel pump perhaps????

 

You're right the one with the three wires wouldn't be the fuel pump relay. The part number for the fuel pump relay should be 10094701. That's what it is on my 89 Iroc-Z and I was told by the parts dept. of my local dealership that the part # was the same up thru 92.

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

 

Thanks again Trickster!!
I trust your judgment on all of this because I've seen your replies in previous posts concerning fuel problems and I believe you know what you are talking about here!

Ok, I checked on that part # and it's only a $8.?? part from gmpartsdirect so autozone should be under $20 for the same part. I'm gonna go down tomorrow and buy one just to rule out that possability.

Is this what it looks like??




Also.....
Where can I find this "FUEL PUMP TEST CONNECTOR" ??
The book says it's on the passenger side of the engine compartment but I'll be a hens egg if I can find it.

Here's a pic of the diagram in the book.

 

Hello sunbitz,

Thank you for your trust in this, unfortunately, I have made a mistake in the part number that I have given you and don't wish that you order the wrong part. I went to gmpartsdirect.com and researched the fuel pump relay for the 1991 camaro. In 1990, the fuel pump relays in the camaro's were given a new design and part number. The new part number is 14089936 for your car. It runs for $7.14 on gmpartsdirect.com. As I mentioned in my previous post, the part number I gave you was what is in my 89 camaro and what my dealer told me was good thru 1992. I do apologize for my error here and hope you get your car running soon. PS: I plan to have a little talk with my parts person. As for the location of the fuel pump test connector, I don't have a clue. However according to the diagram in your book, it is located under the hood and should be a connector with a single red wire going to it.

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

 

The part in the pic is the knock module. The relay is in front of that and has a five wire connector plugged into it. Theres one of two ways to test the pump itself. You can pull the two wire conector off of the oil pressure switch above the oil filter and put a jumper between the two terminals in the connector. That will close the circuit and power the pump. The direct method is to pull the connector out of the fuel pump relay and hook the larger red wire on the end of the conenctor up to a 12 volt sorce on the cars electrical system, like the +12 volt terminal on the back of the alternator. This will power the pump directly. The terminal on the connector is marked as 'E' in your schematic. Ive never seen the test connector in my 88, though, so i dont know there it is.

 

On the 88 camaro's the fuel pump test terminal was 12 volts applied to pin "G" of the ALDL and negative to ground on the frame.

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

 

huh... I think ill stick to my previous method, every time i stick something into the ALDL, or the OBD II, i always stick it in the wrong place

 

I know the feeling dimented24x7, my first time doing it was on a brand new 1985 Z28. Fortunately for me, I was just trying to get a trouble code. Put the paper clip in and turned the key, nothing happened. No flashing light for the codes, nothing. About this time, an old grizzled mechanic walks by, looks down and utters these very memorable words, "wrong hole sonny".

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

 

haha

 

Thanks for all the info and suggestions here guys! I do appreciate it.

Something interesting happened this morning.
I read the replys and starting digging for the oil pressure switch and the fuel relay.
Wiggled some wires and then tried to start the car.

I hop in and put the key to the run position and the pump did the 2 second prime! I heard it.

I tried to start the car and it wanted to fire over, but I guess the pump failed again or something.

Turn off the key and tried it again.
This time no pump prime on the 2 second deal and no engine start.

After a few more tries like this...... the pump did do the prime one more time and then nothing for the remainder of my attempts.

Wiggled the same wires some more and still nothing.

I still can't ruel out the pump at this point, but maybe it has something to do with the wiring. Big surprise!

The 3rd gens are so notorious for having wiring problems. Everything that has ever gone wrong with this car has been a wiring problem.

I'm going to try the direct methods dimented24x7 suggested and see what happens.

And thanks for the corrected part # trickster.

I'll let you guys know more when I find out more.