ButchM

I was moving cars around today and pulled my 97 Z28 out of the garage and let it sit and idle for about 20 or so minutes so I could put it in a different spot in the garage. It stalled and I figured it ran out of gas. We put a couple of gallons in and the gauge now reads way more than enough to start it up. It will not start. Is there a relay or something that could have kicked out? It may be a fuel pump but the dealer replaced it about 5 or so years ago. Back then I could reach under and hit the gas tank with my fist and the pump would take off and run normal. Then after shutting down it would need to me smacked again. The car ran great before that. Since I never drive it during the winter I was just letting it run for awhile like I do every year during winter. PLEASE HELP!!! This weekend has already been a killer. My wife's 05 Silverado suddenly lost the transfer case and my transmission guy is down with pneumonia so I have to wait on him for now on that. It's sad. The only vehicles we have to depend on right now with four vehicles are my 92 Silverado which my wife has to drive to and from work and my 51 year old 65 Chevelle that has never seen snow. the 2 newest won't run.

Injuneer

Check fuel pressure, scan for codes. Can you hear the fuel pump run for 2-seconds when you turn the key to "run"? You can bypass the fuel pump relay and the SECURITY system interlock by supplying 12 volts to the fuel pump prime connector near the PCM. That will tell you if the pump is working.

Courtesy of Shoebox:

http://shbox.com/1/fuel_pump_prime.jpg

ButchM

I will check the prime connector today. I turn the key on and hear nothing right now. Will have to borrow a scanner. Thanks.

ButchM

One question about using 12 volts to check this prim connector, do I just connect a wire from the battery positive to this connector with the key on? Exactly what do I do to check this? Thanks. I am just not used to finally having to work on the newer things. When I still worked for GM I could afford to just have it towed to the dealer and let them fix it. Now that I am retired I have to do these things myself. I can work on my 92 Silverado 4X4 other than trans and transfer case, I can work on my 65 Chevelle with total ease. This thing with all the electronics is a nightmare for me. And now with my wife's transfer case messing up, I am really in a bind. Dealer is a total no right now. Now it would probably be near $1000.00 for a fuel pump. The part (complete assembly with new float and all is only $138.00) as opposed to having the dealer do it. Heck, when I did the water pump it took me 3 days.

Injuneer

Run a length 12 or 14ga wire from the terminal in the red plastic + box near the battery, to the prime connector. I would include a 20-amp inline fuse in the wire, but that is optional. The key does not have to be turned on. You are bypassing the fuel pump relay, and the PCM fuel permit interlock to the SECURITY system. The pump should start as soon as the wire connects to the terminal in the prime connector.

If if doesn't run, check the fuel pump wiring harness under the rear of the car, above the rear axle assembly.

(all photos courtesy of Shoebox)

http://shbox.com/1/fuel_pump_wiring.jpg

http://shbox.com/1/fuel_pump_connector.jpg

As far as replacing the fuel pump, many people cut a hatch in the sheet metal above the fuel tank. There is a "how to" with pictures in a "sticky" thread at the top of the "Fuel and Ignition" forum.

https://www.camaroz28.com/forums/fue...th-gen-619463/

ButchM

Thank you.

ButchM

UPDATE ON MY CAMARO:
OK, after all this time I finally am asking for advice. I got the complete, brand new Delphi fuel pump assembly. After watching several videos including this guy, twotwocold's several videos I got my trap door perfectly cut, the old pump assembly removed and for the heck of it I connected it to the battery charger. It was a dead pump. I checked the new one and it took right off. So far so good. I fought like hell getting the new pump back in the tank and when it finally went in and was sitting where it needed to be with out any binding I had to get my wife to help with the fuel lines because my hands are too big. Between us we got them connected right and plugged it in. The car wouldn't start. Then I tested it with the little bypass connecter by the firewall and it ran so then I checked the fuse and it was blown. New fuse, she fired right up and runs beautiful. Now my problem. My fuel gauge is pegging full. It wouldn't shake loose on a rough road and I made sure there is about 12 or more gallons in the tank. I pulled the tank unit (what we called them at AC Spark Plug/Delphi Flint East in Flint where I worked) again and looked down in the tank, there looks like about a crap ton of baffles so I tried to aim for the one that looks like a can that is toward the back of the car. I got it back in, surprisingly got the fuel lines hooked up myself and turned on the key. It is still pegging full. I can see the float on the level sender in the gas, yeah there is a lot in the tank, and it was bobbing around. One video I watched has an older guy with a hard top doing this job and he had to do his 3 times because his gauge was pegging full too. His problem was a wire came unplugged from the sender. He finally got that attached tight and it worked. Mine has all wires attached and it looks fine. I am done playing with it till next Saturday. I am thinking of pulling the assembly back out and holding it over the hole in the tank so it drains and then crawling under and plugging the harness in and moving the sending unit float while my wife watches the gauge. Any suggestions on how to get this in the tank without so much fuss? I figured my biggest problem was going to be hooking the fuel lines back up because of the way they lay under the part of the body where the sections are put together. That turned out to be simple. PLEASE HELP!!!!!!!

Injuneer

See if this helps, checking the resistance at the harness connector on the chassis:

Courtesy of Shoebox

4th Gen LT1 F-body Tech Articles

ButchM

OK, and this will tell me what the gauge is supposed to be saying. But what is this going to do? I know the tank is nearly full. I personally think the float is not in the correct position. What is the best way to get the pump/float where it is supposed to be? The way things seem to be with it, I have to put it in sideways and wiggle and turn the unit till it seems in the right position. It just seems like somehow I am not getting the thing in right. Not sure. I know I am real tired of pulling it out of the tank and putting it back. I wish these pumps were the mechanical kind bolted to the block. It takes me a whole 20 minutes to do a fuel pump on my 65 Chevelle 6 cylinder and the same time to do one on my son's 65 Chevelle 327. GM seems destined to make people take these newer vehicles to the dealer to get them fixed but I can't afford that crap.

Injuneer

The resistance will tell you the vertical position of the float in the tank. You indicate you have about 12 gallons in the tank and it is "pegging full". What do you mean by pegging full? At 12 gallons, the needle will point pretty much to "F". If the tank is completely full, the needle typically indicates well above "F". All that is summarized in Shoebox's writeup.

Beyond that, I don't know what to tell you. Many years since I messed with the fuel pump, and I don't remember any specific issues with putting the assembly in the tank.

The shop that reworked my fuel tank to add a sump for a second outboard pump also modified my stock sending unit frame to hold a non-standard Bosch high pressure pump,and to use -AN type fittings rather than the GM quick disconnects.

In doing so, they messed up my level sensor, and the gauge always pointed to way above "F". Measured the resistance of the sensor, and there was an open circuit = infinite resistance. A stuck sensor would have indicated about 88 ohms. At that point in time they didn't sell the level sensor separate, and I had to buy a whole new sending unit (less pump) so I could drill the pop rivets out of the assembly, and swap the new sensor onto my old, modified stock sending unit.

ButchM

When I say pegging full I mean the gauge is way above full. It was in that position before I plugged the new pump back in and never moved. I talked to a buddy today who is the service manager at the Chevy dealer we use. He told me the same thing about using my multi meter to check the ohms. For the heck of it I was messing with the old pump and meter. That worked sort of OK. I know that sending unit worked good with the gauge. Tomorrow I am going to pull the pump out of the tank again and hook it up to the meter. My friend also told me to plug the pump back in while I have it out of the tank and have someone watch the fuel gauge. He said to manually move the float and see if the gauge works. I am going to do that too but will not have anyone here to help till Wednesday when my wife doesn't have to work at her pharmacy job. I talked to the manager of the Auto Zone I usually deal with and she told me if I find the sender is not working that she will exchange it even though I got it from a different Auto Zone. My regular store didn't have the Delphi unit in stock that day. She also said I was over charged and she is refunding my over payment. I will be able to check the new pump sending unit tomorrow with the meter. I will keep you posted.

ButchM

UPDATE: The brand new tank unit I originally bought had a bad fuel sending unit. The ohm meter showed the brand new one to be dead. I tested the old one with the bad pump and that one worked fine. I exchanged it today and the funny thing is, this new tank unit looks exactly like the one the dealer did 15 years ago. Just to be safe I crawled under it and plugged it in and had my wife turn the key on and I moved the float. The gauge worked just fine. This one also just slipped right in the tank without any hang ups. Both tank units had the same part number but the float on the bad one was completely different and I had to fight like hell to get it in the tank. I swear, this new one just slipped right in where it needed to be. I got all the lines hooked up and the unit bolted down and crawled under and plugged it in. Then I got out and was so nervous about checking it. I turned the key, the pump fired and the fuel gauge went from empty up to just about 3/4 full. It started right up and I breathed. Tomorrow I will cut a new patch/cover for the trap door and seal it and then put all the carpet back. Then I can start detailing it for the car show. Thank you everyone who answered my questions. I learned quite a bit over this deal.

Injuneer

Glad it finally worked out for you. Good luck with the show.