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Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
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2000 Chevy Express 1500: I bypass the fuel pump relay shut..L..Van

Customer Question

How do I bypass the fuel pump relay shut off on a 2000 Chevy Express 1500, 5.7 L, Choo Choo Custom Van?
Submitted: 9 years ago.
Category: Chevy
Expert:  Bob replied 9 years ago.

What is it that you are trying to do? If you are testing the fuel pump electrical circuit, the gray wire that goes to the top of the tank is the pump voltage lead and should have voltage when you first turn on the key and start cranking the motor. If you look at the diagram below, that is the gray wire on the left side that goes to the fuel pump sender assembly. Sometimes even if these pumps run, they do not develop enough fuel pressure to open the poppet valves on the injectors. These system are really pressure sensitive and just a couple of pounds under is enough to keep them from running. Your system need 60 to 66 pounds at key up to start the truck. You can rent a pressure gage from any parts store and Auto Zone has a loan a tool program that only requires a deposit. The gage just screws on the valve (looks like a tire fill valve) on the fuel injector rail. Thanks and good luck.

Document ID# XXXXX
2002 Chevrolet Express

FIGURE Fuel Controls: Fuel Pump Controls(c)

Object Number: 757160  Size: FS

Document ID# XXXXX
2002 Chevrolet Express

Bob and other Chevy Specialists are ready to help you
Customer: replied 9 years ago.
Reply to Bob's Post: I lost the key that came with the vehicle and the Chevy dealer can only cut a standard key (without the chip).
Expert:  Bob replied 9 years ago.
I think I would check with a couple of other dealers first. That does not make any sense to me. I know they need to test the keys on the VATS interrogator, but I have never heard of a dealer who could not cut a coded key? If so this will be a first for me. But be aware that Buick and Pontiac and GMC all use the same system, so it does not have to be a Chevy dealer. I am not sure if bypassing the relay to get voltage to the pump will work without causing you other problems at the same time. While you are checking around, I am going to check with some other experts to see if they have ever heard of this. Thanks
Customer: replied 9 years ago.
Thanks Bob. According to the dealer the chiped key didn't come from the factory in 2000. That fuel shut off system may have been a after-market product that Choo Choo Customs added during the conversion. Choo Choo Customs is no longer in business and the van will not start without that key. I was hoping to use a standard key and bypass the fuel shut off system.

Expert:  Bob replied 9 years ago.
If Choo Choo used a GM system for the security device, which they most likely did, it should just be a matter of replacing the lock cylinder and key and then reprograming the body module to read the new one. I will look to see if this system can be programed with out the use of the GM tech 2 scan tool and let you know soon. Thanks
Customer: replied 9 years ago.

Thank you Sir. I am making more progress with you than with the three alarm specialist that I have visited. You are appreciated. Hope you are having a great Turkey day. You are making mine a good one :-).

It is a GM system according to the key fob (which I still have) The markings on the fob read: GM 16245100-29 Model /FCC ID:AB01502T

Bill N.
Expert:  Bob replied 9 years ago.

Hi Bill, I am now having problems with MSN and had to come back on through Internet Explorer, so don't be surprised if you loose me, but I will get back on sooner or later. I would like you to check with the dealer and see if the part numbers on the fob will give us an idea of if it is a late model fob or an early one. Then we should be able to decide which style lock cylinder to use. If it is the old style with 2 small white wires going to the lock cylinder we may be able to bypass the system for ever. Read what I was just getting ready to post and we will go from there. I have to leave for a few hours now, but will be back before bed time. We should be able to work this out somehow. Thanks

If they did the system the way I think they did the 30 minute program in the post below may do the job. If that won't work, you may need to have the dealer install his tester on the van and read the resistance value on the system and then maybe we can solder a resistor in the line to bypass the system permanently. I am still waiting for a couple of other opinions on the best way to approach this with out causing you more problems.

Customer: replied 9 years ago.
Thanks for your help. I am going to accept the work you have done - with great appreciation. If you find more please e-mail me later.
[email protected]
Expert:  Bob replied 9 years ago.
Hello again, Bill. See what you can find out from GM about the numbers on the FOB and let me know. I am not at home at the moment and only have partial access. I see the information about programing did not print. I will ad it again when I am on my own computer. Thanks for the accept, will wait until I hear back from you.