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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Wolfgrey04 on June 20, 2012, 08:32:06 pm
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So I traded my old selector switch in my 88 for a new one. It was all new and shiny not like the old worn out dull original. A couple of days past since I have been in the middle of tearing out my interior. Today I tried to start it up and it just turns over but never fires. I got the old switch out and tried it but no luck. It's turning over just fine. Just sounds like there is no fuel going to the engine. Any ideas would be great as I am desperate to get this thing running again.
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Yeah- you guessed right about that competitor.
A little bit more info might be needed to get ya going. Was your truck starting before you took out the old selector switch?
When you first turn the ignition switch on, can you hear a fuel pump start humming?
Did you check all your fuses to be sure they're ok?
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Ok so today I checked the fuses and the ECM ten ap was blown. Put it in and the check engine light came on. Fuel pump is not kicking on and I have no power to the fuel selctor switch. It was running like a champ before this happened except that the right tank wasn't working. I am also getting spark to the plugs so thats not the problem. I've been in the process of tearing out the carpet. It was put down with glue and has been rough getting out. I've been very careful not to cut or pull any wires in the process but at this point I am checking everything. :-\
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1. On a tbi engine, the fuel delivery system is controlled by the ecm. That blown ecm fuse is an indication that a 12 vdc power lead got grounded somehow. It's going to be helpful to you if you have a code reader, or you can use a paper clip inserted at the ALDL connector under the dash to get the codes that the ecm has stored. You jumper terminal A to B, turn the ignition switch on, and see if you get a signal "12" on the dash. The SES light will flash once, then twice. If any other codes are stored in the ecm they will flash next. Each code flashes 3 times. After that, code 12 flashes again. The codes will continue to flash until the jumper is disconnected. Record any codes so someone can help you decipher them.
2. You can also check for a bad fuel system relay. The ecm sends a signal to the fuel pump thru the relay. These relays are pretty good, but they do go bad. It's located on the engine bay back wall (firewall). The same kind of relay is used in the air conditioning system. You can swap them and see if the truck starts. Or, check for B+ (12 vdc) voltage at the relay when power is on.
3. How's your oil pressure system? As a safety, the fuel pump signal also goes thru the oil pressure sensing system before it goes to the fuel pump. That way, if there's a problem in the oil pressure system, the fuel pump won't start. Is the fuse ok in that system?
I hope some of this info can be of some help in getting you going again. hang in there.
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My truck was doing the same thing,wouldnt start,the right side tank wouldnt work.I found that the fuel tank selector valve under the bed was bad,I just by-passed the valve for now and can only use the left tank and it runs like it always did before.The price of gas is to high to use both tanks anyway.
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Wow thats seems to be some good information! Its friday and time time dedicate a weekend to bloody knuckles and greasy fingers. Hopefully it's just a relay or something. I can't imagine it's something too bad. Or should I say I hope it's nothing too bad. I'll keep you posted.
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switched the relays and it fired right up. Gonna run out and grab a new relay right now. So glad that it wasn't something horrible.