I picked up a 1997 f250 HD 5.8 truck with only 130000 miles on it. Some of the injector connectors were replaced due to rodents eating the wires. (the previous owner said that the truck ran great prior to the rodent damage. ) These were repaired. The truck starts easily but is dumping gas into the exhaust like all the injectors are open all the time. Gas runs out of the exhaust system onto the ground. I also get a 542 trouble code.

Help
Thanks

 

542 .fuel pump ckt.
I would check the wiring close for a short to ground in the injector wiring.

 

I was trying to avoid removing the upper intake but guess I have no choice.

 

upper plenum is only 6 bolts.
Easier than it looks

 

I disagree just a bit. Had an allen bolt in the inside center section and the rear inside bolt was a bear to get out.
Got the intake off and low and behold looks like some wires melted together.

 

Charlie ment "easy after a few years practice "
....... looking like you are on the right track finding the wiring issue.

 

Upon deeper investigation I have found that when you turn the key on you hear the fuel pump but you can also hear gas running in the engine. Injectors 2,3,6 & 7 are hot with the key on. Is this normal?

 

No. Fuel pump should time out in 1 second if engine not running
Someone hot wired the pump

 

I suppose I should clarify that this is an OBD1 system. When I turn the key on the fuel pump runs and then shuts off. I pulled the wiring harness off the engine and was checking for ground shorts. Discovered that the grounds on 2,3,5,6 are all hooked together and all the grounds on 1,4,5,8 are hooked together. That just seemed odd to me. Previous owner put a new fuel pump in the front tank. Guess I should have rented a gauge and checked the fuel pressure before I tore it down to check the injector wiring. The truck would start easily and run but the exhaust would be flooded with gasoline to the point it would run out of any open area in the exhaust system.

 

#ad

 

Injectors are tied together. ......should be the power side not ground.

 

I have a schematic off of AlldataDIY and all the grounds are tied together on the two different groups of inectors. I am really starting to lean to a high fuel pressure problem.

 

have you pulled the vacuum line off the regulator, and seen if there is fuel in it yet?

That's a lot of fuel for a single pump system.
The older pre 1990 high pressure pump used to act up like that

 

Might be time to pull the injectors, while the plenum is off
a cap may have come off an injector or two, it might be washing not spraying
Do you have gas in your oil too?

 

Yes there is the smell of stale gas in the oil. I just ordered a new set of reman injectors while I have it all apart. When I get it all back together I'll check the fuel pressure. It could have been high since the vacuum system was so messed up.

Thanks for all the help. We'll see how this goes. As you can see in my avatar this truck is in great shape. Just kinda wish it had a regular bed on it though.