Hi, I've got a 92 4x4 with the 22re. I just replaced the AFM because the door was stuck open. When I go out and start the truck after it's been sitting all night, it fires right up and runs great. If I shut it off and try to start it right away, it will fire right up again. However, If I let the truck sit for a half an hour it will just crank and not start. If I jump the diagnostic port to turn on the pump, it will fire up right away. I assumed that meant it would be the fuel pump relay was bad, so I replaced it. It didn't help. Do you think the pump check valve might be bad? I don't really want to change it unless I have to. The truck/fuel pump has 400k miles on it, but the motor only has 100k. Any ideas would be appreciated 😬. Thanks in advance 👍🏻

 

Sounds like your COR (circuit open relay) is on its way out. I fuel pump is fine if you can jump it. These relays are a common problem. They can be cleaned if you take them apart or cant find a spare.

 

Isn't the COR the fuel pump relay that's located just above the passenger side kick panel behind the speaker? I put a new one of those in yesterday and it didn't help. Where is the cor relay located?

 

There is no "fuel pump relay." The COR is above the passenger kick panel, as is the heater fan relay. Just what DID you replace? Are you sure you got the right part? Did you damage the wiring to the socket?

If the COR is okay but not closing, it would be due to no STA (start) signal from the ignition switch. That shouldn't have anything to do with "letting it sit," but there are only so many ways for the COR to not close.

 

The AFM was the last thing you touched so I also suspect something's wrong with the AFM wiring, like scope says.

Here's how the Circuit Opening Relay works on the first-gen 22RE 4WD:

Hard-start after letting engine sit for a few minutes could be due to vapor lock. Pls search forum.
Or Cold start injector timer switch not sensing properly or not sending proper signal to CSI or ECU

A pressure gage piggybacked on CSI would help diagnose fuel pressure issues.

 

Thanks for your suggestions guys. I lifted the bed today and put in a new fuel pump and my problem is fixed ������.