Long crank and dies on cold start

[HaremStorm]

Heyo, 91 k1500 4.3 4x4. I have a maybe 10-15s crank time then she'll kick off and either high idle for 30 seconds then die (no tach so I would guess about 13-1500 rpm) or it will just right off die. Tried to pull codes off the CEL but just get the system active flashing and I do not have a obd1 reader. New parts include Coolant temp (both) ICM, MAP, Plugs, wires, cap and button as well as new vac lines all over bc rot. Motor was re-sealed and had a timing job less than 8k ago. WTF

 

[Nad_Yvalhosert]

What is your fuel pressure?

 

[HaremStorm]

What is your fuel pressure?

haven't the foggiest. What should it be. i have a gauge kit and can test tomorrow night on my day off.

 

[HaremStorm]

Heyo, 91 k1500 4.3 4x4. I have a maybe 10-15s crank time then she'll kick off and either high idle for 30 seconds then die (no tach so I would guess about 13-1500 rpm) or it will just right off die. Tried to pull codes off the CEL but just get the system active flashing and I do not have a obd1 reader. New parts include Coolant temp (both) ICM, MAP, Plugs, wires, cap and button as well as new vac lines all over because rot. Motor was re-sealed and had a timing job less than 8k ago. WTF Edit: completely forgot I recently cleaned the IAC.

 

[Nad_Yvalhosert]

haven't the foggiest. What should it be. i have a gauge kit and can test tomorrow night on my day off.

9-13 psi.
My '88 did the exact same thing yours is doing 20 years ago. Extended crank, intermittent stall, lack of power on accel.
Then I changed the fuel pump...

 

[HaremStorm]

9-13 psi.
My '88 did the exact same thing yours is doing 20 years ago. Extended crank, intermittent stall, lack of power on accel.
Then I changed the fuel pump...

Fuel pump was replaced a year ago but I'll check for the sake of checking

 

[Schurkey]

Does the fuel system have a 2-second "prime" when the key is turned from "Off" to "Run"?

If the fuel pump relay circuit has failed for any reason, the fuel pump doesn't get power until the engine has cranked long enough to build oil pressure.

 

[HaremStorm]

Sorry for delay, busy busy three days. same issue good fuel pressures and i do get my initial prime with the ignition switch. issue has gotten worse and now it hesitates/bucks when cold. I did some more poking after fuel came back good and found that it cold starts better and bucks less frequently with the MAP unplugged but it runs ridiculously rich and only with MAP unplugged. Obviously my MAP sensor is toast, but with how rich it gets with the MAP unplugged i wonder if there is more to it. I do have a pretty bad exhaust leak because I don't have the gaskets in there when it comes off the header but idk if that'll cause it to be that bad. Any ideas?

Does the fuel system have a 2-second "prime" when the key is turned from "Off" to "Run"?

If the fuel pump relay circuit has failed for any reason, the fuel pump doesn't get power until the engine has cranked long enough to build oil pressure.

9-13 psi.
My '88 did the exact same thing yours is doing 20 years ago. Extended crank, intermittent stall, lack of power on accel.
Then I changed the fuel pump...

 

[Schurkey]

91 k1500 4.3 4x4.

I do not have a obd1 reader.

Time to get one.

 

[Sabinoerc]

same issue good fuel pressures

Curious - what do you call “good”? And where did you check it?