Still hard to start with fuel and fire

[venuspie1]

94 4.0 ohv. I had a timing issue that was resolved in a previous thread. The truck now runs, but still won't start unless I use starting fluid. Even then it runs rough like it is camming for 10 minutes or so. Even puffing bluish black smoke. Eventually it will correct itself. No more smoke, no more camming and runs great and will start back up great.....until the next day.. same issue all over again. During the issue, I have 40 psi fuel pressure during cranking and plugs are firing.

New MAF
New TPS
New crank sensor
New plugs and wires that are firing strong

My guess on possible causes are fuel pump or regulator but with 40 psi probably not.
Maybe o2 sensors. I am lost here. Thanks for any help!

 

[bobbywalter]

any oil on the plugs.

eating oil?

bad valve seals may be gooing it up causing a hard start after a spell.

unless them injectors are sticky.

 

[Bgunner]

Just a thought and could be way off base here, have you checked the temp sensors for the ECU? Both engine and air temp sensors help control the amount of fuel delivered for cold start.

Like Bobby mentioned, the valves seals will produce blueish grey smoke after the engine has sat for a while and clears up usually soon after start. All the ones I have seen it clears up with in a min or two though. I have not experienced a really bad set but have seen them when they are slightly leaking.

 

[bobbywalter]

Just a thought and could be way off base here, have you checked the temp sensors for the ECU? Both engine and air temp sensors help control the amount of fuel delivered for cold start.

indeed

 

[venuspie1]

Heads are brand new NOS. Which sensors are you referring to? I replaced both coolant temp sensors.

 

[venuspie1]

Could be injectors. Not eating oil and plugs are dry. I cleaned the injectors with a rig I made up of carb cleaner spray nozzle and 12v source but maybe sticking open?

 

[venuspie1]

FYI. Truck was running perfect prior to removal of engine. Except the xtremly bad head gasket leak. Did start up easily every time. Ended up pulling motor and rebuilding bottom end with new heads

 

[SenorNoob]

NOS heads could easily have bad valve stem seals. IIRC they would be the only bit of rubber on that part. Rubber usually ages faster on the shelf than it does in use.

 

[venuspie1]

I thought the same thing. They may be bad but would that stop the truck from starting when cold except on starting fluid?

 

[SenorNoob]

Yeah, I can't see that much oil getting into the engine. Gonna have to go with "not likely" on that one.

 

[venuspie1]

Still can’t figure it out. Finally got the jumper on the eec test to work and got code 122 with koeo. With koeo got 122 and 998 I believe.

 

[SenorNoob]

122	(O,M) TP low (possibly grounded or open circuit) – TPS

998	(R) Did not pass Key On Engine Off test yet (Get 111 in KOEO first)
	(O) Transmission Electronic Pressure Control (EPC) solenoid/circuit fault – Transmissions

That's interesting. Not sure what to make of it though. Would a non-functioning throttle position prevent the computer from starting the engine?

 

[venuspie1]

122	(O,M) TP low (possibly grounded or open circuit) – TPS

998	(R) Did not pass Key On Engine Off test yet (Get 111 in KOEO first)
	(O) Transmission Electronic Pressure Control (EPC) solenoid/circuit fault – Transmissions

That's interesting. Not sure what to make of it though. Would a non-functioning throttle position prevent the computer from starting the engine?

I’m not sure. Does same thing with old and new tps. Also didn’t have this problem before I rebuilt engine

 

[venuspie1]

NEW INFO!!!! Just noticed the fuel pump running constantly with just key on. So I left it on and under the hood I heard what sounds like fuel running?? Engine is off and cold. I start removing plugs again and all are dry then after 10 minutes the fuel pump just stops and no more whoosh sound from under the hood. Truck starts right up cold! Let it run for 30 secs and shut off. Turn key back on and pumps starts running non stop. Truck won’t fire up at all!

 

[gaz]

Could be injectors. Not eating oil and plugs are dry. I cleaned the injectors with a rig I made up of carb cleaner spray nozzle and 12v source but maybe sticking open?

Only supposed to use 9v when cleaning injectors; a 12v supply can damage them.

It really sounds like you gave some fuel issues. I would find out why the pump stays running.