92 No Start Issue

[GordoSmasho]

So im reaching out to the better dignostic folks out there. I picked up this 92 2dr 4.0 auto 4wd from a fellow member that didnt have time or resorces to get it running. He bought it not running. It has only 146k on it. It has been worked over and tinkered with quite a bit. Looks like it has been in a front end collision at one point. Ive done all I know to do.


It cranks just fine but will not start. Just stumbles while cranking. As soon as you let go of the key it stops.

-Has spark on all cylinders
-Compression is very good 140-150 across
-Verified fuel pressure new pump and filter 40psi cranking
-Verified the indexing of the distributor
-Tested both the crank position sensor and the cam position sensor, both good
-New plugs wires and rotor
-Was getting a code for the temp sensor so i swapped in a new one and the code is now gone
-The injectors are firing. Verified with node light and fuel pressure drop while cranking with the pump relay pulled
-Ballast resistor is bypassed(new fuel pump is supper loud. May have to reinstall the resistor to sell it)
-No more codes are present
-all the fluids look like they are supposed

Still just a stumble while cranking. I can smell fuel out the tailpipe after cranking for a little bit.

What should i look for/test next? Im not one to just start buying new parts with out making sure the old ones dont work. Thanks guys.

 

[go1lum]

Fuel/spark/air. Sounds like you have two of them. I wonder if the cat is maybe clogged.

 

[GordoSmasho]

I can disconnect the down pipe and give it a go tomorrow.

 

[GordoSmasho]

Disconnected the down pipe. No change. Took a vac blower and hooked it up. As far as i can tell the exhaust had no restriction. Hooked it all back up. No change.

Steady crank with a stumble here and there. Fuel spark and air are present

Which sensors are being looked at diring cranking.
Again its a 92. So obd1

 

[go1lum]

Maybe a fried computer?

 

[muddypunk]

Check your compression it could have jumped time severely.

 

[GordoSmasho]

Compression is solid 140-150 across the board. Iv indexed the distributor twice. Once one tooth ahead and once one tooth behind just for kicks. No change.

 

[GordoSmasho]

Hmm. Would a fried computer be putting out spark and fuel properly and giving me code readouts? Actual question, i am not as familiar with pre 97s

 

[Lkwelch]

Try unplugging the map sensor or test it? That sounds like a tough one.

 

[trippled]

Motor or trans look like they've been out recently? Seen bad or incorrect flex plates do this. Also if dist was replaced make sure you have the right one. Some have the window for the cam sensor 180 degrees different.

 

[GordoSmasho]

Motor and trans do not look like they have been removed at any point. Nor does the distributor. How do i tell which type is in it. I pulled it just to be sure and check timing but as i said before put it back in in three different positions to no avail

Swapped in some new plugs and let the cylinders dry out a bit today. Also tested the tps sensor. Still no change

This is the voltage input

Voltage output throttle closed

Voltage output wot

Wot seems to be out of spec but closed throttle is in spec. I have a solid ground at the plug btw.

 

[XJCasper]

Subscribing... Have similar issue...

 

[87manche]

Do you have a timing light?
verify timing on the crank pulley.

Your sputters but won't fire symptom just reeks of a timing issue.

 

[SuperB60ce]

Do you have a timing light?
verify timing on the crank pulley.

Your sputters but won't fire symptom just reeks of a timing issue.

I was thinking the same thing

 

[Lkwelch]

And just the basics, but are you sure all the spark wires are in the correct order. Been but several times with that.

 

[GordoSmasho]

Yeah im picking up a timing light this weekend. My dad said the same thing. Im positive the wires are right. Ill report back with my findings.

 

[Dragonslayer]

Check the IAC (= Intake Air Controller), or swap in a known good one.