Hey all, new here. I picked up a 94 4 door to build into a rock crawler. The idle was surging badly and would often stall, and it seemed to have half the power it should. No hesitation, and once in gear the idle seems better, as long as it didn't stall when you put it in gear. I pulled off the upper plenum and found a gas puddle on the passenger side, so I put a new fuel pressure regulator in it. Fuel pressure seems to be holding now. I messed with the timing some also. While I was at it I made a little block off plate for the EGR. While I had the gas tank out to build the 4 link suspension, I went ahead and threw in a new fuel pump and filter just for peace of mind. Didn't have room for a cat with all the rock crawler suspension parts under there.

So it is idling a bit better, but it is not fixed. It does all the same stuff it did before, just not quite as bad. Still has no power. I am not pulling much vacuum, like 11 in/hg. But I can't seem to find a vacuum leak.
Here it gets wierd. When I went to set the ignition timing, I could not even see the timing mark, like it was so far out of whack it is not even in view. But the engine runs worse if I move much away from where it is.
No codes, but it is OBD1 so that doesn't mean much.
Starts easily every time. No hesitation either. Runs smooth under load. Just surges the idle up and down, recovers poorly when going into gear and often stalls. And low on power.
Any ideas? Could I have jumped a tooth on the timing chain? I know some of the old engines could run with a jumped chain if you advanced the ignition timing enough.

And if you wanted any details on the build, here they are
D44 front, Ford 3/4 ton 8 lug
GM Corporate 10.5" 14 bolt full float rear, narrowed 5" to match front
5.38:1 gears, Detroit lockers front and rear
TH350 trans, dual RF1A Toyota transfer case
1350 U Joints
Triangulated 4 link coil suspension in rear
3 link suspension with Ballistic Fab 16" travel air shocks in front
39.5x13.5 Super Swamper IROK bias ply tires on 15" DIY beadlock wheels

 

Start checking the timing according procedure. The ECU needs to be disconnected on the 1st gen to set timing with timing light, else you are messing with the additional advance the ECU throws in. Common problem.

Wire should be in the passenger foot room behind the carpet. brown (or tan) to a black with a connector to unplug.

 

I don't really have any suggestions for you, but it's cool to see another rock crawler here. Nice rig.

 

I did.

 

Thank you!

 

So ignition ist spot on now?

Timing could be off but to jump a tooth on the chain the components in there would be so worn out that a replacement is a must.
Vacuum seems odd. I would start at the basics. Engine timing TDC, Ignition timing from there, then fuel pressure when running.
This setup has an IAC (idle air control) another probable culprit. Then sensors MAP being the primary problem as it is driven by a vacuum hose.
The rubber connectors to the plenum (spider or TBI) are rotting and cracking. You may not even see it but they give the MAP a false reading.
TPS is another probable cause it if is loose or in a wrong position.

I would also check for a mechanically sound throttle activation. cable, levers, does it really open completely or close completely?
In such a rig this could be an issue as well.

At the moment all that comes to my mind, which could help.

 

On a 2 Door 94 with the CPI. Mine is reving low at idle and goes sub 12 Volts with the AC on. My timing is definitely off. After 3 days of Crank no start, it magically started by rotating the spark plugs. Cylinder 1 end up being at the 3 spot on the cap to get it started. My Mechanic gave up.