'91 HO appears to be fuel flooding.....

[YELLAHEEP]

Not a lot found by searching - the majority were Renix issues.

'91 HO 5speed began running badly for a day or two, hard starting then just quit running. Previous owner replaced the CPS, TPS, IAC, fuel pump, fuel pressure regulator, plugs, cap, rotor and wires.

When cranking it, it wants to fire. Just sputters and hicups but never actualy fires and runs. Holding the throttle to the floor gets it real close to wanting to run, but it just never does.

Pulled the plugs and they're black/sooty and were wet with fuel. Gap was off too - were .50, but I've since re-gapped to .35 - didn't help the starting though.

I pulled the fuel pump relay and the engine did actually start for just a few revolutions until it burned the gas it had. Replaced the relay and it did it again, then died and went back to sputtering and hicupping when cranking it over.

Previous owner even swapped out the computer with another used one.

It almost seems like the injectors aren't cycling properly.

Any ideas?

[birchlakeXJ]

Camshaft position sensor is the first thing that comes to mind; it is located inside the distributor. One of it's main purposes is to control fuel injector timing. Can be tested pretty simply with a meter....would certainly be worth checking into.

If the cam sensor checks out, may not hurt to actually put a fuel pressure gauge on the schrader valve and see what you get. I know that you replaced the fuel pump and regulator already but never hurts to get actual numbers.

Also be sure the battery is up to snuff.....sounds weird but low available battery voltage can be the cause of a lot of problems. Load test it or swap in a known good battery for a quick test.

[YELLAHEEP]

Yeah, I put a fresh battery in it and that's what seems to have gotten it to get closer to actually firing up.

I don't imagine fuel pressure is the problem since all the plugs are getting fuel fouled - pretty tell-tale that the cylinders are getting more than enough fuel.

I'll look into the camshaft sensor.

[YELLAHEEP]

Possible to have a coil that fires, but gives weak spark? I haven't seen one do it - they generally just go out and quit working all together..... right?

[winterbeater]

On later models like my 2000, the cam position sensor needs to be indexed. I think this also applies to earlier models, but it's a little different. You should check that. And I assume that you have the individual wires coming out of the distributor cap. If so, are you sure that the firing order is right and the #1 plug is over the rotor at the #1 compression TDC?

[YELLAHEEP]

PROBLEM SOLVED!

Completely plugged up catalytic converter.

Of course, I only figured that out AFTER I swapped out the MAP, distributor with cam sensor, coil, plugs and fuel rail/injectors/pressure regulator from a running donor........

When it still wouldn't run after all that, I began to hear a hissing noise - air of some pressure hissing down as it escaped. It was coming from the typical crack in the exhaust header......

Took a sawzall and cut the cat away and BINGO! Fired right up, running like a champ!

[birchlakeXJ]

Originally Posted by YELLAHEEP

Of course, I only figured that out AFTER I swapped out the MAP, distributor with cam sensor, coil, plugs and fuel rail/injectors/pressure regulator from a running donor........

Isn't that the way it works....at least you FOUND the problem! Good deal and thanks for posting back what you found so we can tuck that bit of knowledge away and not remember it the next time somebody has similar symptoms!