Xcessive

Ok... so totally left field here, but do you still have catalytic converter? I dealt with a similar issue on a Oldsmobile Delta 88 I worked on for a customer. Would run great until it got nice and hot (about 10 minutes) and then it would choke out and stall. Every once in a while if I was looking for it I would get a very very faint sulfur smell. With that in mind and everything else either replaced or tested I cut the cat off, put in a test pipe, ran it for a day and it ran perfect, the cat was clogged up. Put in a new cat (to pass emissions) and never had another issue.

And this is what I get for not reading every post on here. So it's now running, but with a stumble?

DFlintstone

Yea, that crossed my mind as well, the cat. In his Vid, (some posts back), it idles, but dogs, and sometimes stalls out when he hits the throttle, then revs right up. My only expierence with a clogged cat was no power, doggen all the time....(I loosened the header pipe bolts and BINGO, she ran great!)

CRUISER’S VACUUM TEST FOR EXHAUST RESTRICTION

Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.

Xcessive

I was thinking that as well at first, but it sounds like he may have a decent exhaust leak (cracked manifold?). It could be at idle that it's just enough to keep him running & when he blips the throttle it creates enough back pressure to cause a stall? I dunno? If mechanically the engine is good, has a fresh tune up, and electrically everything is checking out ok... like I said, just a left field thought, but maybe worth exploring.


Is it possible that he has a couple bad injectors that are either not able to keep up with fuel requirements or are sticking open causing a flood condition?

DFlintstone

Pretty smart thinking!...but. I don't see he mentions a lack of power that I'd expect with a clogged cat. Again I'm at a loss. If it were me I'd double check the function of the MAP sensor, is all I have. Btw, that Fluke meter may well be able to do the "sweep" test, normaly done with an analogue meter. You hook it up to a vacuum pump and watch the voltage sweep as vacuum is applied.

And yea assuming the Jeep is going to be kept and used, an injector up-grade is something to do at any time. The stock truly suck.

Xcessive

I can attest to that. I just did the 703 swap on my white jeep. Gained about 1 mpg, smoother idle, smoother throttle, no more power surge and starts right up instead of cranking a second. I think my green one (also a 96) is going to get a set of 746's as a kind of experiment.

DFlintstone

I wouldn't. The 746 has a slower flow rate.... Also I don't know the resistance of a stock 96, but it may well be a mis-match. As far as I know the 703's are a good option for 91> on.

Xcessive

Hmm I'll look into that. Anyhow, to not hijack the OP's thread.

I'm interested to see what the deal is here with his jeep. I know when I was chasing my electrical gremlins (df helped me a lot on that. Thank you again.) I ended up going over everything and testing everything a minimum of 3 times. Found multiple issues and it was a combination effect that was tripping my ASD relay.

bdcontraplayr

Sorry I've been absent from the forum. Had a death in the family and it's been pretty rough.

I'm going to be reading through what I've missed and I still need to check to MAP sensor, but should be fine since it's new, but doesn't hurt to try.

bdcontraplayr

You know what, I did notice a leakid when I did the sea foam on the engine. And my mom was suggesting the problem might be n in the exhaust

bdcontraplayr

I brought into a shop...


Nothing. They can't figure it out. They said when they tried to plug it into the obd1 that they couldn't get a reading. Going to try another shop

cruiser54

Cuz it's not OBD?

DFlintstone

It would need a DRB II, or a Snap On 2500 with the correct cartridge.

Can you restate exactly what are the issues you are having?

Oh...not sure what you putting in there. It should have gas in the tank, and oil in the crankcase. If you are trying to diagnose a problem adding other products might make that harder. The only thing that might help some people, is pretty hard to find.

bdcontraplayr

Man, I don't think it is. It was in the shop 3 days and they kept trying to plug it into a scanner, I can do that at home with mine. These guys are not mechanics if that's what they do.

bdcontraplayr

It's cutting out and choking/stalling when the motor is warmed up. It can drive, but it'll stall from a dead stop when you try to take off again. I'm guessing its the cat or some kind of blockage. Maybe its the ECU. But something is getting hot and making it read all kinds of funky

cruiser54

Do a vacuum test when warmed up.



CRUISER’S VACUUM TEST FOR EXHAUST RESTRICTION

Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.