I never heard any rattles. When I would find the broken plugs was when it was running rough. Miss firing and bad idle. But no unusual noises. I think that injector was running lean. Pretty sure I have fixed that problem. Now back to the problem I have been dealing with for almost a year now. The hesitation problem.

 

Well cool, you got those injectors out of there. Now you have six new fishing weights! I've never even touched my TPS. From what I've seen here though I'd wonder if that's not why your hesitation at speed. I guess with an analogue meter you can actually watch the needle sweep as the throttle is depressed and see if there are glitches or bad spots. Me if I could, I might even tap on it like a radio **** when it was acting up..if I could.

Also verifying the fuel pressure is right on might be a thought. Pardon me for not re-reading the whole thread! That above is just what comes to mind.

 

Yes I know. I should have upgraded but this is a daily drive. I have a 94 that I want all the upgrades for.

Yes I have changed the TPS. Twice. Adjusted it. Problem never changes. I have a whole other thread on the hesitation problem. Its been a on going battle and I'm not winning.

 

OK "Warning will Robeson". A post 90 adjustable tps? HELP CF! I thought there was no adjustment. You might have the wrong one?




I keep a vac line through on a gauge, as well as a little (phone type), wire routed through the firewall. I put in the little wire for a "live time" reading for my 02 sensor. (that's Renix). OK. you verified the pump and pressure, changed injectors. Too bad having live time fuel pressure isn't as easy as that. .......................Is it predictable? Always cold or hot it, hesitates on the highway?

Once I had a K car that would mostly get around OK, but just wouldn't get it on. When finally loosening the header pipe to manifold bolts to make an exhaust leak, night and day! I never googled the "vac test for restricted exhaust", I just took care or the clogged cat. Loosening those two nuts eliminates any source of exhaust restriction as the problem.

????you adjusted a TPS on a 94??????

Edit, got it ....this is your 90......

 

Note to self... stay away from North California... ugly stuff happens when your Internet is slow

 

I have tried to figure out how to have a live reading on the fuel pressure. Do they make an aftermarket gauge for that?? It only does it at a steady 60 MPH and the tech is running at 2000. But its not all the time. That's when it does it. I do have a better chance of it doing it when its cold out side. But not all the time. Its like its running out of gas. Some times you feel it in the seat of your pants or some times it will move the whole Jeep. And yes this is my 90 renix.

 

You got me man. I might just guess a the fuel pump. Silver lining, some day you WILL need one. If you swap it and that doesn't help, you will have a spare. Still gotta think that with it happening in that one throttle position could be the tps. I wonder what Cruiser would think if INTENTIONALLY, putting it out of adjustment to see if it still does the same thing at 60. Also, myself, since I already have that little phone wire routed, would be easy for me to verify the voltage out the rear of the ballast, running in the cab. Unlikely for sure that the pump is loosing voltage at 60.

You might google that vac test for restricted exhaust, also cruiser has a deal in my sig on that....

And no. There was a time you might run an oil line into the cab for a gauge, but even Flintstone aint' runnen gas in there. I'd drill a hole in the hood for it first.

 

Think about it! A plugged exhaust would affect ALL CYLINDERS not just #1. A defective or misadjuted TPS would affect ALL CYLINDERS too.

Since it's ONLY breaking #1 plug, don't you think it has something o do with THAT CYLINDER and NOT the others? Fuel pressure, lean, rich, timing, advance, low battery, CPS, fuel octane, dent in left front fender etc., and where you park it are unrelated!
THINK!!!!
The plug looks like it's LEAN - too clean and hot compared to the others. AND it looks like it's shattered - almost like it was HIT with something. If the plug gets too hot, the ceramic can crack and break off. Then the broken piece floats around and hits the rest of it, making it look like it does.

LOOK FOR SOMETHING ACCOCIATED WITH THAT CYLINDER ONLY.

Now - what would happen if the exhaust valve did not open properly? If it could not expell the hot gasses, it could make that cylinder run too hot. What if it was only intermittant? And, if it ran too hot, could it occasionally ignite the mixture in the manifold, causing a misfire/hesitation?
Sound familiar?
Why too hot? A broken or sticky exhaust valve spring could do it. Or a lifter that's collaping - not opening far enough - maybe intremittantly - will not open the exhaust valve fully. Even something like a loose or broken rocker that gets out of position can do it.

Pull the valve cover, LOOK closely at the #1 valve assembly. Compare with the others. Watch the valve action while it's running. Put your fingers on the rocker - you often can FEEL a problem. Use a timing light to "freeze frame" the rocker action. Select different plug wires as the trigger for the light's #1 pickup to get different views/phasing. Use it as a strobe light. Vary the speed while you watch with the strobe. You may see something amiss as you rev it. Try it hot, cold etc.
Press down on the rocker to collapse the lifter slightly - watch how it recovers and adjusts compred to other cylinders.
IT'S ASSOCIATED WITH THAT CYLINDER ONLY IF IT'S NOT AFFECTING THE OTHERS.
A vacuum guage on manifold vacuum will tell you a bunch - makle sure it's a short hose to prevent dampening of the pulses. Rev it, drive it while watching the gauge.

 

Thanks Dflintstone and rrich for the advice.

D...I have replaced the fuel pump and bypassed the fuel ballist. Nothiing ever changed it.

I am starting to believe its something internal in the engine. I don't understand if it is internal why does it do it some times and not all the time.

As of right now it runs and the hesitation is something I can live with but I'm tired of trying to figure this problem out.

 

Not sure if you've tried this yet, but have you checked the temp with an IR thermometer around the entire engine after running for a while? rrich's suggestion of a valve problem makes a lot of sense. Also this is just a shot in the dark but is it possible that the cooling passages around that cyl are blocked? (I don't even know how coolant is supposed to flow in the block)

 

Internal - like a cam that has a lobe that comes and goes?

Internal - valve action.

 

I had a very similar problem, my 95 was running very lean would not pass smog. My plugs looked just like yours but without the broken bit. I used an IR thermometer and the # 1 cylinder was about 200 degrees hotter than the others. I also thought I had a small crack in my exhaust manifold until I poured some seafoam in the air intake, my engine compartment filled with smoke. Long story short I replaced the exhaust manifold retook temps and they were lower and even across all cylinders ( also passed smog)