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Discussion Starter · #1 ·
Hey all, I'm new to this site but have owned my 93 YJ Wrangler for about three years. I've gotten by with repairs but this one has me and friends baffled.
I have a stock 93 YJ, 2.5, manual tranny. When I leave my house and get on the highway, which is only 1/4 mile away, and try to get up to speed, at around 45 - 50 mph it starts sputtering real bad. It does clear up sometimes. But, it doesn't do this all the time. I can drive around town fine. It starts and idles great.
I have replaced the fuel filter, distributor and rotor cap. I did notice that when I changed the fuel filter, there was no pressure in the line.I did a check engine light blink test and it only came up with code 12 and 21.
I guess the code 12 is battery power to PCM disconnected is standard because the engine isn't running. The other 21 is the oxygen sensor or circuit.
Any suggestions would be greatly appreciated.
Thanx
--ray--
 

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Discussion Starter · #3 ·
It acts like it is running out of gas is my best analogy. It's not like it loses fire on one or two cylinders. The first time it happen I made it to the gas station to put gas in it and it ran fine till I got home about 20 miles away.
 

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Maybe your fuel system isn't venting right and its building up a vacuum in the tank. after you filled up it ran fine for about 20 miles what I am thinking is you broke the vacuum when you filled up and after 20 miles it built back up. try running with out the cap on and see what happens.
 

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Discussion Starter · #6 ·
I just tried it without the gas cap and it didn't make any difference. Actually it seemed as though it's gettin worse.
It was worth a try. I would take it to a garage but having been laid off for almost 2 years sorta crosses that choice out.
--ray--
 

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Soulds like a clogged cat. Either drill out your cat or have it replaced if your state has inspections. I had the same issue before and that was the culprit.
 

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Discussion Starter · #8 ·
I will give the cat a try now. LOL. Thanx
I also need to mention that when I replaced the fuel filter, a friend said to be careful cause there will be pressure when I disconnect it. Well, there was no pressure that I could see.
--ray--
 

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I would do a fuel pressure test. Some parts stores will rent you a fuel pressure gauge, 100% refundable upon return. I am more familiar with the Chevy's, but with MPI, I would think you would need 35+ psi. My fuel sprayed all over when I changed my filter. Could be a failing fuel pump or leak in the pressurized line inside the tank.
 

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I saw another thread like this and had the same problem but I had it at all speeds.. It was water in the fuel line, so I put in dry gas.. Solved my sputtering problem. Only happens in cold weather, it's like two bucks for the bottle I would try it before any expensive repairs, worth a shot. You can get it at any auto parts store or gas station.
 

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Discussion Starter · #11 ·
SandyMushYJ:
I couldn't find anyone in these two towns that could do a fuel pressure test. I called a major Chrysler-Jeep Sales and they wanted 80 bucks for a test. I looked up Advance Auto and they have the pressure gauge for 42 buck. I'm thinkin of goin out and buy one.

livs:
I've already went thru almost 2 bottles of dry gas and 1 bottle of injectoin cleaner.

Tomorrow I'm goin to cut out my cat and go get that fuel pressure gauge and go from there.

Thanx for the replys gang. Every little bit helps.

--ray--
 

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A lot of auto places have loaner tools; I know Advance Auto here does. They are free to borrow as long as you return them.
Exactly; Autozone, too. You usually "buy" the tool with the understanding that it will be returned for a full refund. Done it several times. Just walk in and tell them you need a loaner or rental. On the other hand, Ray, a fuel pressure gauge is not a bad tool to have if funds permit.
 

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I just fixed this problem on my jeep. It turned out to be the TPS. I got a new one at AutoZone for $35.00. Hope this helps.
 

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Discussion Starter · #15 ·
I have an Advance Auto local and they said they didn't have that to rent out. They are the ones that will sell me one for 41.99. I just need to know if the 93 YJ has the Schrader valve test port. I know where it is, I just don't know if that is what it's called.
Thanx for all the great replies gang.
--ray--
 

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Should be a Schrader valve on the fuel rail, and Chilton's says it should be about 39 psi w/engine running.
 

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Happened to my '97 (5spd 4cyl). It started at 45 (off and on) then got progressively worse/slower. I could drive around town at first, then... not so much. The tone of the exhaust changed and there was a odd smell. A few weeks beforehand I heard the catalytic converter "death rattle", but mistook it for a loose shield and didn't check it out before I started to have a problem. Changed the converter and it is right as rain.

It mildly upset me as a converter is a bit above what I can fix by myself with my current tools and location. Ah, well, C'est la vie.


Merry Christmas... RT
 

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Discussion Starter · #18 ·
I bought a fuel line tester.
To do a test for my fuel pump my Haynes book says to pinch off the return line momentarily to get the pressure upto 95psi and immediatly turn off the engine and let it set for 30 minutes to see how much pressure drops. Either I am totally illiterate or just plain stupid, but I can not determine which line is the return on this 93. Almost 4yrs of college and you would think I'd be able to read of book. Ugh!
--ray--
 

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On most fuel-injected engines, the supply line is slightly larger than the return line. Maybe 5/16" supply and 1/4" return. I will try to find a location description via Google before I brave the rain to look under my hood.
 

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Discussion Starter · #20 ·
Well I just took off the exhaust system and totally wiped out the inside of the cat. It still does it. I'm gonna have to go google the fuel return line pics and see if I can't find it and do that last test with the fuel line pressure. If anything, I'll go and open up my 8x8 inch hole I made in the back above my fuel pump just in case it did go out and pinch it off there.
Thanx for the help gang.
--ray--
 
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