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1991 Wrangler 2.5L problem

I have a 1991 Wrangler with a 2.5 liter fuel injected engine. I have been working on restoring it for a little while but now that I have it where I can drive it, I have a problem somewhere. I have no clue what or where the problem is. All I know is that when the engine is at an idle, it runs very smooth and sounds like a normal engine does. But when I try to drive it, it starts to backfire really bad, but as soon as I let off the gas it goes right back to that smooth idle. I have just about replaced everything in the engine compartment. This problem has really hendered my progress on getting my jeep road ready. If anyone can help please let me know. Also does anyone know what the fuel pressure is supposed to be on this engine?

Thanks Derrick

Reply to
dwd3773
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For the 92 Wrangler (YJ) the factory manual says "System fuel pressure should be approximately 214 kPa (31 psi) with the vacuum line connected to the regulator. With the vacuum line disconnected from the regulator, fuel pressure should be approximately 269 kPa (39 psi)"

Stephen.

snipped-for-privacy@bellsouth.net wrote:

Reply to
Stephen Gibbs

Could you have 2 plug wires mixed or the wrong rotation on the distributor cap?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

Reply to
L.W.( ßill ) Hughes III

Thanks for the replys. I was told that on the 2.5L engine, that the distributor didn't have any adjustments. Also with the distributor, plug wires, and plugs if something in them was wrong would the engine idle rough? I will get the fuel pressure checked at the fuel rail, but I think that the fuel pressure might be the problem. I'm not sure but wouldn't low fuel pressure also cause the same symptoms? See I had converted my jeep to a chevy 350 motor, it was running great but I couldn't get the drive shaft to the correct angle for the type of transmission I had. Also I wanted to be able to drive my jeep everyday, and with gas prices the way they are now, I decided to put the stock engine back in. So if anyone know anybody that wants a complet jeep to chevy engine conversion kit as well as a complete 350 with transmission and transfer case I have it. Now back to the problem, How can I find out if my distributor is turned wrong? and I will change the plug wires and plugs, and I will look into changing the coil as well, but if anyone knows anything else to try please let me know.

Thanks

Reply to
dwd3773

Reply to
L.W.( ßill ) Hughes III

Could it be a stuck or burnt valve? Or something internal with the engine? Because the engine did sit for about 6 months.

Reply to
dwd3773

Reply to
L.W.( ßill ) Hughes III

Engines can run with the timing 180 out or with 2 wires switched sometimes and idle nice still. I helped put a 6 back together and it just purred at idle with no top end at all. It just needed the wires done right.

The distributor rotation or firing order is clockwise (I think) with #1 plug wire located at 8:00 looking from the front of the vehicle as far as I can tell from my book with 1,3,4,2 as the order. Maybe someone else can confirm this.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

LOL

180 out at the distributor would mean 360 on the crank. That would mean the spark plug would be firing on the exhaust stroke. It wouldn't even run, much less "idle nice."

You might get some pretty nice backfires though...

Reply to
bllsht

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