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Symptoms of getting the Distributor off a tooth on install?

Redsnake

NAXJA Forum User
Location
Tulsa, OK
OK... so this last weekend I installed a reman distributor in my '96XJ. This was the first time I've done a dizzy install... and for the most part all went well.

When I fired up the XJ she seemed to run just fine. Took it for a long drive and everything seemed fine... no backfires, no stumbles, et...

... move foreward a week. My gas mileage has been pretty LOUSY for my XJ before the dizzy install and now after a week having the new Dizzy, Mopar Wires and NGK plugs my mileage this AM was 13.9 mpg... before installing a new Radiator last month, Dizzy, tune-up, etc... I averaged about 20 mpg... so WHAT GIVES???

One other thing is about 1 month back I got a new set of tires... 30x9.5/15s that replaced my old hard 235/75R15s... not much difference in size, but a little larger bit of rubber.

I also noticed that my temp guage rarely reads over 180 so I'm wondering if I'm running in continual 'cold cycle' loop and the computer is never running like it's supposed to. I have a nice laser thermometer and can measure temps, but not sure where to check in the engine bay to make sure my guage is accurate, or if it's just off like a lot of OE products are.

... ok, back to my original post. IF I had my dizzy off a tooth (forward or back) would it be very noticeable and would I get missing and a backfire? I figured I would and since I didn't I assumed all is well w/that install. However w/the lousy fuel mileage I'm wondering.

(Also... I replaced my front O2 sensor about 20-30K miles back and that improved the performance of my XJ as it had been stumpling and missing...)

I also ran a can of Seafoam thru the intake about 3 weeks back so I'm hoping that didn't screw up my O2 sensor or something else.

... I'm just shaking my head at the TERRIBLE fuel mileage I've been getting since this only started happening about 1 month back.

Thanks for any and all tips or suggestions.
 
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OK odly enough when the dist in my 90 was off a tooth it would not run at operating temp. I attributed that to it not burning all of the fuel and keeping the cylinders cooler. My mileage was terrible as well and I had stumbles at highway speed. Maybe I'm way off on my assumption but the issue went away with getting the dist right.

I had my dist off due to relying on the timming mark on a "brand new" harmonic balancer, which turned out to be off by many degrees. When I reset the dist the way I always have in the past it fell right on the mark, issue was gone.

Get #1 piston on TDC, compression stroke. Drop the dist in so it will rotate into the #1 terminal position.
 
Thanks for that info...

One thing about mine is it does not stumble at all... as best I can tell. I have had cars in the past who's timing was too high and got terrible pinging/pre-ignition and also had cars that were off timing and backfire at the same time during engine running. That's why I'm asking here as my XJ doesn't give me the impression of being mis-timed... but I'm not sure about the terrible gas mileage I'm getting and thought the dizzy being off a tooth could be the culprit...

keep the suggestions coming and I'll make a list of things to check.
 
A few, or more, years ago I installed the distributor on my 89 MJ 4.0L one tooth off. I was changing the distributor seal at night, and had to go to school the next morning. I threw it in there, it started up, a tiny bit rough at first, but then idled fine and everything seemed normal so I just shut her down and went to bed.

I got up the next morning, started up fine, backed down the driveway just fine, but when I put it in drive, it ran real rough. Idled fine, give it gas and it just lost power and stuttered. It barely made it back up the driveway. It sounded like an old tractor motor, and had no ballz, but it did run.
 
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