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slight misfire with lack of power

90xj06

NAXJA Forum User
Location
Peabody, MA
i have a renix jeep 1988 and i just took it on its first real drive after fixing it.
i think my timing is off but i want to confirm as i don't have the car with me at the moment.

it would misfire ever so slightly when cruising under light load but would go away when under heavy load and had low power. also it had a strong unburnt fuel smell too.
the ears on my distributor are cut off and i took a timing light to it and matched what the ecu was showing with the mt2500.

then also im not sure if the knock sensor being broken and dangling down might have been shorting out on something. i for got about it until after.


i also just changed out the spark plugs and wires with new ones and gaped them correctly to .35

i had driven it short trips with out these symptoms. but that was before the plugs and wires.

so while i dont have access to the jeep i figured id ask
 
Double check your firing order.
 
Look up cruiser54 's renix tips
 
THis sounds like a serious mistake. "the ears on my distributor are cut off and i took a timing light to it and matched what the ecu was showing with the mt2500."
 
i haven't had time to check it yet. but when i got it the distributor was off a tooth. and i fixed that and then aligned the distributor as close as i could to my other renix's orientation.

it ran good. but i took a timing light to it also. the ecu was showing about 7btdc and that was what the timing light was showing.

once i get it all registered i might just swap my other distributor over to it.
 
i haven't had time to check it yet. but when i got it the distributor was off a tooth. and i fixed that and then aligned the distributor as close as i could to my other renix's orientation.

it ran good. but i took a timing light to it also. the ecu was showing about 7btdc and that was what the timing light was showing.

once i get it all registered i might just swap my other distributor over to it.

Keep in mind the physical installation timing (mechanical) of the Dizzy has nothing to with the ECU-timing light timing when the engine is running as the ECU can change the timing electronically at will.
 
i figure if i match the timing to what the ecu says its running would be correct?

What do you mean by "match the timing"?

I honestly am not sure they should match or that dorking with the Dizzy can force them to match?

One is the mechanical timing of the location of the rotor to the #1 pin on the rotor cap when the #1 cylinder is at TDC on the compression stroke (not the exhaust stroke, they are different).

The other is the actual ECU to ICM/HV coil spark timing, electronic firing of the spark timing is 100% controlled by the ECU.

If the spark is too soon or too late, or the Dizzy is off 1-2 teeth or more, the spark goes to the wrong cylinder at the wrong time, or arrives too early of too late (causing misfires).
 
i think i might just pick up a new cap and cut the old cap and set it to the correct gaping past the 1 post.

the when reading the data from the ecu using the mt2500 it does show its ignition timing but now im not sure if its an addition to the base timing.

never the less im going to replace this distributor with a new one.
 
The ECU adds or reduces the base timing electronically on the fly as needed.
 
Turns out jeeps like all 6 sparkplug wires connected. The #1 popped off at the dizzy. I will replace the dizzy anyway because of the missing tabs
 
Turns out jeeps like all 6 sparkplug wires connected. The #1 popped off at the dizzy. I will replace the dizzy anyway because of the missing tabs


LOL, you think?
 
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