Topic: ugh i give up...

[Torch_Ind]

...There was once a time when there were no 4.88's...

still doesn't answer why you don't know lol

[spoonman]

they exact setup i have now was getting 23mpg @65 mph  on freeway and 18 in town. jeep was on the scanner today. there is no timing adjustment, but we could see it didn't advance consistently. sometimes was perfect other times it would hesitate and advance with inconsistent numbers. fuel press looked good.

[dwtaylorpdx]

The difference in mileage for me is about 4 MPG driving 75 instead of 55 on flat ground.

Just a small data point.

Warmed up YJ engine with headwork, cam, light pistons balanced etc...

Dave

[Jeffy]

still doesn't answer why you don't know lol

You asked;

why not go 4.88's then? esp with 35's

Like I said, there were no 4.88's available at that time.  And to do it over again is a waste of money.  It's not that big of a difference.  I'm holding off for 5.13's (with 33's) or 5:38's (with 35's) which will get me back to stock.

[sharpxmen]

they exact setup i have now was getting 23mpg @65 mph  on freeway and 18 in town. jeep was on the scanner today. there is no timing adjustment, but we could see it didn't advance consistently. sometimes was perfect other times it would hesitate and advance with inconsistent numbers. fuel press looked good.

most obvious reason for out of whack and erratic ignition timing would be the crank sensor.

EDIT: how did the MAP and TPS output look?

[Torch_Ind]

You asked;

Like I said, there were no 4.88's available at that time.  And to do it over again is a waste of money.  It's not that big of a difference.  I'm holding off for 5.13's (with 33's) or 5:38's (with 35's) which will get me back to stock.

 

[spoonman]

map and tps were fine. i called a bud who plays with jeeps. he said crank sensor too. he also said ignition module if crank sensor wasn't problem. i just hope it's something easy i can do. thanks for all the help.

[Torch_Ind]

map and tps were fine. i called a bud who plays with jeeps. he said crank sensor too. he also said ignition module if crank sensor wasn't problem. i just hope it's something easy i can do. thanks for all the help.

hope you figure it out soon,  chasing gremlins isn't always that easy!!

[sharpxmen]

map and tps were fine. i called a bud who plays with jeeps. he said crank sensor too. he also said ignition module if crank sensor wasn't problem. i just hope it's something easy i can do. thanks for all the help.

unfortunately there is no ignition module, is integrated in the PCM (ecu) so that would be a bummer.

[FourbangerYJ]

unfortunately there is no ignition module, is integrated in the PCM (ecu) so that would be a bummer.

What do PCM's sell for? Can you buy a used one or is it better to buy new?

[sharpxmen]

What do PCM's sell for? Can you buy a used one or is it better to buy new?

buy used, new are too much $$$ (and with YJs in our case would be hard to find anyway, but you never know some nos sale could turn out cheap).