Topic: Someone please help...Surging TJ

[wefly5]

I have a 2000 wrangler that is surging or almost missing around 2000rpm's. It' driving
me crazy. It's a 2.5 with 160000 miles. I have put a 59.5mm tb on it, the converters
are removed, it has a spacer. I have changed the TPS, the Map sensor is good, also
i installed a MSD coil,cap, wires and rotor. None of this helped. I also changed the
injectors. I dont know what else to do. Form a dead stop you can take off ans shift
at like 3000 rpm's to 2nd which drops the rpm to like 1900 when you release the clutch
and apply the gas it starts to jerk. You can let off the gas and re apply and it will go
on. shift to 3rd and get the same results. Also if you are just crusing at say 1800 rpm
and start up a grade and and apply the gas as you start to get to say 1900 you will
start to feel the surge.....as the rpm go on up the surge gets worse. It will do this to
like 2100 - say 2200 tops. From like 2500 on it's fine. On the road at like 65 in 5th
gear it just feels like it's running rough .......just missing and surging.  Jeep has 4.10
gear w/ 31-10.50 MTX's. It's driving me crazy. Also is the fuel filter in the tank ? What s
the deal with that ?  I feel it's ignition i just cant figure it out. Some one please
help.

[sharpxmen]

I have a 2000 wrangler that is surging or almost missing around 2000rpm's. It' driving
me crazy. It's a 2.5 with 160000 miles. I have put a 59.5mm tb on it, the converters
are removed, it has a spacer. I have changed the TPS, the Map sensor is good, also
i installed a MSD coil,cap, wires and rotor. None of this helped. I also changed the
injectors. I dont know what else to do. Form a dead stop you can take off ans shift
at like 3000 rpm's to 2nd which drops the rpm to like 1900 when you release the clutch
and apply the gas it starts to jerk. You can let off the gas and re apply and it will go
on. shift to 3rd and get the same results. Also if you are just crusing at say 1800 rpm
and start up a grade and and apply the gas as you start to get to say 1900 you will
start to feel the surge.....as the rpm go on up the surge gets worse. It will do this to
like 2100 - say 2200 tops. From like 2500 on it's fine. On the road at like 65 in 5th
gear it just feels like it's running rough .......just missing and surging.  Jeep has 4.10
gear w/ 31-10.50 MTX's. It's driving me crazy. Also is the fuel filter in the tank ? What s
the deal with that ?  I feel it's ignition i just cant figure it out. Some one please
help.

what about the spark plugs?

all is left is the crank sensor (which would be ignition related) and the cam sensor (that's fuel related). You say the MAP is good - how did you determine that.

Also, what is the 59.5mm t/b - off which vehicle?

[wefly5]

I machined  TB .5 under the spacer, then ground out the intake to match the spacer.

Spark plugs are stock champion what the book calls for.

Check the map by applying vacuum and the idle changed.

Should i replace the map, with a new 1 ?

What about the crank sensor.....where is it located ?

[sharpxmen]

I machined  TB .5 under the spacer, then ground out the intake to match the spacer.

Spark plugs are stock champion what the book calls for.

Check the map by applying vacuum and the idle changed.

Should i replace the map, with a new 1 ?

What about the crank sensor.....where is it located ?

the crank sensor is on the transmission bellhousing right above the flywheel (top of the bellhousing close to the engine block on the driver's side)

not sure about the MAP sensor, applying vacuum only tells you that is not completely dead but not if the output information is correct - if you could test with another one would probably be the easiest way to tell if it's faulty or not.

just to get the facts straight: is your engine a 2.5L? is the t/b a 4.0L machined out under the butterfly? if so did you put on your old tps and IAC valve and housing?

[wefly5]

Yes tb is a 4.0 machined under the butterfly....and i did use the old iac and tps.

And yes it is a 2.5...idle is fine

[sharpxmen]

Yes tb is a 4.0 machined under the butterfly....and i did use the old iac and tps.

And yes it is a 2.5...idle is fine

your's has the MAP sensor on the t/b - make sure that little elbow that goes from the MAP to the nipple is not cracked or plugged and also make sure that the hole and nipple in the t/b is not plugged either. If you can get your hands on a spare tps and/or crank sensor give those a shot and see what happens (but i can't say for sure that's the reason so not suggesting to buy them if you can't return them).

also, this is a long shot but how is your catalytic converter doing?

do you get any CEL codes?

[wefly5]

The converters are removed. I still have both O2 sensors in the pipe. No codes

but removing the cats helped. Before they were taken off you had to get out

and push the thing to take off. Now it will at least take off by itself.

[sharpxmen]

The converters are removed. I still have both O2 sensors in the pipe. No codes

but removing the cats helped. Before they were taken off you had to get out

and push the thing to take off. Now it will at least take off by itself.

you're OBD2 and i am not sure how the second O2 comes in play here with no catalytic converter, anyway, what you describe could be related to one of those sensors (MAP, TPS, crank, cam) but it's hard to tell which one (and since you replaced the tps with a new one i assume, i would have a look at the MAP and crank) - this is just me guessing so i don't rule out anything else either. Since you're OBD2 you could also have an on-board diagnostic ran while you're driving and reproducing the behavior, that way might be a lot easier to pinpoint so you don't start replacing one thing at a time

also, make sure you got good electrical contact at all sensors, some pple here had reported issues similar to yours when that happened.

Keep us posted with your progress.

[wefly5]

Changed the map sensor last nite it did not help .  What about the fuel

pressure ?  What about the fuel filter ?  Why was it made not serviceable ?

What kind of hair brain idea was that!

[sharpxmen]

Changed the map sensor last nite it did not help .  What about the fuel

pressure ?  What about the fuel filter ?  Why was it made not serviceable ?

What kind of hair brain idea was that!

checking the fuel pressure is a good idea, but since you don't have the issue at higher rpms i would say it's not the case. same goes for the filter (and in your case is supposed to be lifetime - i think so at least)