rocker65

After getting a new AX15 installed I got my XJ back on the road after sitting for a little over a year. It ran really really rough so I changed out the fuel filter. It runs much better but is still has hesitation when I accelerate or even runs better when I let off the pedal. Someone mentioned both my CPS and TPS. If I replace both of these and it is still an issue what is my next step? It was tuned up before the transmission swap.

Radi

Any sign of vacuum leaks? They seem to crop up when things sit unused for an extended period.

cruiser54

Could be your TPS. Simple to check with a meter.

Did you route your CPS wires properly when changing the trans? If you're not careful, the wires can touch the exhaust manifold.

Radi's suggestion of checking for vacuum leaks is a good one. Grab a can of throttle body cleaner and spray around the intake manifold area at idle. You'll know when you spray a leaking area.

Never hurts to snug up your intake manifold bolts with the engine cold. Start at the center and work your way toward the ends.

rocker65

Thanks for the info Radi and Cruiser54.

cruiser54

Updates are required.............

rocker65

OK Cruiser54 here the update: I tightened up the intake manifold and it is still running rough. While I was under the XJ I noticed a bunch of stuff that seemed to be unattached. I guess the guy that did the trans swap did not get everything back in order. So, now it is time to find a true Jeep mechanic to get things back in order. I posted on craigslist looking for a reputable one in town.

BimmerJeeper

1. TPS (Throttle Position Sensor)
2. Idle Air Control (IAC) motor
3. Vacuum leak
4. MAP sensor?
5. Bad battery (effects ECU)
6. Clean Throttle Body? (getting stuck?)
7. CPS (Crank)
8. Cam PS / Distributor Pickup Switch
9. Distributor cap, rotor, wires, plugs
10. Low fuel pressure?
11. Bad alternator ?
12. O2 sensors (should throw code)
13. Bad injector?
14. Replace coil?
15. Intake Manifold Vacuum leak?
16. EGR valve?
17. CCV hoses clogged?
18. Fuel filter?
19. Air Temperature Sensor?
20. Coolant Temp. Sensor

cruiser54

So what's unhooked and where? Pics??

rocker65

Hopefuly I'll get pics today. I've got a ton of crap to get done today. Couple of these wire come across the top of the transmission. I am going to start replacing parts one at a time until the problem is gone. Bought a Haynes manual yesterday for the vaccuum diagram. Where can I buy replacement vaccuum lines for stuff coming out of the throttle body. They are very very brittle.

cruiser54

Don't replace parts until the wiring is sorted out. We can help you with that.

rocker65

I'm pretty sure one of them is the speedo cable since my speedometer is not working. I will get pics soon.

rocker65

replaced and attached all vaccuum lines. Still runs rough until I back off the accelerator while going through a gear. Had the mechanic that replaced the transmission tell me he could hear fuel running back into the tank after shutting the engine off. He is telling me that he suspects the fuel pump.

BimmerJeeper

Do you get a loud gurgling coming from the gas tank?
Is that the sound of fuel running back into the tank?
I sometimes get this. Listen.
https://www.youtube.com/watch?v=QfQM-_J4DJQ

cruiser54

I would do a fuel pressure test at the fuel rail. It does sound like a fuel starvation problem. Pull the vacuum hose off the fuel pressure regulator at the front of the fuel rail and see if there's any fuel in the vacuum line of regulator nipple.

cruiser54

He has a different sytem than you do. His has a return line.