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jeep stalled now will only idle.....

jcnoble

jcnoble

NAXJA Forum User
Location
Huntsville, AL
Was running fine then stalled, i can get it to idle with the MAP sensor vacuum unplugged otherwise it will not start. Changed MAP ,plugs, wires, dist. cap , is getting gas to rail, changed fuel filter. Cleaned idle adjustment motor on the throttle body and also throttle body was very dirty. Ideas???? thanks! Im gonna go clean my gun next, haha.
 
This condition can be caused by the throttle position sensor. Get it to idle then reach down and actuate the sensor without the throttle. You should see the rpms vary radically and most likely die. Have you washed the engine lately. That is what normally kills the TPS. Carb cleaner is even worse than water.
 
I cleaned the throttle bottle with some spray stuff and also used engine degreaser. Hmmm......
 
Nope, new TPS same thing, hard to start and will only idle till warm. And Thats with the new MAP sensor vacuum unplugged. Heres what i changed (I had overheating problem too):
1, o2 sensor
2. Coil
3.Wires
4. Plugs
5. MAP sensor
6. Battery
7. Thermostat
8. Water Pump
9. Radiator
10. TPS sensor
I cleaned all the connectors with contact cleaner also. I looked at the gas, looks clear. The only thing left is the fuel pump, injectors, and the Electronics Contol Unit. Holy Cow !!.. and I still need to pass smog!!!! failed hydrocarbons and carbon monoxide.

oops and fuel filter and dist. cap and rotor...
 
jcnoble said:
Nope, new TPS same thing, hard to start and will only idle till warm. And Thats with the new MAP sensor vacuum unplugged. Heres what i changed (I had overheating problem too):
1, o2 sensor
2. Coil
3.Wires
4. Plugs
5. MAP sensor
6. Battery
7. Thermostat
8. Water Pump
9. Radiator
10. TPS sensor
I cleaned all the connectors with contact cleaner also. I looked at the gas, looks clear. The only thing left is the fuel pump, injectors, and the Electronics Contol Unit. Holy Cow !!.. and I still need to pass smog!!!! failed hydrocarbons and carbon monoxide.

oops and fuel filter and dist. cap and rotor...
Click to expand...

Silly question, from me. Did your throttle cable break? Have you tried reving directly at the TB?
 
Yeah, i can rev it up very slowly sometimes but it mostly will sputter and stall. Good one though, I always ask "Is it plugged in?"
 
Took off the cat just for the heck of it. Same symptoms but it will start for 5 - 10 seconds with the MAP vacuum attached then die. Still runs for a few minutes with the MAP vacuum unplugged. I think i will test the fuel rail pressure tonight just to get a number. Found the CPS sensor finally, how the heck do you replace that???? Looks like you have to pull the engine.
 
jcnoble said:
New o2 sensor. The output is the typical square wave though.
Click to expand...

I know it's new, but I have had new dead parts before. It is easy to check, and free. You could probably take it to a parts shop and they could check it for you there too for free.
 
It certainly can't hurt. I will ask them about it when i pickup a fuel pressure guage to measure the rail pressure. I did cut into the old 02 and it was cycling once per sec. 1 to 4.5 volts. I think it says in the factory manual the Renix "88" system runs open loop until it warms up then goes into closed loop.
 
jcnoble said:
It certainly can't hurt. I will ask them about it when i pickup a fuel pressure guage to measure the rail pressure. I did cut into the old 02 and it was cycling once per sec. 1 to 4.5 volts. I think it says in the factory manual the Renix "88" system runs open loop until it warms up then goes into closed loop.
Click to expand...

I am not sure what the specs are on the o2 sensor. I have read them on this forum somewhere though. Is your air filter clogged?
 
WOW, i got a fuel pressure guage...ive got fuel flow but no pressure. I think the fuel pump must be bad. Either that or the regulator huh? I guess ill go pick up both and install the regulator first then I can return the pump if its the regulator. I hope this does it then I can get gack to my original problem of not passing smog ..
 
Still wrestling with fuel pump, is it easier to drop the tank?? I will let you all know if this fixes the problem as soon as i can get it in.
 
Yes I did that, hey do you know if the electrical connections to the pump are brass?? One broke so I crimped on a steel one.
 
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