97 ZJ JGC - Wont idle cold and now barely when warm!!

Greetings, I have about 81,000 miles or about 135,000 km. And keep it nice and maintained.

Last fall i had problems , ZJ would not idle when cold, i replaced the IAC and we were back in business. I spayed a can of TB cleaner into the TB as well and threw in a can of injector cleaner in the tank. It never idled smoother.

Its been running great until this week. Developed the no cold idle again. Its wants to idle at about 250-300 instead of its normally robust 500 rpm, it seems to surge and fall from 225 to just under 500.

It runs fine at speed on the freeway.

I pulled the IAC , its was spotless, gave it a wipe. Even shot some TB cleaner into the IAC port and wiped it out. I stuck my finger into the IAC port with a rag as far as I could go and rotated it to clean. Is it possible I broke something in the TB when I did that? I kind of doubt it cuz thats what i did last fall and everything was fine afterward.

Replaced the TPS , if anything it seemed to idle even lower. ( It was not a mopar TPS )

Today, just trying the easy stuff replaced the crankshaft position sensor, still runs bad -- this was more a preventative step ( i.e hoping ).

I disconnected the TPS while its was idling and all it did was throw a code (24- low/high tps voltage ), the motor had no reaction, other than to keep chugging away. i did plug the tps back in and the code is still there but i figure it will clear in 4 or 5 starts.

I have not gotten any codes ( other than the self -inflicted 24 ) Could I have gotten bad TPS sensor? Could the IAC be bad? Kind of doubt it.

All I got left on the TB to replace is the MAP sensor and that puppy is about 150 clams. I could throw more injector cleaner in the tank, but i feel that's not the root problem. Should i pull the TB?

Any pointers appreciated-- oh ya Is it possible to install a TPS wrong? Im not ready to take it to the garage just yet.

Thanks, James

Reply to
jamest
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Today I removed the TB and cleaned it thoroughly, reassembled it and still had no idle.

iI did check the voltages ( Key on- not running ) on the TPS , oddly the center terminal ( orange ) read 4.67v and the terminal to the left of center (BLK) read .01v and right of center(BRN) seemed to be around 5.0V.

terminal ( TPS output to PCM ) should be low ( Greetings,

Reply to
jamest

In todays episode...

Checked the voltages on the TPS-- its cooked. Put back on my MOPAR one and my MOPAR IAC-- The TPS is now working right but still no cold idle-- but once warmed a little is fine. Todays lesson is no more Chinese parts.

I am getting high voltages out of the MAP sensor, so I ordered that -- went to the dealer. Also I only get 7KOhm from the intake manifold temp sensor which is kind of low-- so I also ordered that.

I will install those tomorrow. If that fails then its onto the coolant temp sensor, the O2 sensor.

jt

Reply to
jamest

FWIW, if you go NAPA there are two flavours.. regular NAPA and Echylin. The Echylin parts are more expensive but also identical to OEM. In many cases from the same vendor.

Reply to
DougW

Success - Put on the MAP sensor and it fired up. Put on the IAT sensor since I had it. Thru in a bottle of injector cleaner filled the tank and headed out to Black Lake for the weekend.

Ran f> In todays episode...

Reply to
jamest

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