jbetit

here goes, i replaced the knock sensor(it was broken), my jeep idles way low(around 500 RPMs), and is very sluggish to go from a stop. It stalls every now and then on the take off. sometimes when i start it, it dies. then when i start it again, it starts right up. also, it runs a bit rough now. what could this be?
THANK You, John

jbetit

anyone have anything i can do? i took the iac off, and started it. it idled at 2k rpms, plugged it back in, and went back down to 500 rpms. is this my problem? does this explain why it acts as though it is running rough?

fantic238

Does your iac work when you start it in the morning? Does it rev up and then down how it is supposed to?

jbetit

when i start it in the morning, sometimes it starts up at 1500 rpms, then idles down to 500 rpms. sometimes when i start it, it starts, runs at 500 rpms for like 2 seconds, then quits. i go to start it again, and starts right up, but then idles at 500.

fantic238

your iac is good.

Check the following:
vacuum feed to the MAP sensor
TPS adjustment
electrical connectors of both
close the vacuum feed to the EGR valve

Do the following:
disassemble and clean the throttle body
replace wires, plugs, dist cap and rotor

jbetit

vacuum feed to MAP sensor is good, i replaced plugs and wires 3k miles ago, but i will do the rest of what you explained. THANKS fantic238!

chuckanut

Ive been having an idle issue lately too. I was looking and found a broken vaccume line that goes to something on the firewall (map sensor?) anyways that fixed my issue. Maybe something to look at. Like I said, not sure if that is the MAP sensor or not though and you said you already looked at it so...

fantic238

yes on the firewall is the MAP

redrunner

This is begining to sound like a broken record if you remember 33s or 45s....I think all of us with Renix engines had a chip in them that was set to expire in 2010.

Mine started with these same symtoms about the middle of February. I have done much of the same stuff as everyone else (tuned up new wires, plugs, rotor, cap) replaced the broken knock sensor, adjusted the tps with a voltmeter--I did see a listing that confused me about this. It showed a listing for different setting for an auto and manual trans. Does anyone know if this is true? Replaced the IAC.

About 10 days again this can through the forum and we still don't have a good idea what is causing this and how to fix it.

All of us will be happy when we figure this one out!

My375hp302

Check your vacuum at idle. Another member was having the same problem and was only pulling 12" at idle when it should be something like 18-20". That will throw off the MAP sensor and put you into a rich condition and make it run like crap. Lets us know what you vacuum reading is.

My375hp302

Also, everyone with a Renix should know this page by heart, VERY helpful!

http://www.lunghd.com/Tech_Articles/...iagnostics.htm

redrunner

Here is the information from last week's Renix problems.....

https://www.cherokeeforum.com/f2/90-...ow-idle-41143/

fantic238

yours is another problem

fantic238

if you have a vacuum leak the idle goes UP not down.

My375hp302

Not if it's leaking around the valves/rings, hence the reason for the compression/leakdown tests.