revs to 2K on start up

snyder1010 · Nov 21, 2003

I am a relatively new owner of an 00 GC 4.7L. -Everytime I start the Jeep it revs to at least 1500rpm and sometimes as high as 2K. No codes, and everything else on the jeep seems ok. I tried to run a search but its down

I have an 87 Cherokee that had this problem and it turned out to be the TPS. But since I am unfamiliar with the Grand and the 4.7 I thought I'd reach out to some people who would know.

Thanks in advance for any help

Carl

Stocker · Nov 22, 2003

Not sure about the 4.7, but my 95 5.2 has done that since new. I'm used to it and hardly notice it any more. I assume it must be normal. :?

D-Lo · Nov 22, 2003

Maybe irrelevant, but I don't know. We had a 99 suburban that was bought new. Came off the lot, and now and then it would start up and rev to about 3-4k. They replaced the starter under warranty.

white94zj · Nov 22, 2003

All cars/trucks do that to some extent depending on how cold it is outside to speed up the warming up process.
...could even be a flacky coolant temp sensor.

Hawaiian Style · Nov 22, 2003

NORMAL? I don't think so. My 97 ZJ 5.2 doesn't do that. If yours has done it since new why on earth didn't you take it back to the stealership while it was covered? Reving the engine upon start up is not good for it.

Snyder, I'm in the same boat as you. I know more about the XJ... There seems to be quite a bit of commonality between the two. I'd check the TPS. Can be the TPS starting to go bad. Good luck.

Stocker · Nov 23, 2003

Hawaiian Style said:
If yours has done it since new why on earth didn't you take it back to the stealership while it was covered?

Simple enough to answer - It did it since day one, and I didn't see it as a defect. I agree revving a cold engine may not seem to be the best situation, but I'm not talking about instant WOT, just a brief jump to about 1500 rpm, then decrease to idle speed. After nearly nine years of daily driving, it has not suffered any apparent problems.

Hawaiian Style · Nov 24, 2003

Didn't mean for you to think I was ragging on you. It's not normal. Mine fires up and hovers at about 800 or so RPM's. On a cold day it's normal for the engine to idle a little higher for a while. On a nice day it should jump right to normal idle. Might want to check on that or since you've been living with it for 9 years now it might not be worth the trouble.

snyder1010 · Nov 24, 2003

Hawaiian --I am thinking TPS too --any idea if you can test the voltage input/output like on the XJ??

This started with me at 75K just after warranty(I bought out my fathers lease and it never did this for him) --so it doesnt seem like it should be normal. Plus I live in Southern CA and it never gets below about 50 where I live. I noticed it did it in AZ at about 110 degrees all the way down to 50 degrees., so I dont think temp has anything to do with the problem(at least in my case anyway)

Thanks for your input everybody --I appreciate the info.

Carl

dell30rb · Nov 24, 2003

My zj with the 4.0 has done this since new as well. After a cold start, it will rev up to about 1.5k and then drop to regular idle speed. Its completely normal, i think the engine might be fed more gas/air to speed up the starting process.

Stocker · Nov 25, 2003

Hawaiian Style said:
Didn't mean for you to think I was ragging on you.

No problem - no offense taken.

Great thing about a board like this is getting invaluable input from others and learning from their experiences.

Bender · Nov 25, 2003

mine did that when the wiring to the tps melted.

revs to 2K on start up

snyder1010

Stocker

D-Lo

white94zj

Hawaiian Style

Stocker

Hawaiian Style

snyder1010

dell30rb

Stocker

Bender

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