High idle of 1500rpms

[RamRod302]

Hey guys, just finished putting the 4.7 back together and I get an idle of 1500rpms and never comes down even when the temp gauge reads warmed up. When I tap the throttle it revs up but seems to hang there momentarily before coming back down to 1500rpms. I get codes po132 oxygen sensor circuit high voltage bank 1 sensor 1, and p1128 closed loop fueling not achieved bank 1. So I’m guessing it’s something going on with the driver side. Thoughts on the cause or how to go about diagnosing said problem? Thanks for any help you guys can give me cause I’m not sure where to start with this one. I know the battery needs to be replaced, and even though the temp gauge got up to temperature I noticed only the driver side radiator hose was hot. Let me know what you guys think.

 

[skydog]

Guessing......Throttle body gasket

 

[RamRod302]

Guessing......Throttle body gasket

Why would you suspect the throttle body gasket?

 

[skydog]

vacuum leak will cause a run away (high) idle. You say you tap on it and the rpm increases.

like I said guessing. You can test it with a squirt bottle of water. Couple of squirts around the base and it should settle down.

If not, then it's something else.

 

[RamRod302]

vacuum leak will cause a run away (high) idle. You say you tap on it and the rpm increases.

like I said guessing. You can test it with a squirt bottle of water. Couple of squirts around the base and it should settle down.

If not, then it's something else.

Ok thanks. Does anybody have any thoughts on the pcm needing to relearn the throttle body since it’s drive by wire? I’ve read different ways to “reset” everything

 

[LoneWolf3574]

Duplicate post

Possible vacuum leak?

So finished putting the 4.7 back together and first start up I get a high idle and what sounds like a pretty large vacuum leak from the driver side , not exactly sure where from. I’ve already check the hoses are all hooked up. Is there something I’m just overlooking or thoughts on what it could...

www.ramforum.com

 

[RamRod302]

Ok update. The idle started to come down to 1000-1200 then I got the lightning bolt on the dash and a rough surging idle. Only code was for the 02 sensor still. Thoughts or ideas on what or where to start on diagnosis?

 

[Daw14]

Are the correct wires plugged to the right o2s ? Bad 02 sensor?

 

[RamRod302]

Are the correct wires plugged to the right o2s ? Bad 02 sensor?

I haven’t touched any of the O2 sensors. I got the truck for free cause of dropped valve and put new heads, injectors, plugs, seals, chain and tensioner kit, oil pump, to hopefully get a good running truck. I ordered all 4 just cause it’s been sitting and it was $60 for all 4 from rockauto

 

[Daw14]

These trucks really like mopar branded sensors, running aftermarket sensors can cause weird issues .

 

[RamRod302]

Just replaced an O2 sensor and I’m no longer getting that code but I’m still getting a 1500rpm idle. I noticed on the scanner at “idle” the tp% 12.2 even though I’m not touching the pedal. Is that normal or could that be the cause of my problem and how would I diagnose it? Thanks

 

[RamRod302]

Figured out the problem… some how the intake manifold sucked the oring seal off of the Egr tube. Don’t ask me how, but it did. I got this truck as a project so I’m not surprised that now as I move on I found out the wipers don’t work, and I get low washer fluid light even though it’s full. But the squirters work so that’s a plus haha