High revs on first cold start and not warming up.

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Gasher33

New member
Joined
Feb 11, 2017
Messages
29
I have a very strange situation that i don't know how to figure out.

If it's a cold day and i go start the car, it doesn't matter how long I let it warm up, the revs are still up. Even after driving for 15-20 minutes the car still behaves like it is still cold (revs are around 1500rpm and the overall fell is like I've just started the car)

The strange part is that if after those 15 minutes of driving/warming up the car, I stop the engine and start it again everything is perfect, revs smooth at 900rpm and it fells the way it should even if 1 minute before it was revving like crazy.

It's like the ECU is getting the engine temperature only when it starts and keep that one for the rest of the drive. The dashboard shows the temp changing and going to normal.

I'm interested in if someone encountered this and what was the fix.
Sorry if this was answered in another post and i missed it.
Thanks!
 
Yeah it is warming up, if I kill the engine after i let it warm up and start it again everything is normal
 
I cannot recall previously this exact problem being posted before.
I would however start by removing and cleaning the idle control valve (ICV) out with carb cleaner and refit.
I am wondering if it is sticking a bit. Before removing you could try gently tapping it with some soft wood along its length with the engine running , if it brings the idle down you could quickly establish it as 100% being the cause. If you get no idle speed change still clean it before looking elsewhere. :thumbs:
 
Yes, clean and test the idle air valve. There are plenty of video's on tube for testing. Those things last a long time but they do eventually fail so it wouldn't be unusual.
Actually, testing might be inconclusive for you since it apparently only fails when cold...
Try cleaning it. If that doesn't work, replace it.
You could try checking the voltage to the idle air valve to make sure its not an electrical problem, but I probably wouldn't bother.
Note: When replacing the IACV, you need to reset the PCM and then give it some time to re-learn how its supposed to behave.
 
Here's a chart from a general Ford PCM book. The Puma isn't specifically discussed in this book but the IACV stuff is probably universal.
IACV pg1.png
IACV pg2.png
IACV pg3.png
 
Ok so I changed the ICV and the air temp sensor and everything seems to work now. I hope it will last because in the summer I did a ECU reset due to high idle that fixed it for a short period of time (then it was always idling high)
 
Hi Long shot but it may be as simple as the thermostat sticking open and the rest of the system trying to sort it out. One up to temperature no problems? Just the colder weather making it more important now.
Orion
 
Looks like the initial problem of high revs when taking it out of gear until comming to a stop. How could I test if the thermostat is bad? Or any other ideas to test? Thanks :D
 
Thermostat wont cause high revs.
You are getting excessive air flow from somewhere.
Assuming the new IACV was NEW, and assuming that it is fully functional, the next likely problem is a vacuum leak. Since its intermittent, and apparently temperature related, Its probably not going to be a very obvious location. Maybe one of the gaskets on the intake manifold. Start with anything you've touched recently, including the IACV gasket.
 

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