High revs on idle and when stopping.

ProjectPuma

Help Support ProjectPuma:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Gasher33

New member
Joined
Feb 11, 2017
Messages
29
Hey guys, sorry if this is somehow duplicate but I found different threads that are similar to this one but the collective amount of informations is too large for me.

I have a problem with my 1998 1.7 Puma when starting the car the idle is around 1500 RPMs and it seems not to drop even after the car is warmed up. When driving and shifting gears the RPMs when i press the clutch seems to go up but i might be wrong here.
The major problem is that when I come to a stop and put the car in neutral the RPMs go up to around 3000 RPMs and I can get them to drop only if I put it in gear and start moving.

Anyone had this issues and can tell me where to start looking for the problem.
Sorry again if this was answered in another post and i missed it.
 
I checked for a vacuum leak but i could see anything major. I checked the hoses and couldn't find any cracks. Any common sports that pumas got vacuum leaks? And could I do anything to test the idle control valve before taking it out to see it that is the problem?
 
Check this air blanking plug is not split, or missing:
https://www.projectpuma.com/viewtopic.php?f=65&t=31639&p=367386&hilit=blanking#p367386
 
The air blanking plug is there and it's not cracked. Yesterday i checked the ICV by disconnecting it and the engine just stalls so it might be just dirty. Today i'm going to reset the ECU by disconnecting the battery. Someone told me that it could be something bad related to the thermostat, any tips on how i could check that. I just got an cheap OBD2 reader to check for codes but nothing there, any tests i could do with an OBD2 that could help me find out what's wrong?
 
Hopefully someone will correct me if I'm wrong, but I think wobbly idle can be caused by PAS pressure sensor wiring issue. The sensor is in the front RHS of car underneath near the radiator and crank pulley. The connector and wiring is quite exposed and can get worn out or broken. If this happens the signal that adjusts idle to compensate for PAS load goes haywire and the idle jumps around as a result.

Another tip: to check for air leaks, have the engine running and squirt some easy-start around suspect areas. If the idle jumps or alters then the easy start is getting in around the area you just squirted and that's where the leak is.
 
Just reseted my ECU and idle seems to be normal now. I couldn't go for a drive yesterday to see how it handles stopping and between revs. I am curious if this was a quick fix and how long will it last.

I checked the PAS and it looks good but i don't know how to really test it. I saw a post that someone unplugged it and went for a drive to see if there is any difference, good or bad. Is this a good idea?
 
THE PAS switch is normally open, I believe. Only when steering opened to max, it should close. So it is rather straight forward test. See with multimeter what is its state and them with wire short the connector pins to see if the engine revs rise a bit
 
Could be the throttle position sensor.
I had this very problem with my 1998 when I first bought the car,usually held onto revs between gearchanges and if the engine had been running at speed for any length of time the revs would stay as high as 3000rpm for quite a sew seconds after bringing the car to a stop before eventually dying down.
 
I replaced the ICV with a new one. I checked the clutch sensor to be plugged in, what do you mean with check for 'security and function's and how could I do this.
 
Make sure it is in the correct position, and securely fastened in place.
Check there is an electrical current to the socket. I cannot remember whether the circuit makes or breaks, when the pedal is depressed.
Could be that the switch itself is faulty, but first you need to check for current. Detach the switch from the mounting (keep it connected to the loom), and you should be able put meter probes in the connections. Start the engine and press the switch, to see if you get any meter readings.
 
Managed to figure it out. It was the wiring to the TPS, some pins were dirty and after a good clean everything is fine.
 
The problem is back, and I suspect the PAS sensor but I am unable to find the piece online. Could someone provide me with the code for the PAS sensor?
 
Hey, did you find what the issue was this second time? I've been having the same issue for a while now, for the second time too.

First time it was a vacuum leak, but I can't find anything now.

I replaced the ICV and no improvement. I'll try to clean the TPS connector pins and see if that fixes it.

Anyway, you mention the issue is most noticeable when you come to a stop and put the car in neutral, but don't mention anything related to steering, so why do you suspect the PAS sensor?
 
Yeah, the thing that caused my issue was dirty corroded plugs. For me the TPS plug was clean but I followed the cable and checked every plug and found 2 of them dirty. After cleaning them the problem was gone and it idles fine.

I suspected the PAS sensor mostly because it is a known issue that will cause this symptom. I have a pretty good idea why this is happening and how the PAS can cause this symptom but I don't think I can explain it well enought.
 
Gasher33 said:
Yeah, the thing that caused my issue was dirty corroded plugs. For me the TPS plug was clean but I followed the cable and checked every plug and found 2 of them dirty. After cleaning them the problem was gone and it idles fine

What Plugs ?.
 

Latest posts

Back
Top