Stall at Idle/Stop
10-27-2018, 02:42 AM
#1
Advanced
Thread Starter
Stall at Idle/Stop
Hi Everyone,
Recently, I’ve been finding my 90’ 964 C4 stalling on idle. The regular idle floats around 800 rpm +/-40.
Engine has been rebuilt 15k miles ago, it’s currently at about 85k miles... battery was changed about 1 year ago.
This occurs not long after starting the engine... I’ll let it idle for about a minute or two > then drive it off. I would say the few instances (less than 5 this has happened in the last 3 weeks), I’d drive about 0.25 - 0.5 miles, then at a full stop, the engine would start to stall. Each time, the car wasn’t even in gear, I was just at full stop, or near full stop in neutral... then can immediately see everything drop out.
It’s been starting up normally after the stall... and then I would just rev it pretty hard for a while and after the engine gets a little warmer, I haven’t run into the stalling issue for the rest of the drive. It’s definitely keeping me on edge though playing with the clutch and the gas in case I see feel it drop while the engine is still cold. It’s hard to tell cause whenever I drop it in neutral towards a stop... I can see the RPM drop to 500 for a split second and get back up to the normal 800 RPM range. But it’s hard to anticipate which way it will go.
Any thoughts on what this could be could be super helpful. Would be happy to provide any more information as well.
Thanks,
Kevin
Recently, I’ve been finding my 90’ 964 C4 stalling on idle. The regular idle floats around 800 rpm +/-40.
Engine has been rebuilt 15k miles ago, it’s currently at about 85k miles... battery was changed about 1 year ago.
This occurs not long after starting the engine... I’ll let it idle for about a minute or two > then drive it off. I would say the few instances (less than 5 this has happened in the last 3 weeks), I’d drive about 0.25 - 0.5 miles, then at a full stop, the engine would start to stall. Each time, the car wasn’t even in gear, I was just at full stop, or near full stop in neutral... then can immediately see everything drop out.
It’s been starting up normally after the stall... and then I would just rev it pretty hard for a while and after the engine gets a little warmer, I haven’t run into the stalling issue for the rest of the drive. It’s definitely keeping me on edge though playing with the clutch and the gas in case I see feel it drop while the engine is still cold. It’s hard to tell cause whenever I drop it in neutral towards a stop... I can see the RPM drop to 500 for a split second and get back up to the normal 800 RPM range. But it’s hard to anticipate which way it will go.
Any thoughts on what this could be could be super helpful. Would be happy to provide any more information as well.
Thanks,
Kevin
10-27-2018, 08:53 AM
#3
Rennlist Member
There is a lot of good info on this forum and Search is your friend. A few suggestions:
- did you clean / inspect the ISV?
- any change in gas you are using?
- when was the last fuel filter change?
- when did you last change you air filter?
A lot of times it's not very complicated.
- did you clean / inspect the ISV?
- any change in gas you are using?
- when was the last fuel filter change?
- when did you last change you air filter?
A lot of times it's not very complicated.
11-05-2018, 07:51 PM
#5
Advanced
Thread Starter
Thanks for all the tips all.
@ras62 - I'll have to take a closer lookout it this weekend - I haven't checked either of those before.
@cjoenck - I did check the ISV - thanks for stating the name of the part, it helped me search up the results pretty quickly. It was kind of dirty but I could still hear the mechanism shaking around in there. After some cleaning with a few q-tips, towels, and wooden sticks... I popped it back into the car, and no stalling. However I did warm up the engine a bit before driving off. I'm going to get a better cleaning solution so I can flush away more of the gunk inside this weekend. I did notice how my idle on the tach was a little more steady than usual after doing that though.
- I did change the fuel, by Manufacturer. I usually get Valero... but been switching between Shell and Chevron (sometimes 76)... basically just trying to fuel up wherever I can (but I'll stay away from any places like ARCO). Using 91 of course.
- Not a clue on the last fuel filter change. It was probably done during one of the services prior to when I bought the car, so I'll check the service records
- air filter was changed about 7-10k miles back (also prior to when I got the car)
@klr10 - thanks for the tip. Unfortunately, the garage it's parked in has no outlet
So my solution is a good 50-100 mile drive whenever I can to keep the battery charged haha.
- Kevin
@ras62 - I'll have to take a closer lookout it this weekend - I haven't checked either of those before.
@cjoenck - I did check the ISV - thanks for stating the name of the part, it helped me search up the results pretty quickly. It was kind of dirty but I could still hear the mechanism shaking around in there. After some cleaning with a few q-tips, towels, and wooden sticks... I popped it back into the car, and no stalling. However I did warm up the engine a bit before driving off. I'm going to get a better cleaning solution so I can flush away more of the gunk inside this weekend. I did notice how my idle on the tach was a little more steady than usual after doing that though.
- I did change the fuel, by Manufacturer. I usually get Valero... but been switching between Shell and Chevron (sometimes 76)... basically just trying to fuel up wherever I can (but I'll stay away from any places like ARCO). Using 91 of course.
- Not a clue on the last fuel filter change. It was probably done during one of the services prior to when I bought the car, so I'll check the service records
- air filter was changed about 7-10k miles back (also prior to when I got the car)
@klr10 - thanks for the tip. Unfortunately, the garage it's parked in has no outlet
So my solution is a good 50-100 mile drive whenever I can to keep the battery charged haha. - Kevin
11-07-2018, 03:00 PM
#6
Racer
Join Date: Jul 2014
Location: Long Island, NY
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
Try a new battery. I had similar issue years ago and someone here said try a new battery. Even though my battery was fully charged and only couple of years old, I switched to an Optimum Yellow Top battery. Fixed it immediately and Years later the car has never stalled again.
I have learned to just go with whatever I hear that works in this forum and I don't even question the logic.
I have learned to just go with whatever I hear that works in this forum and I don't even question the logic.
11-07-2018, 08:41 PM
#7
Burning Brakes
I have the same issue especially coming to a stop after a long continuous run (like coming off the freeway).
I switch to a light weight fly wheel and I was warned that would be one of the consequences.
I had my mechanic check out all the other possible issues.
I switch to a light weight fly wheel and I was warned that would be one of the consequences.
I had my mechanic check out all the other possible issues.
Trending Topics
11-09-2018, 01:17 AM
#8
Rennlist Member
Yes LWF can cause potential stalls, especially when coming down from high RPMs and/or AC on. Check with Steve Weiner of Rennsport for a modified chip to help with that. Easy peasy.