refresh951

Need some advice.

I have a 1986 951. I have been trying to figure out why it idles high at about 1100 rpm. I have done the following:

- Attempted to set the idle by jumpering the ports and using the idle screw, no luck.

- Replaced the TPS, no luck.

- Replaced the vacuum lines, removed intake manifold, checked everything underneath. No luck. Vacuum about 17 at temperature.

- Replaced the throttle body o-ring and indle screw. No luck.

Any advice would be greatly appreciated.

_________________________________________
Shawn Deal
1986 951
www.refresh951.com

speedfreak81

Having the same problem right now myself, amongst others.

333pg333

Our tacos are often wrong. They show a higher rev count than is actually happening with your motor.

refresh951

333pg333,

Thanks for the input, I think this is the case. Should have posted first.

_________________________________________
Shawn Deal
1986 951
www.refresh951.com

elargentino

The tach deviation increases with speed - at idle it is very close to correct.

The first thing to check in this situation, (that I see you didn't mention) is that you have an audible "click" from the TPS micro switch, when you open it by hand very slightly. With engine off, of course.
This adjustment is made using the 2 screws on the side - and must definitely be done when you install a new TPS.

beebone

Just to put a new idle screw, there is leak on the old o-ring

carbongecko

i have this same issue the problem i have is idle @ 1200 and when driving the engine stay stays at high rpms even when clutch is pushed in until the clutch is re engaged in the next gear.

Tedro951

Have you checked the idle screw at the stop? (Not the one with the O-ring)

gtuma

Have you checked the ICV? I've have a similar, though low idle problem. In my quest to solve this I removed the ICV (Located under the intake) and cleaned it out. It was pretty gummed up. I could see it getting stuck and not closing all the way, maybe causing the higher idle.

You could also try a separate tach, lots of cheap multi-meters will do this. Just ground one probe and stick the other on the small coil wire and see if it disagrees with your needle at different RPM's.

refresh951

My issue was simply a gauge problem. Once I installed my Zeitronics data-logger, it was obvious the tach was reading high (showed about 1200 rpm) at idle when actually it idled at 850 rpm (my car now idles at 1000 rpm because I have since installed the Rogue M Tune),

gtuma

Any chance your gauge cluster was ever apart? its very easy to stick those needles on without getting them pointed at 'zero' correctly.

refresh951

Yes, pretty sure the mileage had been turned back. When I pulled the cluster to install the illumination kit I found a broken tab and a screw missing.

pnbell

There is also an Idle Air Adjustment Screw (not the idle stop screw) Might be called the Idle Air Bypass Screw...

It controls the amount of air entering the engine at idle... (see picture) its the small screw to the left of the Idle Adjustment Screw -Bronze in color... Turning it 'in and out' adjusts air flow and idle speed..

minho78

Shawn If you are running Rogue's setup(Josh), then I think he has set the idle higher for people that were using aftermarket flywheel IIRC. Call him and ask if that's the case.

refresh951

I have not had any issues but I will talk to Joshua about it. Thanks Manny.