Alex08T

Hello,

My father has a 1989 Turbo that has recently had a couple issues. On startup when the car is cold it runs a little then coughs and the car dies. Once it warms up a little the idle is fine although it is slightly low (800 RPM). Also the cold start feature that raises the idle seems to not function anymore.

When driving the car there is a distinct flat spot (loss in power) at 3k RPM and above. in order to speed up over 3k RPMs you really need to mash the throttle to get any speed increase. The car is making full boost however.

Lastly when the car is shutoff it runs on. I know that they are supposed to run on a little bit but this is running on much more than it ever has before.

Maybe all these issues are related?

Any help would be greatly appreciated as we plan on driving to the grand prix in montreal soon!

Thanks!!

Mark Houghton

More than likely an air leak in either one of the vacuum lines or the intake (intercooler and associated plumbing). Check all hoses first. If nothing external is found amiss, then pull the intercooler and check all the o'rings.

Alex08T

Thanks for the tips! Could one of these hoses still be the issue if I'm making full boost?

Mark Houghton

Yes. If you have a leak post-turbo, you could still run up the boost but will seriously screw up the air to fuel mixture: i.e., that boosted air will leak out before it reaches the intake manifold and result in a very rich condition and loss of power.

There can be other causes for what you're experiencing, but first things first - check the obvious. Vacuum/air leaks on CIS fueled cars can cause what you're describing. I'm assuming your fathers car has not be converted over to EFI.

Alex08T

I'm not familiar with CIS/EFI. I know it's completely original. So it has whatever the stock system is.

Mark Houghton

Stock CIS, continuous injection system where fuel is constantly sprayed via the injectors and the quantity is governed by a fuel distributor that adjusts the amount of fuel dependent upon the amount of air being drawn across a fuel metering plate. As such, that sets up your air to fuel mixture. Let some of that air escape and now the previously set up mixture will be off.

That is a very basic description of what's basically a mechanical injection system, as opposed to electronic (EFI) where the injectors are fired in spurts electronically.

ereedca

What was ever found to fix this issue? I have the same problem.

TT Surgeon

.

Very nice easy to understand description!

Mark Houghton

Thanks for the kudos! I sure as hell don't know but a small % about these cars, but I try to put descriptive words to things that are really pretty basic but not readily understood by everyone. Such basic knowledge helps others to diagnose the crap that plagues them. Education means not shooting in the dark, and that's what these forums are all about.

Mistergee

If you dont hear, another try would be to Check battery , A flat / weak Battery will also cause them to run lke a pig

piatnik

Alex: Have you found the cause ?

I have a similar issue with my 1988 930:

Sometimes (it happened a few time this summer), let say I am constantly around 3K (RPM) in third gear on the highway, during an acceleration (or a wish to accelerate...), instead of accelerating, the motor seems to have some trouble processing the fuel and a black smoke go out of the exhaust. And there is no power at all. I release the pedal (steer on the right to not get in trouble on the highway...), go in second gear, slow down and then after a couple of second, everything go back as usual.

This happened only a couple of time during the summer, but last Friday, during a long ride, after an hour of driving, I had the trouble, but big time. I had some difficulties to reach my destination, but finally reach it driving at slow speed. But on my way back home (two hours ride), no problem at all...

Could it be a bad Throttle position sensor, bad ignition rotor or most likely an air leak as Mark mentioned?

Regards,

Julien

skipp

Guys,

If you haven seen this 930 diagnostic info on Pelican Parts, give it a go.

http://forums.pelicanparts.com/911-9...snt-start.html