HWG09

Hi guys. Purchased an '86 951 not too long ago that needed some love.

Wasn't getting much boost and occasionally would die on me while coasting in gear.

Since have done the following.

New fuel filter
Changed oil
New spark plugs
Lindsey racing vacuum hoses/venturi delete
New J-boot
New cycling valve

Currently the car is running about the same as before. There was a period after I did the fuel filter and before I did the vacuum hoses where I was getting about 1.4 bars of boost but now we're back to 1.2 maybe with higher RPMs in 2nd and 3rd pretty rough. I can hear the turbo spooling but no boost.

I haven't tested the wastegate yet although may do that soon. Didn't mess with the TPS or throttle body and I currently get a good idle but sometimes after having the car under load I'll come to a stop or be taking a turn and the car will die. It usually starts right back up again though.

There's a somewhat loud ticking coming from the fuel injectors which I've been told is normal.

Feels like I've invested a lot of time and reasonable amount of money but can't get the car to run quite up to par.

Am close to taking it to a shop to have them check it out but would appreciate some ideas before I do that.

Thanks

divil

I'd start by pressure testing the intake:



Also, try clamping off the CV-wastegate line and see if that brings the boost back. That will tell you if it's a boost control issue (but be careful with the throttle as you will have no boost control)

Some faults will trigger a fault code in the conputer: you can check for "blink codes" using this procedure

Also check for exhaust leaks before the turbo.

That's some easy stuff to get you started

fejjj

I had a similar problem and it turned out to be a clogged cat.

DER951

+1 on clogged cat.

I've been told gutting the cat is good for about 12 HP, but have never seen documentation of that.

HWG09

What's the procedure on unclogging the cat?

83 944

Cut that sucker out and start a 3in haha. or cut it out and replace it with a 2 1/2 ID pipe =]

Cyberpunky

Could just be an exhaust leak too

odurandina

this....

one of the most often overlooked deal-breakers.

my 968 cat was clogged at purchase (77 k miles).

i'm sure i picked up at least 12~15 hp over new-engine spec when i eliminated it.

DER951

My cat was gutted by removing the rearmost part of the exhaust, then repeatedly ramming a steel bar into the cat material to break it up, then vacuuming it out.

Advantage is the exhaust will still pass a visual inspection if that's what your state requires for older cars, as the "appears" to be present.

Mach 5

I purchased a '86 951 in May and had a problem with inconsistent boost. Not quite the same problem you're having. Mine turned out to be a failing wastegate, which eventually failed altogether resulting in 0 boost. (BTW, the Tial replacement is FANTASTIC!)

It's very easy to check if the wastegate is closing fully. Start the car, let it run for a while, then reach under the passenger side and touch the dump pipe from the wastegate. If its warm, then your wastegate isn't fully closed. It should be cold.

My car already had a cat delete when I got it, so I can't speak to that issue.

Good luck.

Roger