eric951turbo

aaaaaaaah. ok. I will do everything I know to fix this. I've read a thread on 944online about checking grounds on a early 944 10 times..........

I own a 944 turbo, 1986. So far,

-the headgasket was replace twice in 2 years (all new lifters, firewire headgaskets, machined the head, etc...
-Vitesse Maf, injectors, chips, 3bar fuel reg, the whole thing....
-Vitesse Stage 1 water cooled Turbo
-Full Fabspeed 3'' exhaust
- LR dual wastgate
and all the other little pieces........................................................


Now, after installing vitesse maf 2 years ago, my car as been running way too rich. I tough maybe is :

TPS: new from last year
O2 sensor: new from last year
GROUNDS: John keeps tellings me to check my grounds, I did, they are all fine.

Don't get me wrong, John always respond to my emails, and quick.
I would like to thanks him for that.

But I've been searching for this problem for 2 years now, and I had enough.

I keep thinking that if I buy good quality products for my car, that it will run well.better.

And I did so many search, on google and rennlist about the subject: running rich

I found tons of thread, I tried everything, but still... running too rich

So I decided I'll order some parts from Pelican...........

Ordering some parts that I think that are ok, but you never know.

Maybe I have a new defective O2 sensor?

Here is my (expensive) list (for stuff I think that they are ok, but ready to take a chance just in case the car could run ok):

- new (changed last year) Bosch WR7DC+ spark plugs
- new Magnecor Wire set
- another O2 sensor
- Distributor Cap
- Ignition Rotor
- Engine temp sensor

I don't know what to change more, I've tried everything.

As anybody had the same experience as me,

I need a little help here

eric951turbo

oh, and the:

tps
coil
02 sensor

Vaccuum pressure is more than good

all brand new

eric951turbo

rennlist is slow tonight, problem with picture uploading, nevermind the pictures below

fast951

Eric, 99% of the time, the rich running conditions are related to ground issues. Of course there are other causes, which I emailed you already.

Last year You had the rich issue fixed by replacing the O2 sensor, so what did change? Backtrack the changes, and don't assume that what was fine last year is still fine now.
For testing, attach the MAF ground wire straight to the battery GND (-) terminal, how does it affect the car?

I don't recall you having a wideband to monitor AFRs, how do you determine it's running rich and how rich are the AFRs?.
Keep in mind, when cold the engine will run rich till it warms up (warmup cycle), is this what you are noticing?. You mentioned having "white smoke" out of the exhaust but does not smell like fuel. How are you determining it's rich?

will951

Chasing this stuff can be a PITA. I assume you have a wideband hooked up? What are your numbers???

tman

Definately needs a wideband to monitor AFR's.

eric951turbo

thanks John for getting back to me on this, again.

No I don't own a wideband to monitor AFR. I can recall that I did had it check last year by my mechanic and that the #s where really high (I was driving, he was beside me holding the monitor). I then changed the o2 sensor but didn't monitored afterward. It was better, I think. but at that point, I just wanted to believe the car was better. I also didn't drive the car enough afterward to really tell or see the difference because the turbo was toasted, I had to replace it.(done)

When I say the car is running rich, here are the symptoms:
- little backfires, in acceleration
- strong fuel smell, even in the cabin (window open), causing headaches
- high oil consumption
- running a bit rough

with these points, do I really need a wideband.

As for grounding the maf wire to the neg of the battery, I just tried it this morning. I havent notice anything, but I havent had a chance to go actually drive.

As for the rough start, here's a video... this is after not driving the car for only 2 days.

It does stop smoking after 15 min.


http://youtu.be/55qrLB0yTKY

eric951turbo

eric951turbo

What is a normal warmup cycle? 10min., 20min?

Yesterday, after 20min. of driving, it was still backfiring on acceleration.

Ben951S

If you don't have a wideband, you cannot diagnose and troubleshoot this SAFELY.

The Prosport kit is inexpensive (~$250 IIRC), and has output for datalogging, AND for 0-1v (narrow band) output. You do need to have the exhaust drilled and the included bung welded on ((Midas for $70 for all of it)).

You replaced the DME Temp Sensor II, right? <$20, and takes less than a half hour, and is pretty easy.

Lastly, if you have different hardware than EXACTLY what your tune was written for, you might want to go back to your 2.5bar FPR, or get an adjustable.

I run A-tune, and I believe due to my exhaust, cam, and some other things, I can't use the 3.0bar FPR, and I get better numbers (still rich though, but better) with the 2.5bar. I should get an adjustable. Again, that's because I have some other hardware that my tune does not account for, and FPR is affected by vacuum and things. =)

eric951turbo

thanks. the wideband is on my list. I just need to check which one is good, I found this site
http://prosportgauges.com/wideband_AFR_Gauge.aspx

pontifex4

Eric, c'est difficile a comprendre: as-tu changer ces choses?

I noticed a real improvement in my rich acceleration problem when I did the wires, rotor and coil.

eric951turbo

yes, It works....

Thanks all, and thank you John for your patience.

The problem WAS a ground. The MAF ground wasn't installed at a good place.
I did what John suggested, attached it to the negative of battery, and voilà.

I just came back from a great ride. The car runs smooth. Very smooth.

Now I just need to find a new place to attach that ground, I was thinking near the driver side headlight with the other grounds.

I'm glad it finally worked out, I can now enjoy my project, everyday.

fast951

Eric, it's great that you solved the rich issue. That's the good news. The bad news is that you may have ground issues to solve. I would clean the ground connections at: the firewall by the battery, the bell housing, the front of the car by the headlight mechanism.
With the engine running, check the voltage between the old MAF ground location (as in your picture) and the battery negative (-) terminal. A good chance there is a positive voltage there.. Once you clean the ground conditions, there should be no voltage between chassis and battery GND terminal.

Keep in mind, the ground issues affect all the sensors on your car, not just the MAF.

Glad you figured out the cause of the problem. Now a bit more grunt work cleaning the grounds and your car will run even better.

eric951turbo

FINALLY, after two years of searching, the car runs like a champ.

The problem was the idle adjustment.

Before I found the problem I :

- replace all ignition wires
- new dist. cap
- new rotor
- new spark plugs
- the intake wasn't sitting properly with my vitesse stage 1 turbo, I may of had a small leak. I did this : http://www.lindseyracing.com/LR/Parts/TBSCREW.html
- Cleaned all grounds
- Replaced all vacuums with LR kit
- Made sure every hoses where tight
- Installed a new TPS connector http://www.944online.com/cgi-bin/ASI...ector-944turbo
- Rebuilt my throttle body with reseal kit http://www.arnnworx.com/catalog/inde...roducts_id=181
- Replaced the tps last year
- Replaced the coil last year
- Replaced the 02 sensor last year
- brand new Injectors and 3bar reg. from Vitesse that came with maf kit (2 years old)
- new engine temp. sensor
- Cleaned the Idle control valve with carb. cleaner and then shot a little wd40 in it.

The problem was still not fixed... Running rich, backfires, lots of popping sounds, rough idle.

And on top of all that, I've paid 2 qualified 944 mechanics searched the problem over the last two years, never found the problem.

I was to point of giving up. I've been exchanging emails with John at Vitesse for the last 2 years about the subject. But John always gave me hope, suggesting new things, so I wouldn't let go.

My next things in my mind was to:
- Have the injectors checked and cleaned
- Replace the tps (again)
- Replace the O2 sensor (again)
- Get a new ICV
- Change the head gasket for a 3rd time in 2 years.
- Find a new dme...
- started doubting the Vitesse maf functionality, wanted to reinstall my old afm, original injectors and 2.5 bar reg.

until......

I found this last night http://www.lindseyracing.com/LR/Parts/IDLE944T.html

and realized I never did the Step 3. JUMPING THE IDLE STABILIZER.

NOW, I can finally adjust the idle screw at 1/2 turn open (never was able to do that since I own the car).

THE IDLE IS GREAT (840 +/-20 RPM)
THE CAR RUNS GREAT. NOT RUNNING ROUGH ANYMORE. NO MORE BACKFIRING.
THE CAR SMELLS GREAT. NO MORE FUEL SMELL SMELL, NO MORE HEADACHES.
THE POWER IS AMAZING.
THE RIDE IS AMAZING.

I'M WRITING IN CAPITAL CAPS BECAUSE I'M SO HAPPY.

What a waste of time and money. I should of done that from the beginning. Being said, at least I know I have all new parts on my car, and I've learned a lot.