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-   -   need help with CIS (http://forums.pelicanparts.com/porsche-928-technical-forum/673151-need-help-cis.html)

DPW928 02-14-2013 07:51 AM

Airtek,

Boises problem was the engine ran alright when cold but went lean as it warmed up. From reading your thread, your engine is starting with fuel from the cold start valve but you are getting insufficient fuel to the injectors to keep it running. My guess is that the metering slits in the fuel distributor are plugged with varnish from the old fuel. Try spraying injector cleaner through all 8 injector outlet ports to see if this improves the fuel flow. This may also clean varnish out of the distributors central cylinder which would cause the metering piston to lock.

Jadz928 02-14-2013 08:30 AM

Quote:

Originally Posted by MPDano (Post 7273489)
In short, you'll see another one of our members here did the exact same thing using a MB Fuel Disty that was adjustable. He fought it for months trying to get it running right until he finally listened to us to get a stock one. Guess what? He got a stock Disty and it actually ran as it should. Who woulda known?

I think that was a good approach. Having the individual adjusment per cylinder only exaserbated the situation on an engine that wasn't fully in-tune to begin with.

I would use a MB style FD only an an engine first properly tuned w/a stock FD. Following that, would add in the MB FD, adjust system pressure equal to what was there before (in-spec.). Lastly, perform individual cylinder A/F tune.

In short, not for the faint of heart, but totally doable if systematic in process, while keeping variables to an absolute minimum.

Def. not the right thing to do if the engine isn't running, or running right to begin with.

MPDano 02-14-2013 10:18 AM

Quote:

Originally Posted by Jadz928 (Post 7273629)
I think that was a good approach. Having the individual adjusment per cylinder only exaserbated the situation on an engine that wasn't fully in-tune to begin with.

I would use a MB style FD only an an engine first properly tuned w/a stock FD. Following that, would add in the MB FD, adjust system pressure equal to what was there before (in-spec.). Lastly, perform individual cylinder A/F tune.

Exactly. Right now, I "know" all my CIS components are functioing as it should and the car runs great. Now would be a time to throw on a MB Adjustable Disty just to see if I can gain performance. Except, I won't ;)

AirtekHVAC 02-14-2013 10:42 AM

lol...why not???

AirtekHVAC 02-14-2013 10:44 AM

Dennis....good idea....When the injectors arrive (I hope tomorrow!) I will take loose all the lines at the FD, and blow through before I reconnect to the new injectors...will also clean or remove the little screens on the FD and WUR (cant play any tonight...it is VD)

DPW928 02-14-2013 12:57 PM

Also, remove the fuel regulator off the back of the distributor, check the o rings and spray injector cleaner into the ports. It's possible the regulator was stuck open letting system pressure bleed back to the tank. BTW don't remove any spacers/washers on the regulator as they are factory set.

MPDano 02-14-2013 01:00 PM

Quote:

Originally Posted by AirtekHVAC (Post 7273892)
lol...why not???

$$ and time. Plus, the Euro needs a new Tranny.

AirtekHVAC 02-14-2013 05:43 PM

I'm with u on the $$ and time...I seem to lack both as well...

AirtekHVAC 02-14-2013 05:48 PM

Dennis, when I pop the gas cap off, there is a sucking sound...so it does not appear to be pressurizing.....

DPW928 02-14-2013 06:19 PM

There shouldn't be a vacuum in the tank if the lines are clear. You may want to check all your lines and inlets/outlets at the top on the fuel sending unit and between the fill tube and the back of the tank.

gbgastowers 02-14-2013 06:58 PM

Quote:

Originally Posted by MPDano (Post 7273489)
In short, you'll see another one of our members here did the exact same thing using a MB Fuel Disty that was adjustable. He fought it for months trying to get it running right until he finally listened to us to get a stock one. Guess what? He got a stock Disty and it actually ran as it should. Who woulda known?

That's me. I wasted countless hours and energy trying to tune that MB fuel distributor and make it work thinking it was an upgrade. As soon as I ditched it and got the FD that was supposed to be on the car it ran perfect.

AirtekHVAC 02-14-2013 07:18 PM

Huh? Oh boy...I'm screwed now! No wonder it ain't working!!!!




Dennis, perhaps it is air escaping, not sucking....?

Gunnar...right? From the pharmacy? I need to drop in on you one day....

Jadz928 02-14-2013 09:01 PM

Quote:

Originally Posted by gbgastowers (Post 7274931)
That's me. I wasted countless hours and energy trying to tune that MB fuel distributor and make it work thinking it was an upgrade. As soon as I ditched it and got the FD that was supposed to be on the car it ran perfect.

Gunar, do you still have the MB FD? Would you like to part w/it?

gbgastowers 02-15-2013 02:47 AM

Quote:

Originally Posted by Jadz928 (Post 7275048)
Gunar, do you still have the MB FD? Would you like to part w/it?

No- after I pulled it I sold it on ebay to someone in Thailand. Gunar
http://forums.pelicanparts.com/uploa...1360928828.jpg

gbgastowers 02-15-2013 03:02 AM

Quote:

Originally Posted by gbgastowers (Post 7275163)
No- after I pulled it I sold it on ebay to someone in Thailand. Gunar
http://forums.pelicanparts.com/uploa...1360928828.jpg

This was the buyer.

http://forums.pelicanparts.com/uploa...1360929737.jpg

AirtekHVAC 02-15-2013 03:53 AM

LMAO!!!

Jim, I got a buddy that owns a junkyard...I'll see if he has an old V8 benz lying around...may not, but ya never know...

Jadz928 02-15-2013 03:58 AM

Quote:

Originally Posted by gbgastowers (Post 7275173)


That's awesome, Gunar! lol

Quote:

Originally Posted by AirtekHVAC (Post 7275200)
LMAO!!!

Jim, I got a buddy that owns a junkyard...I'll see if he has an old V8 benz lying around...may not, but ya never know...

Thanks, Bro! :)

MPDano 02-15-2013 04:27 AM

Quote:

Originally Posted by gbgastowers (Post 7274931)
That's me. I wasted countless hours and energy trying to tune that MB fuel distributor and make it work thinking it was an upgrade. As soon as I ditched it and got the FD that was supposed to be on the car it ran perfect.

Gunar! Where ya been? Hows the 928 doing?

AirtekHVAC 02-15-2013 05:29 AM

Just talked to my friend...he knows he has an old benz in the yard, and some volvo's...does not remember if they are v-8's or not, he said he would try to check today...

DPW928 02-15-2013 09:05 AM

Airtek,

If you get an MB distributor, you will need to adjust the A/F mixture with the adjustor on the upper plenum due to the different geometries. The A/F mixture can be adjusted without the engine running.


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