I just purchased a 86 928s with a 5.0...car runs but burns rich...Same issue as others irratic idle, hard to start at times...sometimes it starts with very low idle..lots of power,.please help.thanks


Asked by Apr 16, 2013 at 04:16 AM about the 1986 Porsche 928 S Hatchback

Question type: General

Please help me in what could be the issue....I know
about Fords and Mopars not Porshe...I love this car
and want to fix it plus keep it...but I need help before I
change my mind and sell it....Thanks

14 Answers

Needs diagnostic. The '86 Porsche 928 has OBDII you can get it scanned free then bring the codes back here for one of us to discuss and help you decide what to do, or go to http://repairinfo.alldatadiy.com/Porsche-928-1986-OBD_II_Codes_H2t84.php ...might consider not selling it (yet) may be minor

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Best Answer Mark helpful

geez i went looking for diagnostic scanners for the 928 to say maybe buy your own but at http://www.summitracing.com/parts/otc-3825j/overview/year/1986/make/porsche/model/928 they have a nice one....for $5,500 so maybe not.....

4 people found this helpful.

Thank You..no check engine displayed on dash when engine runs the way it does...

Yeah. these days the Check Engine will light up from such a multitude of things, some cars mileage alone...in 1986 not so much. But it could be something like an 02 sensor ..that could make it run rich. Lots of mechanics like to jump to conclusions about the 02. sensor which is possible but just one of many things. The only other problem you may run in to is the 928 was discontinued in 1995 so parts may not be as available as some later Porsche's. But it is FINE car and there are plenty of aftermarket parts.

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Thanks again..if you come up with anything solutions, please let me know.let us all know lol..

Can do. There are not many new questions coming in at 2:30am so I will take some time and look around. I've had enough of the Google Earth Flight Simulator for a while anyway. See if I can find some owners ~~enthusiasts forums.

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http://www.google.com/search?q=porsche+928+reliability&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=firefox-a ...a long list of stuff if you feel like reading up on the 928, conflicting owners opinions, some say it's a real piece of crap and others (more than the former) love it

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If I dis-connect the mass airflow sensor, could that be part of my problem if the motor smooths out....but then it goes into limp mode right...

I did find another thread at: http://forums.rennlist.com/rennforums/928-forum/616153-maf-voltage-idle.html..and this supposedly is the MAF from this car, first the car

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Now the MAF (that he says) is in it

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BUT, when I look at parts suppliers they look like this:

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Now they are expensive..like $250. But they can be cleaned, and if you have a multi meter you can teat the voltage at idle, that site I put up shows what voltage it should show. I'd rather not say a voltage because I don't know only what I saw there and could be wrong ..so I do not want to lead you in the wrong direction. But I do know that after cleaning it some people have had theirs work like new.

2 people found this helpful.

I forgot all about your question, geez, sorry 'bout that. It may or may not go in to 'limp mode' my guess is it would not. http://www.ehow.com/info_12199368_mean-car-goes-limp-mode.html ..explains a lot about limp mode.

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