Greetings 6speeders!

I have been reading the forums for quite sometime, but never posted a question due to the vast knowledge base of material that is here.

I am a new Porsche owner who acquired a 996 Turbo with GIAC flashing running in the neighborhood of .9 bar. I had owned the car and had drove it hard for about 2 weeks when I swang around a corner and punched it in 2nd gear only to find out what a CEL looks like. I received a flashing CEL which yielded a P0301. I headed straight for the forums.

After some research into the history of the car prior to my ownership I realized it was time for a coilpack and sparkplug replacement time. I was only able to get 2 packs in from my local shop, but got 6 plugs. I tore the car apart, replaced drives side front two packs, I believe cylinders 1 and 2 and all 6 plugs. These coilpacks had hairline cracks whereas the others were not that bad. Plugs were FR 6 LDC - Bosch Platinum 2. I cleared the CELs after every change.

After a few drives @ wide open throttle I once again got CELs. This time P0301 and P0303 w/ P0300. I decided other coilpacks must be bad. I ordered in 4 more 997 part coilpacks, ripped the car apart again and proceeded to put in the new packs. I paid attention to the DIY guide over at RennTech and looked at the VarioCam brackets and they seemed to be ok.

Once again, @ WOT I received CELs. This time P0303 and P0304 w/ P0300. After digging in the forums, I checked my MAF voltage, 1.4V at idle, ordered a Durametric and did a data grab on the MAF voltage and it seems to be ok. As I have been running 91 Oct w/ ethanol I then tried a gas change.

I emptied the tank and put in 93 Oct. The car drove good for a bit, but yesterday once again @ WOT I got a P0305, P0306 w/ P0300 again.

The car drives wonderfully if I keep the turbos out of the picture. I have used the Durametric to verify that I get no cylinder misfires when tootling around town keeping the boost below .3 bar.

Does anyone have any suggestions on what I can do to fix this problem? I'm desperate for a working car!

I am a novice owner and barely know how to work the Durametric but am willing to post and gather all logs I can from the device to solve this problem. The nearest dealer is 2 hours from my place!

Thank you 6speed community for any input you can offer!

 

Unplug the MAF and make a drive,if the car runs perfect without the MAF it's the MAF what's causing the problems.Don't take the MAF out,just unplug it.
That's all I can suggest to help you...

 

Are all 6 coil packs the 997 part, or do you have 2+4?

What plugs were in the car, and how did they look?

Have you cleaned your airbox and filter?

I had a misfire and a MAF out of range code, and replaced my filter and MAF, cleared the code and no problems since.

There is a source for the MAF at $2xx somthing if you do a search. I did not see that thread and paid full pop at suncoast like $480.

Tom

 

There are some threads about cleaning the MAF as well. But I went with replacement instead. You may want to try that.

 

Clean the MAF first. A $5 venture.

If it improves, then you know the maf was badly fouled. IT IS LIKELY STILL FOULED, but cleaning removed the soluble crud. (Note that over time, the MAF element will become fouled with an oxide (from the heat/clean cycle) that will not come off with maf cleaner.)

A

 

I want to say its 2 + 4 where the 2 might be 996 a part. I'd have to rip the car apart to determine that. The orignal were Bosch with only a single ground electrode. The plugs in cylinders 1 and 2, closest to drivers seat, were blackend the most, where as 6 and 5, closest to the passenger seat almost looked new.

I cleaned the MAF following the instructions in the various forum posts twice.

I took the airbox out and blew it out with air, with the MAF out, and put in a new OEM air filter.

Today I took the car out and took 2 different Durametric logs. The first is with the MAF in.

The RPM has been divided by 100 and the Boost (in Bar) is times 10 to fit everything on the Excel graph. So 88 boost is really .88 bar and 50 RPM is 5000. The misfire counters are true.

In the first run I'm back to P0301 and P0305 errors. Cylinder 1 recorded 35 misfires, cylinder 4 - 1, and cylinder 5 - 8.



The second run I have unclipped the MAF sensor. This yielded only a P0301, but I didn't punch it as hard due to the fact the P0301 came on so quickly.

 

mafs are cheap and ez to replace . i would take a trip to ace hardwear and spend a few bucks on elec cleaner, take your maf out clean it up and see what happens.

i did this after replacing plugs , coil packs, reprograming, and a bunch of other costly things. check out the maf first it's cheap.......

 

Although the problem still exists taking the MAF out of the system as instructed it is still the suggestion to replace the MAF? Can the MAF not being in the system cause misfires?

 

At this point I would not suspect the MAF, as it kicks the same with and without it.

I don't know if running "mixed" 996 and 997 coil packs could be causing this, but a sure way to find out is to swap them. You could also check with your tuner and see if the tune likes denso's better then the fr6's with your mods.

I think the next place you would need to look is fueling .. and i would take it to a pro if replacing the coils and plugs and perhaps the MAF did not fix this. It will get expensive fast to keep throwing parts at the issue.

If i were in your place I would replace the MAF, and the 2 mismatched coil pack, and check the plugs and see if the same ones are fouled. I would also check for boost leaks. Good Luck