Just found Richards thread from last year:
Boxster 986 3.2 S 2004 MAF Screw size | Porsche Forum from Porsche Club GB
All sorted
Boxster 986 3.2 S 2004 MAF Screw size | Porsche Forum from Porsche Club GB
All sorted
MAF Change 986 3.2S
- Thread starter Cater_Racer
- Start date
After my woes at Snetterton (See Race report thread) I've had a really useful chat with my local Indie who looks after my 993 (RG Lewis, Chester), much recommended (used him for 20 years 944,968,964 and now 993).
I've decided the misfire problems could be MAF related, either the MAF itself or debris from the air-filter removal falling into the MAF.
I'm told the air-box uses 5 star Torx screws, is there a tool recommended for getting this apart?
Any help much appreciated.
Gerry
I've decided the misfire problems could be MAF related, either the MAF itself or debris from the air-filter removal falling into the MAF.
I'm told the air-box uses 5 star Torx screws, is there a tool recommended for getting this apart?
Any help much appreciated.
Gerry
Hi Gerry,
Unfortunately I’d missed your race report post mentioning your odd problem.
I’d agree with your Indy that it’s worth checking the MAF and cleaning or replacing it if necessary. Hopefully all the plugs and coil-packs are in good condition, but since you say that the engine revs OK it seems unlikely that the problem lies there, although you can’t rule out anything. Maybe there’s an issue with the variable valve timing?
Rather than try to fire-fight the problem I think the best thing would be to run some decent Porsche-specific diagnostics - PIWIS or equivalent - to see if/what error conditions are thrown-up.
Jeff
Unfortunately I’d missed your race report post mentioning your odd problem.
I’d agree with your Indy that it’s worth checking the MAF and cleaning or replacing it if necessary. Hopefully all the plugs and coil-packs are in good condition, but since you say that the engine revs OK it seems unlikely that the problem lies there, although you can’t rule out anything. Maybe there’s an issue with the variable valve timing?
Rather than try to fire-fight the problem I think the best thing would be to run some decent Porsche-specific diagnostics - PIWIS or equivalent - to see if/what error conditions are thrown-up.
Jeff
Easy to spend other peoples money but would suggest for a race car then an investment in a durametric setup might be worth while. You could probably just have the enthusiasts version, get all the readings etc and see real time what is going on with maf/mixture etc.
this issue could if course be the maf (in a road car you would disconnect and see if the default “no maf” map made it better or worse) but a reluctance to Rev could be throttle pos sensor or one of the 2 of The brake light switch sensors that Stop you pressing brake and throttle together, or variocam, or plugs etc.
without knowing what isn’t standard on the car it’s always going to be guess but some diag kit will perhaps give you a place to start to look.
this issue could if course be the maf (in a road car you would disconnect and see if the default “no maf” map made it better or worse) but a reluctance to Rev could be throttle pos sensor or one of the 2 of The brake light switch sensors that Stop you pressing brake and throttle together, or variocam, or plugs etc.
without knowing what isn’t standard on the car it’s always going to be guess but some diag kit will perhaps give you a place to start to look.
Thanks Jeff & Paul, the background is, I bought the car unseen on fleabay last September. It had just passed an MOT and had new coil packs fitted and met the emmissions etc. OK.
I didn't get to drive it but it was picked up by the Porsche speciality race engineering company, they drove it on trade plates round for 10 minutes and said "it's fine".
They then stripped it down internally seats steering wheel interior trim out. removed the brakes, suspension, exhaust, gearbox etc. Checked IMS and put in lightened flywheel new comp clutch LSD diff, new Pagid brakes, new shocks, coil-over GAZ units, oli-catch tank, race battery fire extinguisher system, harnesses cage, race seat, compition steering wheel, new hard-top, bonnet and boot latches, new stainless steel cat delete exhaust, windscreen, Team Dynamics 19" wheels and race tyres....
The engine was not touched.
The car was delivered in February and we wanted to test but realised it wouldn't fit on the trailer, the old 944S2 trailer was too narrow.
So mad panic ordered a new trailer and got it 10 days ago.
With no load on the engine it sounds fine, tick-over is fine, waz the throttle and all seems fine.
On track it is obviously mis-firing from 2000rpm thru 4800 rpm with low pulling power. over 5000RPM it pulls well.
No mechanical rattles or noise, but I seem to be using quite a bit of fuel, I ran out on the final 2 laps, 40 litres in 40 minutes round Snetterton???
That's 18 laps or 44 miles, Less than 6 MPG??
I haven't pulled the plugs, because I DNF'd I had to wait to be recovered and put 3 ltres in to drive it back on the trailer it was late so we headed home.
The car is now back at son's house (Tom) in Cambridgeshire. I'm in Chester so cannot get at it until Easter week-end.
Gerry
I didn't get to drive it but it was picked up by the Porsche speciality race engineering company, they drove it on trade plates round for 10 minutes and said "it's fine".
They then stripped it down internally seats steering wheel interior trim out. removed the brakes, suspension, exhaust, gearbox etc. Checked IMS and put in lightened flywheel new comp clutch LSD diff, new Pagid brakes, new shocks, coil-over GAZ units, oli-catch tank, race battery fire extinguisher system, harnesses cage, race seat, compition steering wheel, new hard-top, bonnet and boot latches, new stainless steel cat delete exhaust, windscreen, Team Dynamics 19" wheels and race tyres....
The engine was not touched.
The car was delivered in February and we wanted to test but realised it wouldn't fit on the trailer, the old 944S2 trailer was too narrow.
So mad panic ordered a new trailer and got it 10 days ago.
With no load on the engine it sounds fine, tick-over is fine, waz the throttle and all seems fine.
On track it is obviously mis-firing from 2000rpm thru 4800 rpm with low pulling power. over 5000RPM it pulls well.
No mechanical rattles or noise, but I seem to be using quite a bit of fuel, I ran out on the final 2 laps, 40 litres in 40 minutes round Snetterton???
That's 18 laps or 44 miles, Less than 6 MPG??
I haven't pulled the plugs, because I DNF'd I had to wait to be recovered and put 3 ltres in to drive it back on the trailer it was late so we headed home.
The car is now back at son's house (Tom) in Cambridgeshire. I'm in Chester so cannot get at it until Easter week-end.
Gerry
Internet guesswork at it's finest here....... treat with appropriate pinches of Salt.
If running stock ECU - then you can see if the issue is affected by MAF by disconnecting it - car will default to an "it will do map" rather than a "all over the place" if the maf is faulty..... - if running disconnected makes no difference then I doubt its the MAF.
2nd guess ( but would have expected issue to be there at no load ) - variocam solenoid/actuator - something at the back of my mind says just over 4500 is the "magic number" for the variocam to do its thing.
If its running stock ecu then something like a foxwell or an icarsoft standalone unit will tell you "stuff" that may help diagnosis - suggest asking your local region to see if anyone has got anything they could lend.
Good luck with it.
If running stock ECU - then you can see if the issue is affected by MAF by disconnecting it - car will default to an "it will do map" rather than a "all over the place" if the maf is faulty..... - if running disconnected makes no difference then I doubt its the MAF.
2nd guess ( but would have expected issue to be there at no load ) - variocam solenoid/actuator - something at the back of my mind says just over 4500 is the "magic number" for the variocam to do its thing.
If its running stock ecu then something like a foxwell or an icarsoft standalone unit will tell you "stuff" that may help diagnosis - suggest asking your local region to see if anyone has got anything they could lend.
Good luck with it.
Posts made and opinions expressed are those of the individual forum members
Use of the Forum is subject to the Terms and Conditions
