Backfire at startup

DavidH911 · 03-05-2020, 03:30 PM

Hey folks,
I have a 2002 boxster S, I notice when starting the car it misfires quite a bit when cold. Once it warms up a bit or I restart after driving a bit it is much better. i had read an article about unplugging the MAF to see what happens. I did that and the problem goes away. I have read other articles that indicate this is not necessarily the fault of the MAF.
I have the durametric code reader/diagnostic and don't have any codes presently.

Does anybody else have experience relating to this and if so what cured your problem???

I read one article that said drive it 30 or so miles and let the computer re-learn a few things.

I had changed the throttle body thinking I may have damaged it while cleaning and moving the plate but it appears this may have not been the issue. It is the same with either one.

any help is always appreciated...

Brian Minson · 03-13-2020, 04:10 PM

Have you tried turning the key to the last spot before starting the car, counting to 60 then turn off count to 10 then turn back on to reset the egas? Here is a video I did on replacing my MAF, don't buy cheap ones, buy Bosch!

https://youtu.be/HyVeppti-Wo

Brian

BYprodriver · BYprodriver's Garage

Yes buy a new Bosch MAF & install it. The engine should run better, if not you probably have a fuel supply problem.

Flying-Al · Flying-Al's Garage

I will throw my 2 cents in. Bought a Boxster that was taken in to get a clutch and the owner never paid the bill. Drove it home and had the same symptoms you describe. Took it to the local Porsche dealership and paid almost 200 bucks JUST to run the codes and tell me what they were and a quick once over. They tell me its setting a MAF code and I need to replace it. So i order one of the $125 ones from Pelican, plug it in an almost no diff at all. About this time I got the Durametric software, I ran the codes and it is showing me misfires on 5 out of 6 cyl. So either it wasn't showing them yet as the battery was dead and had to replace it, OR they flat out lied to me. Still not sure which but whatever. the car was leaking directly onto the Cat converter so as I would drive, I was also fogging for Mosquitoes everywhere I went. The dealership also quoted me over $2,500 to fix the leaking valve covers.

After I ran the codes I bought new spark plug tubes, seals, and the newer thicker style ignition coils.

IMMEDIATE difference. No more popping on start up, AND, hasn't leaked a drop of oil even after I bought the cam holders and such so i could do the cam covers myself. So far I have put almost 4K on the new plugs and have not had to top of my oil one single time and no stumble and pop on start up.

Not saying you have the same issue, but it seems that it took awhile to set a code on mine or the dealership only told me part of the story or whatever. Short story is I don't trust em at this point and have enough of my own tools to that I don't need em anyway. Between my best friend and me we have 4 Porsche cars/projects so I prefer to just buy my own tools at this point. But basically a good ole fashioned tune up solved a LOT of my issues. Who would have thunk it ????