Porsche Enthusiasts Club Forum

Hi Guys, first post here,
Let me introduce myself as Dylan, the 20 year old who spends way too much money on his car!

I'm daily driving a 944S 16v

I recently had a clutch replacement after that died on me by the helpful bunch at Pie performance who also did my belts.
I got the car back and it was running AMAZING right up until three days later it backfired and now i have a VERY noisy tappet

I had them check this, flush it through and they changed the oil from Valvoline 20/50 to Mobil 1 10/40 and engine mounts for me, the noise persists but not all the time, and i am happy to live with it until i can afford to get the head off and have them all replaced.

So since i've had it back, with the oil being less thick, my oil pressure is slightly lower.

Here's the problem, the oil pressure guage now bounces around ALL the time, as does the tacho, it rolls between 8-900 rpm whilst sitting still and you can hear the engine revs fluctuating. last night, the car stalled on me out of no where as i went to set off, and the guages all flickered off once or twice whilst driving.

I have asked my auto electrician to help me check all the grounds, o2 sensor, Maf and DME for me but he suggested it may be the ignition coming from the back of the fuse box.

has anybody had the same?

Hi Dylan - welcome to the forum, especially as you are a fellow 944S 16V driver!

I was interested to see that although you are in Windsor, you used Pie up here in Suffolk. I too have always had very good service from Pie, they are a very professional, knowledgeable and approachable bunch - especially Chris, and for me they are only a few miles away!

With regard to your 'tappet' problem, could it be a broken valve spring or a loose valve seat? For one tappet to go so bad as to be very noisy is unusual, they normally all degrade and get gummed up and noisy over time. However, given your 'backfire' event and subsequent cam-box noise and poor running, a valve problem might be the cause?

If it is a tappet, you do not have to take off the head to replace it (or all of them), but you do need to remove the cam cover, the cam chain and camshafts, along with the belt, etc. There is some information regarding tappet types in a recent thread on this forum where I provided some alternative part numbers - do not buy Porsche sourced ones unless you have deep pockets...

You mention that the revs are a little erratic, is the tacho simply following the engine (as it should), or bouncing around in an unrelated manner?

Also, o2 sensor and Maf...? I wasn't aware that any 944S had an o2 sensor over here in the UK, also unless you have had a conversion, you should be running an AFM (Air Flow Meter). The carbon track in the AFM can get worn and cause erratic idle and hesitant performance too. Also, vacuum leaks can do the same and there is quite a lot of rubber pipework to check.

The grounds for the instrument cluster should be checked and cleaned where they connect behind the cluster to the bulkhead, as well as the 'rugby' ball connectors on the back of the cluster circuit board, these are a well known poor connection & bouncing gauge problem area. If a search here doesn't come up with any info, go across to the USA Pelican Parts forum, where there is loads of info on cleaning grounds and the connectors, etc.

If all the gauges flickered off at the same time, it could be a bad connection from the harness to the cluster. These can be a problem as the contact on the cluster appears to be just solder which gets dirty over time with oxide build-up. Give those a gentle clean with the ink end of a pencil eraser - do not go too hard as they are delicate connections. A broken wire in the supply would also cause a failure, but unfortunately, there are several other places and components that could do this too!

Hope some of this info helps - good luck in your investigations. Post up a good photo of your 'S' too...

wow, that's a lot of info!
Thanks

Yeah as for the erratic idle, the tacho is following thr engine revs. this was the case before my tappet issue, however it does seem to have gotten worse.
When the gauges bounce around, the engine does not follow this, I guess it's totally possible the rugby balls are loose, I suspect a ground issue and plan to go around the car this weekend to check them.

As I Said, until my pockets grow a little deeper the tappet can stay noisy as it's quiet sometimes, loud others and just in the background the most time.

I can't find the o2 sensor but read a lot that it can cause the car to bumble around on idle. And maf was a mobile autocorrect.

Vacuum leaks are also of course on the cards but I'm not confident spraying propane or whatever around there to find it. Any ideas for that?
I'll upload a photo once I figure out how to size it correctly

You need to stay away from American forums, your S won't have an O2 sensor unless it's a US or Japanese import.

Must admit that I am rather bemused by that statement - I have found several of the American forums to be extremely useful sources of information, admittedly their cars all have the steering wheel on the wrong side, and rather excessive emissions 'stuff' (o2 sensors included) , but the owners can be very knowledgeable and helpful from that side of the pond. I am a member of Pelican Parts forum and never had any issues with the guys (and gals) on it - they are a pretty international bunch anyway.

.....should I say be aware there are differences in specification that can lead you up the garden path....

Morning guys,

Got under the bonnet looking for obvious things last night, the hose coming from my brake booster to the junction of hoses under the intake mani seems to be leaking around the joint. upon moving this arcound i can only seem to make it worse, not plug it. It is the hose with what feels like a plastic cap on the end, the idle didn't change at all when moving it around though.

Also i noticed that last night instead of doing her usual stumbling, often the idle won't drop below 1.2k rpm, what a headache!

this weekend i was thinking about getting it all off to have a proper look, clean the throttle body & re seal it, but now i've left it too late to order parts!

Going to call Porsche reading now about an intake mani gasket & some hoses methinks

Ahh, now that makes a lot of sense - as yes, you do have to be very aware that the US guys might be talking about very specific US 'stuff', and that can be misleading..

Idle control valve is another common source of hunting idle rpm.... my 968 revs ran up and down, and sometimes it would stall when siting at junctions. cleaned it out with brake cleaner... and tightened the hoses, all good now.

She's stopped hunting so much now, now it's just idling at 1200 rpm, i've ordered a throttle body reseal kit and will get all of it off once it arrives. I'll clean it all out, replace hoses and should be good (i hope)