-nick

Hi folks,
I've got a few things going on with the C4 and I was hoping for a little feedback from those that have taken care of the tune-up basics. This is my first year of ownership so I anticipated spending some cash to get everything up to snuff.

The first is the PDAS and "Brake" warning lights light up occasionally while driving - then they stay on until I restart the car. Seems to happen less often if I restart while the car is hot. I'm thinking plug wires?

Possibly related, I'm only hitting about 22mph on the highway and around 16mpg city. This is with a _very_ heavy foot, but not heavy enough to warrant such bad mileage.

Also, on cold start-ups, the idle tends to fluctuate quite a lot and the car feels like it hesitates slightly on take-off.

The car just crossed 64k miles and I don't have a record of new wires/caps/rotors/plugs. Is it safe to say that this needs done at this point? What are the odds that the new parts plug a valve adjustment will solve all these problems?

The other question is that my brake pad light just lit up for the first time this week and I simultaneously noticed a light brake squeal from the rear. Is there anything to watch out for when replacing the rear pads on a C4 or is it the same protocol as the C2?

I'm shopping around and there is a wide-variety of parts prices on pads. The Porsche-branded pads being around $150/pr, OEM Jurid at $70/pr, etc. Is there actually a difference?

To finish this off - spark plug wires, really $600? That was a bit of a surprise...

Duck

For the PDAS and Brake warning lights, check you brake fluid level. If it is slightly low, it can cause the lights to come on.

Yes, the spark plug wires are expensive. I have not looked lately, but you should be able to find them closer to $500. The trouble is getting them installed. That is no easy task.

dfinnegan

I second the thought of checking the fluid level. They are a bit sensitive to being near, or at, the max.
I get 22 on the highway and ~18 city; with the same foot.

You may need to clean your Idle Stability Valve (ISV)

You can look inside the rotor caps for black track marks indicating that you need to change them. Outside of the wires, the prices for the caps, rotors and plugs aren't too bad. Seems justifiable to just change them. The wires, however, are pricey. Try spraying water mist on them in the dark and check for arching/flashing. If none, then you may be fine.

Sounds like you need pads. Pretty straight forward process.

There are lots of options for pads. Track, street, performance, etc. Pelican parts and Sunset Porsche are good places to get them at reasonable prices.

Yeah. There are 12 of them, but really, that's just rediculous! Someone is making a killing.

dfinnegan

Here are a couple of links to fill in where I left them out before:

Pelican Parts
Cleaning the ISV
Sunset Imports - 15% over cost

springer3

Quite a few of us had bad ignition coils. One of mine went out at 62,000 miles, and that lit up most of the warning lights on the panel (do a search for "christmas tree effect"). Don't decide the coils are fine if they ohm out correctly. Mine ohmed out fine, but that does not detect high-voltage insulation problems. The popping in the radio and all the other electrical problems disappeared only after I replaced both coils. Life is good again!

GMS

Change the DME, ABS and ABS pump relays. Make sure you change ALL of the brake/clutch/4WD fluid.

-nick

Wow - good call on the fluid level. It was at the max line so I didn't think twice, until I read that it should be checked with the system pressurized. Turned the key and let the pump build up then the fluid level was just at the top of the min mark. Topped it up and the warning lights haven't come on yet.

I'll run through the other suggestions and checks too. I love easy fixes.

-nick

Another follow-up.

The ISV looked new and was attached with Norma clamps and not the crush variety. It must have been replaced at some point in the recent past but wasn't in the records. I pulled it off and sprayed some carb cleaner through it and the idle seems more stable when cold.

I found a receipt for new front brake pads about 24k miles ago, so it must just be the rears complaining.

I also pulled one of the dizzy caps and they definitely need replacing. Hopefully that will at least gain me an extra mpg or so. I haven't done the water spray test on the ignition wires yet but they may be just fine.

Thanks for all the help! I'm putting in an order at Sunset tomorrow.

nick

Wachuko

Cool! Feels good does it not?