klokwerk

I know I saw an earlier thread on this but I couldn't find it after searching key words: Wash, and Won't Start.

Anyway, today I took the car to a car wash to spray off some of the winter gunk.
After giving it a spray off I went to start it and drive off, but the it wouldn't start.

Cranks just fine, everything else was working up until I washed it. Now won't start.

A few hours later, I've towed it home and it's in my garage.
With compressed air I blew out the engine bay and no extra water came out. I figure it's pretty dry in there now. But it still won't start.

What the heck? I'll wait until morning and try it again. If it doesn't start then, what do I need to check on?

Thanks!

ilko

Most likely distributor and/or plug wires and ends. When were those replaced last?

After the engine is completely dry try starting it again. If successful, get a spray bottle full of water and spray mist around the distributor and wires (top and bottom of the engine). If you see arching you know where your problem is.

Good luck!

Steve Weiner-Rennsport Systems

You likely have moisture inside the caps & rotors.

Get some WD40 and spray the inside of the caps and over the rotors to displace the moisture in there.

Its a sign that those parts as well as wires need replacement.

klokwerk

Thanks for the suggestions guys.
Quick question; when removing the distributor caps, how do you get to the bottom distributor screw without removing the plug wires?

Thanks again.

Goughary

You want to remove the plug wires. Inspect everything cuz water is getting in there somehow. Reassemble w a bit of dialectic grease on the boots.

I once found the same to be happening. The boots were allowing the spark to arc all over. One of the boots was burning away. I had used beru caps instead of Bosch and the plug connectors that are glued into the cap had a few break away, like a bad glue joint...

klokwerk

Got it. Digging into this now.
Already found one problem. The top distributor cap has a Crack in it and the thru hole for the mounting screw is broken. :-(

wilson234

I was the one that had a similar problem, in my case the fuel pump died. I suggest you take the access panel off to get to the fuel pump and apply 12v to the terminals, brown wire is negative. If you can feel and hear the fuel pump, then you eliminated this possibility.

klokwerk

Thanks for chiming in about your experience.

I'll double check the fuel pump, but I'm pretty sure I hear it priming when I try to start the car. Better to be sure by checking voltage too.

My problem, at the least the most obvious one, is my crank position/reference sensor is broken. I've ordered a replacement unit and when it arrives I'll know for sure if that was my only problem.

Who knew that washing the car could cause so much trouble!

klokwerk

Hi there again, this is turning into an interesting mystery now.

Update on my no start issue now a couple weeks since the infamous car wash of doom.

Here's what I've done so far:

• Installed new distributor caps and ignition rotors
• Installed new crank speed reference sensor and connectors
• Disconnected every electrical connection in the engine bay, inspected, applied dielectric grease where it made sense and reconnected everything.
• Swapped out my new solid state DME for my old one that was working.
• Inspected my spark plug wires and they don't have any obvious wear or damage, but look like they've been there a while. I'll replace them as soon as I can.
• Inspected all of the fuses under the hood and in the engine bay. I found no blown fuses.

I haven't done the following yet.

• Confirm the fuel pump is working, I'll check as recommended in an earlier post
• Confirm the ignition coils work, not sure how to do this
• Confirm the ignition control units work, also not sure how to check this
• This coming weekend I'd like to also confirm that the new reference sensor is working by using my volt meter. I don't know what to measure though.
• At the sensor, I could measure for resistance change when metal passes the sensor.

Are there other fuses to check or somehow to check the DME under the seat?

Again, when I turn the key, the motor turns but doesn't start.
I noted that the tachometer does not move at all when it is cranking which makes me think my connections to the reference sensor could still be an issue. I'm assuming that the tach needle should move when it's cranking. If that's not right, please correct me.

Thanks!

Jjm4life

I have nothing to add here other than my sympathy and hope that you sort it out.
Used to have a car that couldn't get wet. Even the shop that literally built it (noble m400) couldn't chase down the issue. I punted the car at a loss and never looked back.
With your Porsche you have a much deeper knowledge base and larger community to pull from. I'm sure you'll find the answer. Best of luck sorting this

Vandit

If the tach isn't moving then the car isn't registering an RPM therefore the fuel pump isn't turning on (IIRC needs to see 300 RPM before it turns on).

klokwerk

Fuel pump huh? I thought it was getting signal from the flywheel speed sensor!

As soon as I get home this weekend I'll check it out by hotwiring it to see if it buzzes.

Vandit

The fuel pump is the symptom. If the tach is dead, then the flywheel sensor probably isn't registering. The fuel pump won't run if it is unaware that the motor is spinning.

PCar SBA

Measure the output of the FW sensor in the 55-pin DME connector while cranking. It's on pin 47 and 48 and you should see around 2V AC with a digital voltmeter. If you don't get that it's bad. If you get that then it might be time to check the DME relay or the DME.

klokwerk

Thanks, I'll perform that check as soon as I can.
Really want to have my car back up and running this weekend!