Hard starting...

Thomas Spitzer · Thomas Spitzer's Garage

A couple of days ago I changed my distributor cap, rotor and spark plugs. I decided to go with the Bosch Platinum +4's. I originally had Bosch Platinums in it. Now, when the engine is cold, it takes me a few tries to get the engine started. When I do get the engine started, it idles really rough and wants to die. After I nurse it a little bit, it will clear up and run silky smooth again. It runs fine after the initial "stumble" and has absolutely no problems until it's been shut-off and is cold again. Any thoughts? I'm planning on throwing my old plugs back in to see if that makes a difference.

Tom
'88 944 N/A

AFJuvat · 07-06-2002, 09:14 PM

Make sure all of your wires, cap and rotor are on tight, connected properly etc..

In my opinion platinum 4's are overrated and overpriced for what little (if any) benefit they produce. They tend to carbon up after a little while, though this seems to clear up if you open the gap up.

I normally run regular old platinums straight out of the box, don't even set the gap on them.

AFJuvat

wolfrpi · 07-06-2002, 11:11 PM

fpr and dampner

fly944 · 07-07-2002, 07:58 AM

I WOULD ALSO CHECK TO MAKE SURE YOU DIDNT CREATE A VACUME LEAK IN ONE OF THE LINES NEXT TO PLUGS. WHILE MOVING THINGS AROUND.

Thomas Spitzer · Thomas Spitzer's Garage

Thanks for the replies. Before I started it this morning, I checked for any disturbed vacuum lines and checked the cap/rotor again. Same story upon start-up; took me a couple of tries and then it ran like crap for a little while and then it cleared itself out. I dropped in some new Bosch platinums today and let it sit all day long. I just did an ops check on it and it started right up. The platinum +4's didn't look very good for only having 300 miles on them. I guess the real test will be tomorrow morning. If it's the FPR, wouldn't it run bad all the time? Could this be a DME relay related problem too? Thanks...

Tom

DangerIsland · 07-07-2002, 07:38 PM

I had this same problem for a few months, then the car just died completely on the way home one night. It would run for 10 seconds, and then shut off.

I replaced the FPR, and everything seems much better now, starts and runs right away without a problem. I think my FPR was slowly failing, and then died that night, it's a pretty easy/cheap fix, I'd give it a shot.

overkill · 07-07-2002, 07:55 PM

I have same problem and didnt solve it yet.

Thomas Spitzer · Thomas Spitzer's Garage

Overkill,

Did you replace your FPR and still have same the problem?

Tom

Thomas Spitzer · Thomas Spitzer's Garage

...the same problem...

Thomas Spitzer · Thomas Spitzer's Garage

Here's an update: It started right up this morning but ran really rough for maybe like 20 seconds before it smoothed out and idled normal again. No problems after that today. My friendly neighborhood Porsche dealer has a FPR for $85 so I think I'll order one from Pelican and save myself a few $$. Any thoughts on if I should replace the dampner too while I'm at it? Thanks...

Tom

wolfrpi · 07-08-2002, 09:42 PM

are you kidding?

Thomas Spitzer · Thomas Spitzer's Garage

I kid you not...

Tom

Makis · 07-08-2002, 11:26 PM

You don't need to replace the FPR because you can test it. You will need to do fuel pressure test but you need special equipment for this. So alternate solution will be.
First remove the vacuum hose from FPR and see if there is any fuel coming out of it or you notice any smell. Then remove the FPR. You can test it by connecting the FPR inlet to an electric tire pump using an addaptor (usualy the one used to pump up plastic boats) and get a reading. I have an S2 new FPR and I recorded 64psi on my pump. The old one was showing 70psi. Needless to say I kept the old one. Older FPR for porsche have smaller pressure, estimate around 55psi.
A FPR that does not hold pressure should also give you running problems not just starting problems.
The only time I had starting problems with my Porsche was when the Coolant temperature sensor failed. From what you describing this is a possible cause. My temperature sensor by some reason was showing low impedance when cold as a result the engine was difficult to start because the ECM was trying to start a cold engine with warm engine start mixture which is to lean. Then the engine until it warms up it will still run rough. When warm the sensor error reading gets smaller. Again this sensor does not normally fail but is easy to mesure and cheap to replace.
There are other sensors that can affect starting. Please search for similar past topics that cover this problem.

DangerIsland · 07-09-2002, 03:27 PM

If you do end up doing the FPR, let me know if you want some help with it. I'm in tacoma too, and since I did mine two weeks ago, I thought maybe you'd want another set of hands.

jleblanc@real.com, drop me an email!

overkill · 07-09-2002, 04:11 PM

I did not change the FPR yet. I still have problems starting the car. I also have to fix that leak coming from the cam rotor? Behind the DIS rotor. It is actually leaking pretty bad. Till then.

Thomas Spitzer · Thomas Spitzer's Garage

I guess the Porsche gods have smiled upon me for the moment.

It seems to be running absolutely fine now. No starting problems and no rough idling either. ??????? I think I'll hold off on the FPR and wait to see what happens. I plan on checking my fuel pressure this weekend. Some of my vacuum lines look a little questionable so I plan on changing those out soon. I'll keep you guys posted if any new problems pop up...

Tom
'88 944