Cold Start Issue - Video - Page 7

mca · 12-25-2007, 04:14 PM

psalt - The test connector terminals do look a little crusty. I will give them a cleaning and retry. If that doesn't work, I will move forward with your other suggestions.

Paulporsche - Got your PM. Thanks for the info. PM'd you back.

Again, I can't stress how much I appreciate the feedback and continual stream of information that you guys provide. Despite the issue I am having, I find the troubleshooting to be quite enjoyable.

mca · 12-29-2007, 05:04 PM

I forgot to mention another thing that I recently noticed. On warm starts, the idle is lower than normal. Probably around 650-700 RPMs until she warms up ... at which point she sits at 850-900.

I didn't notice this earlier because I don't usually start her up when warm ... but I have been driving her a lot over the holiday and noticed this pattern. Most of the time she is restarted after a day of work or after sitting overnight. But if I let her sit for an hour or two and restart, I get the low idle.

Maybe this will shed some light on the situation.

mca · 02-10-2008, 10:02 AM

For the record: I had my fuel mixture checked by a local specialty shop in January. I also asked them if they thought I had any sort of vacuum leak - without testing, they said that it doesn't "sound" like there is a leak. I took that with a grain of salt. Timing is also set at 5 BTDC and 02 sensor is NOT connected.

Yesterday I took a trip to Costco - got the car nice and warm. Went in to shop for about 45 minutes. Came out to start the car - started but died immediately. Second try - started and and then hung at 500ish rpms. When I got to a stop sign just seconds later, I pushed in the clutch pedal and she nearly died. Rpms dropped almost to 0 and then recovered to 500.

Finally I decided that I have tried everything to fix my cold start issue (and warm start issue now too) ... it was time to adjust the WUR.

This morning I hooked up my CIS gauges. Cold control pressure was around 2.9 bar. Temps in my garage were 63F which meant I needed a CCP of 1.8 - 2.2 bar. With the fuel pump running and heating element on WUR disconnected, I tapped on the WUR pin until I got to 2.0 bar. It was easy and beautiful. I was very pleased with how easy it was.

I pulled the gauge and hooked everything back up. Started her up and she didn't have any problems. Didn't die or struggle at all on the first crank. I took her for a long long drive. Idle was steady at 1000, pulled nicely through all gears ... everything was looking pretty darn dandy.

--------------------- This is where my smile turned upside down ------------------

An hour later I wanted to see how she handled the warm start. First crank she almost died but recovered to 500 rpms. I continued to rev and she would come back to 1000, take a dive towards 0, and then recover at 500.

I will post a video in a bit.

Apparently the WUR is not the issue.

My best guess at this point is that I have a vacuum leak somewhere. I think that as the engine warms and expands that the leak is sealed off. I say this because she runs beautifully when at normal operating temps.

Can someone please help me shed light on this? I tried to use a propane torch around the injectors - no changes in idle.

Thanks,
Craig

mca · 02-10-2008, 10:18 AM

Here is a link to a video of the warm start issue I had today.

http://www.reactionplus.com/pcar/warmstart_021008.html

cay-ahe · 02-10-2008, 06:15 PM

Can anyone give me the FV relay part number?

porsche911girl · porsche911girl's Garage

I'm having a very similar issue with mine. We thought at first it was the battery b/c the car would turn over but not start. So we charged the battery, and when it was fully charged, we tried again, and I'd get it to turn over and then the revs would drop and it would immediately die.

But now it's backfiring immediately after we get it to start.

This afternoon when I went to start it, it would only make a clicking noise, yet all the interior and exterior lights worked, so I figured the battery wasn't shot completely. So we charged the battery for about an hr and tried again, only this time it'd do the same thing, turn over then die, it did this once and then it backfired on the 2nd attempt. So we didn't mess with it anymore.

mca · 02-16-2008, 11:38 AM

Well what do you know?

A slight turn of the idle adjustment screw (bypass screw) and all is well!!

After numerous cold starts and numerous warm starts I can confidently say that my problem has been solved.

SUMMARY OF STEPS TO CORRECT MY COLD START:

Adjusted WUR - knocked pin in order to get cold control pressure down
Adjusted Mixture
Adjusted Bypass Screw

Paulporsche · 02-17-2008, 06:34 AM

CONGRATULATIONS!

As FDR said: "The only thing we have to fear is fear itself!"

Paulporsche · 02-17-2008, 06:38 AM

Porsche911girl:

Have you tried what mca did? Checking all ignition items first, checking for vac leaks, adjusting WUR to get control pressures correct (if reqd), setting mixture and idle speed?

Robbbyg · Robbbyg's Garage

Dirty Fuel?

mca · 09-11-2008, 06:10 AM

Since this thread has been brought back to life, let me give everyone an update.

I bought and rebuilt an 80 engine. I then pulled the 82 engine out of my car and put the 80 engine in. I used the CIS from the 82 - replaced injector o-rings, replaced injector sleeves, replaced injector sleeve o-rings, replaced the intake boots, and had the injectors cleaned at a local shop.

No more cold start issues whatsoever. My best guess is that the clogged injectors were causing the problems. When tested, they were dribbling fuel instead of spraying. This created a lean condition at start up - not good for cold starts.

The injector o-rings and sleeves were pretty crusty too so that could have also had an impact. The intake boots were still in good condition so I don't think I was getting an leaks in those areas (which would also cause a lean condition).

I hope this helps!

Paulporsche · 09-11-2008, 06:50 AM

Congrats!

We are now checking fuel delivery to try to diagnose a similar problem w/ my car.

mca · 09-11-2008, 07:07 AM

Quote:

Originally Posted by Paulporsche

Congrats!

We are now checking fuel delivery to try to diagnose a similar problem w/ my car.

Paul,

The change in my car was VERY significant. The shop that fixed mine had a tool that would allow them to flush the injectors from spraying side. Basically reverse flushed them. They then bench tested them to make sure the pray was nice and event. Worked out very well - saved me from having to buy new injectors.

Good luck. I am still following your thread.

Craig