Getting the Urge to Swap again

Scuba Steve · 09-26-2014, 06:41 AM

I've been chasing down a hard start / high idle trouble on the 560SL for a while now and it's really hit me how different, same year vs. same year the car is from the 924S I used to own. The Mercedes is vastly more complex and difficult to work on than the Porsche was. The only truly ugly job on that car was changing the clutch but with this one it's always an adventure. A lot of the hardware hasn't been turned since the car was built, but access in general is a huge issue. The online community is also nowhere near as good as PP and Clark's Garage is.

I've started thinking about 951s, but I plan on sticking with this one for a while. How are 911s of a similar vintage? I've only played around with the water cooled ones.

scottmandue · 09-26-2014, 06:58 AM

Let me start with I love, love, love, 944's and I dearly miss mine...
Maybe some day if I hit the lotto (not likely because I don't play the lotto) I would consider getting a hot rod 951 or 968...
However... if you consider bang for your buck I think you could find other cars might bring more to the table.
Just my two cents YMMV

Scuba Steve · 09-26-2014, 08:36 AM

I'm curious which? The affordable 996 thread has been plenty of fun to keep up with but I've never had the joy/pain of working on one.

There is a bit of 'I miss my 924S' in there as well, but also a little frustration with trying to troubleshoot the thing. It's really strange. When cold it can be hard to start but when it does it'll idle OK unless you turn the a/c on or put it in drive. Then it stumbles and stalls as though it becomes starved for fuel. Once the car warms up a bit more you can put it in gear and go just fine, albeit with a high idle.

scottmandue · 09-26-2014, 09:17 AM

I have never owned a 911 but I too lust after "the affordable 996"... Boxsters are coming down in price too.

Because I'm a poor white boy I opted to try the Miata experience... I have dubbed mine the tinymobile when properly set up (pardon the pun) they are great fun and very tossable... I read somewhere that there are more Miata's racing/autocrossing than any other make of automobile. The aftermarket is insane, any part you can imagine can be had from multiple vendors and multiple levels of quality (Cheap Chinese knock offs, original Mazda, fancy CF racing stuff)
However tiny has it's drawbacks... getting my ham sized fists into some of tight corners can make it a bit of a challenge to work on... as is hauling my fat old butt in and out of the drivers seat.

I do see me selling the Miata and getting something with a little creature comforts a few years down the road.

Scuba Steve · 06:26 AM

I've always liked Miatas. In 2000 I test drove one and thought it was great, but ended up with a Celica GT-S instead. Every bit as fun as driving around a giant go-kart.

Support with the SL is really lacking. If you want to figure out what kind of soft top to buy or rims to replace yours with Benzworld is great for that. Peachparts doesn't have much activity but both boards have decent search results. It's sort of like the 1990s again but this time with google instead of a Chilton manual.

At this point I know that the idle settings at the fuel distributor has been messed with by the PO and is way out of adjustment, and I'm hoping that I can figure this thing out somehow... my calibrated nose tells me it's running rich. Mercedes KE-Jetronic and Porsche K-Jet seem similar enough for there to be some decent reading material out there.

E Sully · E Sully's Garage

The 560's are great cars, but stayed with CIS, while starting with '84, 911's went Motronic. '84 ond on 911 Carreras are great engines and car.
560's would need a little tuning of the CIS for the new gas formulations. Neighbor just had his 560 done and it runs great.

porsche4life · porsche4life's Garage

Don't drive a 944 turbo unless you are ready to switch. That boost is addictive!

Shaun @ Tru6 · 09-27-2014, 09:35 AM

I've never driven a 951 but have a few 86 and 87 944s. I honestly don't understand the love for them. My sense is a 951, I probably would.

After recently driving, almost buying a 2003 Boxster S, that will be my next car. Something to consider.

onewhippedpuppy · 09-27-2014, 09:36 AM

986/996 is exponentially easier to work on than a 951.

beepbeep · 09-27-2014, 10:03 AM

Quote:

Originally Posted by E Sully

The 560's are great cars, but stayed with CIS, while starting with '84, 911's went Motronic. '84 ond on 911 Carreras are great engines and car.
560's would need a little tuning of the CIS for the new gas formulations. Neighbor just had his 560 done and it runs great.

560 K-Jetronic and 930 K-Jetronic are more or less identical. Only difference is that 930 CIS fuel "head" has two outputs plugged. So whatever troubleshooting needs to be done, I bet 930 forum has lot of info.

It's usually same old "measure control pressure after cold start" and "make sure there are no air leaks".

Scuba Steve · 01:21 PM

I had no idea that 996/986s were more simple than 951s. On paper it's tempting because it's basically the same weight but a huge hp difference. On this board I read enough complaints about the turbo and plumbing getting in the way of everything to believe that they would be easier to work on. I miss Motronic. Happy sensors + happy DME and a spare DME relay in the glove box = happy car. I never had a problem with bolts sticking and breaking all the time like they do on this car, but not everyone has been as lucky.

Right now the 560 will do one of three things when you try and start it:
- Start and run (600rpm - 1,100rpm)
- Start and stall (500rpm-800rpm)
- Not start at all (flooded engine?)

Today it went from doing #1, 2, and now 3. I checked for spark at the rotor and there is none. At least I have something consistent to troubleshoot now.

kaisen · 09-27-2014, 02:06 PM

Have you checked the cold start valve, 9th injector?

Scuba Steve · 09-27-2014, 06:05 PM

Yep, it was quite pressurized. I went back to check this no spark condition again now that it's dark out and the problem jumped out in front of me. I had very weak spark at the rotor and a ton of arcing to a metal power steering line. The wire has basically burned through.

I'll be the first to admit when I was wrong... It's hard to troubleshoot a problem on any car when another one sneaks in undetected on top of it.

billybek · billybek's Garage

Thought this was going to be another divorce thread...

Glad to see it is something much less expensive!

Scuba Steve · 01:09 PM

Something like that might be easier than this to straighten out.

I'm back to the fuel issue again. Starting fluid down the intake tells me the car isn't getting gas but does have air and spark. Immediately after I crank the engine the cold start injector line is still pressurized but the others going to different injectors are not. I'm not sure if this is normal though.

The car will start if the air plate is pressed down somewhat.

At this point I'm about ready to throw in the towel. Have the car dragged to a shop, tell them to just make the thing run and immediately turn around and sell it on Craigslist.

Scuba Steve · 09-30-2014, 01:35 PM

Update:
I figured it out after reading some 930 and 928 troubleshooting guides. How I did it was, I loosened and bagged the cold start injector, cranked it and got nothing. Then I jumped the cold start thermoswitch and tried again. This time I had some gas in the bag.

Now we're on to something.

Reinstall the cold start injector with the switch jumpered, fire it up and the car starts but stalls immediately. Two weeks ago I took the car to a shop to replace the flex discs and the mentioned having trouble starting the car when cold, and playing around with the air plate adjustment a lot to "make it start." 20 minutes of trial and error later and I found the correct range to make it start and run. It's idling about 500rpm high but I'm back in the neighborhood where it'll start and run at least, and I'll tune it back down once I have a new thermoswitch.