My SC decided to run like crap ! Help !

[Deschodt]

Last week, I received signs of impending doom on my ignition switch so I booked the car for a replacement. I was going to drive it to the shop this morning, but now, while the ignition switch seems to be working beautifully again, it's the car that won't run right...

That's new !! It fires up and idles at 200 rpm, alternator light on and off of course given the low speed, if you can call that idling ! it does not respond to the throttle at all and hunts like crazy, farts, shakes, and eventually dies after 30 seconds or so...

I can hear the fuel pump, I think.. I checked the relay and fuel pump fuse for corrosion, none... I also cleaned up the nasty looking distributor cap and rotor (next on the list).

I tried again, it's a tiny bit better but it's got more to do with the 10 successive attempts at running it than my lame repairs ;-)

Now if I start it and floor it, it will reach 5000 rpm after a few seconds, and once beyond 3000 rpm it is relatively smooth, but there is not much control between the 200 rpm and the 3000, it's mostly an on-off switch. Sunds weird and not as fuel pump related as I thought then, if it delivers at 5000 rpm ! Still idles like crap . Gonna have to have it towed, I'd rather not try to get to the shop and have to abandon it on the road!

Still sounds like fuel to me, the motor was running great 3 days ago... also bear in mind this car had not been used much for the past 2 years and I've just used it non-stop for a month, so it's bound to have some "issues"... any ideas for troubleshooting, bearing in mind a valve adjustment on a 356 is the upper end of my skills ? Maybe a bypass of the fuel pump relay ?
Well, at least like all good Porsches, she died at home, not leaving me stranded on the road !

PS: I should mention, it's the most humid day on record in FL today, I've read on this board people had issues with CIS on humid days... Possible?

[Walter_Middie]

Greg,

It sounds like you have a really big vacuum leak. Check to see that the airflow boot is still attached - its the large rubber boot that connects the throttle valve with the air flow plate - just behind and above the air cleaner.

[TerryH]

Could be anything at this point...

wet spark plug = no spark = bad wire, plug, rotor, cap?
pull plug wire = no difference = no fuel = clogged injector, fuel filter?


I would start with a new cap and rotor if yours is "nasty". Then try to find which cylinder(s) aren't firing.

[Deschodt]

Thanks.. I checked for obvious leaks but I can't find one... Besides, it ran great 2 days ago when I parked it, and now it won't run to save its life. You'd think a huge vac-leak would have been felt before I parked it, a boot did not just slip/split with the engine off?? . Oh well, I've prodded, poked, cleaned and replaced a thing and cleaned up the distributor cap and rotor, but its the same.

I was going to replace the fuel filter but the one I have is for a 73.5 CIS, much smaller than that of the 83 apparently ! What I don't get is that it will run at 5000 rpm if you insist, so there is spark and fuel... Just horrible between 200 rpm and 3000 ! I'd have thought any of the usual suspects would have probably been gradual...that is what I don't get. Ran great, next start, it's dead as a doorknob....

Off to arrange transport with a friend that has a trailer !!

[john walker's workshop]

might want to check the O2 sensor computer relay under the inner front of right seat and the domelight fuse that powers it. if the fuse is good, unplug the relay when the car is running and see if it makes any difference. idle should drop off and get rougher if it was working.

[Deschodt]

Mr John Walker ! I've heard about you on this board but it is the first time I personally experience your magic ;-) You are THE MAN !
I don't know what you sell, if anything, but from now on I am buying from you, voting for you, vouching for you, whatever !!!

I cannot believe I did not see it this morning ! The fuse to the OXS was indeed cracked - but - ever so slightly where a casual inspection would not have revealed it. Only when I took it out did it crumble in my hand ! I also did not notice because the interior lights are always off in my car... and only the clock was a tell-tale and I did not notice ! A friggin' fuse !!!

I am ashamed I did not spot that, but I had no idea it could create such havoc ! For that matter I wonder why it happened, but it was a tiny brittle old fuse... John, you're a genius !!! Thanks very very much !!!

My baby's firing on all cylinders again !

[jester911]

John is the man around here. We have had the use of his wisdom for years. I only wish I lived near him so I could take my car to him when needed.

I had an idling problem with my car and asked John's help.
He was right about my car as well.

[TerryH]

Originally posted by Deschodt
Mr John Walker ! I've heard about you on this board but it is the first time I personally experience your magic ;-) You are THE MAN !

He is the man. I had written a response earlier that you had John's attention and it would be wise to follow his advice, but that is so obvious here, that I decided not to post it. LOL

My o2 wires are hidden from the smog police and haven't been hooked up in years. I wonder if it makes a difference that mine is a Euro model. My car runs like a bat out of hell, but my gas mileage is mediocre.