83 SC - throttle problems / misfire when cold - need help

[ixxified]

hey there,

i got a 83 sc (us-version, ca) and i have a problem while starting the car when cold.

it starts right away, idles at around 1200 (warm up regulator has been replaced with a new one). when i step on the throttle, I can hear misfires and the car dies. it starts again, step on the throttle, misfires and dies .. this takes a while and even if i get it to run (and not dying all the time), it's not accepting throttle, again misfires and so on .. when I drive for lets say 15 min and the engine gets warm - no problems whatsoever. can stop - start again, runs fine ..

i didn't do anything to it but had it at two garages - both couldn't fix it. now i try to help myself in a way. any suggestions are welcome - willing to try anything (besides donor the car to the red cross ;-)

i've taken a few pictures that made me curious while trying to find anything .. and of course - i've read all of the threads here, but nothing was really comparable to the issue i have..








any help is appreciated ..

[Luccia at Pelican Parts]

First, welcome to the Pelican community. Your thread was stuck in moderation over the weekend so I just wanted to give it a friendly bump back on to the first page so other Pelicans can chime in with some advice for you. I also posted our free tech articles below that may be help to you now or in the future - so be sure to check them out. Enjoy your time here and if you ever have any forum or questions about our parts catalog please let me know.

Porsche 911 (1965-1989) Technical Articles - Pelican Parts

[boyt911sc]

ixxified,


You are missing the enrichment engine harness for your lambda system. Surprised
you could get it to start and idle (?). Look for a 12-pin lambda engine harness or ask Dennis P. (Timmy2) to make one for you.

Tony

[T77911S]

he needs a throttle switch if he does not have one.

just curious, what is the part number on the warm up regulator.

what is the line with the hole in it?

did you just get the car/

if you have taken it to 2 shops and they did not notice you are missing a wiring harness I don't think I would go back.

I would like to see more pics of the engine, you might be missing other parts or maybe you have a CIS off another engine on there.

[boyt911sc]

ixxified,

You should be happy that your engine is able to start and run at all. Is this car new to you? A quick look at the pictures you posted revealed some interesting missing CIS components.

Enrichment lambda engine harness
Frequency valve
Vacuum lines

Could you post some pictures of the following?

WUR
Ignition distributor
Left side of the engine
Right side of the engine
Front side (showing the alternator fan)

Were the shops or mechanics who last worked on this car experienced Porsche mechanics? Do you still have the ECU under the passenger seat? Thanks.

Tony

[T77911S]

tony,
he could have the CIS off an earlier motor.

[boyt911sc]

Originally Posted by T77911S

tony,
he could have the CIS off an earlier motor.

Ty,

Unfortunately, the OP does not respond and no feedback. There is nothing we could do except wait. See what happens next.

Tony

[ixxified]

Hey guys, thanks for all your replies.

Try to answer all the points and send the requested pictures afterwards.

Lamda harness - I am pretty sure there was one when I got the car .. What gets me thinking - even if those shops could get the car running - why would they delete the harness and not just unplug the cable from the connector?

Throttle switch?! - what does it look like? Can you post a picture?!

Warm Up Regulator - I've taken a picture - does that help? Where would be the number?

Line with the hole - no idea what that is - any suggestions?

Frequency valve - what does it look like? Can you post a picture?

Well, the last shop told me, I have the intake manifolds of an 2.7 - which is hard to believe. I told them, I want those old manifolds back - still nothing (and I didnt pay the bill so far). The told me they've changed those to the right (3.0) ones .. Don't know if thats true or not.

Another thing came to mind - what is so different with this CIS - or - how to remove the whole lambda thing to make it work properly? The only issue it has - when the engine is cold, it's not throttle responsive, it misfires and eventually dies. Can I change the CO to make the mixture richer so it runs better when cold?

Thanks guys!

[ixxified]

[LM3929]

I have a 3.0 83SC that has the same problem (the popping when cold) not the missing parts.

The lambda system is just for emission control but the missing/not hooked up cold start and fuel enrichment system might be a problem later.

My 3.0 engine was running great but overly rich and the only thing I did was adjust the fuel mixture 6 clicks counter clockwise so I will try 3 clockwise later to day and see if that gets me back to where I want

[boyt911sc]

Originally Posted by ixxified

ixxified,

Let's do it step by step from the picture above, you could almost see the WUR ID numbers 0 438 140 xxx. What are the last 3 digits? We need these numbers. Next, remove the air filter cover (snorkel) so you could have a better look at the fuel distributor ID number. There is an aluminum plate/tag on the FD. It would read like 0 438 100 ???. Need the last three (3) digits. The ignition distributor would be 0 237 306 zzz. Keep us posted.

Tony

[T77911S]

you need to post part numbers off of:
fuel distributor
WUR
air flow meter
distributor
engine number, front of case


the line with the hole, where do the 2 ends go?

that silver ign coil is crap.

there should also be some round "disks" with hoses going to them, are they there?

[ixxified]

Hey guys, here are the numbers ..

WUR number 0438 140 090
Fuel distributor 0438 100 077
Ignition distributor 0237 306 001

Can’t find a number on the air flow meter

Engine number is 64D4099

The silver ignition coil is from Beru, Porsche itself installed it after the coil and CDI broke. CDI has been overhauled.

Round disks - where? At the ignition distributor? Yes, with a one vacuum line on it .. There is one round disk on the right back of the engine, there are hoses connected to it.

[boyt911sc]

Originally Posted by ixxified

Hey guys, here are the numbers ..

WUR number 0438 140 090
Fuel distributor 0438 100 077
Ignition distributor 0237 306 001

Can’t find a number on the air flow meter

Engine number is 64D4099

The silver ignition coil is from Beru, Porsche itself installed it after the coil and CDI broke. CDI has been overhauled.

Round disks - where? At the ignition distributor? Yes, with a one vacuum line on it .. There is one round disk on the right back of the engine, there are hoses connected to it.

Ixxified,

Please check the heater resistance (Ohms) of the WUR when engine is stone cold and engine not ran for atleast 12 hours. This is a new WUR and should be well calibrated (?). BTW, was the ignition distributor replaced too? Do you have a CIS fuel pressure gauge? Keep us posted.

Tony

[ixxified]

Wur resistance is at 13.2 ohms

Ignition Distributor was replaced with a used one..

No pressure gauge

[ixxified]

Question: may I be able to fix the issue with replacing the CIS parts from a 1979 SC?

[boyt911sc]

Martin,

Where are you located? Are you planning to do it yourself or need some sort of
outside assistance? PM sent.

Tony

[ixxified]

Hamburg, Germany .. Not really just around the corner ..

[TibetanT]

Hello There:

I am no expert but I did notice something about your distributor, 1) the last three (3) numbers are 001 and 2) there is only one(1) vacuum hose from the vacuum advance mechanism on the distributor. So, with that said, American 1983 911SC has distributor 016 (last three numbers) and two (2) hoses from the Vacuum Advance.

Have you checked the timing ? You may have to retard or advance the timing some to get a good idle. Sounds like your are getting too much fuel when the car is cold.

Hope this helps, and all the best to you on finding the issues with your car.