I drove up to school today (3 hours), and I believe I have myself a new problem.

The car will sometimes jerk for a split second. You know how sometimes when you have a crappy start in 1st the engine kind of sputters a little and the whole car bucks and jerks? Well it's similar to that, but my RPMs aren't changing. It usually happens in 5th at ~2800 rpm but lately it's been doing it all over the place.

Yesterday I was in 1st and had just started rolling, and suddenly the throttle just started cutting in and out. I'm concerned that this is a major driveline problem.

It almost feels like a misfire or a bad injector. Or maybe it's not getting air for half a second. It really could be a lot of things. Anyone else ever have this happen?

 

Like you said it could be a lot of things, is it damp out when this happens?

 

It's not a driveline problem. It is an intermittent ignition problem. My bet is that it is the key switch itself. Always check this first, it will save you hours and hours of troubleshooting and frustration. GL.

 

Plumbum, nope, it's just normal everyday weather (in TX, everyday = hot and not a chance of rain)

Dave, I'll troubleshoot my ignition system. Anyone know any tips and tricks to test the ignition switch?

 

The first step in troubleshooting the ignition switch is to ask yourself if it has ever been replaced and when. If you don't know, then assume it is the original and 20 some years old. I would just replace it (cheap and easy) . Then drive the car and see if this condition returns. If the problem persists at least you know that the switch is not the problem and you can have piece of mind knowing that future troubleshooting will be based on a known good power source.

 

YUP, start with a new switch or burn up the network looking for other possibilities. Also, check the battery connections and the ground attachment on the top of the bellhousing. If they are loose, it'll cut out all voltage to everything.

 

I had a similar problem on my old 944. Changed everything up to the throttle switch. Then I tried changing the spark plugs just for the hell of it. Guess what it was...

Black magic I say.

 

I'll order one right away, thanks guys. Would this be the exact part I need?

http://www.pelicanparts.com/cgi-bin/...%2520Each%2520

(oddly long link)

It said 83-85.1 944, looks like the same switch as the 914/924/924S. Never messed with this sort of thing before.

 

Probably ignition switch but a quick item to also check are the speed/reference connectors. If those are cracked at all they can cause all sorts of issues with bucking and stalling. I ended up having to Ty-Rap mine together on my 83 until I could find ones.

 

I'll also inspect them. They're over the flywheel, right? I remember thinking they were causing a no-start a month or so ago but never actually messed with them because it turned out to be that damn DME relay...

Anyone have a part # or a recommended resource for the ignition switch for a 1983 944? I've found a few different ones and they range from $5 to $120... not sure if I want to deal with either extreme.

 

The connectors are attached to a metal bracket at the rear drivers side of the intake manifold. If they have any cracks, loose pins, or don't snap shut I would replace them. The heat can make them very brittle over the last 30 years.

The early cars use the cheaper switch. Pelican (Link) and Paragon (Link) both carry the switch; not sure if one is better than the other though.

 

"Anyone have a part # or a recommended resource for the ignition switch for a 1983 944? I've found a few different ones and they range from $5 to $120... not sure if I want to deal with either extreme"

If it were me I would go with the OEM one sold by Pelican or go to a good foreign auto parts store that caters to VW/Audi/Porsche. No shipping charges.

http://www.pelicanparts.com/cgi-bin/...g_description=

The Porsche part no. and nomenclature for the early 944 part is : 111.905.855, ignition starter switch. Hope this helps.

 

AFM?
Recent thread:

https://rennlist.com/forums/924-931-...sue-fixed.html

J_AZ

 

Thanks for the info. I'm going to be trying the AFM trick as soon as I can.

Ref sensors were replaced '04 so I'll check them over, but I doubt that's the problem.

 

Update- I did a parking lot tuneup and it definitely runs more smoothly.

I massaged the leads going to the AFM and ref sensors, re-attached the AFM harness as per thread that John linked (although I didn't have the vent hose thing) after I cleaned and blew on the contacts.

Well, blowing on the contacts solved a lot of problems on the Nintendo 64...

I noticed that some of the ignition wires from weren't clicked all the way on to the distributor cap, could have been loosened after a 3 hour drive with no balance shafts and a failing motor mount...

Anywho, it turned right over, noticeably faster than recent start-ups. I took her for a spin around town and there was still a little tugging/jerking at the bottom of second, but it went away when I gave it throttle or clutched in. I'll probably replace the ignition switch anyway, because it's cheap and it probably needs to be replaced at some point soon anyway.