Pretty common problem, but not sure how to fix it., Engine? Fuel Injection? Misfiring? Options

[tumamilhem]

So recently my car is occasionally making some shaking and jerking. Sometimes it doesn't start. Sometimes when driving, the power shuts off if I let off the accelerator. And sometimes when I drive, it jerks, like the power is cutting in and out.

FI problem?

Engine problem?

Distributor?

Spark plugs?

Misfiring?

Timing off?

I've done some work on my other 914s, and I had this problem with each one at some point or another, but it's been so long I can't recall. And I'm not really a mechanic. My guess is it's misfiring. Any suggestions and input on how to remedy this would be great, especially explanation on how to fix it myself. Otherwise, I'll have to take it to a shop.

[jasons]

When I had this problem on my DJET car... My FI Trigger points were worn. And its not the contacts that were worn, it was the bushings that ride on the distributor cams which open and close the points. My bushings were worn so much the points weren't always opening/closing.

[rmital]

...the usual response is, check the basics...like you mentioned.
timing, dwell, etc...

just curious, do you have points or pertronics (sp.?)??

[tumamilhem]

When I had this problem on my DJET car... My FI Trigger points were worn. And its not the contacts that were worn, it was the bushings that ride on the distributor cams which open and close the points. My bushings were worn so much the points weren't always opening/closing.

Where are those bushings and FI trigger points located? Picture? Sorry, I'm still learning about these...

Thanks for your help!

[jasons]

When I had this problem on my DJET car... My FI Trigger points were worn. And its not the contacts that were worn, it was the bushings that ride on the distributor cams which open and close the points. My bushings were worn so much the points weren't always opening/closing.

Where are those bushings and FI trigger points located? Picture? Sorry, I'm still learning about these...

Thanks for your help!

I will back pedal and give you the standard, check all the more obvious stuff first. Timing, plugs, fuel pressure etc. rmital is right on this. I could be handing you a red herring. Like I typed this was MY problem and fix.

Disclaimer over, there is a module that screws into the body of your dizzy and there is a plug with 5 or 6 wires that plugs into that module. This is where the FI points are. The plug is for the FI points and there are 2 screws (IIRC ) that remove the FI points.

[SirAndy]

And sometimes when I drive, it jerks, like the power is cutting in and out.

Check and make sure your coil is clamped down correctly. The blue Bosch is a just a tad too small for the stock clamp and will move and short out.

I had to add some padding to the clamp to get it to fit tight ...
(IMG:style_emoticons/default/idea.gif)

[tumamilhem]

Check and make sure your coil is clamped down correctly. The blue Bosch is a just a tad too small for the stock clamp and will move and short out.

I had to add some padding to the clamp to get it to fit tight ...
(IMG:style_emoticons/default/idea.gif)

Thanks, Andy! Coil is firmly secure as are its connections. Coil has rubber strip for tight clamping. All good there.

I just tried to start it up and it comes on and then power keeps going out. (IMG:style_emoticons/default/headbang.gif)

[SirAndy]

I just tried to start it up and it comes on and then power keeps going out. (IMG:style_emoticons/default/headbang.gif)

Fuel filter clogged?
(IMG:style_emoticons/default/idea.gif)

[Java2570]

Check the fuel pump fuse to make sure it's good and that it's staying seated in the fuse holder. It's located in the engine compartment, left side under a black cover.
I would suggest picking up the Haynes manual as it has most info regarding basic
maintenance and component locations. I bring up the fuel pump fuse because at
one point, I was having intermittent loss of power....the engine would just shut
down and sometimes wouldn't start because that fuse came loose. Not sure it has
to do with the jerking, etc. it sounds like a couple of other things could be happening.
Like others have said, check all the basics.... Jon

[r_towle]

D-bible

http://members.rennlist.com/pbanders/DjetParts.htm

[JRust]

You have petronix not points

[rmital]

CHT

If you do have a pertronics unit instead of points and it hasn't failed, my next guess would be the CHT. Very easy to check.... Just went thru this myself.
Take a test line and connect or ground the connection where the CHT ties into the harness; connect to the harness at that point and connect to the negative on the battery. If your car runs fine, it was the CHT.

[76-914]

Wow. That's a lot of (IMG:style_emoticons/default/stromberg.gif) going on at once Tommy. I'd go with fuel pressure. CHT sender or MPS unit. Did this all begin at once or have the problems accumulated? Has it ever been "tuned" correctly? i.e. the A/F ratio, too?

[tumamilhem]

Wow. That's a lot of (IMG:style_emoticons/default/stromberg.gif) going on at once Tommy. I'd go with fuel pressure. CHT sender or MPS unit. Did this all begin at once or have the problems accumulated? Has it ever been "tuned" correctly? i.e. the A/F ratio, too?

What's 'CHT' short for?

I don't know if it's been accumulating. I bought the car in December. It seemed to be underpowered compared to my 1.8, although my 1.8 is now a 2.2 with larger pistons and jugs. But I came to find out the compression was very low. Putting it on a tow truck and putting it in 1st gear, it still rolled back as if it wasn't in gear. Then more loss of power with the with the power not being constant while driving. Slight jerking hiccups turned into full on conniptions to the point that I had to ride the accelerator just to keep the car on, which now doesn't even work. If I can start it at all.

From my basic knowledge, I would assume it's misfiring from the timing being off. I've never adjusted the timing before, though I have seen it doen when Phil Sparta adjusted it on my other car. But I didn't really understand how it works or what to do exactly.

I don't think it's the fuel filter. Or the wire harness. The same symptoms of random loss of power will occur, but not sudden jerking.

Ironically, the same thing just happened to my VW GLI VR6. But it was the coil (mine has 6 coils). It's happened before. That car vibrates a bit more than jerks, but obviously because it's a different technical engine than it's 40 year old flat 4 pappy.

I've had it at my friend's mechanic shop for the last week. He still hasn't touched it yet, though he's worked on other cars that came in after. Which kind of pisses me off because I told him I wanted to drive it to the Amelia Island Concours d'Elegance this past weekend. If it's misfiring, it's a simple and short repair. And after a week, I would've though he would've at least looked at it by now. And now there's also the compression problem.

[StratPlayer]

CHT= Cylinder Head Temperature, its a sensor the is screwed into the head and connects to your fuel injection wiring harness.

[tumamilhem]

Wow. That's a lot of (IMG:style_emoticons/default/stromberg.gif) going on at once Tommy. I'd go with fuel pressure. CHT sender or MPS unit. Did this all begin at once or have the problems accumulated? Has it ever been "tuned" correctly? i.e. the A/F ratio, too?

What's MPS unit?

As far as the A/F ratio, it runs a bit rich. I'd rather it run a bit leaner, but I don't know how to adjust it on the D-jet. It was simple on the L-jet.