"Trailer-hitching" bucking problem, Rapid detrioration from running perfectly Options

[boxster914]

Hi everyone

My perfectly running 71 914 1.7 D-jet has deteriorated rapidly this past week.

Early in the week I noticed what felt like a power drop out during a drive. It was very slight and only happened once and I wasn't sure I didn't cause it by unconciously lifting off the gas.

The next drive it happened a few times and was more pronounced. It was then that I knew this wasn't an imagined problem.

On the third drive it was like a bucking bronco, surging and stopping and the engine cut out a few times. It was undriveable.

Today it will start but won't run. The engine cuts out when I try to rev it and the red light comes on.

I've done some searching here but haven't been able to draw any conclusions or come up with an actionable strategy to diagnose the problem. I'm seeing people trace it to spark plug wires, air fuel ratios and bad distributors.

Is there a step-by-step process that you can recommend for me to get to the cause of this? (I'm a newb so I probably will need help with abbreviations like AFR, TPS, etc.)

Here is a video of it's rough idle yesterday when it was still running.

https://youtu.be/n61CP6O8UgM

[boxster914]

I have more data to report on this issue.

The car has driven flawlessly up until yesterday when I started it cold and it ran rough and when I drove it it was bucking.

I drove for about 1/4 mile with lots of bucking and then turned it off.

About 30 minutes later I tried to start it and it was completely dead no click, no lights no nothing upon turning the key.

I opened the hood and manipulated the battery wires.

I've included a picture with yellow circles around the wires that I manipulated.



I turned the key and it started fine and no bucking.

This would suggest that this is an electrical issue, yes?

Is there a map on the web somewhere of the ground wires that I can check?

Any other suggestions?

[wonkipop]

I have more data to report on this issue.

The car has driven flawlessly up until yesterday when I started it cold and it ran rough and when I drove it it was bucking.

I drove for about 1/4 mile with lots of bucking and then turned it off.

About 30 minutes later I tried to start it and it was completely dead no click, no lights no nothing upon turning the key.

I opened the hood and manipulated the battery wires.

I've included a picture with yellow circles around the wires that I manipulated.



I turned the key and it started fine and no bucking.

This would suggest that this is an electrical issue, yes?

Is there a map on the web somewhere of the ground wires that I can check?

Any other suggestions?

when you say you were manipulating battery wires.
you mean just jiggling the wires but the clamps are still tight on the battery.
those clamps are not rotating when you jiggle them?

if the clamps are good and tight its saying that maybe one of the wires inside the outer coating isn't so good? or your connection of wire to clamp is not so good.

as mentioned above those screw down "anti theft" battery disconnectors as well as not being screwed down tight - can go bad, or even be bad from new.
the first one i fitted to my big citroen which has constant battery drain problems was a dud and gave me all sorts of problems even screwed down tight.
i threw it away and replaced it. no trouble afterwards.

worth cleaning up all your ground points while you are at it as suggested.
i gave that battery earth on a real good wire brush and sand paper clean on mine a couple of years ago and did the transmission one at the same time when i had the gearbox out for a clutch.
the trans one had never been done since new and it was real dirty.
a lot of road muck ends up on that one under the car. worth an inspection.

it does sound suspiciously like one of those battery cables is not good somehow.
or its that anti theft device?