Rolling home from Philadelphia on the turnpike at about 75mph, my 914 cut out on me about 6 times. Each time, it restarted on it's own (I was in 5th grear) and I heard a loud bang (backfire maybe?) from the engine bay. After the restart, it continued running like a dream until the next episode.

It's a 2056 D-jet engine.

Any ideas on where to start looking?

driving to slow?

Bob, sorry to hear this. My first reaction is that it sounds ignition related, like a loose connection, but it could also be fuel related. Off the top of my head I'd check the following:

1. Verify timing
2. Check all coil/spark plug wire connections
3. Verify MPS is connected to harness and to vacuum securely.
4. Check trigger point connections

Do you have stock dizzy or 123 dizzy?

Bob, check all the grounds.Simple first step. My old D-jet would do this. In my case it was the one on backside of engine near rear trunk panel.

Dion, great point. Loose ground at the case will cause fuel pump to cut out intermittently.

Start with the basics, clean all your grounds, do a valve adjustment, points if you have them, etc.

Grounds are usually the issue when funky electrical things happen. Do them all, battery posts, + and - to the body, trans strap, under the relay board FI grounds, even under the fuse panel.

I'm in for "electrical" as well.

Mine did that, it was poor connections between the two harness plugs and the relay plate. Remove, clean, **slightly** spread the male quarter-pins for better contact, dielectric grease, done. Never again a problem.

Stock dizzy, still running points.

Got to be loose wire/grounds

+1 for loose ground wires. Happened to me.

What did the tach do during this interruption?

Keep in mind that the ignition system is independent from DJET.

Key switch?

Fuel pump OK?

Mine started doing this when the 3-port pump bypass was leaking by.

@Spoke

Tach dropped to zero.

Well...yes...and no.

Fuse S9 powers the ignition coil as well as the solenoid control circuit for the power relay. Absent that, the power relay won't latch.

Once latched, the power relay powers the D-Jet system as well as the control solenoid for the fuel pump relay, which is grounded by the D-Jet ECU.

And it aaaaaall goes through the relay plate...which is where I'd focus my investigative ire, as I did when I had the same problem (see above what I did to resolve it).

So while these two systems are mostly-independent, as in West Virginia*, it's all related.

GA

*Don't give me any grief about West "By God!" Virginia. One of my fav tracks to run is over there (was just there a couple weekends ago). I might even convince myself to move there someday...

Very important point. So the issue is ignition electric, not fuel related or FI ECU related. Even if the fuel pump cut out or the ECU briefly died, the dizzy and coil would still fire the plugs and the tach would work.

As @GregAmy points out, the ignition system is powered by fuse F9. Maybe clean and check F9. Following the wires, from F9, ignition power goes to the relay board then onto the engine. I would try removing and replacing both connectors on the relay board. Also check the connectors on the coil and the wiring to the dizzy.

If you decide to R&R the relay board connectors, disconnect the battery NEG as the battery POS goes to the relay board w/o fuses and any accidental crossing of the battery POS pins could let the smoke out of wires.

This is incorrect. Power from the ignition switch does go to fuse 9 where the wire to the coil joins it on the non fused side. D-jet will run without fuse 9. Brake and backup lights and a few other thing need fuse 9 but the ignition and FI does not.

Wazzup, Ed*!

I rechecked the electrical diagrams for my '74...the power relay solenoid power comes from S9...I don't see how the D-Jet system will get power if there's nothing coming from S9, as the power relay (J16) won't latch. No latched power relay, no D-Jet or fuel pump solenoid power.

GA

*I still want to grab that front valence from you...

Well then come up here and we'll go over the diagram together

I'll be at Palmer at least a couple times this year.

I see it now. The battery, ignition switch, coil, and power relay are all on the same side of fuse S9. The ignition switch completes the circuit to the power relay (as it should).

It also means that there is absolutely no fuse between the battery and the ignition switch, and between the ignition switch and the power relay, coil, and D-Jet system. The heater blower gets a fuse on the relay plate, but nothing else does...watch them hot wires, kids...

Did you check your fuel filters/strainer? It is easy to pick up crud, from a fuel station that was just restocked.

Cheap and easy to fix.
I’ve a ‘73 2.0 that would do the same thing. Cut out, startup, sometimes not start. Was the sock all along.

That wouldn't affect the tach, though...

Yep. Its gotta be electrical.

If the purple/black wire from the dizzy to the tach grounds out anywhere it will kill the engine and the tach.

There are not that many wires to and from the dizzy. You will probably find one that had wiggled a little loose and is grounding somewhere. Just enough to skip a beat.

Zach

Update: Yesterday I cleaned/reset all the grounds, cleaned fuse S9 and reset all the connections on the relay board. Took it for a test drive and it ran flawlessly. Thinking I had it, I hit the road for Philly. A little over half way, it started cutting out the same way as before. I pressed on as it was very intermittent <----this proved to be a very bad decision.

The car stalled pulling into a rest stop. I restarted it and hit the Schuylkill expressway. It started bucking very badly, lost power and eventually died in an area with a very narrow berm & rush hour traffic.

It would start, but died immediately. I had it towed to Vanessa's condo.

We took a look at it today. When I first tried to start it today, it would start, then immediately die, same as yesterday. After a few more tries to restart, it wont even try to start. I pulled a plug to test for spark - nothing.

I'm working in a parking lot with limited tools & test equipment. So far, I've swapped out the following with my spares:

Coil
Relay Board
Distributor (complete, with all components).
ECU

Any further ideas would be appreciated. Again, I've got no spark.

Click to view attachment

did you try to jump 12v straight to the + on coil ?

If that works it could be ignition switch, or ignition harness.

Also would enable you to drive it home. you will have to disconnect that wire to shut it off though.



Just tossing out an idea here.

@Olympic 914

That would be a sweet workaround to get me home. Do I just run a wire from directly from the positive battery terminal to the + on the coil?

Never tried a direct connection; you still have to start up using the ignition switch ?

Yes.

You still need to have the ignition switch for starting, and leave it in the ON position to run.

Don't leave it connected to long without the engine running. It will burn your points. Or if you have a Petronix unit it will damage that. Minute or so shouldn't hurt though.

I would not run a wire from the battery to the coil. As soon as you make that connection, if the points are closed, the coil may saturate and high currents will flow and can damage the points, coil, and maybe the wires.

If you are going to wire directly to the battery, it is best to run the wires into the cabin and use some type of switch even like an AC light switch to make the connection as you crank the motor and to cut it off when you shut off the motor.

Do you have AAA Premier? If so, you have a free 200 mile tow. If not, it's cheap insurance for the future.

Give a close inspection of the wires leading to and from the coil. Something like what you describe happened on my yellow car and it ended up being a sketchy wire.

I had the same issue with my 73. Replace the tach. I can't remember where I read it, maybe DR's technical tips or this site. But that's all it took.

Happy Easter all!

Still battling. I've tried momentarily wiring 12V directly to the "+" side of 2 different coil & 2 complete distributor combinations. Also disconnected black-purple tach wire at the coil.

Still no spark at the plug. I'm beginning to wonder if my spare coil (used) is bad. Is there any way to test coils without a VOM?

I've got the mid-grade AAA package with 100 miles of free towing. I'm about 20 miles over that. I'll call them tomorrow to see if I can upgrade & use it right away.

Might have to push the car down the hill though, as I don't think AAA will tow from a location that they towed a car to.

Hurts my eyes to see your car on a flatbed. Nice Zambezi; confident you can get it running by the NE Gathering. This is what's worrying my wife for the trip; she doesn't do well in stressful situations....

Assuming the new distributor has different points/condenser and was installed correctly, one could rule out the distributor.

The ignition system is quite simple: 12V, coil, points/condenser, rotating distributor, cap, rotor, wires, plugs, ground.

You've replaced most of the components and even connected 12V directly to the coil and removed the tach wire taking that out of the circuit.

Assuming the engine cranks you can assume the ground strap to the transmission is ok enough to fire the coil.

It's pretty difficult to troubleshoot this system in a parking lot. It's a hard pill to swallow but might be best to get it back to the garage and do an indepth analysis of the issue.

BTW, you're a brave man for driving your 914 on the Sure-kill Expressway in Philly.

Rob what’s your status now? I have a tilt trailer and may be able to get your car out to Dillsburg. PM me with your contact info.

I appreciate all the suggestions & comments, including Tony's generous offer to help get it home.

I tried everything my parts & tools would allow with no luck.

She's getting towed home. AAA is covering 100 miles of the 118 mile tow.

2 trips on a rollback in 4 days!

Please DO let us know the diagnosis! With the NE Gathering coming up, want to be prepared

How is this problem going?
If you want some suggestions about where to start,,,,
Start with the basics,, assume nothing.
You need 3 things for your car to run. Fuel, air, and spark.
You can check for spark by removing a plug wire and hold it close to ground. When you crank the engine you should see spark arc from wire to the ground. Have a helper crank the car so you can watch.

You can check if you have fuel arriving to your engine with a pressure gauge,,, or see if your spark plugs are wet.

One of these 2 tests should point you in the correct path to fix your car.

Describe what happens and the board can help you get her started right up.

-Robert

Got the car running again today.

I had spark when the car broke down - it was still firing, but running very rough, stalling and had no power.

I wasn't at my best troubleshooting in the condo parking lot. Regarding my lack of spark - one of the first things I swapped out after the breakdown was the dizzy. I could have sworn I had fullly tested the spare a few years back...but didn't. The points were bad in the spare so I didn't get spark. I thought I swapped back for the original dizzy at some point while changing parts...but didn't.

After losing spark, finding it became my primary focus, but It never got resolved in the parking lot. This was a secondary problem created by me,

The primary reason for the breakdown was that MPS had failed. Put original dizzy back in, plugged in my spare MPS, set the dwell/timing and was back on the road. I had the spare MPS with me in Philly, but got sidetracked in the "no spark" rabbit hole.

Hopefully the original problem of the engine cutting out magically fixed itself through this ordeal.

I'll be staying off the Schuykill for a few weeks while I gain confidence again in my car.

Thanks again for all the help.

Great news !
Keeping track of our own moves when under stress is difficult.
We've all been there, perseverance and patience pay.
Good job.

Good news, Bob!

You know, there's a 1-2-3 Group Buy going on....

Great news, indeed!
Hope to meet you at NE Gathering.