1911 L-jet, 20K miles on it. Weather has been nice, so I have been driving every day.

A couple days ago I noticed that within a few minutes of the beginning of almost every drive, the car acts strange. Kinda feels like how the car feels when you are popping the clutch to roll-start it. One big jerk, then the engine is running and you head on.

I pull to a stop sign, look both ways, let off the clutch and increase the gas pedal when all of a sudden there is a big whole car jerk with a what I believe is a brief "engine stop". Sometimes I have enough gas pedal going and it is just a hiccup.

Sometimes I don't and the car stalls. Starts right back up and for the most part the rest of the drive is trouble free.

Seems like it may be FI electrical. What do you think?

Clark

A clutch issue, maybe?

Problems with the torque converter

1st stop sign on the way to work this morning, just pulling away and it happened (as usual).

Then, strangely enough, 10 minutes later I was on the interstate, cruzing at 70-ish, and the same small jolt happened.

No clutch.... or Torque Converter was engaged.

I had a similar problem with a 1972 Volvo 142E when new. Took it to a dealer several times, and finally, after removing the throttle position switch to test it, the problem disappeared. I suspect there was some junk in the switch that would work its way into a position to momentarily block the electrical connection, then get dislodged when I pumped the accelerator. Never happened again, even though they did not replace the TPS. I believe the Volvo injection was similar to our 914's. You might check your TPS.

A lot (if not all) Volvos of the era were running D-Jet injection, just like the 914. I know the "bucking" problem can be caused by a dirty/worn TPS. I'd clean up the TPS as a start.

My $0.02

Konrad

Just unplug the tps. Its surprising how well the car runs without it. If it runs better unplugged, then you have a tps problem

The Jetronic system is often the first thing suspect with such an issue, but 9 times out of 10, the problem is ignition. I had a similar problem recently, cured by replacing points set, as I had pinched the lead wire under the dist. cap.

Really, our Jetronic FI systems are about the most dependable feature of our cars...so always eliminate ignition as a source of trouble first. Do you notice tach needle dropping at the same time as your miss? This can often be a clue.

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Been there: My L-Jet hiccuped because the circuit to the fuel pump had a marginal connection. It occurred at the dual relay; the FP wire connector was worn and the base slipped down. Replaced the connector and zip tied the base to the relay

thanks gentlemen, you have given me some things to look for this evening.

It could still be the ignition, but not points. Via a Tim_ND recommendation, I replaced the points with an electronic module from these guys....

http://www.hot-spark.com/

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bought a spare on too.

The hiccup always startles me. I can't remember what the gauges do. I'll have to make a point to check the tach. The engine does get very quiet for that brief second tho. My lunch time cruise did not have a hiccup. Maybe outside air temp has something to do with it, cause it is hotter today than it has been.

I remember during rebuild and wiring back in '13 that the dual relay was a point of concern. Has anyone ever come up with a better, maybe more solid state replacement? That thing scares me, I don't even want to touch it. Old wire, old weak connectors all crammed together.

I looked at the Throttle Body connection during lunch today... or I tried to. I can't even see it or touch it on the btm side of the TB. Too much stuff all around it. I'll have to remove a lot of stuff to give that rec a try.

BTW Tim, I have my team working on the torque converter as we speak....

I have a question about the fuel pump. I wondered if it might be troublesome.

Isn't there pressure in the fuel ring when the pump (and car) are turned off with the key?

So if the pump quit for just a second, would the engine even know it?

Makes sense to me that with an occasional and intermittant fuel pump issue, residual pressure in the fuel system would make for a less jarring sort of symptom. Maybe an intermittant ignition problem, or injector firing problem would more likely result in the sudden power loss and return. Keep us posted

Ok, my 2cents here what I had with my MK1 golf, not sure if it is the same symptom, but maybe it helps. At some points the car would have a hiccup. it was like the engine just shut off for a second and then picked up again. It was really weird. I could never find out why...It got worse by the way as time passed.
Eventually we found out it was the ignitionswitch that was worn out, and since I had a bunch of keys hanging from the ignitionswitch, the weight on the switch triggered it with some bumps or moves. Taking off all the crap hanging from the switch and only using the key in there helped a bit but eventually I had to replace the switch and hiccups gone. Maybe not related, but who knows....

I agree, you probably have a 'dead' spot where the TPS is most comonly positioned.

Isn't the TPS a switch? ON or OFF, signal or no-signal? Not sure what the system does with the signal or no-signal, but is it "signal" at idle (valve closed) and "signal" at WOT (wide open valve) and "no-signal" everywhere else?

Not knowing what the system does with the signal, I can guess that pulling away from a stop sign could be a change (or lack of a change) from "signal" to "no-signal" and that is where my prob is. But where do the cruising at 3200 rpm hiccups come from?

I don't believe the innards of the TPS look like the innards of the AFM with a sweep arm touching a PCB, does it?

Then you should remove the tps and have a look inside. Show us what you find?

on my list, but so much other stuff has to be removed. I do have a spare, I'll open it when I get home this evening.

Should have a barn door flap with an armature on the top that rides on a board. Problematic in the D jet, but might be it.

Also my .02

Mikeys' 2.0 that he just got was having some issues that were intermittent, went through it and couldn't find the issue. Took it to my mechanic who drove it for a week. Turns out there was a little too much hose in the front under the tank and finally noted that a right turn precipitated the stumble. Turned out that the tank shifted just enough to pinch the hose. Not all the way, but enough to affect the engine.

Had this same experience/set of symptoms on my 914 at around the 100k mile point. Replacing the ignition switch solved it.

LJet tps is a pcb just like DJet. They can get gummed up as the sweep arm sits at the same "cruise" spot most all the time. This can be cleaned a bit with a soft pencil eraser. The AFM also has a pcb and sweep arm and it too can get gummed. Same fix...

A previous poster is right though, 90% of what gets blamed on EFI is not the EFI...

With the engine running, wiggle the key in the ignition switch. If it shuts off the switch is bad.

I had to travel this weekend. Did not get a chance to troubleshoot. But I did open up a TPS that I had as a spare. Here is what I found. Not sure if this is L or D-Jet, but it seems to operate as folks have stated.

From stop to stop The throttle makes 1/4 turn. Using a clock as an example Idle is the hour hand at 3o'clock (I think). WOT would be 12 o'clock

at IDLE 2 contacts touch. (labeled "18" and "2" on the connector) thru CCW movement of the throttle to 2:30 (hour hand between 2&3) when the contact open.

from 2:30 to 12:30 no contacts touch.

at WOT 2 contacts touch. (labeled "18" and "3") thru CCW movement to 12 o'clock

Click to view attachment

It will be interesting to compare mine to the picture above.

This is all fine and good. But what does the computer do with this info? I suppose I could clean mine up and freshen up the contacts. Anyone think this could be causing my stumbling or hiccup? I will try to remove it and run today.

More info for the masses.....

Driving to lunch, before I left, I decided to pull the front mounted fuel pump out into the front trunk. I did remember a slight kink in the large input hose (I could not straighten out) during the last filter change.

So the pump is now dangling. All hoses are un-kinked. With the car idling, I listen to and held the pump. I feel turbulent flow out of the pump, not into it, just out. You can hear what is probably bubbles flowing out.

Is this normal?

OH yeah. I did wiggle the key while driving, up and down, side to side. No hiccup during the wiggling.

Fuel pumps are normally noisy, I wonder if it has something to do with the fuel running by the check ball at 100mph?

You have a intermittent problem, which can be very difficult to chase. So every morning you get this issue?

Yes every morning, usually in the neighborhood about 1 mile.

Then going to lunch. Stop sign is about 1/2 mile from my parking place.

Sometimes leaving work at the same place but not always at quittin time.

Usually the rest of the drive is smooth: Coming in to work, going home, running errands or just on a sunday drive.

If it was me, I would try isolating each component through-out your work week since this is your daily driver.

For tomorrow's morning drive, start your car and then install a jumper from the positive battery post to the positive terminal on the ignition coil. Drive your car to work and observe if you still have your hiccup. Make sure you remove this jumper when you get to work. This test will bypass part of the ignition switch

Wednesday morning, start your car then jumper pin 88d of the dual relay to the positive battery post, then drive your car. Same thing as above, remove the jumper when you get to work. This test bypasses the dual relay and supplies power straight to the fuel pump.

Thursday morning, start your car then jump pin 88a to the positive battery post. This test injects power straight to the ECU computer and the AFM fuel trigger points.

The data collected from the tests above may help point you in the right direction.

Tim, In dealing with the relay, when you say "jumper", do you mean to pull the wire out of the relay and clip a wire to the connector and to + post?

Or do I need to "back plug" a wire into the suggested relay slots for each test?

"jumper from the positive battery post to the positive terminal on the ignition coil".

Just for fun, and to make sure I could do it, I tried this test. I know it is not morning. But I did it. I felt a slight, faint hesitation early in the drive, but it was slight and it was not at the usual location on my drive out of the hood. So I could just be too sensitive to how the car runs.

So that is a MAYBE for now. I guess the trip to work will give me the real answer.

I did notice that the car did not turn off when I turned the key. I had to unclip the jumper. So now I know we jumped the key cut-off circuit, right.

These tests are only for mornings, when the engine is cold, which is when you are experience the "hiccups".

Start the engine, apply the jumper, then drive to work. When you arrive at work, keep the engine running, remove jumper, then turn the key off.

I know, I just wanted to practice. And while they are not as frequent and as startling I occasionally get a hiccup when the engine is warm. I figured if it hiccups now, during a test, it will hiccup in the AM. and I might could rule it out.... did not happen. Plus I got this Okteenerfest thing and I'd love to not worry about hiccups in Banner ELk.

OK, now what about the relay jumper? How do I attach the wire? Back-probe? I can't pull the wire out of the relay, right?

Besides IIRC the connectors have tabs on them that help hold them in, it would be tuff to pull one.

I need to practice my back probing.

OK the official run of test #1 was smooth as glass. Not one single hiccup or flutter.

Since I do experience the problem at other times of day, I will put the jumper back on when I go to lunch and then for the drive home today.

I assume if "no hiccup" continues, I should be looking to replace the ignition switch? This will be the 3rd or 4th in 20K miles. IIRC, So I would get a good one, I bought the current one from the PORSCHE dealer in Nashville.

I don't think you are out of the woods yet. I would repeat the test again tomorrow, just to make sure that today's result wasn't some anomaly.

Tomorrow, if you get the same results, it would seem that it could be the ignition switch.

But, you need to rule out the wire and connections and the relay board itself before ordering a new ignition switch. At the ignition coil, you should have a black wire with red stripe on the positive terminal. Connect one meter lead to this and set your voltmeter to DC. Now, find the black wire AT the ignition switch. Connect your other meter lead to this black wire. Start the car, then observe what your voltmeter is saying. Ideally, you should be reading 0.00 volts dc.

If you get 0.00vdc with that last test, that proves that the wire going from the ignition switch to the fuse box to the relay box and finally to the ignition coil is good.

Next, at the ignition switch you will see that black wire that you already probed. Attach one meter lead to this black wire. Next, attach your 2nd meter lead to the solid red wire. Set your meter for DC volts and start your car. Again, you should read 0.00volts DC. If you are reading anything, this would indicate that you have a voltage drop across the contacts within the ignition switch. This would conclude you have a bad ignition switch.



Now, you stated that you have replaced the switch many times over the year. Something is causing these ignition switch failures. Either you have a aftermarket radio or vibrating heated seat cushions, something isn't right. The ignition switch can only handle so much current before it will degrade and fail. You may want to modify your switch and add a external relay to drive whatever is power hungry.

Thank you sir.... (again, and again and again...). I assume access to this black wire at the switch is going to require steering wheel removal, etc....or IIRC: maybe just the knee pad

I do have a Blaupunkt San Francisco radio, but no heated seats or any other item that would pull power. That can be a project for another day.

Thanks,

Clark

OK I am back from 888 miles of Okteenerfest (used the jumper all weekend, not one hiccup)and I gave your test a shot. Here is what I found:

COIL + has 1 red wire going to the hotspark. 2 black wires using one connector. I pulled the dbl blk wire ever so slightly off of the spade connection and attached the lead from the VOM to the spade.

I found the only black wire on the ignition switch (a red wire shares the connection). I inserted the VOM lead and started the car.

I got 0.14 volts at idle and up to 0.22V at 2500 RPM.

MY guess is since I can't (or did not) isolate the proper wire, THIS TELLS US NOTHING, correct?

2nd test: I have 2 red wires on my ignition switch, 3 if you count the one that shares a connection with the blk wire. I probed 1 (non sharing) and the blk wire.... 0.0 volts

Probed the other (non-sharing) blk and the red wire and got 0.0volts.

Testing the voltage drop from the ignition switch all the way to the ignition coil must of been a chore, did you remove the back window to make the meter leads reach?

0.22VDC drop (roughly 2%) is acceptable, I just wanted to make sure you didn't have anything higher than 0.50VDC.

Toward the 2nd test, it doesn't tell us much. Since your problem seems to be intermittent, you can have the ignition switch show both, 0.0 volt drop when the car is working fine, and some weird some random 2-4 volt drop when the planets all align. It's difficult tracing something like that down, as you would need to measure the voltage drop right when it happens.

Since you have little voltage drop from the wire at the ignition switch leading back to the ignition coil, and you proved that the car runs fine when you jump the ignition coil straight to the battery, tells me that the fault must lie within the ignition switch.

Replace the ignition switch, but you should really consider adding a relay somewhere behind the dash to take some of the load away from the ignition switch. Since your car is electrically non stock, you should really do something otherwise you will be eating up them switches. Consider installing the clapper.

well it took me some time to get motivated to remove the air bag....

Click to view attachment

Or more keys than the 45 year veteran elementary school custodian? (The one that has the keys from every lock EVER at the school. . even the ones that have been replaced twice). A ten ton key ring might be problematic.

I have heard about the heavy key ring syndrome.

I have the key that starts the car and an aluminum bottle opener on the ring. That is it.

I can check that syndrome off as a possiblity. Thanks.

Tim, you suggested a relay.... I am all for making this problem go away, but I do not know near enough about that sort of thing to even begin.

I am sure I can wire it up, but I am certainly gonna need instructions.


wires certainly look like they have seen better days..

fat RED has been hot before. Connector block is labeled 30 for that wire.

The liquid electrical tape was put on by me, I can't remember what it looked like underneath. My guess is that the insulation was gone, or melted.

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Anyone else ever done an ignition switch relay?

Thanks,
Clark


the black block is labeled very small and next to each hole the wires go into:
50 = BIG YLW
15 = BIG BLK paired with a small red
X = med RED
SU = small GRY/red
P = GRY
30 = BIG RED

I think I have seen the labels on current flow diagrams. Maybe I can find where the extras go using that.

EDIT: On the flow diag P = spark plug connector... there is no X or SU, so that is out.

double post...

The big red wire is the main supply wire for the ignition switch. You're correct, it has seen some heat, the whole connector should be replaced.

Adding a relay is straight forward. Build the module as in the picture. T off the big red wire and terminate into the K2's com terminal. Cut the black wire from the ignition switch connector and connect to K2's bottom terminal. Begin the clapping
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Ok. Maybe the word "directions" was not what i need. That would require some "hand holding" or a for sale sign.

OK, I have found my German Switch. I thought it was installed, but I found it in my stash, still in the bag. I don't think I bought 2. Anyway, I also bought a $4 relay.

I would like to cut a couple inches out of the wires feeding the switch and get the burnt wire and liquid electrical tape cleaned up.

Problem is I will need special crimp type connectors to re-install into the black block. And maybe a new block.

Does anyone have a source for that type of female connector with a tab on the back to hold it in the block? I found some on Alibaba, but I don't need 300 of one size.

And a source for a good block?

Clark

UPDATE on the hiccup:

I have rounded up all my parts and been given my direction on relay installation and I think I am ready to go.

Thanks to Garold for the connection block. (Bruce too, he offered one)
Thanks to Tim for the direction.... so far
Got the connectors, but might not use them, might just butt splice since Garold's block and wires are in better shape than mine.
And Tim directed me to a good cheap relay.

Assembly begins tonight, wish me luck.

The block and wire pigtail

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Two sizes of special connectors with a tab to "click" into the block. found at this link

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amazon link to the $4 RELAY

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My napkin drawing of where the wires go. connector wires not connected to the relay will connect to their mate on the harness side.

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ALL DONE: and the car is running great. No HICCUPS.