Makes me wanna cry -- D-Jet torment, 1973 1.7 D-Jet malfunctions... Options

[Mike!!]

Aloha,
I'm just about ready to cry uncle, I've been trying to get my 1973 1.7 back on the road for literally years now. Every time I think nothing else could possibly be wrong, something else is wrong. The car enjoys tormenting me.

Long Story Short: here's my problem, after fixing just about everything that needed fixing, I can't get the thing to run reliably, fires right up, and if I pump the gas continuously I can get it run, but if I just hold down the gas or take my foot off the pedal it either dies or does this oddly impressive extreme low-idle / dieseling at about 50 rpm. The issues started when I replaced a blown out MPS with a shiny rebuilt one from AA.

Long Story Longer: The car had NO rust, it was parked in a garage in Oklahoma since 1981. The car's engine always seem to work fine since I bought it 4 years ago, fired right up, ran smooth, but I couldn't drive it since the brakes were fried, the shocks were trashed, fuel injectors were cracked and dripped gas, all electrical harnesses were literally duct tape together in places, all fuses were 30 amps because anything smaller would instantly pop, fuel pump was literally dangling from the fuel lines and power leads under the car (one way to prevent vapor lock I assume), door handles were non-functional, etc. etc.

So slowly over the course of the last four years I've replaced or repaired everything, rebuilt the electrical harnesses, re-located the fuel pump under the fuel tank ala the old service bulletin, stainless steel fuel lines, repaired or replaced everything that was broken.

I pulled the engine and transmission, cleaned out years of sludge. Replaced the thermometer bellows thingy, Replaced the dizzy with a 123Ignition, replaced the oil pump, changed out the clutch, etc. etc.

After all this I put the engine back in, and to my utter astonishment, it fired right up! Like immediately! I took it on a couple of test drives around the block and I knew something was not right, no power, misfiring, just not working. But at least now I thought I had a rolling project rather than a garage decoration. It was running enough to make a run down to the gas station and put a couple of gallons of gas in, but I barely made it home, it actually completely died just as I coasted to a stop in my driveway.

Did some initial troubleshooting and it turns out the MPS was blown out, it did not hold vacuum at all, I was essentially running as if WOT the whole time. I don't know why I didn't check that before. Plugs completely fouled, oil smelled like gas, etc.

I then bought a rebuilt MPS from AA and now, for the life of me, I can't get the engine to run.

Diagnostics:
Good / okay compression all cylinders (110 - 130PSI)
New MPS tests fine, or as fine as I can tell with a multimeter and vacuum guage
When it was running I was able to shoot/adjust the timing 27 @3500RPM, I cannot shoot the timing now because the engine does not run right
123 Ignition has basic custom curve 7.4@500rpm, 7.4@1500, 27@3200, flat line 27 to 8krpm with rev limit at 6krpm, MAP curve zero'd.
Fuel pressure was 29PSI, but I cranked it up a little to 32PSI, I figure 10% boost, but that didn't help
CHT seem to be on the curve, it's warm here in Hawaii
AAR functions properly
Adjusted valve clearance to spec when I had the engine out
Sent the injectors out to Mr. Injector, all are good now.
TPS seems to test out correctly with a multimeter.
Replaced fouled plugs, oil and oil filter

I ran though a bunch (all???) of the D-Jet troubleshooting posts here and The Paul Anders Rennlist site as well as D-Jet A-Z by Dr. DJet. No joy.

What am I missing here? Anyone have any insights? I actually find it really hard to believe that the rebuilt MPS is faulty, but maybe? Is there anyway that the timing is now off because I set the timing when the engine was running super, super rich? What else should I look at?

I'm committed, but sometimes I think this silly, little yellow car is going to get the best of me.

Thanks!

P.S. Really, thanks to all of you on this here forum, I could not have even gotten this far without this collected wisdom and experience, now I just need that last little clue to get my teener rolling again...

[FlacaProductions]

Greetings and welcome. Good for staying with it.
So many places to start but I’ll jump in and say lates make sure you have the correct mps in there. What are the last 3 numbers on it?

Reason I ask is that I had similar starting and running issues after I installed a 123 and suddenly it didn’t like the mps and would hardly run. Changed MPS and all was well. So - what part and does it hold vac?

Is the mps new or rebuilt? If it’s rebuilt is it tuned or tunable or is the main screw sealed back up.?

[JeffBowlsby]

A few questions you may have heard before:

Confirmed all components are correct for the 1973 1.7L?
MPS holds solid vacuum, using a vac gauge, no leak down?
Fired each injector into a can/jar, and is the spray pattern equal at all injectors?
The rebuilt harnesses, 100% confident that each circuit is correct and has continuity? Did you use the correct terminals?
Fuel filter changed recently?
Hoses under the fuel tank not kinked or pinched?
100% confident in the 123 dizzy install?

Please post a few photos of the engine bay & DJet components and connections.

[dtmehall]

and how about spark?

[Spoke]

I put a '70 DJET system on a 1.8L a while back. Tested all the FI parts on the bench and once in the car, I installed an AFR sensor on the exhaust and adjusted the MPS for the proper AFR at different throttle/load conditions.

Good luck with your troubleshooting.

[Superhawk996]

What am I missing here? Anyone have any insights?

You’re making assumptions somewhere in your story that aren’t valid.

You need to revisit assumptions.

Thoughts:
You say the say the engine was running and fired right up yet then go on to outline that it was never running properly. Correct me if I’m not reading correctly or putting words in your mouth.

The term “running” is the probably the most mis-used & abused word on this forum. There is a big difference between an engine that is somehow rotating under its own power but backfiring, lacking power, won’t rev, etc and a properly performing engine. This isn’t directed at you personally, it’s just something that I see over and over when people are having trouble - they say it ran or is running but in reality it isn’t running anywhere near correctly.

You say you cleaned out years of sludge from the engine - what does that mean? Did you split the engine case / rebuild the engine or just cleaned grunge off the exterior?

Possibilities:
Distributor isn’t installed properly - 180 degrees out is not uncommon. This can be due to a variety of misinstall issues: dizzy drive not installed properly, distributor itself not installed properly, or timing issues set at something other than cylinder #1 at TDC of compression stroke.

Valves not adjusted properly. Have you ever done valve adjustments before?

MPS problems - how long does your MPS hold vacuum?

CHT problems - your description of how you verified it is too vague. Which CHT do you have 012 or 017? I’ll post the full calibration curves for each across the whole temp range.

Mismatched components. You reference the Anders and D-jet site but didn’t explicitly confirm you had matching ECU, MPS, CHT, etc.

Wiring & grounds. Lots of crispy wiring out there on 50 year old cars. Easy to knock ground wires loose when working on replacing MPS, dizzy, etc.

Next Steps:

Revisit your assumptions.

Put your fuel pressure back where it belongs.

Post photos of plugs. Have plugs been changed since they were originally fouled? Plugs that are heavily carbon and fuel fouled don’t reuse well and can be a source of frustration. It sounds like you have - if so post photos of how they look now.

Video is hugely helpful - post / link to YouTube if you have that ability to upload to YouTube

Photo of your distributor drive orientation may be necessary

[Ishley]

Good suggestions from others. I’d add rechecking spark starting with the plug wires. I struggled with issues and found my wires were intermittently dropping out. Is it a fat blue spark? Is the Coil new and wired right? Is the plug gap right. When I struggled I over looked these spark issues… I wrongly assumed that when I saw spark that it was good. Once I checked/worked thru the spark issues everything else fell into place.

[Superhawk996]

[914sgofast2]

Have you replaced the 4 hoses on the intake tubes to the intake plenum? After 50 years they are shot. Make sure you use the smaller diameter hoses for the 1.7 engine. Don’t try to use hoses for a 2.0 engine.

[rfinegan]

I had an issue with my 2.0 DJet and the same symptom, I had to pump the accelerator (quickly) just to start and keep the engine running. It would even let me move the car in and out of the garage doing this. Stop pumping and stop running.

The World is slow running again so hard to find my post. I am pretty sure it was a short to ground CHT (internal) leaning the engine to the point of now start, but the pumping of the pedal woks as an accelerator pump (like a carb) and adding extra fuel.

Quick test is get another sensor (even the amazon or ebay/ Uro for about 15 bucks) Connect to harness and ground the other end. No need to remove from head at this point. See if car will start and run? It should at this point...
Permanently Install replacement sensor if needed.

Ill look for my post Here on the World

[pbanders]

I suggest taking it to a mechanic with air-cooled experience. Putting a second set of eyes on it might find out what's wrong.

FWIW, it doesn't take much of an issue to have a non-running situation. Single point of failure things are what you need to be looking for, like the trigger contact points. Is the wiring harness connector fully inserted? Are you sure your ECU is good? Are you 100% sure the wiring harness connections are correct and you have continuity? What happens if you spray starting fluid into the intake, does it keep running? Have you verified you have spark?

Don't give up. If you have good compression the motor will run, something is wrong.

[emerygt350]

I suggest taking it to a mechanic with air-cooled experience. Putting a second set of eyes on it might find out what's wrong.

FWIW, it doesn't take much of an issue to have a non-running situation. Single point of failure things are what you need to be looking for, like the trigger contact points. Is the wiring harness connector fully inserted? Are you sure your ECU is good? Are you 100% sure the wiring harness connections are correct and you have continuity? What happens if you spray starting fluid into the intake, does it keep running? Have you verified you have spark?

Don't give up. If you have good compression the motor will run, something is wrong.

That's an excellent point, start simple, did you hook up the trigger point leads correctly to the 123? Are you confident in your 123 initialization?

Where in Hawaii? I will be in hilo in the beginning of May...

[Mike!!]

Aloha and thanks for all the valuable inputs!

I wasn't able to do any heavy duty troubleshooting today, still had to work and all that. But I was able to do some basic things and take some pictures.

I thought I figured it out when I looked at the remanufactured MPS and it was not the 049, but instead 003 part number. I called Auto Atlanta where I bought it and talked to Dr914 who assured me that the 003 part was fine, so that does not appear to be the issue. The remanufactured MPS has the adjustment screw epoxied, plus without an AFR hooked up, I wouldn't even try to adjust it. The MPS holds a solid vacuum, no leakdown after 5 minutes.

I pulled all the plugs and they looked carbon fouled, which is strange since they are brand new and I've only been able to get the engine to run in fits and starts for a minute or two since I replaced them. Probably less than 15 minutes total run time with those plugs. I assumed the mix was way too lean, that's why pumping the gas kept it running, but maybe not. But I would think if the mix was still too rich, I wouldn't be having this problem.

For the rebuilt harness I tested each connection at the ECU plug and everything appears to be correct. I used the 914Rubber kit for the component ends and the ECU end is from Repo-Parts in Germany with all new weird fork-spade plugs. Good quality TXL 16 gauge wires, with 14 gauge going to the relay board plug. I'm pretty sure the wiring harness is good, but in retrospect, I should have just bought one from Bowlsby in the first place. Fuel filter is brand new, hoses were rerouted, I relocated the fuel pump up front and I don't think the lines are kinked, but I'll pull the tank this weekend to check.

I was not able to test the fuel injectors today, but I will pull them this weekend and test. I had sent them off to Mr. Injector to get cleaned and qualified, but with all of the fuel line installation and rerouting there could have been goobers in the fuel line after the filter that got sucked in, but I'm think that would have also been a problem when the failed MPS was in too, and I was gettimg way too much gas rather than too little.

I'm almost certain the dizzy is installed correctly. I had the engine out of the car when I installed it and was able to verify I was #1 TDC by looking at the armature in the old dizzy, pointed at #1 and by checking the valves were both closed on #1, I could get the feeler gauge in between the rockers and the top of the valves but not on #3.

I've never adjusted valves before, but with a decent feeler gauge and the engine out of the car it did not seem like a real challenge.

Spark seems good, but with the new fouling on the plugs it's at best a subjective assessment. I ordered another set of plugs for this weekend.

CHT test out at 2.3K ohm at 78F, which puts it on the 012 curve, tested at the connector for the CHT and at the ECU harness plug. All injectors test out at 2.4Ohm at ECU plug.

I have replaced all the vacuum hoses and the intake runner plenum hoses, they seem really tight but I did not pipe clamp them on since they fit so snug. I just bought a smoke tester and will check for leaks this weekend. But, and check me on this, as long as the engine is relatively cold the AAR will be open so you in fact have a giant vacuum leak into the plenum until the AAR comes up to temp? I'm confused as to how important small vacuum leaks are until the AAR closes?

There is apparently a single air cooled mechanic on island now, I going to reach out to him and hope he has experience with D-Jet...

I'll include pics and here's a link to a video showing the issue.

https://youtube.com/shorts/F-Rci3Kvx88

Thanks!

[Mike!!]

I suggest taking it to a mechanic with air-cooled experience. Putting a second set of eyes on it might find out what's wrong.

FWIW, it doesn't take much of an issue to have a non-running situation. Single point of failure things are what you need to be looking for, like the trigger contact points. Is the wiring harness connector fully inserted? Are you sure your ECU is good? Are you 100% sure the wiring harness connections are correct and you have continuity? What happens if you spray starting fluid into the intake, does it keep running? Have you verified you have spark?

Don't give up. If you have good compression the motor will run, something is wrong.

That's an excellent point, start simple, did you hook up the trigger point leads correctly to the 123? Are you confident in your 123 initialization?

Where in Hawaii? I will be in hilo in the beginning of May...

I'm on Oahu.

But you have reminded me of something that has always bugged me with the 123 install. The original OEM dizzy has three terminals for the FI trigger, 12, 21 and 22. But the 123 dizzy only has a yellow and a white lead for the FI trigger. When I installed the 123 I connected the yellow lead to terminal 21 and the white to 22. I forget why, I must have read that somewhere because I have a handwritten note in my shop notebook. But what's up with the original terminal 12? My hypothesis was that it was a hot lead from the ECU to the dizzy that would alternately fire the opposite injectors, but that the 123 provided the +12v itself, so no need for a lead from the ECU. So now I just have the terminal 12 lead capped off. But now I can't remember why I had yellow to 21 and white to 22. Could this be reversed? Does anyone know for sure?

Thanks!

[mgphoto]

Center connector on the dizzy harness is a ground, not needed on the 123.

[JeffBowlsby]

12 is a common, not ground. Serves the same purpose I guess.

[Ishley]

Looking at your pics... you're getting fuel... it's not burning it correctly... you know you have compression... My best guess is you have a timing or spark issue.

On the dizzy... several thoughts... Is it seated correctly. On mine I had to remove ( or move I cant remember) the little ring to get it to seat down properly. Make sure its seated all the way in. You also need to go back thru the TDC check. Get #1 to TDC... remove the distributor cap and make sure it's pointed where the #1 wire is connected. That's the key. Recheck that you have the firing order right. You may need to change those plugs again. Make sure those wires are good.

Is it a 123+ with bluetooth? if so... there is a log file created on your phone. This can show you the voltage at the dizzy and the coil current. There is a youtube video on 123+ app training. The log file is a little weird but you can load into a spreadsheet... it grabs data every couple of seconds.

[Superhawk996]

I'm almost certain the dizzy is installed correctly.

I had the engine out of the car when I installed it and was able to verify I was #1 TDC by looking at the armature in the old dizzy, pointed at #1 and by checking the valves were both closed on #1,

I’m not convinced.

There is more to it than just matching where #1 was on the old distributor combined with the fact that it wasn’t running properly even back then.

The position of the distributor drive gear is actually what establishes the timing relationship between the crankshaft and the distributor.

Good job with all the follow up pictures and the video. (IMG:style_emoticons/default/smilie_pokal.gif)

I suspect your timing isn’t correct and that you’ll need to pull the dizzy and check the orientation of the distributor drive gear. I believe your dizzy drive gear is off by one tooth (30 degrees). I think the position of your distributor cap relative to the engine fan shroud also bears this out. Late (retarded) ignition timing kills manifold vacuum and that also seems to be consistent with your inability to get a steady idle.

I understand if you are reluctant to do this but if the timing & orientation of the dizzy drive isn’t correct, it will affect everything else (vacuum, RPM’s, engine power, etc).

Here are two pictures of the correct orientation. The two c-shapes are not symmetric and the smaller one should be oriented at the bottom as shown in roughly the 5 o’clock position.

[emerygt350]

What superhawk said.

The engine sounds like it wants to perform but it does have the feels of a timing issue.

Don't worry about vacuum leaks, that will, as you said, just raise the idle. After you get this hashed out then you can go chasing leaks if there are any.
The sootiness doesn't look bad enough or wet enough to simply be too much fuel, but definitely turn that fuel pressure back to stock.

Does anybody ship cars among islands for fun? I bet the big island would be a ton of fun in a 914. That little road up Moana Loa lookout must be amazing in a 914. It was fun in a 15 person van.

[Olympic 914]

I understand that you have checked the CHT and it Seems to read correctly

But I had a similar issue, and the problem was an intermittent failure of the CHT.

It read good hot and cold, but when running would act very wonky. I FINALLY substituted a 100 Ohm resistor in place of the CHT to mimic a hot condition and it ran better.

Now it also could have been a bad ground connection at the CHT, But since changing it things are much better.


Just another thing to check out.