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.