Will not start after a 13-year hibernation, 1973 2.0 D-Jet Options

[emerygt350]

The clicking is the result of the TPS. That is good.

The problem here is that it appears the trigger points are not working but that doesn't mean they are bad. It could be something else. Verify the connection to the trigger points.

Without the engine running for any length of time it is hard to know if that fuel pressure is accurate.

Does the seat belt lock out stop the fuel or the spark or the starter? I can never remember....

[Superhawk996]

Does the seat belt lock out stop the fuel or the spark or the starter? I can never remember....

The 73’ seat belt system has nothing to do with the starter, spark,
or fuel pump.

That interlock came in 74’

[JeffBowlsby]

When the key is turned to the "START" position (engine cranking), fuel pressure rises to 26 psi, engine doesn't attempt to start, just spins. I then unplug the fuel injection harness connectors from the injectors and plug in the noid light, key is turned to the "START" position (engine cranking) and noid light does not light up.

The above is incongruent with "engine will run with starting fluid." Not sure what is going on here, could be something simple like a bad connection somewhere.

[Superhawk996]

When the key is turned to the "START" position (engine cranking), fuel pressure rises to 26 psi, engine doesn't attempt to start, just spins. I then unplug the fuel injection harness connectors from the injectors and plug in the noid light, key is turned to the "START" position (engine cranking) and noid light does not light up.

The above is incongruent with "engine will run with starting fluid." Not sure what is going on here, could be something simple like a bad connection somewhere.

Not necessarily.

If fuel injectors aren’t firing while cranking, it won’t start but would cough / “run” on starting fluid.

The weird thing is OP says the injectors fire when moving throttle / TPS.


Question 1: if you have fuel pressure present at the injectors, and use the TPS to fire the injectors (with fuel pressure present), that dumps gasoline into the intake and valves. If you then attempt to crank and start - does it cough or try to run at least momentarily?

Question 2: where are you measuring fuel pressure at on the diagram below?

[emerygt350]

Does the seat belt lock out stop the fuel or the spark or the starter? I can never remember....

The 73’ seat belt system has nothing to do with the starter, spark,
or fuel pump.

That interlock came in 74’

you are assuming it's a 73 model year and not just 73 build date... Anyway, looks like that relay stops the starter. Was just a thought.

[Alden]

The injectors click but it is fuel starved.

Fuel pressure spec is 28.5 psi, so bump it up to that pressure.

New injectors…next step would be to fire them into jars. If they don’t flow, get them cleaned/serviced. Definitely put a hand vacuum pump on the MPS and pull it down to 18 in/hg to verify that it holds steadyvacuum.

Leaving fuel pressure at 26 psi for now.

Manifold pressure sensor not holding vacuum. Pulled vacuum to 18 in/Hg and 4 minutes later was at 0 in/Hg. Will need a rebuild.

[Alden]

When the key is turned to the "START" position (engine cranking), fuel pressure rises to 26 psi, engine doesn't attempt to start, just spins. I then unplug the fuel injection harness connectors from the injectors and plug in the noid light, key is turned to the "START" position (engine cranking) and noid light does not light up.

The above is incongruent with "engine will run with starting fluid." Not sure what is going on here, could be something simple like a bad connection somewhere.

Not necessarily.

If fuel injectors aren’t firing while cranking, it won’t start but would cough / “run” on starting fluid.

The weird thing is OP says the injectors fire when moving throttle / TPS.


Question 1: if you have fuel pressure present at the injectors, and use the TPS to fire the injectors (with fuel pressure present), that dumps gasoline into the intake and valves. If you then attempt to crank and start - does it cough or try to run at least momentarily?

Question 2: where are you measuring fuel pressure at on the diagram below?

Verified trigger points connection at the distributor.

I supplied the fuel pump with a standalone (independent from the car) 12 volt connection, fuel pump constantly running at 26 psi. Turned key to the accessory "ON" position (no engine cranking),
applied throttle and heard fuel injectors clicking. Quickly unconnected standalone 12 volt supply to the fuel pump and connected the fuel pump as normal. Turned key to the "START" position
(engine cranking) and the car ran momentarily like with starting fluid. Additional attempts to start, engine just spinning. When engine cranking verified fuel pressure is 26 psi.

Fuel pressure gauge attached with a "T" just before the driver's side fuel rail at fuel injector 2.

[emerygt350]

Check the resistance on the mps while you are at it. If it doesn't hold vacuum it will still work, it will just be rich, the opposite problem of what you have. If there is something fundamentally broken in there (windings) the resistance check will tell you, and that is much more likely to cause your symptoms.

And did you try running it without the TPS connected?

[Alden]

Check the resistance on the mps while you are at it. If it doesn't hold vacuum it will still work, it will just be rich, the opposite problem of what you have. If there is something fundamentally broken in there (windings) the resistance check will tell you, and that is much more likely to cause your symptoms.

And did you try running it without the TPS connected?

I used this video to check my manifold pressure sensor (MPS)
https://www.youtube.com/watch?v=3lvTXN7d5-8
How to test Bosch D-Jetronic pressure sensor / Map sensor

Bosch 0 028 100 037 / VW 022 906 051C
Manifold pressure sensor not holding vacuum and the following resistance readings
terminal 7 to 15, OL open loop (spec is 90 ohms, tolerance of 80-120 ohms)
terminal 8 to 10, 326 ohms (spec is 380 ohms, tolerance of 300-400 ohms)

Engine will not start with throttle position sensor (TPS) disconnected.

[Superhawk996]

Taking everything you said from post 27 as fact.

It seems there is something not right where the trigger point signal isn’t working to trigger while cranking .

Here’s a couple things to check:

1) Trigger points themselves - there is a common ground inside the trigger points that if it goes bad you’ll have no signal to either set of injectors. Pic below is what I found on a set I had. No bueno. Have you actually removed - inspected what you have to make sure you don’t have something like this going on?



2) Another possibility is the trigger points signal isn’t making it to the ECU. Bad wiring is a very real possibility.

3) ECU has gone south - not likely but can’t rule out at this stage

4) engine is cranking over too slowly? There is a minimum RPM the ECU needs to see from the trigger points - can’t remember off the top of my head but it’s something like 100 rpm’s. If you are trying to crank with a weak battery you could be cranking too slowly. Again not as likely but need you to rule this out. Is your battery topped up and spinning the engine with authority?

Items #1 & #2 are easily checked and verified with a DMM.

[Alden]

Taking everything you said from post 27 as fact.

It seems there is something not right where the trigger point signal isn’t working to trigger while cranking .

Here’s a couple things to check:

1) Trigger points themselves - there is a common ground inside the trigger points that if it goes bad you’ll have no signal to either set of injectors. Pic below is what I found on a set I had. No bueno. Have you actually removed - inspected what you have to make sure you don’t have something like this going on?



2) Another possibility is the trigger points signal isn’t making it to the ECU. Bad wiring is a very real possibility.

3) ECU has gone south - not likely but can’t rule out at this stage

4) engine is cranking over too slowly? There is a minimum RPM the ECU needs to see from the trigger points - can’t remember off the top of my head but it’s something like 100 rpm’s. If you are trying to crank with a weak battery you could be cranking too slowly. Again not as likely but need you to rule this out. Is your battery topped up and spinning the engine with authority?

Items #1 & #2 are easily checked and verified with a DMM.

For item #1, I should be able to show continuity from center pin to chassis ground?

For item #2, I have to disconnect the 25 pole connector at the ECU and run a continuity check to from the 25 pole connector to left and right pins of the distributor?
https://members.rennlist.com/pbanders/DJetParts.htm#setups



Item #3, I have a spare ECU (from another troubleshooting session years ago, the issue ended up that my Python rebuilt fuel injector failed in the open position)

Item #4, Strong battery (group 75) from my C5 Corvette, put screw in posts on the side terminals and made it work. I've put a charge on it a few times.

[JeffBowlsby]

Circuit 12 is common, not ground. The TP cycles between 12&21, then 12&22 to signal the ECU which of two banks to fire.

[Superhawk996]

Circuit 12 is common, not ground. The TP cycles between 12&21, then 12&22 to signal the ECU which of two banks to fire.

(IMG:style_emoticons/default/agree.gif) Jeff is right, poor choice of words when I said common ground.