crank no start perplexed, what else Options

[Wew]

Hi all,

I have read and done a bunch of research and still no luck getting my ride to turn over.

1973 2.0 with fuel injection. Has a 2056 build with a performance cam. (still within parameters for a fuel injected car)

Battery at 12.6 Volts
Throttle body serviced
Compression: 130 all four cylinders
Spark: yes
Timing: checked and set at 0 TDC. (will set @ 27BTDC at 3500rpm when I can get it to run)
123 ignition rotor pointing at #1 spark plug wire.
Fuel pressure 28 PSI
Checked injectors and they are squirting fuel.
I do not have the proper CHT which I believe should measure at 1300 ohms.
The one I have measures at 2700 ohms.
I had checked the MPS and if memory serves me right it held air for quite a long time at 17 or 20 psi???? I could be wrong on this as this has been a while.
Have checked for vacuum leaks and done a smoke test when car was running and no leaks found.
All new vacuum lines with clamps.
The car would drive fire right up cold and idle rough. It would buck under load and also didn't start if it was warm.

What changed?

I took out the Throttle body and saw fuel in the plenum which I believe is fuel from the cold start injector.
In all my infinite wisdom I ended up messing around with the throttle position sensor and thought I got it back to its correct setting using one of those line testers like Gary Cotton has used in his video. Maybe I am screwing this up but I don't think so..
I also realized that I had the 123ignition vacuum port connected to my retard side (rear) on the throttle body. (advance was plugged). I changed this and put the smaller vacuum line on the 123 ignition and attached to the advanced port on (front) of the throttle body.
Now I get no love... It just cranks and cranks but will not start. (IMG:style_emoticons/default/chair.gif)

I am aware that this is the incorrect CHT. It doesn't seem like these are available in the 1973 version any longer. Any solutions or mods I will gladly take on. Was wondering about one of those potentiometer to draw down the ohms from 2700 to 1300 if that is possible. If so, any specific recommendations on what you used and worked would be appreciated.
Maybe I beat up the TPS. I had purchased it new from 914 rubber and has gotten very little use other than me messing around with it and the short stops and starts trying to get it going. I have attached a couple of pictures.
I don't want to just start throwing parts at this.. It has to be something I did.
Where I am at is I can't even try and make it run better now because it won't even start.
Ugh (IMG:style_emoticons/default/headbang.gif)

I have also included a link to a youtube video I shot prior to changing the vacuum hose from retard to advance. You will see it idles o.k and then when I accelerate it gets sticky and remains at a higher idle. I have checked the throttle cable and it is not wrapped around the clutch cable.
If I had my druthers I would go back to what it was, but again it would flatten out or buck when I would accelerate and hard start once warm.


I lack the intuitive mechanical skills that many other have on this site and am hopeful I can get some advice on next steps.

Much appreciated.

Gary


https://youtube.com/shorts/idT2vM8uaOg?si=MixjnXL2zrQaNrnV

[Superhawk996]

The ballast resistor works against you when the engine is at ambient by raising resistance by 270 ohms higher than the already high value (approx. 1300 +270 vs 2500 + 270)

However, when the engine is warm and the CHT goes to say 100 ohms, the engine is going to run lean(er) without the ballast resistor present. At that point not having the 270 ohms in the circuit is a much bigger difference as a percentage (approx 100 ohms vs 370 ohms so almost 4x more)

See attached plot for CHT 012 vs 017 (correct for 73’). Not how they converge when hot.

The way you’ve measured CHT so far is fine but be aware that you could still have an open circuit between the wiring right at the CHT and the ECU. Do not assume the wiring is OK. There are a lot of very crispy 50 year old harness's out there. I’d be looking at the wire very carefully. Chances are it’s probably not broken given it was running previously but at some point you may have to measure it at the ECU to verify.

I would replace the plugs before I replace a battery. Plugs can get fouled and even though you clean them they still don’t fire properly. However, given the coughing on stating fluid I would still focus on whether you’re flooding it during cold cranking. Have you pulled the plugs immediately after cranking and failing to start? Are they soaking wet and gas coated?

It isn’t unusual at all to have a battery drop slightly below 12v after an extended period of cranking. Don’t get distracted and start chasing ghosts. Just keep charging the battery as needed.

To get rid of the question about the CHT. Get a 1300 ohm 1/2 watt resistor (or dial in a potentiometer to 1300 ohms) substitute that for the CHT. One side to the harness, the other side grounded to the block (fan shroud, or battery negative OK too). The adjustable potentiometer is the better way because assuming it starts you can dial the pot down as the engine warms to keep it running.

Can’t help you on a 123 and how to slightly advance your static timing. I have never had one. Sorry. I’d assume it’s done via DIP switches or their app depending on what model you have.