Engine test stand

[Captain Obvious]

Yeah, I definitely think there's something else going on. There's absolutely no reason you should need to disconnect the WTS to improve anything. Disconnecting that should do nothing but produce billowing clouds of eye burning rich fumes.

Have you checked the timing with a timing light? Should be able to get a quick and dirty measurement if you can keep it running long enough. Are you sure you have the thermotime and WTS connectors in the correct positions (sorry, but have to ask).

If you think you're looking for an intake leak, you could smoke the system.

The injectors are powered through the dropping resistors as shown. Bank of four and back of two. On the low side, they are grounded in groups of three. (1, 2, 3) and (4, 5, 6) through the two output power transistors.

Wish I was closer to give you a hand.

[Dave WM]

ok to ask, and yes have the connectors right double checked and been testing at the 36pin, the ohms track per the FSM to the temps. I have a pot (5k) ready to try, but that is at best a patch, my 500 ohm pot did not help, still died when hooked up.

yes I will do a timing light check.

could pickup a Havana on the way out for a smoke test.

What bugs me is the seemly same amount of fuel spritzing during the engine crank with injectors pulled back from the head to see the flow, No obvious diff and this is done while cranking with the throttle closed.

[Dave WM]

whats also odd is the way it will "catch" that is stop misfiring, and then I can throttle up and down, still not right due to the WTS issue, but odd none the less. If I connect up the WTS it suddenly starts missing, disconnect and it misfire until "catching" again then good to go ("catch" = engine will suddenly rev up a lot and smooth out)

before it "catches" the throttle has little response just a chugging along miss firing engine at low rpm.

I will try to get a video, but will need my helper as I will be messing with the engine.

 

Edited April 26, 2019 by Dave WM

[Zed Head]

When my ignition module was going bad it would "over spark", causing the tachometer to read high and the engine to run rich.  A possibility.  Maybe you have the opposite problem, with a weak ECU trigger pulse.  Along the same lines as the tachometer connection issue.

Pin 1 "expects" a certain type of "pulse".  I don't really know how it works, if it's flyback from the coil discharge or if it's a high and low voltage thing.  Do you have all of your wires bundled together?  Maybe you have some crosstalk on those signals, or the Pin 1 pulse is getting attenuated.  Try splitting them up and checking all connections.  Make sure that the ECU has a good ground, maybe the Pin 1 pulse needs that to start the cycle.  I know little about electronics.

[JSM]

1 hour ago, Dave WM said:

whats also odd is the way it will "catch" that is stop misfiring, and then I can throttle up and down, still not right due to the WTS issue, but odd none the less. If I connect up the WTS it suddenly starts missing, disconnect and it misfire until "catching" again then good to go ("catch" = engine will suddenly rev up a lot and smooth out)

before it "catches" the throttle has little response just a chugging along miss firing engine at low rpm.

I will try to get a video, but will need my helper as I will be messing with the engine.

 

Have you verified Fuel Pressure yet Dave?   And i'm assuming the answer is yes to this one, but have to ask, did verify you didn't mix thermotime wires up with WTS?

[Captain Obvious]

4 hours ago, Dave WM said:

What bugs me is the seemly same amount of fuel spritzing during the engine crank with injectors pulled back from the head to see the flow, No obvious diff

What do you mean by that? Do you mean the same amount of fuel spritzing from each injector? If so, that's the way it's supposed to be. Why would that bug you?

[Dave WM]

6 minutes ago, Captain Obvious said:

What do you mean by that? Do you mean the same amount of fuel spritzing from each injector? If so, that's the way it's supposed to be. Why would that bug you?

bugs me cause I wanted to see a big difference based on the condition of the plugs. since its all even I cant account for drastic rich on one and normal on the other. I was hoping for a clog or some other defect, but since it appears they are all matched then it gets tougher to figure out issue.

[Dave WM]

2 hours ago, JSM said:

Have you verified Fuel Pressure yet Dave?   And i'm assuming the answer is yes to this one, but have to ask, did verify you didn't mix thermotime wires up with WTS?

oh yes all good, 36-36 not running, about 30 when it catches with 18inHg showing in between when its miss firing. Frankly I am kinda surprised at the decent vacuum when its running , I expected it to be much worse considering the less that optimum operating conditions. I was hoping to find a smoking gun on the injectors, no joy.

Edited April 26, 2019 by Dave WM

[Dave WM]

3 hours ago, Zed Head said:

When my ignition module was going bad it would "over spark", causing the tachometer to read high and the engine to run rich.  A possibility.  Maybe you have the opposite problem, with a weak ECU trigger pulse.  Along the same lines as the tachometer connection issue.

Pin 1 "expects" a certain type of "pulse".  I don't really know how it works, if it's flyback from the coil discharge or if it's a high and low voltage thing.  Do you have all of your wires bundled together?  Maybe you have some crosstalk on those signals, or the Pin 1 pulse is getting attenuated.  Try splitting them up and checking all connections.  Make sure that the ECU has a good ground, maybe the Pin 1 pulse needs that to start the cycle.  I know little about electronics.

I have the loom installed, even used the same cap and loom from my running car.

[Captain Obvious]

4 minutes ago, Dave WM said:

bugs me cause I wanted to see a big difference based on the condition of the plugs. since its all even I cant account for drastic rich on one and normal on the other.

Oh yeah. Got it.

Duh.    

[siteunseen]

I'm sure this has been discussed but I must. Is your cold start valve out of the picture?

[Captain Obvious]

And for today's amusement, the part of Captain Obvious will be played by siteunseen.