This is a great and helpful thread and seems to be exactly what I need, for my 86 3.2.

Before I go and check the grounds which seems to be what I need, and from what I understand continuity to the ECM as well, I wanted to ask, should there be power to both sides of the injector connector?

I used a lamp tester and I can see power on both sides with the ignition on, is this supposed to be like this and the ECM switches to ground to create the pulse? (I will use a voltmeter now I've learnt how to from here)

Its been a long road to start this this 3.2 not started in 7 years or more, a true barn find (parked in a muddy field actually), I did get it started after sorting out no spark/no fuel pump issues and it runs on starter fluid, but no pulse to the injectors. I don't have a noid light but used a very sketchy way to crank with the injectors out and there was no spray, but the rails have good pressure fuel in them.

Yes!

Yes!

Your injectors are stuck closed.

Thanks for your response!

Yes the old injectors were completely rusted through and blocked, I have a set of refurbished ones there now.

I will find time to run through the grounds, thanks!

I've run through all the steps and everything is as it should be;

I have 12v at each injector connector and there's continuity to the ECM terminals 14 and 15 also checked the ground terminal as well, I still don't seem to have any injector pulses, I'm waiting for my noid lights to come in to narrow it down to the injectors, I just bought refurbished injectors.

In the meantime I wanted to find out if there's anything else that can disrupt or stop the injectors from pulsing.

The ECM is brand new and so is the DME relay

1. Did you measure the ohms between the ecu ground and the battery neg cable up front ? (Bat disconnected)

2. Idem for intake runner ground ohms to bat neg cable up front ? (Bat disconnected)

3. The CHT sensor on cyl 3 takes its ground from the case - is that coated perhaps ?
I think that without a correct CHT reading it will not start. (Ohms value in range when sensor disconnected ?)

4. The ECU is not going to fire the injectors unless it sees 200 rpm or so and a ref signal from the 2 sensors on the flywheel. Measuring the ohms on them is not enough. You can measure the voltage they output (Ac volt mode on multimeter) and it should be >2.4 V (speed sensor), thevref sensor output is a bit more difficult to see on the voltmeter (certainly on the digital ones) as it is one short pulse per rotation.

Better yet - I use a cheap oscilloscope (called DSO shell, 35 usd on amazon) to really verify a correct signal from these sensors.

Speed sensor (idle at about 900 rpm)
https://uploads.tapatalk-cdn.com/202...33f4e62b1f.jpg

Ref sensor (freq measurement is wrong here)
https://uploads.tapatalk-cdn.com/202...866686a415.jpg

And then the coil signal should look like this (primary)
https://uploads.tapatalk-cdn.com/202...5bb6bc9e25.jpg

And an injector being grounded (see left side of screen) and when fully opened being kept open by a series of short pulses (peak&hold driver). And a large spike at the end when the injector closes.

https://uploads.tapatalk-cdn.com/202...0bf28aee6a.jpg


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Thanks for taking your time to respond in detail FrankM...

1&2: No I didn't check the ground from the ECU ground or the intake runner ground, I will do that, what readings should we be looking at?

3: The CHT sensor? Would that be the one with the white connector? I just changed the CHT sensor and both the speed and reference sensor, I had no spark till I changed them and gapped to 0.8mm as instructed by the manual.

The CHT sensor is this the one that connects in the same bracket as the speed and reference sensor? All of them are new.

4: How and where do I probe the speed sensor to measure?

I will have to look into getting and oscilloscope.

Thanks again.

One shorted injector will kill the other 5 from firing. Unplug 3 injectors on drivers side and see if it starts with just the passenger side injectors.

If not flip to the other bank and plug back in drivers and unplug passenger side.

And are you 100% you have spark?

To prove it's a fuel issue squirt few shots of starter fluid directly into the intake, remove the idle control valve lower hose and squirt 3 or 4 shots of fluid into the intake at that port. Then try starting, the engine will catch and start if you have spark.

One other sanity check: turn key to RUN but do not start engine. Then go back in engine bay and see if idle control valve is humming and vibrating. If it is it means the DME is booted up and has power. Be sure this is the case.

Thanks! I will try unplugging the injectors and see how that goes.

Yes we have spark, the car starts and runs on starter fluid.

Ahhhh yes the idle control valve indeed does hum, I was wondering if that was normal.

Read post #62 again and get a noid light!. You knew you had spark, which eliminates the pickups.
You knew it's a fuel problem. Others have wasted your time!

You can use a test-light in place of a noid light, by having the alligator clip on +12 and the ice-pick touching one of the injector pins.
You can also back-probe either pin 14 or 15 on the DME ECM. Disconnecting the temp sensor will allow the test-light to flash brighter.
Hopefully, the ECM hasn't been over-voltaged by a bad alternator
or jump-charger. This can damage the injector output stage.

Thanks Dave.

So what you're saying is clip side of a test-light to battery +ve and probe to any of the terminals of the injector connector or must it be the grounds same ones that run to 14/15 on the harness?

Noid lights are about a week away from me...

Yes! You must try BOTH pins of a injector connector. Disconnect all other injectors.

You can also test the injectors at pins 14 & 15 of the DME ECM, but you only can do that
with the back of the connector (black) removed. The connector must be plugged in.