LH 2.2 740 Turbo No Injector Pulse/Ground

[93Regina]

That’s a tool I need to get

Sound Card Oscilloscope - Turn your computer's sound card into an oscilloscope to measure limited electrical signals, using Windows software and a simple circuit.

Time Required: 1–3 Hours
 Difficulty: Easy

Caveat - Since the sound card on your computer can only handle a small amount of voltage (around +/- .6V to .8V) you need to scale it down.
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I have a multi meter that can measure max/avg/min voltages....which would be required to know

Otherwise, a Hantek will work

[93Regina]

RE: "I ended up replacing the EZK module"

Of of a working vehicle....or from Fleabay?

[bmdubya1198]

RE: "I ended up replacing the EZK module"

Of of a working vehicle....or from Fleabay?

It’s from eBay, but it’s warranted for life and was “tested and guaranteed working.” The reason I replaced it was that I did not have spark and the fuel pumps were not engaging. After putting this one in, those problems were resolved.

[93Regina]

did not have spark and the fuel pumps were not engaging.

IIRC, fuel pump operation (power) is via LH side (via relay), which means EZK is delivering RPM signal to LH. (Note- I'm aware of LH2.4 and & LH2.0)

On LH2.2's wiring connector to LH2.2 are several different grounds.

On LH2.2, pin 18, is a power source coming from EZK's relay, as based upon this photo. If there is a physical relay, I'd find the wire going to LH2.2, and hook up a power wire to it....also pin 9 appears to supply power to LH2.2...appears, check it out also

Either defective grounds, or not enough power is being supplied to LH2.2 is my best guess. Flipping injectors' grounds off/on will require a current draw inside of LH2.2 box.

[93Regina]

Hence, if both pins 9 & 18 supply power to LH2.2...then either one may not. Both Pins are supplied via relays, and relays do go bad on contact side.

I'd manually supply power to both

[bmdubya1198]

Funny you should mention that, I don't seem to have sufficient power to LH 2.2 while cranking. I'll copy my post on the TB thread below...

Got some new info...
I tested the ECU terminals one by one per the typical values document from volvowiringdiagrams.com. I noticed some issues...

At pin 9 while cranking, my meter shows 7-8 volts. It's supposed to be between 11-14V. Pin 17 is supposed to be between 0-1V while cranking, it was 5 volts. Pin 21 should be 11-14V key on, it was 1.6V.

Those are the values with my spare ECU. My original one had even more values that were incorrect (like 12V on pin 19, a ground wire) but those 3 above are the only ones that concern me.
My original ECU showed the same reading on pin 9 while cranking, 0.05V while cranking on pin 17, and 0.51V on pin 21 with key on.
Interestingly, all of those pins are related to the fuel relay. Probably related to the lack of ground on pin 13.

I tested once again for injector pulse with this ECU and sure enough, nothing. The readings I got could have been low because of the battery, but the other things that were supposed to be 11-14V were within range. The battery was still over 12 volts.

The throttle switch signal on pin 12 seemed off too, but that may be a bad switch for the WOT signal. It showed 0.31V both with the throttle closed and and fully open. It's supposed to be 0 fully open and 5V closed. I'm leaning more towards the fuel relay pins being the main issue.

Is this still the ECU, or is it a wiring issue? Or a problem with the fuel relay itself? The relay looks to be working just fine, so maybe I just have two ECUs that failed in different ways, or I just have an issue with the wiring at the fuel relay.

[93Regina]

Funny you should mention that,....

It's about total current drawn, not the voltage relative value...there will be voltage drops, but LH2.2 must have full current.

Pins 9 & 18, one of them is not supplying full current.

[bmdubya1198]

Funny you should mention that,....

It's about total current drawn, not the voltage relative value...there will be voltage drops, but LH2.2 must have full current.

Pins 9 & 18, one of them is not supplying full current.

How do I go about testing current on those terminals?

[93Regina]

How do I go about testing current on those terminals?

Correct me, if in error. At LH2.2's connection plug, can a probe like this

images.jpg (5.28 KiB) Viewed 1313 times

touch each terminal individually? If so, get a 12 or 14 gauge wire with alligator clips on both ends, and attach one end to probe, and the other end to a 12volt source. Then touch terminal 9, and have someone crank it. Same with terminal 18.

OR, There is suppose to be a LH relay that feeds pin 9...I'd find that sucker, unplug it, and feed power to terminal going to LH2.2. I don't know if EZK's relay is internal to it....but since RPM signal is working, I suspect it is working.

[bmdubya1198]

So just use the test light as a probe to manually apply power? I can give that a go.
LH2.2 uses the fuel system relay for power. I was thinking about jumping that relay with my Y-jumper (it’s a dual relay for injectors and pump) and cranking to see if the relay is preventing full power.