V88 no injector signal

[waade395]

Hi,

Trying to work out why we are getting no injector pulldown from our V88.
Has been professionally tuned and working a few days ago. However after a re-wire we are seeing no ground signal from any of our 6 configured injector drives..

The two spare injector drives are not terminated and are disabled in software.

All ECU parameters in runtimes are OK.
Logging shows injector duty time @ 20ms while cranking. For a period of at least 8ms. (we were advised an injector short would show only 4ms of injector duty cycle before disabling)
Injectors have 12v at plug confirmed.
While cranking voltage does not go below 10v.

Injector test results in nothing. Using an oscilloscope across the injector shows nothing too (if we tap the oscilloscope ground on the chassis we see 12v peak so scope is working)
Ignition test works!

We've had this exact issue before and it was due to a loose wire.... I want to say the +14v on B loom. But my brother seems to think it was no +14v to the hold power IGN sense (seems illogical to me).
Regardless, we have 14v to both A & B loom 14v inputs. As well as to hold power IGN sense.

Are there any clues as to what on a V88 can lead to lack of injector drive? (But ignition drive is fine... as well as seemingly all other ECU functions)

Thanks!
Wade

[waade395]

Further testing shows when unplugging an injector plug and checking voltage on each pin. Engine not cranking or running:

+14v on the +14v IGN pin.
+4v on the ecu trigger pin.

We have been advised the ecu should drive the injector triggers high to +14v when not triggering. Is this correct?

[Adamw]

6 hours ago, waade395 said:

We have been advised the ecu should drive the injector triggers high to +14v when not triggering. Is this correct?

Yes, the injector outputs will be pulled up to about 12V when off and ground when on.  

I suggest you remove an injector wire from the ECU completely then put your scope probe or test light directly on the ECU pin while using the injector test function, this will then eliminate any software settings and wiring effects.  

Also do us a short log of it cranking so we can see if there are any other clues.

[waade395]

The engine loom hasn't been re-wired, only body loom and ECU support loom. We have confirmed continuity from injector pins to loom ecu connector.

Cranking log, pcl and a few scope captures attached. (capture filenames indicate what each is testing)

Unsure what to make of what we're seeing on the scope. Pretty sure I've now heard an injector clicking after leaving it on test for quite some time. We've picked up some noid lights we'll test with shortly.

Thanks for the help so far!

waade395_v88_cranking_Log 6-04-19 11;46;46 am.llg waade395_S14 1Jz vvti vipec v88 borg warner 17-08-18 with 150ti.pcl

[waade395]

Well, we lied to you earlier. Turns out INJ7 (unused) was shorted directly to ground. This has been fixed.

We now have +12v on the ecu INJ triggers. But still no luck getting injectors to trigger. We have tried a spare injector too to no avail.
Scope output remains the same.

Could this short have cooked the injector drivers?
 

[Adamw]

The first two scope pics show the injector drives functioning correctly in test mode, what you see is short 2ms pulses to ground, repeating at 10Hz.  The 3rd scope I dont know what that is meant to be showing.

Your log shows very erratic RPM and the trigger error counter continuously counting up.  So it appears to me you have a trigger problem, not an injector problem.

Can you connect your scope to trigger 1 & 2 pins and do us a capture off the cam/crank signals.

[waade395]

Problem fixed! 

Cheap fusebox failed us. The +14v injector feed circuit had almost no continuity.. just enough to show voltage until a load was introduced.
Swapping to another fusebox circuit has the car running again.

But you were absolutely right about the flakey trigger signal. Upon checking the crank sensor a wire pulled out. This has been fixed too.

Thanks for your help! Appreciate the response on a weekend. Will be in contact with beer $$