Dead injector driver?

[3VOLUTIONIST]

So, with my never ending saga of electrical gremlins, I'm faced with a new problem!

On my way home today the car suddenly decided to start running on three cylinders (shuddering horribly and not making any power).
Got home, did the usual checks, no leaks, and getting spark to all cylinders. However, I'm not getting fuel to cylinder 4. Disconnecting the injector plug made no difference.

Dead injector was my first thought. Swapped injectors 3 and 4 over. Still the same issue, at cylinder 4. So it isn't the injectors. I even swapped all four over to my new set of 750's, the issue still persisted.

Next step was the resistor pack. 11.5 ohms at each resistor, no problems there. Swapped injector 3 and 4's resistors (by swapping the pins in the plug), however the issue still stayed at cylinder 4 (didn't switch to cylinder 3, which it would do if a resistor was bad).
Next step in the line is the ECU.. No big black spots on the board, and no burny smell.. So, thoughts?
Looks like injector no. 4's driver has gone and died on me. Which means I'm up for another Evo 7 ECU :fuuuuu:
Only other solution I can think of would be to try and desolder an injector driver off my Evo 6 ECU board, and replace no. 4 on the Evo 7 board....

Oh, and I checked continuity between the ECU pin and the injector plug for each injector. You dont get continuity between the pin and the plug, however you do between all of the other injector pins
So, if I put one probe on injector no. 4's plug, and then touch the ECU pin for injector no. 4, I dont get continuity, but I do get continuity when I touch the probe to injector no 1/2/3's ECU pin.

Also checked compression, holds 150psi with no problems.

 

[Miniman_alis]

so with your last test you did, that would mean the wiring for number 4 injector is broken?

 

[BYBY5L]

Even when ya said the issue stayed at number 4 would make me think the loom too

 

[4piknup]

You could swap the pins at the ecu plug. It wont upset car too much by injector timing being a bit out for a minute.
Swap 3-4 injector pins at ecu plug. See if miss moves. If it does-ecu issue. If not, wiring issue.

i had a dead injector on nissan. It was in the crimp on the injector plug. We fixed it no worries.

 

[3VOLUTIONIST]

You could swap the pins at the ecu plug. It wont upset car too much by injector timing being a bit out for a minute.
Swap 3-4 injector pins at ecu plug. See if miss moves. If it does-ecu issue. If not, wiring issue.

i had a dead injector on nissan. It was in the crimp on the injector plug. We fixed it no worries.

That's the next step, i wasn't sure if the car would start on two cylinders haha

 

[4piknup]

It will run like crap on 2 cylinders and prolly not idle. But just having the injector timing out, wont make it miss. It wont be as smooth, but it will be fine.
Most early efi stuff was batch fire with no injector timing at all

 

[3VOLUTIONIST]

I just started it from totally cold, havent done any pin swaps yet, so everythings standard. And it ran sweet for about two minutes. Then all of a sudden dropped injector no. 4.

Edit 1: Just swapped injector 3 and 4 at the ECU (Swapped pins 2 and 15) and the issue stayed at injector 4. Which makes no sense at all, but at least it means the ECU doesnt need replacing.

Edit 2: Started it up again, issue still at cylinder 4. But, if i unplug injector 3, and 4. Then plug injector 4's plug into injector 3. Injector 3 starts working...
Plugging injector 3's plug into injector 4 makes no difference.

Edit 3: Pulled plug no. 4 again after running the car for a while. Its wet..
So, i'm getting fuel?
And im definitely getting spark. It arcs across a good inch of air to the rocker cover. Compression is definitely good, 150psi, and the gauge isnt moving.

Edit 4: I let it air out for a while after thinking it might have flooded itself. I took the coils off and swapped the ring terminals around, then swapped the plug leads to match, so that cylinder 4 was being driven by the other coil. Now if the coils were the issue, the problem should have shifted to cylinder 2. However it stayed at cylinder 4... So that's another thing checked off my list

Coils - Good
Plugs - Good
Injectors - Good
ECU - Good
Leads - Good
Wiring - Good
Compression - Good

The only thing I haven't been able to switch out is the resistor pack (MD099628) because I don't have a spare. I'm going to try and get ahold of one to test that theory. If it's not that, then I have no idea.

 

[4piknup]

Swap your plugs between 3-4
Swap your leads between 3-4

You must be close to finding it.

you doing a good job of diagnosis here.

 

[3VOLUTIONIST]

Swapping plugs 3&4 was one of the first things i did yesterday, to no effect unfortunately. Ive tried a set of four brand new Simens Deka 750's, issue still stayed at injector 4. Also tried changing just injector 4 to an Evo 510cc, still no success.

Swapped out lead no. 4 for the standard one (i put new Eagle leads in last month)
No joy.

Currently in malaga visiting wreckers.. Looking for the resistor pack.

 

[vr401]

Doesn't evoscan have injector triger that you can turn it on one at a time?

 

[3VOLUTIONIST]

Yeh, the actuators section. I could never get any of the actuators to work for whatever reason. It just says "no response from ECU"

 

[Miniman_alis]

if changing all these electronical things doesn't change a miss in cylinder 4, then wouldn't that mean a valve or piston/ring problem?

 

[BMGTZ]

unless the ignitor is different to an early gsr...I have a some

 

[3VOLUTIONIST]

I dont think it's a valve/ring problem, it holds compression fine :/

Pretty sure it's not the ignitors either. I changed the terminals over so that the other coil was driving cylinder 4, and it still didnt come good, going to borrow a resistor pack to see if that makes any difference. If it doesn't, I have no idea what to do next haha
Probably change the computer

 

[vr401]

Yeh, the actuators section. I could never get any of the actuators to work for whatever reason. It just says "no response from ECU"

Try option under evo 6 not late evos.

 

[3VOLUTIONIST]

Will do. But its an evo 7 ecu?

 

[vr401]

Will do. But its an evo 7 ecu?

Works on my 7

 

[khubner1]

probe the plug at the injector end with a noid light or an led test light if no pulse move into the ecu and probe the ecu plug for injector 4 (earth switched) if it pulses you know you have a break in the wire somewhere. if still no pulse ecu issue

 

[3VOLUTIONIST]

probe the plug at the injector end with a noid light or an led test light if no pulse move into the ecu and probe the ecu plug for injector 4 (earth switched) if it pulses you know you have a break in the wire somewhere. if still no pulse ecu issue

Have already checked all continuity.
And if injector plug no. 4 had issues, then when i plug it into injector 3, injector 3 shouldnt start suddenly firing like normal.

Dad had a look when i was at work, used his stethoscope, injector is definitely firing away.

I tried a 100% functioning resistor pack and igniter (off a running GSR). No difference.

Dad found small white bubbles in the coolant.. His inference is that water vapour is finding its way into the cylinder and preventing ignition.
Sooo, looks like its time for the head to come off!

 

[khubner1]

Have already checked all continuity.
And if injector plug no. 4 had issues, then when i plug it into injector 3, injector 3 shouldnt start suddenly firing like normal.

Dad had a look when i was at work, used his stethoscope, injector is definitely firing away.

I tried a 100% functioning resistor pack and igniter (off a running GSR). No difference.

Dad found small white bubbles in the coolant.. His inference is that water vapour is finding its way into the cylinder and preventing ignition.
Sooo, looks like its time for the head to come off!

stethoscope ok good the works.

what realy gets me is all these people saying oh yeah i checked the injectors and i can't fin an issue normally without a noid light it's impossible to check for injector pulse as a std test light one flash at the speed needed. a multi meter doesn't react quickly enough etc. get back to us when you find out whats wrong.