I had a major boost leak on a long ride home in my mostly finished build. On the home stretch, I noticed that the car was struggling to hold idle, and eventually stalled in my driveway (black, not blue, smoke out the exhaust). She wouldn't start again. Had some major overhauls since then:

Starter:


Spark plugs:


I've also checked the coil packs and injectors/pump:

You can see the spark plug tester, and tons of fuel spitting from the cylinder.

Timing looks not amazing but alright:


I threw one of those little tube camera things into the cylinder as well, to see if any of the cylinders were blown up or something (I don't know):

Looks a little greasy, but nothing an Italian tune up wouldn't fix (most of that is probably just gasoline).

I'm still waiting on a compression tester, but everything else looks pretty pristine to me. The car doesn't even try to start; absolutely nothing. I can't think of a single reason (other than bent valves) she wouldn't even kick. Cranking doesn't sound bad like no compression, she sounds pretty normal. Any suggestions?

 

Looks like you lost spark or started DUMPING fuel. Have you checked for any stored or pending DTCs? From your pics, those cylinders look wet with fuel.
If your timing is good, it could be the crank trigger/position sensor issue causing it. I've seen quite a few threads about built motors and issues with the CPS or the trigger wheel.
Once you get it sorted, change your oil ASAP as it will be super diluted with fuel!

 

That's good to know, I never thought about the crank sensor.

The car seems to be dumping fuel, not sure if that's normal for cold starts... You can see that the spark plugs at least work from the tester in the pic, but maybe they're not working in the block??

No DTCs at all. There was a "Possible cylinder 2 misfire" but I'm 99% sure that showed up when I was messing with the broken starter.

 

Update: so the gas spraying is only happening in one cylinder. After running the starter for a few seconds, the entire cylinder filled up with gas. So the two questions of the hour are:
- Why is cylinder 2 DUMPING gas into the engine?
- Are cylinders 1, 3, 4 getting any gas at all?
I'll have a look tomorrow and see what I can find. All 4 injectors are 750cc, why the hell would 1 of them be hogging all the fuel? Doesn't make sense to me.

 

Maybe the injector is stuck open. You could try switching them around and see if the problem moves. Another thing would be to check the control signals from the ECU to the injectors to see if its holding it open. The ECU sends ground to open the injector so a damaged harness that is grounding out or an ECU fault could be the cause if that is the case.

 

I switched out injector 1 & 2, and now 1 is spitting gas, not 2. I said "dumping" earlier, but I think that was more backsplash; it looks like a pretty reasonable mist now that it's all evaporated. Is it possible that 3 out of 4 injectors are 100% gummed up or stuck? I've never cleaned injectors before, so I have no idea if this is a reasonable theory.

Edit: I measured a couple of the plugs and there's ~9v through them with keys in. Do the injectors pulse to open or pulse to close?

 

9v is pretty low, it should be closer to battery voltage (or maybe your battery is just low?). The ECU sends ground to open the injectors (active Low). So you will see constant voltage at the injectors with the key on. If moving an injector moved the problem then it sounds like its an injector issue.

 

Ok I'm a little lost. With key in, between wires it measures 9v, but red wire to ground measures 12v, and black 2v?????

Just tested one of the not-working injectors with the battery and it clicks... I'll test the rest for now.

Edit: I reread your reply. So it sits at something, then grounds the line when it's ready? Alright. Is it possible that the injectors can open... but not send gas?

 

that sounds....not good. I'm 99% sure the meter should be reading 0 (or very close to it) between the two pins in the connector unless the ECU is commanding the injector to fire.

Edit: With the injector unplugged.

 

Tested each injector and connector: all the same. I still don't understand what I'm reading from my multimeter, but I verified it was working properly (a single copper strand poked through my heat shrink job, and grounding that caused the injector to click). I guess the 3 injectors must be plugged then?

 

you can check the resistance of the injector coils themselves, which should be between 10.5 and 13.5ohms. The method for checking the drive circuit in the service manual is using an oscilloscope which is not exactly something most folks have on their bench. What I think you might be able to do though is use a test light. Put the clamp on battery positive and touch the probe to the negative terminal in the injector harness (Injector unplugged). While cranking you should see the light pulse. If it just stays on, or doesn't light up at all then you might have an ECU/Harness problem. Test lights should have a very high resistance, as long as it is greater than 10.5 ohms, which is the factory spec for the injector, there should be no chance of harming the ECU testing this way.

 

I checked the resistance a little while back. I don't remember what exactly they read, but they were within spec. Obviously I'm not 100% sure, but I don't think it's a harness issue, because cylinder 2 would be firing regardless of which injector it had.

I brought the injectors to a local diesel shop who said they'd have a look. Hoping to hear back before the end of the day.

Edit: just a side note, I realized last night that cylinder 2 had the only spark plug that wasn't torched. Doesn't make a lot of sense to me; why would the plugs fry themselves if there was no gas? Whatever.

 

Alright so I got word back from the shop. The guy says that the 3 I thought weren't working, are working fine, and the one that was spitting gas was stuck open. Gonna go grab them tonight after they're cleaned. I supposed that explains why the all the other plugs were torched haha.

I have no idea what else would be wrong? Is it possible that the "stuck" injector was hogging all the fuel pressure? It's just a stock pump. I can't think of anything else beyond that. Other than timing being COMPLETELY destroyed, but it looked fine when I checked.

Edit: so I've gone ahead and ordered some injectors. The only ones I could get from a local shop were 1050cc for $500 and a week to arrive. Better than waiting 3 weeks for something to clear customs, I guess.

 

One injector getting stuck open would absolutely cause all of the symptoms you were experiencing. Try just replacing injectors (and rescaling your map, it seems from your options) and I bet you're good to go. Don't dive down the rabbit hole of the diagnostics you did that were inconclusive. That data is likely going to be irrelevant.

Oh, and change your oil! It probably has a litre of gas in it!

 

I guess the next question would be why did it get stuck? Have you modified the fuel system at all? Reason I ask is the only reason I can imagine that happening is debris getting into the injector and jamming it up. Usually the OEM fuel filter does a pretty good job, but if you have removed it without a replacement then that could be something to look into. I agree you should probably side table all those other readings you got for now since you have found the likeliest cause of your problems. Personally I would replace the injectors because of how critical they are, but that's up to you and your wallet. Replacing them doesn't seem unreasonable to me compared to what could happen if they fail again.