Engine Specific Info and Questions > IDI Engine
What the hell just happened?
RunninWild:
Long story short. Rebuilt aaz put maybe 50-100km on it then pulled it and swapped it into a tacoma. Started it up the first time 2 days ago. Started first crank and sounded wicked and ran it for a couple min. Yesterday had it idling and went to grab a wrench around the corner and it started misfiring like crazy and black smoke coming out the exhaust. Restarted it and it would run smooth for 5-10 seconds then start to misfire. Checked the injectors to discover injector #1 was loose (I torqued it properly 52ft-lbs with new heatshields when the motor was assembled). Today i reinstalled the injector with a new heatshield and it ran smooth for a few more seconds before misfiring again. I then tried 2 other spare injectors and cylinder 1 is completely dead. Doesnt run smooth at all. Wtf happened? Pulled the valve cover and nothing obvious stands out. Fuel gushes out if i loosen the fuel nut so its getting fuel. How the hell does this happen 😢
ORCoaster:
When it comes to electrical problems we put the blame on gremlins.
When it comes to mechanical crap like what you just described it is a bit easier to try and correct. No, hauling to the junker is not an option. Well it is, just not the good one.
I would say if you have gone through 3 different injectors and you still have a misfire going on then back up to the IP pump delivery valves. You say you are getting fuel gushing out the top of the nut. OK, but is it at the correct pressure, you know 130 or 155 bars? The delivery valve at the head of the IP might be jammed open and the fuel is pressurized into the line then slightly opening up the injector and the rest doubles back into the pump.
It might be time to pull that delivery valve and inspect it for a tiny bit of something keeping it from closing down properly. Essentially keeping all the fuel on the line side of the pump. It isn't al lot of volume that goes in there in the first place, when you think about the height of the cam inside the IP as the amount of fuel being pushed down the center of that funny looking, highly machined shaft in the head.
I had the crazy incident of not tightening one of the nuts on the delivery valves after a timing check and adjustment. I couldn't figure out why it wouldn't start. Then I noticed the puddle of fuel at my feet. OH YEAH I loosened them nuts too.
How does this stuff happen? I wish I knew because I would avoid it at all costs. Seems to keep the hood up though.
Later hope you find something in the inspection. Oh and Use a good socket not a wrench on those valves. They really are in there tight and you will just round them up if you don't go to a box end or socket on them. Trust me, I have done it once already.
Modification: I also am wondering if you somehow cracked the injector line somehow. That would show as a bunch of fuel spraying out somewhere and you didn't mention that as an observation. Any chance that happened?
srgtlord:
headgasket?
RunninWild:
I'm doubtful its the headgasket.
Yes scrapping the truck would be unfortunate. I paid $5000 for the rolling shell with no motor or transmission. Bit too much of a loss to just walk away at this point.
I was planning to pull the head tomorrow but I like the idea of checking the delivery valve first. I've never looked at them before. Is it going to be obvious what im looking for? Is it just a simple disassemble clean and put back together kinda thing?
The thing that is really freaking me out that doesn't make any sense to me is how the injector magically came loose. The return lines weren't kinked or twisted like it wiggled itself out. It was loose enough that I could wiggle the injector around with my finger, like 1 full turn kinda loose, not even finger snug. I also don't believe that its a coincidence that cylinder magically doesn't work all of a sudden. I'm really thinking something internally is ***ed up. Either a bent or stuck valve or a snapped ring or a super scored cylinder. I just don't understand how it could loosen like that. The threads around the injector hole in the head arnt cracked or damaged and the threads on the injector look fine as well. I'm completely stumped.
One thing I didn't mention is the motor was kind of ghetto rigged just for testing when it happened. the turbo was mounted but there was no piping hooking it to the intake nor is an exhaust hooked up and worst of all no air filter. the only thing that I can think of that could have got sucked in would be a bug but I dont see how something like that could do this kind of damage.
libbydiesel:
Black smoke typically means either excessive fuel or intake restriction. Idling eliminates the excessive fuel possibility and so leaves an intake restriction. Pull the intake manifold and remove the lost rag from the intake manifold/port.
The practice of starting engines without them fully installed has always struck me as a bad practice. At best it is an inefficient waste of time just for a mediocre sense of instant gratification. At worst it causes a lot of problems. "I just wanted to hear it run." [facepalm] I'd rather practice a bit of delayed gratification, hook it all up right with the sure knowledge that it will run because I did it all right... and then take it for a DRIVE, which is, after all, the whole point.
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