What the hell just happened? - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• What the hell just happened? by RunninWild on 12 Jul, 2018 19:41
• 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 😢
• #1 by ORCoaster on 12 Jul, 2018 20:02
• 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?
• #2 by srgtlord on 12 Jul, 2018 20:25
• headgasket?
• #3 by RunninWild on 12 Jul, 2018 21:57
• 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.
  
• #4 by libbydiesel on 13 Jul, 2018 08:43
• 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.     
• #5 by RunninWild on 13 Jul, 2018 09:43
• Intake wasnt open for long and i didnt stick a rag in it. I swapped turbos from he211 to a he221 and my piping and couplers didn't fit the new turbo. Starting it was to check the wiring and to check for coolant leaks. I know starting it was dumb but sucking something in the intake wouldn't explain the injector coming loose. I'm 100% sure I torqued it properly when i installed them. I've also swapped the drain lines 3 times since they were installed and definitely would have noticed the injector being as loose as it was.
  
  Also the smoke is more white/gray and black when revving it.
  
  But thanks for the tip. I'll definitely check the delivery valves and the intake before I pull the head. Hopefully its nothing major but I dont have my hopes up.
• #6 by RunninWild on 13 Jul, 2018 18:28
• I just swapped injector 1 and 4 around to completely rule out the injectors. The dead spot stayed with cylinder 1. I then took the delivery valve apart and it looked fine but cleaned it out and put it back on. I also pushed the cold start back in (cable is disconnected but the lever was pulled forward). I then cranked it over and was able to notice that its definitely got a rotation of no compression. I then disconnected the 12v to the ip and cranked it over and I can hear compression leaking out every 4th rotation. I gotta get someone to crank it while i try and find where its leaking but I'm betting its something to do with the socket injector 1 sits in. I cant see any cracks around the outside of the threaded part where they normally crack and the threads inside look fine.
• #7 by ORCoaster on 13 Jul, 2018 19:50
• So you think you cracked the boss on the head for the injector?  I had that happen for no good reason one time.  I was thinking about pulling the injectors and having them cleaned and calibrated as I wasn't impressed with the Hwy MPG I was getting.  I had the hood up and was eyeballing the work I had to do and trying to figure out if I could get the injectors out on a Sunday evening, run them over to the Portland shop on Monday morning and retrieve them Thurs night. 
  As I was wiping down the head of excess oil from the valve gasket leak I noticed a fine hairline crack in the #1 lip that wraps around the face of the injector.  Holy Crap I thought.  I will break that sure as snot if I try to remove the injectors.  I decided to locate and rebuild a head instead and put new injectors in it.  I was able to drive the Rabbit for a few weeks before pulling it apart.  When I did get the injector out the hair line vanished.  So maybe you need to spray some soapy water next to the injector and the hole it sits in.  If there is air leaking out bubbles will form and maybe even foam. 
  
  Best of luck.  Several here have had success getting or welding the aluminum to save the head.  May not be as costly as buying a second head.
  
  But then aren't two heads better than one?   LOL
• #8 by RunninWild on 13 Jul, 2018 21:09
• I didn't look too closely at the seat but it looks fine. I did however pull the intake and exhaust manifolds and the intake port is soaked and the valve has a bunch of buildup on it. Its looking like something got sucked up and ***ered it. Going boat camping this weekend. I'll pull the head Monday and reassess.
  
  
  Question: the ahu aaz are basically the same block other then the crank position sensor. Could I drop ahu pistons and an ahu head and throw a rover pump on it for mtdi?
• #9 by libbydiesel on 14 Jul, 2018 23:56
• Yes, you can do as you say (pistons/head/injectors/pump) and make it an mTDI.  The ALH rods are stronger but the AAZ rods will work.  The TDI injection pump bracket is different from the AAZ bracket in that it accommodates an extra timing belt roller between the pump and cam sprockets.  Some have run without it.  I tend to think it is important. 
  
  I am actually currently in the process of rebuilding an AAZ into an mTDI.  I got the Nural ASV pistons from metalmanparts:  https://www.metalmanparts.com/product.sc?productId=344&categoryId=19.  I will be using the ALH rods and an AHU head.   
• #10 by RunninWild on 15 Jul, 2018 20:29
• Well the heads coming off tomorrow. If i can salvage it and the cylinder isn't destroyed ill just fix it and keep it an aaz for now. If the cylinder is toast its probably just gonna get a used ahu(hard to find in my area) or alh with a rover pump.
• #11 by RunninWild on 16 Jul, 2018 20:23
• intake valve is very bent. Figure this one out. Cylinder, piston and the valve (other then being bent) look mint. No nicks, scratches, dents, imprints or any indication anything hit the valve. I'm stumped but all things considered this is probably a best case scenario. Should I replace the valve guide or do you think I can get away with just a new valve?
  
• #12 by ORCoaster on 17 Jul, 2018 19:28
• I would replace the guide as well as the valve.  Something stressed that piece of metal and the guide goes all around it.  So I would think the same stress was applied to the inside walls of the guide.  It will be a matter of time but it will leak sooner than the others you have.  Play it safe, put a new one and a seal in that cylinder. 
  
  MHO.
• #13 by libbydiesel on 17 Jul, 2018 22:26
• Do you have the tools for replacing the guide?
• #14 by RunninWild on 18 Jul, 2018 08:01
• No I don't. What's involved in that? I dont have a tool to put the valve in either. Was thinking of bringing it to the shop when i get all the parts