Quick question, hopefully this weekend to have an answer. - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Quick question, hopefully this weekend to have an answer. by vanagonturbo on 04 Sep, 2010 19:45
• Ok, so i thought I would bounce this off the masses because I cant call Giles until Monday. I have a 1.7l engine (3rd overbore 1.6l), 1.9l head, portmatched intake and exhaust, 3" DP, GT2560R turbo, GTD nozzles popped at 154BAR, and a Giles pump.
  
  I got it running a couple of weeks ago, but it wasnt finished enough to drive. So, after I got it running, I revved it a couple of times and the idle would hang. One time while letting it warm up, the idle started to take off all by itself and I shut it down. I called Giles and he advised that i should back off the max fuel screw (the one with the 13mm locknut and the 6mm screw).
  
  I finally got all the little stuff done enough to take it for a road test today. I ended up backing the max fuel screw off about two turns. this resulted in almost no smoke when revving the engine, poor idle, and almost no boost. I have the residual fuel screw (I think this is right, the one that the throttle linkage stops on at idle) backed all the way out until it does not touch the linkage. I have achieved an entire 5psi of boost at WOT and 4k rpm. The wastegate line is not even connected! There are no boost leaks.
  
  So, here is where I am at. The engine that was in the car before had a tweaked pump (governor mod, cranked up max fuel screw). I could make clouds just by revving it while stationary. My GTD has the same mods and does the same thing. When I did those mods to the other two engines, I had to tweak the max fuel screw so it would not hang idle and have good power.
  
  I naturally thought that maybe the max fuel screw on the car in question was in too far as the idle would hang. I backed it out in half turn increments and the result was just less power. Still only 4-5PSI of boost. Now I know that the turbo may not be properly sized for this application, but it was free.
  
  Any ideas?
  
  Oh yeah, the pump is an AAZ pump.
  
  Thanks!
• #1 by rallydiesel on 04 Sep, 2010 19:51
• Half-turns is way too much. A few degrees at a time is what I do.
• #2 by vanagonturbo on 04 Sep, 2010 19:56
• Yeah, I know, I just figured that at gross adjustments of half turns I would at least get kinda close to the sweet spot. I have turned it a total of 3 turns out and back in from where it was when I got it back from Giles and there really was not much improvement other than eliminating the hanging idle.
• #3 by vanagonturbo on 04 Sep, 2010 20:17
• Oh yeah, one other anecdote: the pump is timed @ 1.05mm. I dont think that makes a difference in smoke and hanging idle though. Maybe power and poor idle..
• #4 by vanagonturbo on 04 Sep, 2010 20:30
• It is an ATP Eliminator turbo kit turbo. Normally used on the 1.8t for an upgrade. Factory on the SR20DET. I dont think the turbo is too far out of range of efficiency that it would only produce 4psi at WOT. It is also a dual ball bearing turbo, so turbo lag should not be that much of an issue (turbo still spins for a good 20 secs after shutting the engine off). I do have a bit of plumbing for the intercooler, but the bends are MUCH more efficient than the intercooler and plumbing I had in there before.
  
   I think the problem may lie in the fueling. No clouds of smoke=no boost. I have no clouds of smoke. Mostly just a haze and its very light. In my GTD if I WOT it things seems to be almost invisible in the rear view mirror. Same was the case on this car with the previous engine.
• #5 by Vincent Waldon on 04 Sep, 2010 20:38
• Giles pumps are optimized for low low smoke... that's one of the beauties of them... so if you're looking for smoke to confirm it's fueling correctly you may be chasing your tail.
  
  As an aside, when you talk to Giles on Tuesday (Monday is a holiday) he's gonna tell you 1.05 is pretty advanced for one of his pumps.  He builds in a ton of dynamic advance and will recommend 0.95mm as the sweet spot.  Doesn't speak to your hanging idle.. but is part of setting your beast up properly.
  
  In terms of power...I think you've gotta get your fuel screw back to near where it was... low fuel = no power or boost... which seems to be where you are at the moment?
  
  Just checking that you've confirmed there's no mechanical reasons why the idle is hanging?  Throttle cable sticking?  Springs binding? Throttle pedal linkage?
• #6 by vanagonturbo on 04 Sep, 2010 20:42
• Thanks! I already talked to him when I first got it running and he did mention that the timing was too far advanced, I didnt have the chance to move it back down today.
  
  The problem with putting the fuel screw back to where it was is that it will hang idle at 2k RPM and climb from there. And yes, low power and no boost is where I am at. Although, it does feel really strong for having no boost..
  
  I have looked at the mechanical aspects of potential hanging and there are no obstructions. It does it with the throttle cable disconnected and the springs are not binding. the lever returns to where it started from every time..
• #7 by vanagonturbo on 04 Sep, 2010 20:43
• Oh one other thing, Labor Day is a holiday for Canada as well?
• #8 by Vincent Waldon on 04 Sep, 2010 20:46
• Quote from: vanagonturbo on 04 Sep, 2010 20:43

  Oh one other thing, Labor Day is a holiday for Canada as well?
  

  
  'Tis.
  
  I'm planning to be Labouring under a TDI...  
  
  
  If you're checked out all the mechanical reasons for a hanging idle and can replicate it by dialing up the fuel I'm thinking you've done what you can till you talk to the guy who built it.
  
  The idle was hanging right from the first time you fired this pump up?
• #9 by vanagonturbo on 04 Sep, 2010 20:54
• Ahh good to hear you guys get the holiday also!
  
  I can replicate it by putting the pump back to where it was when i got it back. I guess I was just hoping for an easy fix. Lol!
  
  Yes, the idle was hanging from the start before I messed with anything. The only thing that I think I could have changed as far as adjustments was to set the timing @ 1.05mm. Other than that, the throttle cable was not connected and neither was the cold start timing advance cable. I operated the timing advance lever by hand as it warmed up.
• #10 by bugnut on 05 Sep, 2010 00:07
• Well I cant help you with the hanging idle but I did have a problem with the low boost/no fuel with a Giles pump.  I have to ask this question.  How long has it been since you got the pump from Giles.  With mine I ran it on a 1.5na for two years as the franken engine was being built.  In that time of not using the lda the fuel pin stuck close. So now with the new engine with boost I was not getting fuel enrichment while under boost.  He had me take the top of the lda off and put oil in there and work the pin in and out.  Got that fixed now and wow.  The engine would now smoke and go.  Before that the engine made no smoke at all.  The car would just go and burn nice and clean but still lacked power.  The egt's before the pin fix was 1100 tops.  After the fix it would hit 1600 plus.  So I don't know if you had the pump sitting for awhile or not but that might be a solution for the low power.  As for the idle, sorry no help here.  
• #11 by vanagonturbo on 05 Sep, 2010 00:28
• That is good info! I actually have had the pump for about two years. I know, sucks. But maybe that is the problem? The first start up, I did not have the LDA line hooked up. The first test drive I did not have the LDA line hooked up either. After two test drives I hooked up the LDA line and cranked the max fuel screw back to about 1 turn from what it was set to and still no boost.
  
  I hope that makes sense. Paulaner Hefe has been here
• #12 by R.O.R-2.0 on 05 Sep, 2010 08:58
• gasser turbos spool WAY LATE on a diesel engine.. diesel turbos are made to be spooled at way low rpms..
• #13 by rallydiesel on 05 Sep, 2010 10:46
• Have you run this set-up before? I agree that a large gasser turbo would probably spool very high in the rpm range, like over 4000k. Also, using a 1.9 head will affect the optimum timing. I'm pretty sure a lot of frankenmotor's require much more advanced timing. I remember someone had to go to 1.25 to get it to run right. However, if it was too retarded at 1.05, you would see white smoke and irregular idle.
• #14 by vanagonturbo on 05 Sep, 2010 11:01
• I have not run this setup before. It does not idle unevenly or smoke at the current timing setting.
  
  I know the turbo is not ideal for this application, but even on the gas motor it reaches full boost at 2500rpm. So I dont think that the fact that it is a gasser turbo is really the root of my problem.