IP Internal Pressure - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• IP Internal Pressure by SolarSteve on 15 Oct, 2009 08:56
• Yesterday I increased the pressure on my IP and I believe I when a little too far.  It is more clattery and its advanced to the point that the advance handle does not do anything.  The IP is not leaking, so I don't think I went "really" far, but its pretty obvious that its too much.
  
  Today I tried to remove the adjustment plug to decrease the pressure a bit and I can't seem to get the plug out.  Does anyone know of a tool that will allow me to remove the plug?
  
  So far all I can think of is finding a 10mm crowsfoot or bending my 10mm open end wrench.
  
  Thanks
• #1 by anto on 15 Oct, 2009 09:02
• Ive always been able to get at it with a normal 10mm open ended spanner.
• #2 by 410 on 15 Oct, 2009 16:24
• What worked for me is a 6 sided 12mm socket that I squished in the vise.  This way there is no grinding required.
• #3 by SolarSteve on 16 Oct, 2009 22:41
•  
  Thanks.
   
  I ground out a 6 point (didn't see the squished 12 point idea at the time) and it worked.
   
  I really don't have the time right now or the money to buy the gauges and necessary stuff to build a tach to do this the right way, so, I know I shouldn't be messing with it at all then, but I did.  The IP has 308K on it and I figured it probably needs a little more pressure...  Here's what I did.
   
  I measured the distance from the top of the "bolt" to the top of the "plunger".  That dimension was .070.  I then started to tap on the plunger hopeing to only push it in .020 more and see how it ran.  Well, it was kind of stuck and I had to hit it a little harder and when I measured it it was at 1.010, .040 more than I wanted.
   
  This caused the idle speed to be higher than normal, A lot of clattering and the cold start handle didn't make any difference when pulled and very little low end power.
   
  After I removed the "bolt", I tapped on the plunger from the other side.  It seems there is a spring behind it that I had to compress with my punch first before striking the punch.  It took more force than I expected, but I got the dimension to .085.  This quieted the clattering and seems to have restored some low end power.  The CS handle does increase the RPM at idle but not nearly as much as before.
   
  So I guess I will run it and see how it handles the adjustment.
   
  By the way, what is it that makes a diesel clattery?  Is it the valves slamming shut?
   
  Thanks for the help.
  
• #4 by rallydiesel on 16 Oct, 2009 22:53
• It's not the valves. There's a video of Giles running a pump on a test bench. There is no engine involved (well there's the gas drive engine but that's pretty quiet) and the noise the pump and injectors make is pretty loud. Also, the actual combustion process is loud. Just think of a gas engine and how loud a detonation is. The diesel engine is basically detonating all the time.
• #5 by smutts on 17 Oct, 2009 08:12
• I'll just like to say that the adjustment is VERY sensitive, and I was also suprised at how little tapping was needed. Safest way would be to use a bolt and nut, the bolt used as a drift on the regulator gizmo, and the nut as a safety net to stop it going in too far. I usually try for about 35 psi at 1000 engine rpm, but maybe 40 psi is better? as who knows what is correct. The relevant obsolete and useless to anyone but a few dozen dieselheads info is sat beneath a dog in a horse feeding device somewhere in Germany.
  
  The clatter, or nailing, as mentioned is similar to pinking in petrol engines. As the air in the cylinder is compressed it rapidly gets hotter as the space gets smaller, when the diesel starts to be sprayed into this very hot air, there is a slight delay until the first droplets of the diesel mist boil, heat up, and finally ignite. Also the cold diesel spraying in behind it will keep it too cool until it gets far enough away to heat up and burn. This probably takes milliseconds, but it explains why there is a little cloud of unburnt diesel that suddenly detonates (making the clatter of a running diesel engine), after that any further fuel is smoothly and quietly consumed as it sprays from the injector into the fireball.
  
  Injection advance is needed to allow time for things to start burning. But if the diesel is sprayed in too soon, where there is less air compression, the air is colder, so it takes more time for the first droplets to heat up and go bang. This extra delay means much more fuel is injected before it finally goes bang. MUCH more noise, and the engine is fighting itself, doing nasty things to the big ends, It's all bit of a compromise.
• #6 by SolarSteve on 17 Oct, 2009 17:45
• Thanks for all of the great info!
  
  I guess the reason why the cold start handle did not do anything is because I had so much pressure it was dyhnamically advancing past what the cold start handle mechanically advances it, right?
  
  Anyway, it has become a bit difficult for me to make timely replies.  Recently at work the communication guys upgraded my computer to Vista and for some reason I can no longer post on this site from work, so I have to wait until I get home to post.  So thanks for the patience!
• #7 by smutts on 20 Oct, 2009 10:04
• Quote

  I guess the reason why the cold start handle did not do anything is because I had so much pressure it was dyhnamically advancing past what the cold start handle mechanically advances it, right?

  
  You will be bang on the money there
  
  I will be busy with the dremel this weekend too sacraficing an old 10mm socket too.
  
  Which flavour of ESItronic does one need for these pumps?
• #8 by SolarSteve on 20 Oct, 2009 12:58
• Test
• #9 by SolarSteve on 20 Oct, 2009 13:02
• It appears I can post again!!
  
  I pulled the plug out again today and pushed the plunger back a little more because it was still a bit clattery while the engine was cold.  It was great on the highway and at idle when hot.
  
  I pushed the plunger back so that I am now at .085".  It seems to be pretty good now.  Just a little bit of clatter while cold and I re-gained my low end power.  I believe my mileage has increased a little as well.
  
  I'll let it ride at this setting for a while and see how it goes.
• #10 by dennis on 22 Oct, 2009 05:39
• I recently did the same thing to my Volvo pump. (Same pump but a six banger) If I understand correctly the fitting which has the dowl pin in it can be unscrewed on the car, and I can push the dowl back out? I jacked up my internal pressure out of lazyness and stupidity. I did this before I checked for fuel starvation, and the really stupid thing on my part was it was the filter causing the starvation.
  
  Thanks for an informative post.
  Dennis
• #11 by smutts on 23 Oct, 2009 11:42
• http://www.vwdieselparts.com/forum/viewtopic.php?t=5936
  
  There is a good link somewhere in this lot about pump pressures, but your mileage may vary.
• #12 by SolarSteve on 23 Oct, 2009 15:11
• I have not changed my pump pressure since the last adjustment because the engine seems to be running well and my mileage appears to be improving.  I can't accurately determine mileage because I run WVO and my pumping system at home does not have a gallon counter, but in 1 week of driving to work I am definately using less fuel.
  
  Anyway, like I previously posted, being that my pressure is higher, my idle is higher due to the dynamic advance and the cold start handle does very little to change the RPM of the motor at idle.  If I lower the idle from the idle screw will it cause my cold start handle to increase the idle when pulled?  By doing this, will it make it easier to start when it is very cold out?  Lately the coldest it has been is in the low 40's (F) and has been starting well (without block heater, no outlet at work).
  
  I really won't have a problem if I have to leave the idle high due to the pressure, I was just wondering if lowering it will help or hinder.
  
  Thanks