Very rough starts on my ALH - page 1 - TDI Engine -General Info - VWDiesel.net The IDI, TDI, and mTDI source.

• Very rough starts on my ALH by Smokey Eddy on 01 Mar, 2011 22:01
• Having brutal cold starts on the ALH lately.
  I just tested all the plugs and they work fantastically.
  
  (ps. can anyone tell me how those two what appear to be 14ga wires power all four glow plugs?! i ran individual 10ga wires to each of my glow plugs on my AAZ...)
  
  anyways;
  The battery is charged very well according to my battery tester.
  When its cold, the glow plug light doesn't stay on for very long at all (in my opinion) almost no time at all compared to my IDI. When the engine is hot i dont think the light even comes on. Maybe for a second or two at most?
  
  Then i crank, it turns quickly at first then slows and struggles... the battery light comes on... starts poorly... idles cold (white) often grey smoke too from flooding?
  
  I noticed while it was running some air coming from the filter. I turned it off, cleaned the clear lines and these bubbles arrived immediately from both the pump and the filter side.
  Sorry for the poor photos. Taken with my phone.
  
  
  
  Is that enough to be of concern? I suspect so. If it is, do i want to replace the special crimped lines to and from the filter/injection pump or do i want to change the fuel filter?
  or heck, may as well do both?
  
  Any input is appreciated. I don't know anything about the electronics of the ALH and its glow plug system. I can only imagine its similar to the AAZ and 1.6TD
  
  Immediately before those photos were taken the car sat for about 30 minutes after driving for over an hour.
• #1 by the caveman on 01 Mar, 2011 23:34
• ya the glow plug buss bars on TDI's are sad...
  Tdi's generally have to crank pretty fast to start, the ECU needs a good signal to fire everything. Mk4's have lousy starters, so do a diagnostic on your starter circuit.
   As kind of a side bar-if you have to take the battery out for some reason, i really really suggest also removing the air box and battery tray. Pull the snorkel for the air box, i guaranty the screen is blocked [ won't solve the starting but may solve others]. Under the tray you will see one big and a couple of other smaller ground junctions. remove and clean them, re-attach with die-eletric grease. This may also help with other things besides the starting issue
• #2 by Smokey Eddy on 01 Mar, 2011 23:36
• Great Thanks. I'll do all those things.
  I'll clean all grounds to & from the batt and trans/block area as well. I'll check the starter wire too although i gave it a glance and at first it looked great (its in a heat shrink sleeve which is good but also hides any corrosion)
  I'll give that all a go tomorrow.
  As well as the air box stuff.
  It's feeling sluggish like it did when the intake was full of soot...
• #3 by Vincent Waldon on 01 Mar, 2011 23:37
• The glow plug should stay on for 10-15 seconds during the winter, just like your IDI or a bit shorter.
  
  If not you most likely have a bad coolant sensor... a frequent fail item and about 15 bucks to replace.
  
  You can confirm by pulling the connector off the sensor on a cold morning... if you get a longer glow plug light diagnosis confirmed.
  
  I'd get the glow plug system working perfectly before worrying about anything else related to starting, smoke, etc.  In the summer they don't get used at all but in the Canadian winter they can be the root of all evil.
  
  Oh, and they are wired in pairs so that the ECU can compare one set against the other and warn you if there's a difference.  By mid 2002 they ran separate wires to each glow plug so that the ECU could tell you exactly which plug was bad.
  
  14 ga wire is certainly capable of carrying 10 amps at each plug... and under the air filter is the main glow plug harness which is a nice hefty pair of 10 gauge wires.  
• #4 by Smokey Eddy on 01 Mar, 2011 23:54
• Excellent info Vince! I'll try that sensor in the morning!
• #5 by Vincent Waldon on 01 Mar, 2011 23:56
• Dem bubbles is nothing man... my money's on your coolant sensor... fingers crossed for ya, since coolant sensors are cheap and easy.
  
  Remind you of anyone?!   
• #6 by Smokey Eddy on 02 Mar, 2011 00:04
• Hmmm let me mill over that one ... I'm sure it will come to me
• #7 by nathan_b on 02 Mar, 2011 00:14
• Injection quantity checked recently? ever had the top cover off the pump? If you have, the injection quantity IS off. Unless you've reset it with vag com that is.
  
  Too low (high number)IQ and it will crank forever. Too high (low number) IQ and it will run ragged and smokey on startup
• #8 by Smokey Eddy on 02 Mar, 2011 01:03
• I've never done anything to the car...
• #9 by Powered by Spearco on 02 Mar, 2011 01:30
• If you look in the Bentley manual, it says the air bubbles are completely normal.
  
  You should get Vagcom or have someone who does, check the pump timing and injection quantity.
  If the timing is off, such as retarded, it'll start but start ruff. Also if the quantitiy is not right, you'll need to correct it buy performing the "hammer mod". That too could lead to ruff starts. Check it out on the TDIclub forums.
  
  What I've found out about the glow plug codes is that if there is four individual wires for them and lets say that cylinder #4 is bad. Thats really #1  . #1 is #4, #2 is #3, #3 is #2 and #4 is #1.
  Anyone else get that. Pull the GP's out and verify that they all heat up as fast as the others.
  
  Also check relay #109. I find that the relay is the colprit for all sorts of issues.
  
  Good luck
• #10 by the caveman on 02 Mar, 2011 09:22
• I completely agree with everything that was posted after me. It was late when i read and posted and should have been asleep instead of babbling. But i would still do what I said at some point...
• #11 by 8v-of-fury on 02 Mar, 2011 16:02
• I do believe a faulty 109 relay will cause a no start situation, and because he is seeing the glow plug light in the cluster and the car is starting.. That it is operating properly.
• #12 by Smokey Eddy on 02 Mar, 2011 17:27
• It hardly starts though... a good 3-5 seconds of cracking.
• #13 by 8v-of-fury on 02 Mar, 2011 17:53
• What temp is it out there ED? The Gp's in the TDI's don't even come on above 10c or somewhere around there.. BUT if its below that and you still only see the light for a second.. I would try and jump the GP's from the battery manually and see if it starts better.
• #14 by nathan_b on 02 Mar, 2011 18:46
• so basically your saying you never have done any work on your car,
  
  and you don't plan on it,
  
  and you sill complain about it cranking too long.
  
  It is either A). timing. or B). IQ.
  Anyone with vag com can verify both of those in less than 5min.