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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: Smokey Eddy on March 01, 2011, 07:01:19 pm
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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.
(http://i49.photobucket.com/albums/f279/edmcclung/IMAG0191.jpg)
(http://i49.photobucket.com/albums/f279/edmcclung/IMAG0190.jpg)
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.
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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
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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...
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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. ;)
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Excellent info Vince! I'll try that sensor in the morning!
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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?! :D :D
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Hmmm let me mill over that one ... I'm sure it will come to me :P
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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
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I've never done anything to the car...
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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 :o. #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
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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...
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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.
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It hardly starts though... a good 3-5 seconds of cracking.
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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.
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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.
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Yeah well thanks buds perhaps I don't have one. It's not MY car. Just asking some questions my grumpy pants.
Jer, its about ...-1 at night.
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When its cold, the glow plug light doesn't stay on for very long at all
IMHO this ^^^^^^^^^ needs to be looked into long before timing or IQ. ;)
Regardless of temperature you should always get a brief flicker of the glow plug light when starting... as a bulb test. If you don't get this flicker you suspect relay 109... if you are getting this flicker 109 is probably fine, at least for the purposes of starting.
The glow plugs come into play below about 45F/ 7C... at -1C I'd expect about 5 seconds of glow plug time.
BTW, just like the IDIs the TDIs have a glow plug strip fuse...it's in the fuse box on the top of the battery box. And just like the IDIs the glow plug light has nothing to do with whether the glow plugs are actually getting power. :)
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Ahh see what posting from your phone does! You miss stuff!
Vince, if a gp has died what does the ECU do to notify the driver. So the light not staying on means the plugs are not seeing power.. EDMUND try jumping the plugs! I am confident this will solve your rough start problem
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Vince, if a gp has died what does the ECU do to notify the driver
It throws a code (P0380 most often on the pre-2002 cars) and triggers the CEL. It should do this if the fuse goes as well.
So the light not staying on means the plugs are not seeing power.
Unfortunately no... just like our IDI engines the light is a "wait until I go off before you start" light rather than a "the glow plugs have power" light.
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Right, so then being like the idi engines.. the light will go off when the relay has kicked out. The light stays on for a second and goes out meaning even if the plugs were getting power it was only for a secondÉ (that means a question mark my browser is being funky)
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Right, so then being like the idi engines.. the light will go off when the relay has kicked out.
Nope... 'cause now the system is different. ;D
Assuming the engine starts the TDI glow plugs stay on for 3-4 minutes even if they didn't come on to start it in the first place. Spring/summer/fall/winter... the glow plugs always come on *after* the engine starts, even if they weren't used to help start the engine.
The light says "ok to start me" and that's all... the glow plugs themselves has a completely different mind of their own. ;)
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Well shyyyoot I thought I had it conquered. Ok well here is another point, if the car eventually starts after cranking indicating lack of gp usage.. and then continues to run rough when the afterglow ¨Should¨ be working.. yet doesn't seem like it is.
Either way, what i am trying to say.. is that the gps dont seem to be working at all. ;D
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Pull the temp sensor and see what happens (tricks the ecm into thinking temp is max cold)
Then test the resistance from the terminal of the gp to the head. if it is excessive (more than .8 ohm) then replace them. Failed gps have infinite resistance 90% of the time.
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I already pulled them out and tested them.
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Does the coolant temp take for ever to warm up?
If its a manual trans TDI, take out three GPs in the coolant flange and swap them with the engine GPs. See if it starts any better. :D
Or perform the tests outlined before to verify them being bad.
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You can confirm by pulling the connector off the sensor on a cold morning... if you get a longer glow plug light diagnosis confirmed.
There's a connector plugged into #6... pull it already and see if the glow plugs come on long time and engine start properly:
(http://i197.photobucket.com/albums/aa85/vwaldon/coolantsystem.gif)
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I will I will!
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Not sure if this applies to your car or not but I had to modify the glow cycle with Vag-Com on my father's 98 because the glow plugs would come on for pitifully short cycles and it would run rough and start hard.
Replacing the temperature sensor is a great place to start. I know they had some wiring harness defects but not sure they apply to the A4/MK4. My dad replaced his, I modified the glow time with vag-com and it starts great in all temperatures. Doesn't stumble hardly any and smooths out immediately. If you have to, after you've exhausted the other possibilities, extend the glow time, I can get you the instructions on how to do it. Just send me a PM.
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Does anyone know the part number or year/model/engine code for the GR relay that doesn't use a input from the ECU but stays on for a short time after start & also has the temp input for no GP warm starts? I had one, it died & I forgot the part number.
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(http://i49.photobucket.com/albums/f279/edmcclung/th_VIDEO0007.jpg) (http://s49.photobucket.com/albums/f279/edmcclung/?action=view¤t=VIDEO0007.mp4)
that's what i mean by short. That was one of the warmest days too... i think it was +4 or +6 ... (that is a video by the way. click on the image)
when its cold in the morning like -6 it barely feels like it's going to start...
the sound sucks because its from my phone but maybe someone can say its the starter? (turning slowly)
i should have done the "pull the sensor" trick but im so unorganized all the time im almost always late... i will try tomorrow.
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Bump? I tried to pull the sensor off on a cold morning and I pulled and pulled and pinched what I thought was a clip but I felt so sure I was going to snap something I gave up.
This is a new page but please view the video. It was actually closer to zero that morning and the light was on for less than a second.
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pull the electrical plug off the temp sensor. It's your standard mk4 electrical plug..
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Yup... standard MK4 connector... completely different lock than MK3 or Mk2 or MK1. ::)
Stick a screwdriver at right angles to the slot at the end of the connector and then twist the screwdriver 45 degrees while pulling out on the body of the connector.
The CTS sensor is in an awkward spot so in the past I've practiced on a another connector under the hood that's in plain view and easily accessible to remind myself how they work. I also usually remove the big corrugated air-hose between the airfilter and intake manifold so that I can see what the hell I'm doing as I mess with the CTS.
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Push in before you pull out.
works every time.
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maybe you have a weak starter, draining your battery on start up, mixed with sensor... my 2 cents.. maybe 1 cent