95 Diesel Starting trouble - try this one!

I have a 1995 diesel Jetta and I cannot figure out why it does not start well (at all) cold. It does start fine if the block heater is plugged in. I have...

  1. tested glow plugs many times (even visually with injectors out)- all are okay. starting does not improve even if glow plugs are jumped to battery.
  2. tested compression - above minimum.
  3. had injectors tested - okay.
  4. replaced, fuel filter and air filter
  5. the fuel is NOT draining back at night.
  6. Injector timing has been checked.
  7. The car runs fine when it has finally started (and starts okay if plugged in).. but it takes a lot of cranking to get it going if it is cold or has sat for 6 or more hours.

Any other things I should check?? Besides replacing the injector pump?? - yikes.

Help would be GREATLY appreciated.

Jesse

Reply to
jettared
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A new battery and thinner, synthetic oil (5W-40 or even 0W-40) should make it turn over faster and start better when cold. Also check your battery cables, including the ground straps.

Reply to
tylernt

Have you tried a diesel additive that will make sure your diesel isn't starting to Gel? It's like $8 for a large can and it should do you almost all winter.

Reply to
HotRod

You've certainly checked all the right things.

It really sounds like low compression... did you do the compression test stone cold ?? I've seen several engines that tested fine in the mechanics shop but were very low the next morning after sitting overnight in the garage.

Or a slow starter... is it cranking over like it always has ? If you boost it does it spin faster ? Grounds and battery cables all OK ?

Reply to
Vince Waldon

The compression test was done when the engine was fairly warm.

1-380 2-460 3-460 4-420

I also tried a new battery today... was a little better but still takes a lot of cranking to get it going when it is cold (it is about 40 degrees outside). After cranking for a while it will start for 1 seconds then stop. Then on 2nd or 3rd try it will keep going.

Reply to
jettared

"jettared" wrote

Check for any possible place for a small vacuum leak.

Engine could be full of carbon from high mileage. Carbon behind the valves and on the head acting like an insulator keeping heat from spreading fast. Even on a gas model when I refurbished the head, I had over 1/8 thick carbon on the back of the valves. A carbonless or near head is a lot more efficient.

If it is heavy carbon deposits the only cure is to remove the head and have it refurbished or rebuilt for better efficiency.

Harry

Reply to
Harry

Try adding this:

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Stanadyne Performance Formula® Diesel Fuel Additive

I use it year around in my 1992 Jetta Turbo Diesel (406K kms) and have no cold start problems. I'm in Toronto, Ontario, Canada where temps. are around -5C to -10C at this time of the year.

Reply to
AJ

Just how did you check the glow plugs? My experience with VW diesels, most at high to very high mileage starting in the winter is "REPLACE THE GLOW PLUGS. I've never had pump problems other then the replaceable seal behind the pulley.

JoBo

Reply to
Jo Bo

If possible I'd sure be tempted to try the compression test cold... you may witness a big drop which would explain why it starts easily when warm but not when cold.

Reply to
Vince Waldon
1-I would check compression cold, because that's where it is important to getting it to start.

2- can't remember if the valves are hydraulic or not. If adjustable set them on the loose side

3- pull the float unit and see if the screen is plugged up

4- check pump timing.

Reply to
Lost In Space/Woodchuck

Can a glow plug be bad even if it glows red when you look at it with the injectors out... in other words, do they get less effecient over time and use? They are only a couple of years old and do not have carbon built up on them.

The car has 250,000 km total.

Jesse

Reply to
jettared

From a reply to my old post

Well #1 could be plugs, but #2 and #3 are more likely to be injectors.

You can test the plugs a lot of ways. One is to take them out and hook them up directly to the battery. Another way is to use an ammeter (amp meter) to see how much current they are drawing -- 36 amps means all are working, 27A means one is dead, 18A means two dead plugs, etc.

The ghetto way to test them is to cycle the glow plugs on a stone cold engine about 10 times without starting the car (hope you have a strong battery!). Then go put your finger on the cylinder head above each plug, and see if it got warm in that spot. Cold spots indicate dead plugs.

If you do take the plugs out, look and see if any of them are burned away. A burned off plug indicates a bad injector. It's not necessary to replace injectors as a set of four, you can just do the bad one(s) -- it's a lot less expensive that way. You *might* be able to restore dirty injectors by running off a quart or two of straight ATF, Diesel Rooter, or Diesel Purge to clean them out, but you'd have to be pretty lucky to fix a dirty injector that way.

Could also be injection timing. Check the bolts that hold the injection pump to the bracket, and the bracket to the engine. If any are loose, you may just need to have someone re-time the pump.

Reply to
HotRod

I don't know the answer to this question, but after reading your original post, it sounded like one or two glow plugs weren't doing its job. You sure did some thorough checking of other things...and it seems like if they glow red they should be okay, but just based on my almost 27 years with driving VW diesels (damn I am getting old) when I had starting issues like you describe they were related to a bad glow plug.

Good luck...and let us know how you fix it.

Reply to
Tony Bad

I have to agree--your symptoms sound like classic broken glow plug fuse link. Are you *certain* you are getting power to the glow plugs during the normal start process? I.e., you didn't check the glow plugs by connecting the bus bar directly to the battery and just assumed the glow plugs were getting power when you tried to start it normally, did you? My experience is with older ('85) diesels; I apologize if the '95 glow plug circuit is significantly different. Good luck.

Denny Straussfogel Two '85 Diesel Golfs (since '85 and '89, respectively)

Reply to
Dennis Straussfogel

Reply to
none2u

I disagree on the "they work or they don't"! The newer TDI's monitor the glow plugs and the first sign of then going bad is when the MIL sometimes goes on and off. The glow plug will produce a "sporadic" fault if at times they don't heat. I have seen glow plugs in the older VW's glow red at 50*F but not glow when near 0*F outside.

Reply to
Lost In Space/Woodchuck

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