98 jetta hard start

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
hi. I've had my tdi for about a year now but have been having starting issues since last winter. I live in upstate NY. It is hard to start even if the temps are above 50F if the engine is cold. My local greasemonkeys don't have the knowledge to address the tdi, and have replaced the glow plugs, relay, etc. with no luck. Where can I go either on this site or otherwise for a hard start tutorial? thanks
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
If you have access to anyone with VCDS, you could learn alot about what is going on with your engine but you need to go over some basics like fuel quality and over all engine health.

Have you had the compression checked? Are you running the original injectors and injection pump? How many miles on these parts? How is the power? Any smoke? What is the maintenance history of the car?

There are lots of other questions folks will want to know to help you.
 

greenskeeper

Top Post Dawg
Joined
Mar 10, 2003
Location
USA
TDI
1998 Jetta TDI
hi. I've had my tdi for about a year now but have been having starting issues since last winter. I live in upstate NY. It is hard to start even if the temps are above 50F if the engine is cold. My local greasemonkeys don't have the knowledge to address the tdi, and have replaced the glow plugs, relay, etc. with no luck. Where can I go either on this site or otherwise for a hard start tutorial? thanks
above 50F (actually 40F) the GPs aren't even turned on.

when was the timing belt changed? if the timing is retarded it could lead to hard starting. find (or buy ~ best value) a vagcom to see what is going on.

how many miles? once started does the car have power without any smoke indicating a compression or wear problem?
 

maxwellp

Veteran Member
Joined
Oct 22, 2011
Location
VERONA, WI
TDI
1998 TDI Beetle
hi. I've had my TDI for about a year now but have been having starting issues since last winter. I live in upstate NY. It is hard to start even if the temps are above 50F if the engine is cold. My local greasemonkeys don't have the knowledge to address the TDI, and have replaced the glow plugs, relay, etc. with no luck. Where can I go either on this site or otherwise for a hard start tutorial? thanks

Does it start hard when the engine is cold? As in sitting over night.
Does it start hard when the engine is hot? As is just drove it 30 minutes, shut is off, 5 minutes later it is hard to start.
Is there any time that is starts well? (not using the spray)

Just trying to lay some ground work. :D
 

maxwellp

Veteran Member
Joined
Oct 22, 2011
Location
VERONA, WI
TDI
1998 TDI Beetle
I just installed a Malone Tuning Stage 2, Fixed my hot and cold start problems!!!
 

alphaseinor

TDI Innovator, Gone but Not Forgotten
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
My guess is fuel, or compression... your engine is a AHU, not an ALH, so keep that in mind.

Do you run WVO? if so it's probably an air leak, or some seal somewhere causing an air leak.
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
I'm sorry to all who have taken the time to try to help me that I haven't aanswered your comments sooner. I don't even know how to answer threads, I really have no experience with these forums, so bear with me...

If you have access to anyone with VCDS, you could learn alot about what is going on with your engine but you need to go over some basics like fuel quality and over all engine health.

I don't have that access. also, the computer won't recognize the scanner (or vise versa), which seems to be problem #1, becasue there's no communuication with the engine.
Any ideas about making the ecu read to the scanner?

Have you had the compression checked? Are you running the original injectors and injection pump? How many miles on these parts? How is the power? Any smoke? What is the maintenance history of the car?

I haven't had the compression checked because my local mechanics don't have specific tools for diesel. There is a dealer, about an hour from me, but that's about it. As far as I know, all of the parts you asked about are original, but I will go thru the past bills to be sure. (The previous owner kept great records).
It has great power for 300,000. One other interesting thing about it's mis-functions is that the odometer zeroed out around 5k ago.
Very little to no smoke, except on starting, and especially, of course, hard starts.

There are lots of other questions folks will want to know to help you.
Thanks again, whitedog, and everyone else. I think I have figured out how to respond to answers, and just changed the options for answers to come to my email address (had the wrong setting on).
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
One thing you mentioned about the electrical is that on the 98 Jetta, the odometer will reset to zero at 300,000 miles.

On the generation of cars after your, an aftermarket radio will cause problems connection to the ECU, but I don't know about your A3 generation.

Be very cautious of the dealer since they are known for not knowing much about the TDI engine. Be prepared to drive a few hundred miles to get to a knowledgeable TDI mechanic since they seem to be scarce in parts of NY. But mainly, don't fall back on the dealer to save some time. Often times they will do repairs that cost way more than a days wages than can be done for a small fraction of the price by a competent TDI mechanic.
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
Hi Greenskeeper, thanks for the input, sorry about not getting back sooner, besides trying to figure out my vehicle woes, I'm also totallly unfamiliar with forums and how to respond, post, etc, but I hope I've got it down now.

above 50F (actually 40F) the GPs aren't even turned on.

when was the timing belt changed? if the timing is retarded it could lead to hard starting. find (or buy ~ best value) a vagcom to see what is going on.

Unfortunately, one main problem is that the ecu wont register on the vag com at the dealer who said he needs at least 3 hours just to try and figure out whty it won't register! So I have no readings or hints about timing, etc. The previous owner claimed to have changed the belt, so that would have been about 20-30,000 ago.

how many miles? once started does the car have power without any smoke indicating a compression or wear problem?
I just got off the phone with the previous owner who said he swapped out the motor about 4-5 years ago with an engine that had 140,000 on it, so it probably has close to 200,000. he also put on a new (or perhaps rebuilt) turbo at the same time. He claims he religiously got 50mpg (this was about 3 years ago. I've never gotten above 40 since I've had it for over a year.)
Once running, I don't see any smoke.

Can I check the timing without using a vag com? can it be adjusted without special tools? do I need to also set the timing in the injector pump, as someone told me I would?

Thanks for your help!-kevin
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
Does it start hard when the engine is cold? As in sitting over night.
Does it start hard when the engine is hot? As is just drove it 30 minutes, shut is off, 5 minutes later it is hard to start.
Is there any time that is starts well? (not using the spray)

Just trying to lay some ground work. :D
Hi maxwell, thanks for the response, sorry to take so much time, I didn't see your answer until today!

Hard start only when cold, even in mild (50-60f) temps. Spraying worked fast, but now not at all. (just a tiny 'pfft!" would get it going). when the car cooled down in cooler temps (30-40), it would take a spray to get it going after sitting a few hours.

Runs good when warm, with intermittant power losses sometimes on demand. Bad mpg (less than 40). No compression test done, but has great power when running well, just bad mpg. No smoke after warm up.

can I check for a vaccuum leak or check the timing without using a vag com ?
thanks again., kevin
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
a3627849 said:
My guess is fuel, or compression... your engine is a AHU, not an ALH, so keep that in mind.

Do you run WVO? if so it's probably an air leak, or some seal somewhere causing an air leak.
Hi lphaseinor, thanks for the response. sorry to have not gotten back sooner; still tring to figure out how to navigate this forum.

what is the difference or significance of an ahu vs. and alh motor?

I do not use wvo, but the previous owner did who reported none of the effects I am experiencing.

Thanks again, kevin
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
One thing you mentioned about the electrical is that on the 98 Jetta, the odometer will reset to zero at 300,000 miles.

On the generation of cars after your, an aftermarket radio will cause problems connection to the ECU, but I don't know about your A3 generation.

Be very cautious of the dealer since they are known for not knowing much about the TDI engine. Be prepared to drive a few hundred miles to get to a knowledgeable TDI mechanic since they seem to be scarce in parts of NY. But mainly, don't fall back on the dealer to save some time. Often times they will do repairs that cost way more than a days wages than can be done for a small fraction of the price by a competent TDI mechanic.
I have a factory radio in the car, but it stopped working last winter when I changed the battery and never got the code to reset it.

Thanks for the heads up about the dealer. I don't know anything about their mechanic other than he is German and is supposed to eat sleep and breathe diesel. But I guess they all say that...
 

Nutsnbolts

Vendor , w/Business number
Joined
Nov 1, 2001
Location
Weare, NH
TDI
2000 Jetta, Silver Arrow
Kevin: Design-wise, the ALH and the AHU are very similar. They have the same displacement, but small bits are different, such as the way the engine mounts are set up, the turbo is a different type, the oil filter housing is different, and the ECMs are a different design. Either one is very durable.

WVO is not a good thing for these engines, due to the low combustion temperatures in these engines. High temperatures are necessary to consume WVO, so soot and sludge are left behind, which begins a process of degredation that ultimately ends when the engine can no longer develope adequate compression pressure, and will consume vast quantities of oil as the rings lose their ability to seal, because they seize in the piston as the sludge formed acts like a glue. The only option at that point is a rebuild. A compression test will tell you a bit about the rings and valves.

Unfortunately, without the VAG-COM, it is a bit difficult to determine what the overall running condition of the engine and its related bits are, and impossible to check its running timing, but the car certainly needs to be scanned, and the use of starting fluid needs to stop, or it will get very, very expensive.

-Rich
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
thanks Rich for the info, especially about the wvo, which I'm still interested in, but need to get the bugs out of the car first before I start screwing with something else...

I have been seeing a few posts regarding vacuum leakage. can this be checked without a vag com?
 

Nutsnbolts

Vendor , w/Business number
Joined
Nov 1, 2001
Location
Weare, NH
TDI
2000 Jetta, Silver Arrow
The AHU engine that you have does not have as critical a vacuum system as something like an ALH. In either case, it will not prevent the engine from starting, and with the AHU, there is no anti-shudder valve that can get stuck.

-Rich
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
so, without the anti shudder valve to get stuck, you're saying that vacuum could not be a problem regarding hard starts? In other words, even if it were not the valve getting stuck, could a vac leak in the engine effect starting in any other way?
Air in the fuel lines was also an interesting topic for hard starts here. One writer found that a badly connecting check valve between the tank and the pump allowed air to let fuel flow back into the tank after the car was shut off. I don't know if the AHU has one, but what are your thoughts about air being a culprit? Maybe not a check valve, but air somehow getting into the fuel line?

All of my problems may or may not be related somehow, but the car (at around 240k) doesn't smoke but does has power issues from time to time (especially after its been running for 20 mins or more). I can lose power in on-demand situations. I think shutting it off seems to help.
No smoke after warm up and plenty of power when its running good, just bad (40 or less) MPG. And, of course, hard starts...
thanks again, kevin
 

Nutsnbolts

Vendor , w/Business number
Joined
Nov 1, 2001
Location
Weare, NH
TDI
2000 Jetta, Silver Arrow
Kevin:

Correct. In your case, there is nothing that the vacuum system controls that will cause hard starting.

As far as losing power goes, that will be revealed in the scan. I have seen MAF sensors cause poewr losses, as well as over/underboost conditions that put the car into "limp" mode. This is why a restart clears it.

Air injestion is a good theory, but the presence of air must be checked and verified before throwing parts around. A bad thermostatic T on top of the fuel filter can allow air into the filter housing and up into the pump, but the way to test this would be to see if the car has trouble with a hot restart, or just a cold one.

Another source of air is the seals on the pump. If the distributor head seal, or the top cover seals are leaking (those are the most common) then fuel will be visible on the outside of the pump, and might allow the pump to with air while it sits. If you have bled the injection lines, and are getting fuel spurting out of them when they are cracked open, then air is most likely not your problem.

-Rich
 

greenskeeper

Top Post Dawg
Joined
Mar 10, 2003
Location
USA
TDI
1998 Jetta TDI
Hi Greenskeeper, thanks for the input, sorry about not getting back sooner, besides trying to figure out my vehicle woes, I'm also totallly unfamiliar with forums and how to respond, post, etc, but I hope I've got it down now.



I just got off the phone with the previous owner who said he swapped out the motor about 4-5 years ago with an engine that had 140,000 on it, so it probably has close to 200,000. he also put on a new (or perhaps rebuilt) turbo at the same time. He claims he religiously got 50mpg (this was about 3 years ago. I've never gotten above 40 since I've had it for over a year.)
Once running, I don't see any smoke.

Can I check the timing without using a vag com? can it be adjusted without special tools? do I need to also set the timing in the injector pump, as someone told me I would?

Thanks for your help!-kevin
To set the timing "by the book" you need vagcom to see where the timing is electronically. There is nothing on the pump itself to adjust like the older mechanical 1.6L diesels.

I'll probably get responses about this, but you could loosen the injection pump bolts and push the IP towards the engine until it hits the stop. The timing will be well above the "window" which is in vagcom, but it won't hurt a thing. You can't advance the pump enough to cause damage because the mounting bracket won't let you go that far.

I run my pump as far advanced as possible with the mounting bracket, and have adapted my timing to 5 degrees.

This would at least be a test to see if that will help with the starting until you can get vagcom to "dial it in" so to speak.
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
To set the timing "by the book" you need vagcom to see where the timing is electronically. There is nothing on the pump itself to adjust like the older mechanical 1.6L diesels.

I'll probably get responses about this, but you could loosen the injection pump bolts and push the IP towards the engine until it hits the stop. The timing will be well above the "window" which is in vagcom, but it won't hurt a thing. You can't advance the pump enough to cause damage because the mounting bracket won't let you go that far.

I run my pump as far advanced as possible with the mounting bracket, and have adapted my timing to 5 degrees.

This would at least be a test to see if that will help with the starting until you can get vagcom to "dial it in" so to speak.
Excellent. I'm going to check the timing tomorrow. If I need to adjust timing, I will consider trying this. Thanks again, kevin
 

kevinmcgrease

Member
Joined
Nov 22, 2010
Location
sullivan county, ny
TDI
98 jetta
Hey all
I have to give my tremendous thanks to sootwagen and 1tdi4u. Andy not only answered all my questions, but gave me innumerable links to sites for help to get my car going. Then both these guys made a one hour trip (each way!) to my house to help me diagnose my problem in the freezing cold.
Today they hooked me up to a vagcom, got the thing to recognize my ecu (VW dealer couldn't!) and adjusted my timing. so far, the car starts GREAT!
THANK YOU GUYS SO MUCH!!
 

sootwagen

Veteran Member
Joined
May 25, 2003
Location
Nowhere
TDI
None
Wonderful news. So what did they do to get the ECU to talk to VCDS?
We pulled the radio. The car has a Volkswagen radio in it, but it appears to be an older model radio. It was putting +12v on the K-line. After we removed the radio, we were able to scan the ECU with VCDS normally.

A scan showed injection timing so far advanced that it was off the graph. We adjusted the injection timing to the upper end of the range. We also replaced some dry-rotted hoses. There is more to be done, but hopefully this will fix Kevin's cold hard-start issues.

Membership in TDIClub is an honor and a privilege for me. I get a lot out of the club in the way of new friendships. I have met some of the nicest people on the planet through this forum. Being able to help other TDIClub members is my way of giving back to the TDI community.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
We pulled the radio. The car has a Volkswagen radio in it, but it appears to be an older model radio. It was putting +12v on the K-line. After we removed the radio, we were able to scan the ECU with VCDS normally.
For which the dealer wpould have charged three hours diagnostic. Well done all around.
 
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