how to troubleshoot TDI ALH boost/smoke/power problem?

Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by speedy223, Aug 4, 2017.

  1. speedy223

    speedy223 New Member

    Joined:
    May 13, 2013
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    Car:
    98 new beetle tdi
    Have a 99 TDI ALH 5 spd New Beetle. right at 300 k. Timing belt 50 k old. Has upgraded turbo at timing belt change ( a mild BW upgrade from kerma from their 150 hp package), also stage 2 clutch. upgraded map, new maf, kerma tune and Bosio DLC 1019 injectors. all tuned in. has run like a dream for the wife since done. out of the blue it lost power and started smoking like a toad. also was a bit hard starting and then real hard starting. I changed fuel filter, and also starter which fixed slow starting problem but not power and smoke issue. I know something is wrong even though it still scoots along and its STILL better than stock it is not even close to what it was capable of and the smoke is way increased under heavy foot. I noted my boost gauge will now peak at 15 to 16 psi whereas it used to spike to 23 -24 quickly and then level at about 20 when you really romped on it. it also seems to build boost slower. takes longer to hit 15 in other words. used to jump right up there. I have worked on it for some time now and am wondering how to narrow this down. I have VCDS. IQ is at 4.9ish. Injector timing is right at midline where it always has been since timing belt. verified today. again. On some of my hard 3rd /4th gear runs on hill I lose boost and have to cycle key to get it back. sometimes pops code when that happens but only for that.

    I noted a bit of a hose dilemma where the hose exits to turbo to intercooler and repaired that. need to upgrade to proper stuff but have not yet needs custom lines since no kits for new beetle with upgrades. sigh . it has run 50 k no problems but noted a small leak in line at exit. replaced hose with satisfactory temp one clamped down drove it no leaks there at least obvious ones and no improvement. intercooler looks ok no oil etc but not sure if that is good enough. very disappointing thought for sure that was it

    it really looks sound as far as boost lines are concerned after repair but not sure if the leak is happening when engine torques under load but shouldn't there be oil at leak site if that's happening?
    I guess my question is what does this sound like? how would you troubleshoot it? last time I took it to a shop in Ft worth that was allegedly reputable I got hosed by the sloppy job and insane prices for my prison shower repair job and really would prefer to look at this myself. I did the timing belt and the turbo and clutch and have had the front end off and on 50 times so pretty familiar with the cursed Beetle holding the blessed TDI and wish the wife would drive a jetta like me lol... any advice on how to procede would be greatly appreciated.

    will VCDS tell me anything? Requested and actual boost seem to match, IQ is ok, timing is ok? what if any data would help me narrow this down? not sure how to interpret N75 duty cycle
    In summary:
    what could be causing the boost to be a bit slow to climb, peg at 15-16 or so instead of usual 20' and it feel slower and spit smoke. also sometimes on my trouble shooting runs it suddenly chokes in 2nd gear rolling out of a slow turn and then suddenly comes on line again which has never happened before. Then it is consistently every time slower in 3rd upwards with the smoke, lower power and lower boost but only if you are romping on it going slow and easy it feels almost ok. should I just buy/make a boost leak checker and run it up to 20 psi or does this sound like it could be something else. the lines look good after repair. Also it is running hotter I am guessing egts are soaring with the heavy smoke and I am trying not to overdo it or damage it so limiting my test runs and letting it run easy afterwards...
    any advice on troubleshooting this efficiently would be appreciated.
     
    Last edited by a moderator: Aug 5, 2017
  2. speedy223

    speedy223 New Member

    Joined:
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    Car:
    98 new beetle tdi
    just ordered a boost leak checker. will update when I get it. sure would like to know if there is anything else I can check or log in the meantime since visual inspection is not showing any problems with the lines. thanks again.
     
  3. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    anyone have any ideas of something to check till i can pressurize boost lines with my adapter ? is there any other vcds or other things to check ?
     
  4. crsmp5

    crsmp5 Well-Known Member

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    imo no oil residue no leak...pull you ccv/pvc pipe off and go round the block and look at the oil residue it will leve in 5 min from the vapors... that same oil goes thru the ic system.. and is the cause of oil residue... and when it has a hole.. it uses it as a releif type valve and escapes when under boost

    smoke machine will be interesting... but.. ya know... unless you pull the cam or block off the upper ic pipe at the manifold.. you will be loosing smoke thru the valves/crankcase... next if you really really think its a leak... can wd40.. with car running.. spray it in a way where its fumes not liquid can get sucked into the area.. like a gas car looking for a vac leak, wd40 will effect how a diesel runs.. does not take much.. just a good wiff.. and any changes in sound/way its running will reflect its a leak.. id only attempt with wd40... and done wrong can damage your car!!! so at your own risk..
     
    Last edited: Aug 5, 2017
  5. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    ok, thanks for the reply. i kind of felt the same way, seems like it should show some residue. this will be neat to see when i get it pressurized. i ordered a part yesterday to be able to do the boost leak check, to lazy to go try to piece one together. on that note, it was hard starting again today. feel like yelling at it. it would not crank from cold. i mean would not. took about 7 tries with wait intervals seemed like an hour but then it finally cranked. then after that it cranked/started every time pretty readily. this is all from a car that has run flawlessly up till like a week ago. even though i have experience with part installs on these since i did all my own work this is really the first one that just kind of broke down, so troubleshooting is kind of new to me. any advice in logical progression of troubleshooting the above mentioned problems still appreciated.
    new fuel filter, always run diesel kleen in it, newish injectors, newish turbo, air filter good not the bug screen, egr was deleted. once it starts seems ok until you need boost. new starter, new battery, kind of sick about the starter thought for sure i was onto something there. VCDS showed 150's rpm when it was cranking so i figured it was bad and then seemed to start fine after replacing it but about 5 tries later and that many days back to the long crank poor start first time of the day and then less than adequate boost when under load. surely boost issue not related to starting but both appeared together?
    any advice will be continually appreciated as i learn to troubleshoot the tdi.
     
  6. crsmp5

    crsmp5 Well-Known Member

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    1st off diagnosis vs changing anything..... do not touch that fuel filter... it can cause other issues then you have to resolve multi things...

    now.. you say no crank...

    lets get your wording first... as i am lost... so for a hour you turned the key and nothing happened.. no clicks, no engine turning nothing??? just like no batt in car... thats what no crank means... and again i see no reason to keep doing this for a hour.. why i ask

    no start... this would mean your turning the key, the engine is turning but not starting/running on its own..

    so lets define what you mean so i can assist from this point..
     
  7. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    no. sorry been a hot day in east texas and i have been working on my spare car getting it ready to come out of retirement since this one is acting so unreliable. i mean it turns over. and over and over wont start. sorry bout using "no crank". should know better.
    when all this started it went from perfect car to monster sort of instantly. the first symptom was hard to start meaning cranked forever and finally started. i checked on here, all my fueling seemed good, i changed fuel filter since it was 20 k old and still kept being hard to start, cranking forever. i read it could be starter not turning fast enough. swapped battery to test, no joy, noticed it would fire better if i had extra juice on either battery so figured starter was old.Cleaned every line, ground, did voltage drop tests on starter lines all within spec. checked vcds log i made and starter was turning about 150-160 rpm which was allegedly slow. so i changed it and the battery since i needed a new one for another project and i donated the new battery and starter to the wifes car. started pretty good, thought hey it's resolved. on test drive then noted that it was not boosting right as described above. wife would never notice since she drives it at about 55 everywhere she goes lol.
    after fixing boost leak i did find still no joy with boost above 15 psi on guage. also slow and tons of smoke. as above.
    then to make matter happier today i went back out to mess with the lines and double check and lo and behold it would not start. cranked and cranked and cranked with appropriate rest intervals and finally it caught and started. seemed fine again except for boost issue. once it warmed up it cranked right up again. i checked connector on fuel filter does not appear to be leaking and once it starts it runs ok again except for when you need more boost at highway speeds.
    so now i am wondering are these things related? does not seem right and the start thing has been intermittant. some days fires right up since starter change, today back to one hour of refusing to.

    i do plan on doing a thorough boost leak check when that adapter arrives but in the interim what would you gurus do? if this was your car what would you do. i appreciate any info as again i am kind of weak on troubleshooting these since that was my first tdi and it has never broken and my daily driver similarly has just kept right on ticking wiht no problems.
    i have VCDS so should i be checking anything on there? should i just wait for my boost leak test at 20 psi. what could be causing the hard starting? new starter, battery, good cables. changed that bs relay with a spare thinking that might be it. i really am stumped. if it is air leaking in my fuel filter how would i tell. i dont have clear lines on return thinking about getting some though.

    again any advice greatly appreciated. i promise to update this with any relevant fix info as this forum has been beyond invaluable to me when i did the timing belts and all that the first time round not to mention when i had to trouble shoot no ac on my jetta and myriads of other things.
     
  8. crsmp5

    crsmp5 Well-Known Member

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    ive had many people pull the it does not crank thing when they mean does not start... why i know to ask when stuff is confusing... better to act stupid at times and ask then assume...

    using the vagcom look and watch the crank sensor... when they fail the computer will not set off a light as the computer does not know your cranking it over...

    so is it a common let it sit over night/first start of day issue?? what id do.. rig up a jerry can via a can of lubramoley diesel purge.. napa sells it.. couple zip ties and couple pieces of hose it will even sit under hood so you can go round the block... why... the jerry can removes the fuel system from the fuel pump.. alge/check valves, fuel filter so on are all tested by this... if it starts normal.. after trying this... start at float unit removing it looking to see if screen plugged up... then onto check valves... at this point id run the car.. see if anything messed up... note.. have not said to do anything with filter yet...

    is it now fixed?? if not its not the fuel system so can skip all following typed words down to the "no jerry can did not fix" area... and its not the filter so saved some $$ as its pricy

    alge will cause a restriction that causes the fuel to suck back into the fuel tank... this drains the pump causing starting issues... if not... on the bank of the fuel pump to injectors (points at #2-3 injectors).., there is a bolt head on the side of the fuel pump... cannot think of its size... 13/14/15mm... remove it and look inside the hole did it leak fuel out or is there a lack of fuel?? if lacks fuel... not making a mess an not pouring dirt in the hole fill it up with fuel... get car good and warm... now change the filter...

    that "inspection" port looking for fuel is a "dirty trick" of mine... :p but it tells you if the pump is sucked dry of fuel...

    why filter last.. ive never seen one plug up vs pick ups/check valves... makes it a pain to reprime the fuel system from big pocket of air the filter causes if alge plugging up other stuff... i tell people the only time you change the filter is on a perfectly running tdi (changing on broken one sux so bad)... as that plastic return piece can fail sucking air.. which it may be but changing the filter and it sucking air from the filter change as yes you replace both at same time... but alge plugging up other stuff is bigger question..

    ok no the jerry can did not fix... now its a pump/electronic thing... or some mechanical issue preventing air flow.... like stuck turbo, plugged cat, plugged intake, oil logged ic... but see how i go thru diagnostics?? vag com first to check cps then fuel system then into the shit with electronics/lets get dirty
     
    Last edited: Aug 5, 2017
  9. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    outstanding. thanks for the advice. just the kind of gold i am looking for. i will sure give this a whirl tomorrow. now you mean just use the lubramoley diesel purge no diesel...just verifying that is what you meant. it can run 100% lubramoly safely for the test i guess is what i am tryiing to verify..just making sure you didnt mean just use that size container with diesel in it....

    i will look up how to check crank sensor as well and check that also. forgot these things have one...
     
  10. crsmp5

    crsmp5 Well-Known Member

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    yup diesel purge is meant to run 100% pure.. yes you can use diesel also... but diesel purge is intended to be used as a jerry can to clean the pump/injectors... its also in a nice clean can to not need to worry bout dust/dirt in bottom... couple feet new rubber hose stuck side by side in the top of the can, feed one goes to bottom of can.. i like to drive it thru the rpm range vs sit/idle so i know the injectors get a good flow how i know the can zip ties to the ac hose real well.. :p as it sits on the other ac hose..

    if you use diesel in a other type can.. if you cannot be sure its dirt free use a bug/mower type gas filter as dust/dirt bad in pump..

    what i do know.. vagcom hates you trying to crank it so its a monitor type thing.. i suggested said test to a guy one day and they ****ed with it long nuff to see it failed to count so changed it and issue resolved.. but what he was looking at not sure.. just know it can be done :) he basically used vag com every time he went to start car and compaired the #s between hard to start and fired right up..

    i find crank sensors fail like batts... either very hot out or very cold out right after a really cold/hot day.. in opposite temp direction.. aka 90*f day.. 35*f at night... its like the plastic expansion of the wire/sensor cases a break in it... be it gm/vw/ford honda so on... and none of them set of check engine lights as none can tell the engine is turning over... how i thought up the does it count test on vagcom as generic readers for other car companies fail.. that guy was so cheap he refused to change it unless jhe knew 100% bad
     
    Last edited: Aug 6, 2017
  11. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    by the way guys i have not given up nor have i forgotten to update, however work is desperate for help and i have been doing some semi mandatory OT so will get back on it first chance i get probably this weekend. i do have my boost leak checker ready to use and a jerry can set up and hoses ready to put on. will certainly update when i get a chance to work on it.
     
  12. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    ok. so still have not done boost leak check will update with that but wanted to move it to the shop to work on the slow start issue and it took forever to start after sitting all week, cracked some lines by injectors and it started acting like it wanted to start after prolonged cranking with appropriate rest intervals. so skipped ahead to the jerry can, rigged one up both hoses in jug, cranked some more while cracking lines and bleeding out air and it started. started right up every time after that. will check it again in the morning to see if it cranks up and if it does then problem is definitely before injector pump which seems almost certain.
    so now to highlight my ignorance where and how do i access the screen by the float and where are the check valves and how do i test them? i will also try to read up on this tomorrow but if anyone wants to chime in it will as always be appreciated. I will update tomorrow to confirm it starts right up (still in jerry can setup)
     
  13. speedy223

    speedy223 New Member

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    Car:
    98 new beetle tdi
    this am, took two pretty long tries to start. still in can. did start. took front clip off in prep to change the condenser and will have front end off shortly . did a boost leak check and ominously would not build over 8 psi the loudest hissing sound sounded like it was midblock on front. that cant be good. i cant tell where since it is the awful beetle and you cant see or reach jack with the front end on. will be updating when i verify where it is but now starting to think the head might be blown and that is the source of my ever growing boost leak. wish me luck and please chime in if you have any ideas/tips.
     
  14. speedy223

    speedy223 New Member

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    98 new beetle tdi
    engine is out, it has been needing this for some time. i will update when i find the leak, have 100 small hard to reach jobs to do while i am at it.
     

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