Volkswagen Jetta Engine Questions



  • bpeeblesbpeebles Member Posts: 4,085
    There are only 2 possible problems

    1) Ignition system (sparkplug fireing issue)
    2)fuel system (injectors)

    I would bet that your ignition system is the culprit. I would start with new spark plugs/wires. (if you have the 2.0 engine)

    If you have another engine, there may not be sparkplug wires on it.
  • vwdawgvwdawg Member Posts: 162
    Hello: Does anyone know how to determine whether a 2.0 is an ABA vs. AEG? Thanks, vw dawg
  • bpeeblesbpeebles Member Posts: 4,085
    Please do not double-post your questions... this was already answered in another forum you asked it.
  • whitgallmanwhitgallman Member Posts: 121
    2000 Jetta VR6 has freaky headlight problem. The Left Low beam headlight does not work when the weather has been dry a couple of days but works OK if the weather has been wet. :cry:
    I've replaced the headlight switch on the dashboard, tested the light bulbs and fuses and run conductivity on all the wires going from the light bulb socket. Any body else had this problem? What did you find?
    The left headlight is near the battery, but the seals on the box around the left headlight bulb seem OK.


    Whit Gallman
  • 77camaro77camaro Member Posts: 4
    no codes at ecm and VR6 is supposed tobe good car plenty of power to coil but cant locat ecm signal at coil plug when turning over .2002 jetta VR6 sorry forgot to mension what car my girl is driving. :mad:
  • bpeeblesbpeebles Member Posts: 4,085
    Is there a relay for the HI/LOW beams? Have you replaced it?

    Also, I have seen headlight bulbs act funky like you describe. Try SWAPPING the bulbs from side-to-side and see if problm moves. (this will rule out the bulb as the culprit)

    If that does not help... you may have to troubleshoot WHILE THE PROBLEM IS HAPPENING to isolate the failing component.
  • dp2226dp2226 Member Posts: 28
    2002 VW Jetta 2.0 4 cyl 135,000 miles

    Car started to sound like it had a bad muffler.

    Two weeks ago check engine light came on and flashed. Garage stated wires were bad and plugs fouled so I had them replaced. They recommended the ignition coil as well but at $400 for just the part I pasted. Car ran fine.

    2 days later the check engine light came on again. I replaced the ignition coil myself. Easy repair. Put the plug wires back as they came out, number 1 in A 2 in B 3 in C 4 in D.

    Car seemed to be running fine, expected the check engine light to reset after 100 miles and it did not. Still makes that sound if you hit the gas when it is in neutral like the exhaust has a chest cold (only way I can think of describing it)

    There was a recall on the catalytic converter and was replaced at 85K. Took the car to auto zone and they said the code was for a bad ignition coil still. Unless the garage put the wires back in coil in the wrong, order I am out of ideas. I have the single ignition coil unit not four separate ones like on a V6.

    Out of ideas...O2 Sensors maybe? I did recently change my brand oil of oil from Mobile 1 Full Syn to Castrol Edge Full Syn. Probably grasping at straws at this point
  • bpeeblesbpeebles Member Posts: 4,085
    What SPECIFICALLY was the code they pulled out of your car?

    I am not sure there is a code that says "Bad ignition coil".... It sure looks to me that all of these folks are mis-interpeting what the code is telling them.... As witnessed by the fact that none of them have successfully diagnosed the problem yet.

    You did a great job of describing the problem and the steps you have taken thus far... perhaps if you tell us the SPECIFIC code, we may be able to help troubleshoot.

    The MAF (MassAirFlow) sensor on your engine may be going bad. An easy way to check the MAF sensor is to pop the electrical connector from it and let it dangle. (yes - this WILL cause the CEL to light up) Then start engine and drive for a few days. If things are better, then suspect the MAF is bad.

    Also, check the color of your ECT (Engine Coolant Tempararure) sensor. If it is not GREEN, replace it. (about $15 and the Oring) The ECT of that vintage are KNOWN to go bad and VW came out with a better design which is colored GREEN so it is easy to tell if you have the newer one installed.

    You cannot tell if the ECT is bad by looking at the guage on the dash because the ECT has 2 sensors within in.... 1 for the dashboard and the other for the EngineComputer. If the computer "thinks" that the engine is always cold, your engine may run like [email protected]

    Also, you should make certain that the engine is MECHANICALY sound. A compression-test may be a good way to validate that you do not have troubles with valves. (which could also cause this problem)
  • 77camaro77camaro Member Posts: 4
    you should not had paid for the coil there is a pending law suite against VW for the coils in jetta and golf also audi that uses same coil you should have done more research in the lemon laws.if you have any ?'s e-mail me. :lemon:
  • vwdawgvwdawg Member Posts: 162
    Hi dp2226: It sounds like bpeebles has a better grasp than anyone of the possible issues here, but I have a footnote to 77camaro's advice. I believe he/she is correct regarding the coil lawsuit, but I also believe that this was resolved with VW agreeing to a replacement of ALL coils of that vintage, and including reimbursement for repairs of defective coils previously replaced (with appropriate documentation). I had similar issues with my '02 Passat 1.8T. Get this resolved asap, as failure to do so could ruin your cat converter, a $700 repair item. Good luck. vwdawg/audiphile1
  • bpeeblesbpeebles Member Posts: 4,085
    Are you CERTIAN you are not thinking about the about COP (Coil On Plug) ignition-units on the which had a bad batch get into the mix? The status of the those COP units was ONLY if one failed, then VW would replace it.

    The 2.0 engine that we are talking about here DOES NOT have COP ignition-units.

    If there is something "pending" which you are refering to besides the COP units... please append some reference URLS that support that statement. I would be very interested to review those documents because both of my daughters have VWs of that vintage with 2.0L engines.
  • vwdawgvwdawg Member Posts: 162
    bpeebles: Not sure which system 77camaro was referring to, but I was referring to the 1.8T, which DOES use the COPs. I'm not familiar with the 2002 2.0, but I assume it's a NON-turbo, which would not use the COP units, right? If that engine does not use COPs, then you are very likely correct...I have not heard of any pending suits for the non-COP systems. vwdawg/audiphile1
  • jeffyscottjeffyscott Member Posts: 3,855
    BTW, there is now a recall on the ignition coils for the 2.5 engine...not sure what years are included, we have a 2005.
  • 77camaro77camaro Member Posts: 4
    there is a site you can check for recalls- lemon law volkswagen ignition coil when you go here the left margin has where you can plug in year make model engine etc. they will tell you of pending suites or if recall has been resolved good luck the dealer still has not released coils to me do to pending suit car has been down for over a month tired of putting used coils just ordered set of bremi's I just registered in suite to get reimbursed. :mad:
  • bpeeblesbpeebles Member Posts: 4,085
    The 2.5L engine uses COP (Coil On Plug) ignition units. Apparently, these COP units have been troublesome for VW.

    There is a reason that COP units are considerd high-tech.... each indivudual ignition-unit is plugged DIRECTLY into the top of the sparkplug. This means the COP unit must endure extremely high heat from the cylinder head. Heat and electronics do not mix well. (The heat always wins in the end)
  • bpeeblesbpeebles Member Posts: 4,085
    There are several websites that list recalls and TSB (Technicial Service Bullitens)

    My personal favorite is ALLDATA... but you may need to be a 'subscriber' to get all the details of each recall/TSB
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    If you have the # and date of the TSB I'll post the details for him.
  • dp2226dp2226 Member Posts: 28
    Here are the specific codes

    PO351, PO352,PO353,PO354 -I believe corresponds to each of the connections to igintion coil, slots A-D.

    Presently slot A has plug 1, B -2, C-3, D-4

    All wires and plugs are new

    The last code is PO302 which is misfire cylinder 2

    I know I do not have the green ECT so will grab one. The needle sits at 0 for as long as I can recall. Years. Was told that is just how they are. I will also unhook the MAF as well
  • daltonb40daltonb40 Member Posts: 1
    I own a 2000 Jetta VR6. I bought it at an auction and it didn't come with an owner's manual. The vehicle has 149,000 miles on it. I've been hearing that they don't have a timing belt on them but wasn't sure if that was true or not. Someone said that I should replace the belt. Does the car even have one though?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    No it has a chain, but these have been known to wear out (especially the guides and tensioners) on these cars. No need to replace it preemptively, but if you start hearing timing chain noise, get to it right away. Big job, not easy. At your mileage I would check for timing chain noise when the engine first starts in the morning. If you aren't sure what chain noise is, have a technician listen for you---if the guides break, you've got yourself a big mess.
  • bpeeblesbpeebles Member Posts: 4,085
    If you are seeing ALL those codes (P0351, P0352,P0353,P0354 )... and have new plugs and wires... all that is left is the coilpack itself. (or bad ground-connection to the coilpack) This is not an inexpensive part. I would personally consider a good used one from scrapyard if I could find one.

    BTW: I just installed a new (green) ECT (Engine Coolant Temparature) sensor in my wifes Jetta yesterday. Then I hooked up my laptop computer and reset all the codes. So far, the light on the dashboard has NOT come back on and the temparture guage has been working as expected.
  • suz18suz18 Member Posts: 1
    I have a 2011 2.0 VW Jetta, 16400 miles. Just had the axles replaced because the cv boots had slight tears. From the very first driver after they were replaced, I have loud noise when it reaches 38 RMP. I can not take it to 75-80 because the noise gets louder and you can feel it. My mechanic is confused. He then replaced the Rear Tranny mount (dog bone) because he noticed it did have more play in it then should have thinking this was the problem. He is now playing the guessing game. He even thought maybe the wheel bearing but it doesn't make the noise constantly. I do not have any $$$ to take it to the dealership. Help!!!
  • bpeeblesbpeebles Member Posts: 4,085
    The rubbers on the CV joints were torn at 16K miles.... OWCHIE... The only time I have EVER had such a problem is when porcupines were nibbling on them to get at the road-salt from the winter. Most vehicles will go well over 100,000 miles before CV joints need any attention.

    Some of the cheap rebuilt "aftermarket" parts will not perform nor last nearly as long as real VW components.

    If you are CERTAIN that the new axles were properly installed and are original GERMAN components... then I am sorry to tell you that what you describe may be INSIDE the transmission.
  • vwdawgvwdawg Member Posts: 162
    calivdub: If that noise was not there before the CV replacement, it sure sounds like the repair was not done correctly, or the replacements were defective. Has your tech gone back to make sure all bolts and fittings were properly tightened? Also, some vdubs have different axle lengths for each side, but I wouldn't think they could be mixed up. vwdawg
  • ndmike88ndmike88 Member Posts: 155
    Wouldn't your Jetta be under warranty? Its a 2011 with 16,000 miles. All repairs should be covered. Am I missing something here?
  • dnjettadnjetta Member Posts: 1
    I have the exact same problem as you. I just had my axle replaced because of torn CV boots and now there is a very loud loise at 3800 RPM. I am afraid to drive it on the freeway because it is so loud. Did they finally figure out what was wrong with it?
  • bravurabravura Member Posts: 1
    Hi there
    can anyone assist me on how to determine whether the 99 jetta engine is aba or aeg
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    The engine code and engine number (serial number) are die-stamped on the front of the cylinder block above the crankcase breather.

    In addition, an adhesive label on the drive belt cover lists the engine code and engine number.

    The engine code is also listed on the vehicle identification sticker in the luggage compartment.
  • shelfershelfer Member Posts: 4
    Car cut out. Spark and Compression are fine. Plugs are dry, so my diagnosis is lack of fuel...either plugged filter (or bad fuel pump) Car has about 140k miles on it and it looks to be an older filter (yes I know, daughters car for a long time that we bought foir other daughter). She usually had work done somewhere.

    Anyway, how does one release the fuel line connections? There are two very small holes on the connector - is there a special tool that goes in there or does it use the knid that goes in via the end of the line and spreads out the clip?

    In either case, is it a sized tool only for the German cars, or a standardized size.

    I've poked, probed and chanted...have yet to call a voodoo doctor or Mr. Spock to put the Vulcan pinch on it.

    Thanks in advance.
  • vwdawgvwdawg Member Posts: 162
    Hey All: 2006 Golf w/ 86k miles. Typical annoying VW electrical "ghosts". Locks are supposed to self-lock after about one minute if no doors are opened (safety feature which re-locks the doors if unlocked due to remote "unlock" button being inadvertantly depressed). So...prob is, I assume, that the sensor on the driver door latch has failed, so the self-lock mechanism doesn't know the driver door has been opened, and the automatic locking activates anyway. Very annoying, and also presents the issue of the keys being locked in the car if you leave them inside (as my son discovered a few months back). All this to it possible to disable the self-lock feature? I have access to a VAG-COM. I would just as soon NOT spend $200 for a new latch plus several hours of labor tearing the door apart. Or am I on the wrong track here...some other solution that might be offered? Help! Thanks...vwdawg.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    edited May 2012
    You should be able to pop the cover off the fuel pump---then briefly crank the starter motor or have someone do that (work safely!). You should hear the fuel pump start up audibly. If it doesn't, then I'd check the fuse circuit for the fuel pump (I think it is #G6) and if that's okay, then the fuel pump relay is suspect.

    You can also check for fuel in the fuel rail by depressing the little Schrader valve under the hood (wear safety glasses to protect your eyes).
  • bpeeblesbpeebles Member Posts: 4,085
    I can pretty-much GUARANTEE that your no-start problem is not caused by fuel-filter.

    You should be able to hear the fuel-pump run for about 3 seconds if you turn the key to "ON" without cranking the engine. (Some older VWs even pre-pressurized the fuel-system when you opened the drivers door... I know my daughters Gulf did that)

    Also check fuel-pump fuse and relay.
  • shelfershelfer Member Posts: 4
    Actually figured out how to undo the clips-

    Careful scrutiny and voodoo (with chanting) revealed that the outermost portion of the clip, directly across from the two pin holes was indeed a small button (raised about 1 mm high) which relased the grip on the fitting. An interior panel tool worked well to remove the line.

    After a voltage test on the wiring on the connector to the fuel pump (the two outermost wires) revealed that the voltage was getting to the connector.

    The pump did not hum, so I have taken it out, and then connected it directly to the battery, with the wires attached to the pump itself.

    Chanting and more voodoo did not bring it back to life.

    Thus, a new fuel pum, with gauge float and rheostat has been ordered and should arrive in a day or so.

    I will certainly post if this was indeed the culprit when it it returned to life, as I hate diagnostic threads without conclusions and eventual success.

  • shelfershelfer Member Posts: 4
    OK. It was indeed the fuel pump. However, for 2004, there are appapently 2 diffent size flanges on teh top of the fuel pimp where it goes into the tank. One measures about 5 inches across in diameter, the other is 5.5 in diameter.

    Of course, I ended up getting the wrong size off of an online order, so I disconnected the float and wiring from the new unit as well as the fuel lines and connected them to the old top flange.

    Cost of new pump was $80 on line, much better than via a parts house around here where pirices ranged from $218 - $308.

    Reinstalled it and away we went (of course I tested it for hum prior to putting it in the tank - older unit had no hum at all, see earlier post).

    Car has much better acceleration now than it has had for some time, leading me to believe that the fuel flow volume was down or just that the pressure was not coming from the pump as it should have been.

    For those that wish to test the unit in the car also - the outermost wires on the connection plug are the ones that power the fuel pump. You can check for current with the key on at that point (Seeing if the relay is still supplying power.)

    I would also guess that one could bypass the relay in order to run the pump in an emergency situation if the relay was bad.

    I put my findings out here so hopefully they will aid someone else in the future.
  • heyjack1heyjack1 Member Posts: 1
    My wife washec the car the other day and sprayed off the engine and now is running rough and now the check engine light comes on and flashes for a couple seconds and then stays on and just keeps repeating. Someone please tell me what is wrong. We love this car to death and dont want to get rid of it.
  • shelfershelfer Member Posts: 4
    You should be able to go to a Kragen, O'Rielly or Autozone and they can pull the code. My guess is that it is an igniter problem. (P03xx) with xx being the cylinder where the igniter is shorted out. The igniter swap is relatively easy just don't force the connector. The part is much cheaper aftermarket than it is at Volkswagen if that is indeed the problem. Let me know if that does the trick!
  • vdudzz84vdudzz84 Member Posts: 8
    Someone please tell me if air coming out of the oil tank is normal? Guy at Valvoline said it's normal.
  • bpeeblesbpeebles Member Posts: 4,085
    I have been fixing vehicles for many years.... but I am not sure what you mean by "Oil Tank".... Please be specific.
  • vdudzz84vdudzz84 Member Posts: 8
    So i have air coming outta my oil valve. When the oil cap is loose it bounces around. I went to Valvoline and they told me it's normal for jetta to do that. It seems kind of odd to me. I work to late in the day to make it to a vw machanic so i have no idea if this is a problem.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Oh you mean you have pressure in the crankcase? Yeah, that could be a defective PCV valve or "oil separator" (fancy name for it).
  • vdudzz84vdudzz84 Member Posts: 8
    I was told that my car doesn't have a pcv valve? This is my first VW so I'm not 100% with it yet
  • vdudzz84vdudzz84 Member Posts: 8
    Ment the oil valve. Crank case
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    maybe they call it an oil separator.
  • vdudzz84vdudzz84 Member Posts: 8
    Is there a way to test to see if the oil separator is junk?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Let's back up. Tell us the year, model and engine you have, and what your symptoms are.
  • vdudzz84vdudzz84 Member Posts: 8
    I have a 99 aeg 2.0 vw jetta. I just had a full tune up. When i bought the car it had been sitting for 6 months. Right now my oil light stays blinking. I have a lot of air coming out of the top of the oil valve where the cap is. Loosing the cap and it dances sort of speak. It alsogoes thru oil like crazy. I had an oil change 3 week later it was bone dry. It has 119k on the motor.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    edited June 2013
    THIS MIGHT BE what you need.

  • bpeeblesbpeebles Member Posts: 4,085
    Your VW engine does *not* have a "PCV valve" like many American-Named vehicles. Instead, VW uses a simple oil-separator which attempts to keep the oil in the crankcase while allowing air to escape into the intake manifold

    When you loosen the oil-fill cap, you are simply allowing some of the excess pressure to escape so the oil-separator does not have to work so hard.

    Unfortunately, there may not be any way you can replace external parts to fix the problem you describe.

    Your description sure sounds as if you have a SERIOUS mechanical problem with your engine. There is sooooo much blowby past the piston-rings, the oil-separator cannot keep up with the amount of airflow past it.

    The blinking oil-lite is another indicator that the engine is in SERIOUS trouble. This means that the oil-pump cannot build up enough pressure to protect the engine.
Sign In or Register to comment.