How do I test my fuel injectors?

+ Reply to Thread
Results 1 to 6 of 6
  1. #1
    4th Gear
    Join Date
    Aug 1999
    Location
    Aurora CO USA - '03 2.7T A6
    Age
    49
    Posts
    2,800

    How do I test my fuel injectors?

    So after many years of never having a problem, suddenly my '99 1.8T 5 speed Passat is starting to shit the bed.

    For months now I have been tracking down a vac leak that is causing a CEL and throwing a code of 17544 - LTFT Add. Fuel Bank 1 too lean blah, blah, blah...
    To this date I still haven't figured it out even through I've replaced every bit of rubber that has anything to do with vacume or fuel.
    As a side note, when I try and do a test of block 071, the fuel tank leak test, it aborts right as it begines the leak down part of the test. The leak detection pump goes through all of it's bumping and whining noises and then nothing. It just says, "Test Aborted." Why?

    But now I have something else that is even more frustrating. When under WOT the car now bucks and shudders. And usually only in third gear when the boost really starts to rise. I have checked to see that the ICM is in fine working order. And it is. So I'm think that this problem is a fuel related issue and not spark related, because the bucking only happens when I really stick my foot into it. Just runnning around town at about half throttle produces no problems. It's only when I go to full throttle that it shudders. And of coarse this causes a Flashing CEL. Not good.

    The code is in two parts:

    #1) 16684 - Random/Multiple Cyl. Misfire Detected - Intermittant

    and

    #2) 16686 - Cyl. 2 Misfire Detected - Intermittant

    Also, I have checked the spark plug in cyl. # 2 and it seem fine. I just replaced them about 2 or 3 months ago. Their coloration looks normal.

    This all leads me back to a fuel injector not working properly. I looked around the base of the injectors where they fit into the manifold and suprisingly there is no leaking coming from around any of them. That never was an issue with this engine like it has been with other 1.8Ts.

    So, how can I test the fuel injector to see if it is within specs? And what are the specs I should be looking for? I did a search this morning to see if I could find anything in the forums, but no luck.

    again, HELP!!!!

    The bucking is getting very bad now and the car isn't very reliable at this point and I need it to be.

  2. Remove Advertisements
    VW Passat Forum
    Advertisements
     

  3. #2
    PassatWorld Staff
    Join Date
    Jun 2002
    Location
    Albuquerque, 1.8T A
    Posts
    12,267
    Hey, Chas, what up?

    1) Don't you have a Bentley? If you do, it has a procedure for checking the injectors.

    2) Did you ever read my Horrible, Fluttering Misfire post? Given that you have a cyl 2 misfire code, you should immediately swap that coilpack with a different cylinder and see if the misfire follows the coil pack.

    3) My money says it's not a fuel issue. Betcha it's the coil pack.

  4. #3
    4th Gear
    Join Date
    Aug 1999
    Location
    Aurora CO USA - '03 2.7T A6
    Age
    49
    Posts
    2,800
    Well guess what, the all knowing and wise Rusty was correct. Even before I got back on line to see if anyone responded to this thread I started to think this through all the way. The word Misfire kept giving me pause.

    At first I thought it had to be a fuel related/boost issue because it only happened under higher boost times. But if the injector for cyl. 2 wasn't feeding enough fuel, then it wouldn't be a misfire, but a lean condition and a different code would be thrown. And block 032 second field would show something too I bet. But that still hasn't changed for months now. Believe me, I know. I check it weekly.

    So then I got on the phone with my buddy at the parts dept. at Tynann's VW. With his help and some proper thought, we desided to try the coil pack switch out test. And sure enough, when I changed coil pack 2 to the 3rd cyl. bad stuff started to happen with cyl. #3. So I installed a new coil pack I bought from Tynann's and Whammo! New found power! Ok, maybe not new power, but I found the lost power let's say. The tires aren't going to be happy about this!

    Anyhow, Thanks guys and thanks Rusty. Even though I didn't look at your reply until after I figured and fixed out the problem you came through again!!!

    So why is it always cyl. # 2 that fails? It was that way with the stupid IMC when it failed too.

  5. #4
    5th Gear
    Join Date
    Mar 2003
    Location
    Louisville, KY
    Posts
    6,172
    Cyl 2 is directly in-line with the throttle body, and gets *slightly* more air than the other cylinders (runs *slightly* leaner). Since leaner=hotter, the plug and coilpack are exposed to slightly higher temperatures. Even if all the crappy coilpacks are destined to fail eventually, the warmest coilpack is likely to fail first.

    No idea why the ICM also prefers cyl 2.

  6. #5
    4th Gear
    Join Date
    Aug 1999
    Location
    Aurora CO USA - '03 2.7T A6
    Age
    49
    Posts
    2,800
    OK, that's it. I want my last 45 minutes of my life back Rusty!

    I read that 6 page nightmare and I forgot I did contribute (word used loosely) to that thread.

    It's funny, before today I was thinking it was a DV issue as well. I even went as far as rebuilding my Forge unit two different times and then finally replaced it with the old stock unit. Which by the way still works fine. I need to get the Forge DV back into the mix. I don't think the stock DV likes all that extra boost.

    I'm pretty happy about getting this issue fixed. I'm still fighting with the LTFTs being all whacked. But I'm starting to think it might be related to that leak detection pump somehow. Or maybe the N80 Evap valve. Eitherway, I'm sure it's going to cost me some more money.

  7. #6
    PassatWorld Staff
    Join Date
    Jun 2002
    Location
    Albuquerque, 1.8T A
    Posts
    12,267
    Quote Originally Posted by Chas
    OK, that's it. I want my last 45 minutes of my life back Rusty!
    LOL! I want the six months (that it took me to fix it) back!!! Glad you figured yours out so fast.

  8. Remove Advertisements
    VW Passat Forum
    Advertisements
     

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Powered by vBadvanced CMPS v4.1.2