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VW MKIII-A3/B4 TDIs This is a discussion about MKIII-A3/MkIII Jetta/Golf (<99.5) and B4 Passats (96,97) TDI's. Non TDI related postings will be moved or removed.

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Old February 19th, 2018, 06:26   #1
mustangmarty
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Just finished changing the timing belt and cleaning out the intake ports and intake manifold. My injection pump was leaking so I replaced the head seal and the top two seals while I was at it. Also I turned the motor over several times manually to make sure the pistons weren’t meeting the valves. Engine is running rough now. I don’t have a Ross Tech cable. But I do have an ObdEleven which showed my IQ at 1.6 to 1.8. Will this cause the engine to run rough?
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Old February 19th, 2018, 06:33   #2
oilhammer
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Recheck your physical cam and pump timing. Is the engine smoking or making noise?
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Old February 19th, 2018, 06:44   #3
Mongler98
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big 10/4 on oilhammer's (check your timing marks). If you did not move the IP, then you should be fine on the timing advance but if your a tooth off, it will run like crap. i always have to adjust my belt at the cam a tiny bit to get it just right.

as for the IP, might be a bit of air left in it?
1.6-1.8 is low, my AHU does not start to idle rough until 1.2-1.4 so..... that might be the issue, bump it up to 2.5 and see if it runs good.

Let me ask you a few things, Exactly HOW did you clean the head's runners?
hope you did it right so that nothing got past the valve!
DID you do the cross pin sequence on the IP with the cam fully extended when you changed the IP head o'ring? if you did not, you dropped the washer off the cam and your ip needs to be pulled apart and fixed.
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Old February 19th, 2018, 07:17   #4
iluvmydiesels
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i dont think IQ directly relates to your both static,ie- mechanical and/or injection timing. if static timed, that is crank and cam @TDC, pin in inj pump, thats the TDC static mark, set belt tensioner, (there are a few other steps), tighten cam bolt, etc, to turn engine over by hand, at least 2x(@-crank revolutions). after this start up, it shouldnt run *that bad, in fact it should (appear) to run just about normally. you need the vag-com cable and laptop and set inj pump timing. at this point its a guess, correct pump timing may correct the rough running. then again rough running is also an easy symptom of air infiltration in fuel system. other place to check is the pump work that you just did. is air getting in there, the seals you just re-did?
i doubt bumping IQ off the info youve given is a good starting point. either pump timing(re-check your mechanical timing first), or air in pump. seal job you just did. another thing, how long did you let motor run, can take a few minutes for an opened system to purge all the air out. esp if you opened pump, let idle for a few more minutes and see.(??).
the ross-tech cable is a little expensive, to say its more than a little expensive. you can try the partsplace cable if you want. i dont know personally as far as if PP cable works ok, i have a ross-tech cable, so that i know.
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Old February 19th, 2018, 07:42   #5
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I did not move the IP since I used the lock pin. There are small air bubbles in the fuel line going to the pump. I did bring the IP head out and back in with the criss-cross pattern to maintain pump head alignment. I also made sure the cam was fully extended to keep full tension on the head. I cleaned the intake ports with walnut shell blasting one port at a time with both valves fully closed and the other ports sealed so nothing would get in them. I made sure to get all the media out of each port before moving on to the next. I also have an open downpipe at the moment if that makes a difference.
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Old February 19th, 2018, 07:50   #6
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small air bubbles are normal in the clear section, ditzle mod or nictane kit fixes this if you want but its normal otherwise. a set of self made plastic scrapers from dinner ware is best, with a shop vac and some brake cleaner is best to clean the head when still on the block. if you were careful like i was, im sure what you did was fine. when cold, the QA should be 6 ish and when warm, 2.5ish
make sure your electrical connections are solid, i made that mistake before, the IP was not fully clipped in on the 12 pin.

probably air though. run it for a few minutes and if it does not clear up, hammer mod a few more points on the QA. sounds like your timing belt job was fine. i personally would have not used walnut shell, soda blasting would have been better!
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Old February 19th, 2018, 07:59   #7
mustangmarty
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Never heard of soda blasting. Looks like it’ll be awhile before I can afford a Ross Tech cable. Muffler shop just hit me with $200 to weld in a new exhaust flex pipe. And I already had the flex pipe!
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Old February 19th, 2018, 08:08   #8
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Quote:
Originally Posted by mustangmarty View Post
I did not move the IP since I used the lock pin. There are small air bubbles in the fuel line going to the pump.
the small bubbles i think can be an indication of a leak anywhere either in/@ pump, or fuel line/system. as you just replaced seals id start there. one way to to try is use spray to find a leak, if it seals(temporarily as you spray right in leaking area) engine will run better. i doubt in this case you use brake cleaner, perhaps wd40, or similar, something not -very combustible and mild. in this case not necessarily it will either (temp)seal leak, or you will get a report that you will notice, ie a smoother running motor, perhaps worth a try.
when you change a timing belt the pump timing doesnt stay where it was at prev belt. almost always it needs to be adjusted(VCDS, or vag-com), 100% of the time it needs to be checked(again its VCDS). in the old mechanical diesels you could get away, if you were really good, at 'hill-billy' timing. however even here the pump timing will almost certainly need to be adjusted, and to stress that proper static/mechanical timing steps using *all TDC marks is the best method. and will cause the least chance of problems, and if you do it correct you know your timing is right.
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Old February 19th, 2018, 08:11   #9
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Quote:
Originally Posted by iluvmydiesels View Post
as you just replaced seals id start there. one way to to try is use spray to find a leak, if it seals(temporarily as you spray right in leaking area) engine will run better. i doubt in this case you use brake cleaner, perhaps wd40, or similar, something not -very combustible and mild.
(*bulb)-idea, put diesel or fuel conditioner in a spray bottle and try this.
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Old February 19th, 2018, 08:14   #10
mustangmarty
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I had all TDC marks spot on. Fly wheel, injection pump, and camshaft. In fact before I even started, the camshaft was one tooth off, which I corrected when I put the new timing belt on. I’ve been letting it idle till full operations temp and kept it running another half hour. No difference.

I’m gonna do a compression test later today too.

Last edited by mustangmarty; February 19th, 2018 at 08:26.
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Old February 19th, 2018, 08:38   #11
Mongler98
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i can send you my vag-com cable, for loan, you pay shipping and ill send it to you, provided you send it back lol. PM me
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Old February 19th, 2018, 08:41   #12
iluvmydiesels
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so you removed the camshaft gear off of the camshaft when you started timing job, correct?
'one tooth' off @cam gear is a lot, valves get really close to pistons, they do anyway, much closer in this case. on the other hand it sounds like youve run the motor quite *-long enough, youd have had a valve 'hang up' and lose it by now.
sounds like your re-sealing job has air leaking. most likely case, air in the clear fuel line seems to point to that. or when you were working on it you jostled fuel line or connection and its leaking. most likely your seal job, check it out.
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Last edited by iluvmydiesels; February 19th, 2018 at 13:32.
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Old February 19th, 2018, 10:49   #13
mustangmarty
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Yes. I loosened the camshaft from the cam gear in order to line up the cam locking plate.

Thank you Mongler! I sent you a PM.
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Old February 19th, 2018, 13:59   #14
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Yes, I have seen lumpy running at IQ's that low. With the engine running, I would loosen the QA bolts and tap the head towards the passenger side. I like them running around 3-4 for stock injectors and 4-6 for upgraded injectors, adjusting for smoke. The timing will come into play with the IQ, so you want a slightly more advanced timing with lower IQ number (indicating more fuel). I also tighten the top bolts with the engine running since how you tighten them can swing the IQ one way or the other. Just make sure not to overtighten them, which most people do.

The air bubbles are probably from resealing the IP. Small ones won't affect how the car runs. I have seen quite a few as the result of the o-ring on the fuel pump needing just a little grease to seal better. Over time the o-ring and thermostatic-T can get worn and create occasional air bubbles.
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Last edited by Abacus; February 19th, 2018 at 14:03.
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Old February 19th, 2018, 16:35   #15
mustangmarty
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I loosened the QA bolts slightly and tapped it toward the passenger side until I reached 4 and then tightened it down at which point it changed to 5.

I did a compression test. They are at 450, 470, 450, & 450. So compression is good.

I read something about “limp mode” somewhere not too long ago. Could that be it? Reason I ask is because it has no guts whatsoever. Barely gets up a hill in second gear.
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