ve start of injection timing

cygnus · Dec 18, 2017

code 17656 RESOLVED (bad ecu)

I have a 2002 alh throwing a
17656 code. Hard start and lack of power.
checked timing in vag-com and couldnt even find it on the graph
vertical straight yellow line only so it tells me its too far advanced.
Adjusted pump max retard and still cant get it down on the graph.
It does idle and sound a bit better
I noticed it has very fine air bubbles in the fuel return( not normal fuel line air)
checked timing fly,cam,pump and still not on graph

nikolay_ss · Dec 18, 2017

Check the 2nd column while you are on 000, its your timing, probably its above 100 if you can't see it on graph, adjust it until it's near 50-55, that's the best timing for an ALH. Also set your mgs near 3~3.4. You should all this on hot engine (above 80C)

KLXD · Dec 18, 2017

A little history would help. How long has it been like this? Sudden occurrence? Since you last did the timing belt? Since you acquired it? Does it smoke when it starts?

Sometimes when timing is too late VCDS sees it as too early but you said retarding it helped.

When you retarded it which direction did you move the pump shaft relative to the sprocket?

This is odd since a properly installed ALH timing belt should not have the timing so far out that the sprocket doesn't have enough adjustment.

oilhammer · Dec 18, 2017

Could just be the pump is broken internally. It happens. Not often, but it does.

cygnus · Dec 18, 2017

Its been like this a couple of weeks.Car is currently not my daily driver.
I thought it came on all of a sudden, but in hind site it might have been gradual.
I thought hard start was due to weak battery and colder temperatures.
Timing belt was done about 2.5 years ago and has about 60000 km remaining on recommended interval.
Owned vehicle for 8 years only issue had very intermittent idle fluctuation for past 5 years(maybe 900 to 1050 rpm) originally thought pump was having issues but never got any worse.
I moved the pump shaft in both directions multiple graduations in order to try dialing it in.
would broken internals be a cause of excessive air in the lines?
possible it is belt stretch?

BobnOH · Dec 18, 2017

Broken or worn internals might cause air.
Not belt stretch, not for that amount.
Try resetting the mechanical timing. Monitor some pump functions like IQ, modulating piston, see if they bounce around.

cygnus · Dec 18, 2017

ok still not able to get the values on the graph no matter what i try.
So when i can get a chance ill swap in another pump
If that helps ill do an autopsy on old one
thanks for the help

burn_your_money · Dec 18, 2017

No bubbles going in but bubbles coming out is almost always the input shaft seal.

whitedog · Dec 18, 2017

I think you can pop the little "rounded diamond" plate off in place and inspect for FOD.

cygnus · Dec 18, 2017

yeah i guess missed post.
I meant to say fine air bubbles in the clear supply line(filter to pump) only when running

cygnus · Dec 19, 2017

The timing value in the bottom left corner of the graph( next to the fuel temp)
Does not change much. hovers around 250 regardless of were i adjust the pump.Even jumping a tooth on the pump only doesnt change that value.

KLXD · Dec 19, 2017

Strange one. The only thing I can come up with for a properly timed pump to move to too advanced is if the advance mechanism stuck.

Hard to believe since the force of the cam plate on the rollers wants to push it back to the fully retarded position.

Belt stretch or the belt jumping should tend to retard it.

I understand you to say you can't get it in by moving the sprocket on the belt?

Seems to me there was another feller on here recently that couldn't get timing adjustments to show on VCDS. Don't remember if he resolved it yet.

I wonder if there's a software problem.

cygnus · Jan 5, 2018

ok so was able to get back to it
Got a known working pump and swapped it in
No change to issues timing still up at 254
still noticing excess air in fuel line.
bypassed tank and filter and supplied pump with fuel direct.
Air settled down to normal(just the odd large bubble in the clear supply line )
So i must have air getting in back from the pump to tank somewhere( line ,filter, in tank)
Possible that so much air will have that effect?

munly · Jan 5, 2018

I just went through a similar issue. I was mechanically adjusting the pump but the ECU wasn't picking up the changes. My problem was the number 3 injector was faulty. The ECU seemed to go into a default timing setting, although my timing was stuck at 38. Once I had a new/rebuilt injector installed I was able to adjust the timing and it was picked up by the ECU. I believe my code was the same as yours.

Nevada_TDI · Jan 5, 2018

Wow, different pump and same issue... Are you sure everything in the timing circuit (belt) are all in the right spot? You did not mention if you went through all of the timing belt pinnings. I just re-read your post and I (like the above poster) had a problem with the #3 injector wiring. The suck thing is the code wasn't definitive and my problem was intermittent until it wasn't and I had to replace the injector. You might consider contacting Mark at DFIS, Portland and talk to him; he is quite the pump issue guru. He rebuilt my pump a few months back, and I could not be more happy; he may also have a #3 injector available at a reasonable cost as well.

cygnus · Jan 5, 2018

Yes thats right same issue with the second pump
and yes i reset all the timing points.included manual rotation (crank).
still a bit paranoid about interference on my timing jobs
The thing that gets me is why the fine air In the line went away when i eliminated from the filter back.
I do have some good used injectors around if it comes to that

cygnus · Jan 5, 2018

recent vcds scan.
start of injection.specified 3.7 btdc actual 20.7 btdc
start of injection quantity quantity 48.4mg/str actual 20.9 btdc
iq cylinder 1 to 4 vary from -.31, -.16,.12, .33 mg/str

Rrusse11 · Jan 6, 2018

Change the #3 injector.

Nevada_TDI · Jan 6, 2018

Since you have an "extra" #3 injector--hopefully it has the same size nozzles as the ones you have now--go ahead and replace it. Otherwise can you put the old set back in maybe just for a test run?

cygnus · Jan 7, 2018

Ok so injector 3 swap complete.Injector not tight at all in there.
Has definitely helped power. Will Have to wait to get access to vcds to adjust the pump.
Still have tons of fine air in the system.Air leaking out around glow plug,
Small air leak out around injector 3. Might have to torque injector holder ,

Genesis · Jan 7, 2018

CAREEEEEFUL. Do not overtorque that hold-down bolt!

That injector replacement requires either re-annealing the copper seal washer or a new one. If you re-used it that's where the leak is coming from.

cygnus · Jan 7, 2018

Good to know
thanks for that

Rrusse11 · Jan 7, 2018

cygnus,

You can anneal the old injector washers. I'd recommend cleaning up the surfaces, polish them gently on a flat sharpening stone. Figure 8s
on the fine side pushing on the hole will flatten 'em out.
Then take a piece of coat hanger wire and heat 'em red hot with a propane torch, immediately dunk in cold water. Softened!

Seat the injector with a good bump with a slide hammer if you've got one. Frank06 uses a hammer and a brass punch. DON'T use the holder clamp to torque down, that's what setting the injector into the soft washer is all about.

If you've got other leaks, you probably need to clean carefully around all the holes. Don't let crap get into the cylinders, and don't rely on tightening things up to get a seal. Remove the glow plugs
CAREFULLY. Lots of penetrating oil, gently torque tap 'em in BOTH directions. They have a habit of breaking off in the threads
if you muscle them.

If you're making better power with the "new" #3, you're getting there! Now it's communicating with the IP.

cygnus · Jan 7, 2018

Ok great got it
I will anneal the washer and seat it without using the holder.
Ill look up the holder bolt torque and clean out the surfaces better.
The glow plugs are snug and havent been touched so im not sure why they are leaking air but ill clean them up .
Thanks

cygnus · Jan 10, 2018

So got the injector set up and sealed.
Finally able to read timing on vcds
First reading at low 200s easy start and no smoke moderate power(like limp mode)
Adjusted pump down to just above blue line(aroud 70 or so) hard start ,copious smoke and less power than ever(farm tractor)
Looks like now start of injection actual is .4 btdc and actual reads early and switches to late at idle.Thats with timing in the sweet spot of the graph.
possible out a tooth on pump sprocket? i know i locked out all timing points

whitedog · Jan 10, 2018

Many people have swore up and down that they got the IP timing right and come to find out they had the pin in wrong. Please make sure that the pin is in the hole as it's lined up with the centerline of the pump case.

Nevada_TDI · Jan 11, 2018

^^^This sometimes happens... I was going to mention the "dummy" hole. This is no offense to the OP, but it is a lot easier to get the pin into the wrong hole than it is to the into the correct one. IIRC, the hole in SAE is 11/64 and a common drill bit size.
I personally had a hard time getting the pin in correctly the first couple of tries at timing the pump. Even with the crankshaft and camshaft at the correct timing marks, there is tension on the pump sprocket.

KLXD · Jan 11, 2018

Yep, the springs in the pump want to rotate the shaft backwards. You have to hold it in the correct position to get the pin in the right place.

cygnus · Jan 11, 2018

Fair enough maybe we rushed it . Ill re check.
The timing is jumping around right now between 20 and 60.
if timing marks up ill swap in all injectors and go from there

burn_your_money · Jan 12, 2018

Pull the pressure regulator out of the pump and make sure that it hasn't fallen apart. You should use new o-rings on reassembly.

ve start of injection timing

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