ALH air in fuel lines after sitting overnight (and a bunch of other issues)

[Herm TDI]

Hello people,

So here’s the deal, I had an issue with my Jetta sputtering a bit when started after sitting overnight, after researching and discovering the thermo T issue, I decided to change over to a CAT filter on a Wix base. While I was at it I replaced the rubber fuel lines from the hard line to filter, from filter to IP, and the return from the IP to the return hard line. Also the injector return lines. Well, the problem persists, one way or another air is getting in the lines and causing rough starts and rough idle for a several seconds till it works the air out of the system. Where do I go from here?
I even tried a whole new filter and new base as well, with no change.
I also removed the filter and base (assembled) and pressure tested it but couldn’t find any leaks.

Any ideas appreciated.
Thanks

On the injection pump body there is a fuel shut-off solenoid. The solenoid has an o-ring. Yours is likely dried out brittle and leaking air into the system.

 

[J_dude]

On the injection pump body there is a fuel shut-off solenoid. The solenoid has an o-ring. Yours is likely dried out brittle and leaking air into the system.

Thanks, I have since verified air intrusion is not the issue (at least, not anymore).
Good tip for anyone else looking at this thread down the road though.

 

[J_dude]

Take an 001-004 log i guess? Did you set pump timing down where I suggest? Halfway from red to blue?

Also could take 004 only log, just note try coolant temp

What are your injector balance readings in measuring block 13?

Guess I'll do this tomorrow, in the middle of injectors on the truck today.

 

[ts888]

Thanks, I have since verified air intrusion is not the issue (at least, not anymore).
Good tip for anyone else looking at this thread down the road though.

I should check this. I get a bubble in the clear line when the car sits overnight. Doesn't affect starting or running, but it still bugs me...

 

[wonneber]

I had the same bubble.
I think it's normal.

 

[P2B]

I should check this. I get a bubble in the clear line when the car sits overnight.

Never met an ALH that doesn't. 1/4 - 3/8"

 

[Prairieview]

Soon, only criminals will have air bubbles.

This whole things reads like an old woman's soap opera.

I have a fleet of older 1.6's and ALH's in constant service. When I acquire or put together any of these, I literally toss the "clear" lines and sub-in black rubber lines from O'reilly's, etc. I reseal the pumps and also TOSS the re-cirulating fuel filters and "T" fittings. I keep good 1/8 inch black plastic line between the injectors (bleed-off) and I am NEVER walking or wimping around trying to get one started in cold or hot weather.

A simple life.....is a good life.

 

[J_dude]

I... TOSS the re-cirulating fuel filters and "T" fittings.

What filter do you run?

 

[fatmobile]

On the injection pump body there is a fuel shut-off solenoid. The solenoid has an o-ring. Yours is likely dried out brittle and leaking air into the system.

Isn't that under pressure?
When it opens it allows fuel from inside the pump, which is at over 35psi even at idle, to go to the injectors.
If so you would see fuel leak out instead of pulling air in.

 

[J_dude]

What are your injector balance readings in measuring block 13?

All within spec, not too bad really.

Also, changing the pump did seem to improve the cold start, still not perfect but it's better. I think I'm just going to order some injectors...

 

[bowlerman]

i will say i wasnt a believer in the fuel filter o rings till yesterday. replaced my ip and still had air. i had just fuel and had to put a new sender and clean tank. then i had solid fuel at hose to fuel filter. so i put a new filter and new orings. NO one even the book shows where the blue and black go. the black seems bigger so i put that top and blue on bottom. after that solid fuel. i thought my ip was bad but seemed to be clogged fuel sender and leaking o rings. just some experience.

 

[Odsysean]

All within spec, not too bad really.

Also, changing the pump did seem to improve the cold start, still not perfect but it's better. I think I'm just going to order some injectors...

Did you end up getting new injectors?

 

[J_dude]

Did you end up getting new injectors?

Yeah I picked up a set of Powertdi .260's but the issue persists. So I had to park it and have been out of province for a while but when I get home I will check compression and go from there.
I fear I may have to swap my spare engine over and then tear this one down and figure out what the issue is.

 

[wonneber]

It lasted about 2 weeks before the retaining ring had to be reseated. I think I'll have someone tack it with a tig welder next time I pull it.

What will you do if at some time in the future you have pull the pin??

Any way you could make metal strip and attach it over the pin to hold it in place?
I don't think it would have to be thick.

 

[J_dude]

Well I finally found time to do a compression test, and cylinders 2, 3, and 4 are all hitting 425. Cylinder 1 was around 410 the first time so I checked it again and it was about 420. Not really the smoking gun I was hoping for.
I guess I will check them again when cold and compare, since it’s only having issues starting when cold.

 

[jettawreck]

Well I finally found time to do a compression test, and cylinders 2, 3, and 4 are all hitting 425. Cylinder 1 was around 410 the first time so I checked it again and it was about 420. Not really the smoking gun I was hoping for.
I guess I will check them again when cold and compare, since it’s only having issues starting when cold.

Not enough difference to matter IMHO.

 

[J_dude]

Redid my compression test today on a cold engine and everything reads within 5psi of the hot numbers so that’s all good.
Now I’m really at a loss lol.
I suppose there’s a chance it’s some sort of wiring issue?

 

[CanadianALH]

Maybe your coolant glow plug sensor is bad. And the plugs aren’t warming up for cold starts. Or maybe a flaky crank or cam sensor?

 

[J_dude]

Maybe your coolant glow plug sensor is bad. And the plugs aren’t warming up for cold starts. Or maybe a flaky crank or cam sensor?

It starts hard any time it’s sits for a several hours, regardless of ambient temperature, so I don’t think it can be related to that.

Could be a sensor, I don’t know enough about that part of things.

 

[burpod]

well, sanity check block 007 after it's been sitting overnight to make sure the temps all ready roughly the same

 

[J_dude]

well, sanity check block 007 after it's been sitting overnight to make sure the temps all ready roughly the same

Oh, right, I forgot about that. So I looked back through my posts here but I guess I never mentioned it; I’ve checked that at least twice since I started this thread, everything is always within a degree or two.

 

[Cue82]

Oh, right, I forgot about that. So I looked back through my posts here but I guess I never mentioned it; I’ve checked that at least twice since I started this thread, everything is always within a degree or two.

Any luck finding your problem? Im about to pull my hair out.

 

[fatmobile]

In the old Rabbits, if it wouldn't start after sitting it was often because of a bad fuel line seal
for example in one of the little lines going between the injectors.
That would let fuel syphon back to the tank because it was lower.
This would pull air into the fuel system.
On the TDI it is more likely to be something electrical
but sometimes going old school and checking for foam leaving the pump when starting
can give you an idea of how well fuel is flowing to and from the pump.
A bad mainshaft seal can let air in too.

 

[J_dude]

Any luck finding your problem? Im about to pull my hair out.

The car has been parked for the winter, it’s still having issues. I’m guessing it’s something electrical at this point.