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Discussion Starter · #1 ·
Hi,

So I got air into the system and tried priming the pump and bleeding the injectors. I get some fuel through but I'm pretty sure there's a leak! It hesitates and won't start you can see air bubbles in the clear fuel feed pipe to the pump.

I've ordered a mityvac and want to find said leak but am unsure of the procedure..... Or would I want to pressurise the system to find the leak? Blow instead of suck and where is what I'm asking basically? Hahaha

Thanks in advance!
 

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Discussion Starter · #3 · (Edited)
Just tow start it. The SDI is like the old VE engine and does not bleed air out the fuelsystem by itself.
Had it running on ez start but it still doesn't wanna run alone. Will towing it make a difference though?

EDIT UPDATE: Fuel coming in from the tank, fuel coming in from the filter, fuel into the pump feed ok, no bubbles. On the pump return priming it..... Full of bubbles.... That isn't good is it?
 

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yes the pump will be turning over at a way higher rpm thus being able to push the air out to the tank, where it actually gets vented out. make sure you have the car at 30mph before you let the clutch come up to start it. (key needs to be in position 1) it'll start up almost instantly. Had this before with a few VE type engines, next time clamp off both fuel pipes after the filter and top the filter housing up with either fresh diesel or a diesel injector cleaner. the tip above stops air getting to the fuel lines and the pump ( it'll have a minimal amount of air in the filter housing that way)so usually after that the car starts straight up of the key usually within 3 to 5 seconds.
 

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Discussion Starter · #5 ·
yes the pump will be turning over at a way higher rpm thus being able to push the air out to the tank, where it actually gets vented out. make sure you have the car at 30mph before you let the clutch come up to start it. (key needs to be in position 1) it'll start up almost instantly. Had this before with a few VE type engines, next time clamp off both fuel pipes after the filter and top the filter housing up with either fresh diesel or a diesel injector cleaner. the tip above stops air getting to the fuel lines and the pump ( it'll have a minimal amount of air in the filter housing that way)so usually after that the car starts straight up of the key usually within 3 to 5 seconds.
That sounds like solid advice to me! Cheers mate, gonna give that a go. Will report back!
 

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Discussion Starter · #7 · (Edited)
I couldn't get a tow so went back to trying to suck from the tank, attach to full filter, got it started and then it runs but doesn't rev up properly, smokes and runs the filter dry and won't start again unless I re-prime it. Gonna try again and crack an injector or two.

Wish I could get a tow but it ain't happening

Update: Got it started again and cracked the injectors. All getting fuel it would seem. I just wonder if I damaged the pump in some way by cranking when it was dry?
 

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no the pump is what actually pushes the fuel around... i think that your in-tank lift pump is goosed otherwise the fuel filter would not run dry. Before trying to start it, put the key in ignition and turn it to position 1... you should hear some buzzing noise coming from under the back seat if it doesn't do that, either your relay is gone ( it's a known problem) or the in tank fuel pump has a problem with getting power because of rust or cable damage...
  • the relay that is problematic is the one with number 109 on it if it is the OEM grey one, replace it with the black 109 version.
  • the in-tank fuelpump access panel is under the rear seat pull the bench up and remove the screws from the panel, 3 philips heads, than you'll see the connectors of the cables right on top... visibly check for corrosion/ rust/ cable damage lean as needed than measure with a multimeter if the lot actually gets power when the key is switched to position 1. if it gets power but doesn't prime at all even after you've replaced the relay... than you'll need to replace the lift pump.... any ve engined one will fit and if you have any wits about you you'd get the one from the GT TGE 110 with either the AHF or ASV engine ( they pump fuel faster. And no need to worry, the in-tank lift pump does not make for the use of more fuel that is 100% dictated by the VE fuel pump.

PS all VE engined mk4 diesels will suffer from this at some point as for 1 the OEM relay used for the pump likes to overheat causing problems with the in-tank fuelpump and because they are almost hitting 23 to 25 years of age so parts are worn out.
 

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Discussion Starter · #9 ·
This is a mk2 caddy sdi AYQ though. There isn't a pump in the tank. I'm going to leave it and ring a mechanic after Christmas. Don't need it desperately.

Cheers for trying mate

Forgot to mention I attached the pump feed to a bottle with fuel and it runs the same. Think I've killed the pump...
 

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Discussion Starter · #11 ·
Will do!I'm not giving up yet. Although I feel like it.... Checked the lines from the tank to the filter and they hold vacuum. No leaks. Sender looks, ummmm... sendy? Nothing looking broken or clogged

Pipes onto and from the filter all good. Pipe onto pump good. Not replaced the return hoses on the injectors and apparently they crack.

But...

After it's been running at idle when I remove the T-valve you can hear a good rush of air being sucked in to the filter. That's good I assume? It's building vacuum?


Is there anyway to tell if it's an issue with the pump?

I need a definitive guide... Or a miracle 😂
 

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right the last thing you want to do is introduce air into the fuelsystem... if you doubt the leak-off pipes just replace them (they are heap enough). I replaced the lot on mine after 16 years and bought it off eBay by the meter, as that was cheaper than buying it from Halfords/ECP/ GSF, but their kits are more than long enough to replace the lot. Also i got a copper t-piece instead of the plastic one as they do deteriorate and can let air in... but if you keep running the filter dry, than there is only one problem an air-lock in the return traject. Normally the VE- pump can overcome that but only when being tow started. Unless it's the pump itself that has a perished/damaged seal somewhere than it won't be able to push out the air as it is sucking it in at every rotation.

So replace those leak off pipes, replace the t-piece for a metal one, top up the filter with an injector cleaner and try a tow start. If it still runs the filter dry after that... than the VE pump probably needs new seals as that way you've literally made sure the only thing that can be introducing air is the pump itself.
They can be refurbished by the way, there are a few diesel specialists online that actually can sell you a reconditioned one or fix yours.
 

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Discussion Starter · #13 · (Edited)
Thanks for that NP. I have an update and things are starting to (possibly) reveal themselves. I've not got a great knowledge of how things work but I'm learning!

So far: Filter change, complete mess up didn't prime filter correctly, lots of air introduced by cranking and cranking until the battery eventually died.

So the problem was air introduced to the system by me at the filter. Fix? To bleed the air from the fuel system to allow the pump to pull the fuel from the tank into itself and then to the injectors. All under vacuum? ie. a closed circuit no air? Think I'm learning.... Or not lol

Racing ahead a friend said to use ez start and it would just pull the fuel through eventually. I tried this and it would run on the fluid but I still wasn't getting enough diesel through. So there's been a lot of cranking once more!

So with a recharged battery I follow the guides online and prime the filter and pump then crank the engine with the injectors cracked then retighten. This didn't seem to work although I almost got it to start a couple of times... I think I've got a leak letting air in. So I check the lines visually and pull fuel from tank, get it to the filter get it to the pump and try again. I still couldn't get the air out! I was letting some in every time I removed the vac. The fuel would race back to the tank. Eventually I learn to clamp the hose and quickly reattach it before it syphoned backwards.

I fill the tank with more diesel and try again this time with no visible air in the lines. Hey presto it starts after a prolonged crank! But won't rev and quickly dies after 10-15 secs. Gutted. Stumped. lost. Possible to still have air in there. A friend suggests to check the pipes from the tank. I undo all the false floor remove the bulkhead (it's a caddy van) and test the fuel lines are holding vacuum... Which they are. Great. So it's definitely getting fuel and no air from the tank. Again I prime everything up and try again. Now it fires up and idles but runs like absolute garbage. Loads of smoke, coughs and splutters, won't rev above 2krpm sounds awful and I think I've killed it. Sad face. I still don't think I've got a leak in the pipes. (and still don't)

This is after you had suggested a tow so I've made progress. I tell my friend and he says take it for a drive! Good idea! So I venture out around the corner and up the road, smoke billowing from the exhaust other motorists backing away as I trundle towards a roundabout. I get scared as things didn't improve so pull u-turn and manage to get home without stalling. Hmmmmm

There's a mk2 caddy page on fb that I get parts and advice from so update everyone with my troubles. A guy mentions timing. So with vcds I check basic settings 004

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I rush ahead and try adjusting the ignition timing thinking this was the problem. I managed to change the ign. timing to 15 btdc and it starts a lot easier but obviously 15 btdc aint good so get it back to 1.5 btdc. I have noticed occasionally the early text changes to late as the engine is running. I'm guessing this is bad? In the youtube vids it mirrors the btdc value on the right. No where does it say early and fluctuate between late.


Is this the symptom of a knackered pump?

Is there anything else I can check?

Once again thanks for bearing with me! This is has been an absolute ordeal but I'm not giving up!

Another little update: The van doesn't have as many sensors and measuring settings in vcds as my mk4 golf but I've found a few things relating to the injectors I think. Injection quantity, mg/stroke/voltage and other flashing numbers lol

I've also got a multimeter so will learn how to test the pump harness. I read a thread about a guy replacing his pump, then an injector but it was an issue with his ecu not sending power to a pin on the pump harness.

Further update: Managed to check the timing with a graph! This looks to be good but I do have a fault code that clears but seems to return: 1756 start of injection timing regulation p1248 - 35-00 . I'm looking into this now. Again it's running really bad, incredible hard start apart from the one time I had 15btdc
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Further, further update: Researching the above code has led me to this video:

He runs an output test on the n108 valve that is responsible for timing the pump with a valve (I think) . The engine tone should change as it cycles on and off. Mine doesn't and neither does his. Although his car drives fine....
 

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I would check the timing is set properly by setting the engine at TDC and check all the timing markings that are on the engine to see if they line up. If they do than you won't have to mess about with the timing advanc at all.

Injector 3 might have a problem as that is the one that gives feedback to the ecu. You can just buy a used one of ebay/scrappy and put that in after you've made sure the timing is spot on and it still runs bad.

Another thing to check is if the pcv valve is blocked as that will cause to much pressure and blow the valve stem seals out of their seats. Result of that is a very smoky engine, colour of the smoke is grey and will literally leave a cloud of fog behind you. Car might run good if it is just that though and your not driving fast.

Fix for getting air out the pump is cracking the injector pipes while turning the engine over. Make sure you have a rag over it as it'll violently spray diesel out as soon as the air has escaped. (You have to do this to all 4 injector lines)

Topping up the filter: DO NOT forget to clamp off both fuelpipes (feed and return) that connect to the top of the fuelfilter housing. (This way you isolate the fuelpump and injectors from air) than you top up the filterhousing to much if possible close it and that should have a minimal amount of air once you have it closed again. Than you can take off the clamps from the fuelpipes.

I've got no other info for you right now just report back once this hasn't helped.
 

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Discussion Starter · #15 ·
Good tip for topping up the filter. But I'm not sure what you mean about the feed and return. I just pull the t-valve out and fill it in the hole. What do I need to clamp? Ah do you mean the pipe from the tank to the filter and pipe from filter to pump? Clamp those? There's no air in there now at least, well not in the clear line to the pump. That's my only victory. Will check the filter again when I know what to clamp. On my golf it's always full to the top, almost overflowing when you check it, but the van always seems low and feels very light. Hmmmmmm

I'm just stumped as to how I've ended up in this situation after changing the fuel filter, getting an air lock, bleeding it and now it'll hardly start or drive. On a side note I thought I got a whiff of petrol when I checked the sender unit in the tank. I fill up with diesel in the caddy and a big jerry can for the mower and then smaller 5 litre cans for the two stroke tools as and when I need to. I haven't needed to refuel for ages though (over a month as it's winter) so even if I did put petrol in the caddy it's been fine for ages. I certainly didn't prime the filter with petrol because I didn't prime the filter at all hahahahaha kill me

Cheers again
 

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the 2 fuel pipes coming off the fuel filter... that are connected to the top of the fuel-filter housings lid. Those 2 are held in by clamps (you got it much easier) release the filter from it's holder, turn it upside down, remove the white screw in the bottom, fill it all the way up with diesel or a diesel injector cleaner, replace the lid, put it back in it's holder

PS do not mess about with any off the spill off pipes when you've done this as it'll let air in... so if you are going to replace them do that before you top up the filter. the above is for when you are done and want to try and start the car, easy start is not needed car should fire up if the battery is full in 3 to 5 seconds...if it doesn't tow start it.

my TDI had a heated fuel filter housing with a replaceable paper/cotton filter, so that is why you didn't understand what i was on about.. you got this type:


PPS if you have petrol in your tank than that'll be why the engine runs like a bag of spanners being shaken about. either drain the tank and put in some fresh diesel or if it's a little bit fill the tank up to the brim with diesel. it'll counter act the amount of petrol but only if you have 5 to 10L of petrol in there. if you got more just drain it. and add diesel to the tank.
 

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Discussion Starter · #17 · (Edited)
Cheers Np, I'm not convinced I've got all the air out. The filter still seems almost empty and is never full after it running for a bit. How long can it take to get all the air out?... I might prime everything up, start it and crack each injector to let any air out. Then if I see air or the filter runs dry/low. There must be a problem somewhere!

Somone mentioned pump/ignition timing so I tried adjusting that. When it was at 15 btdc (vcds checked) it fired up perfectly yet ran rough still..... So it's back at 1.5btc.

I don't think it's the fuel as it ran fine before the filter disaster and has had another 15 litres in it.

Is there a definitive way to test the fuel lines for leaks? I guess I could take each pipe off and vacuum test them.

Don't know anyone selling a van do ya?!

Thanks again have a good one 👍🏻

Quick thing: will get some diesel injection cleaner, wyns ok? Then put that neat in the filter or mix it?
 

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I wouldn't bother I'm sure your fuel lines are fine.... what you can do is park the car with the back up higher than the front, making it harder for the fuel to return to the tank because of gravity.

Yes Wynn's is fine but I'd get a bottle of Dipetane and brim the fuel-filter with that. Than add half of that bottle to the tank, it'll stabilize the fuel and it'll also clean the entire fuel system (including the VE pump) plus it removes water, varnish, carbon and algae from the complete fuel-system.

and nope i don't know anyone selling a van but quite sure eBay and Autotrader got loads of them...
 

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Discussion Starter · #19 ·
Great advice cheers, I'll order some dipetane and get the back end in the air!

I'm hoping this is just fuel related but I'm slightly worried I've damaged the engine using a load of easy start. Is there anyway to know without pulling the engine apart?
 

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Not to my knowledge... but I've been there with mine and in the end it was just an air problem, since I decided that the engine needed a full gasket replace so I took my complete engine apart.

When I was done it refused to start, nothing helped, than decided to have it towed to a mate who is a mechanic, but during the towing I tried to put it in gear to see if it would start since we were doing 30mph... it started straight up.

Signaled the towing car, came to a full stop tried to start it again, and it started straight up. Ran like a dream too.

Now mine was a GT TDI 110 AHF engine, so mine had a turbo but in essence your engine is the same. And the reason why I keep saying tow start it. The VE pump you got is a bit tougher than the newer model I had on mine so it should be fine. Unless you keep introducing air into the fuelsystem.
 
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