Stuck fuel shut off solenoid (n109)

Has anyone had a fuel shut off solenoid get stuck?

Full story:I have an AHU swapped in a Eurovan. It's been there for 50k miles. It was getting tired so I pulled it for a rebuild (50k in the Eurovan, unknown total miles). I thought I would put a spare AFN in while I rebuild the AHU so that we could still use it. The AFN has been sitting in my shop for a couple years.

l have the AFN fully installed and it should be ready to go BUTTTTT I can't get any fuel. I cracked a line at an injector and turned it over and over. No fuel. I've checked the solenoid, it is getting battery voltage during cranking. It "clicks" and sounds just like my B4 that does start. I pulled the engine side harness and checked it with an ohm meter for a broken wire. It all looks good. I can pull inlet hose off the pump, pull a small vacuum and get fuel in my vacuum pump reservoir. I scanned it with VCDS and I get a coolant sensor open error... but that's it. What else could it be besides a stuck valve if they don't stick?

take the valve off, you can test it to see if it pulls up. It is possible that it can get stuck.

Possible but seems unlikely; it's pretty loose inside. Have you applied 12v to it directly to see if it clicks? The QA in the pump also clicks when you turn on the key and it's louder than the solenoid.

To really exonerate it you could remove the plunger and reinstall just the solenoid. The QA going to zero will still shut down the motor. The solenoid is a secondary cutoff.

All that being said, I doubt it's the problem. I'd pull a vacuum on the return line from the pump. Disconnect it and suck there. Plug the open hose that goes to the filter.

My experience is that once most of the air is pulled through and fuel gets to the pump flow slows dramatically due to the tight path through the gear pump. Keep at it until you have fuel coming out.

Maybe it's gummed up from sitting which won't help but I doubt it.

Thanks for the replies guys.

I had ran a jumper to the solenoid earlier this week. Sorry I left that out. It clicks. I also put a meter on it while cranking. It sees battery voltage.

Today I didn't have a lot of time to look at it. I did however, pull the return line off the filter, cap the filter connection, and pull fuel through the pump. I probably pulled a quart through the pump (my best guess). I also cranked it over a lot. Nothing. The line to the injector is still open also so if it's just way out of time, I would still see fuel......

I think my next step is to pull the solenoid. Hopefully tomorrow.

Can't hurt. But if you hear it moving. I suppose the rubber tip could have come off.

I'd loosen all the injector pipes while cranking. Maybe remove the top cover to see if it is gummed up.

I pulled the solenoid. I tested it. It works.

I pulled the cover off the pump. It looked nice and clean.

I pulled a bunch more fuel through it with the mityvac. I opened all the pipes at the injectors. I cranked on it a long time...... nothing.

Pretty frustrated. This was supposed to be a quick bandaid. I've spent a week of free-time trying to get it primed. I've never had problems like this trying to prime one!

Is the quantity adjuster moving when you hit the key? It’ll do a full sweep as a check before the car starts. If it doesn’t do this it’s most likely a wiring issue.

How do I check that the quantity adjuster is moving?

Take the cover back off the pump and watch the QA arm while turning on the key. You can move it by hand first to see if it's free.

Thanks!

Hand me that gas can and lighter...........

The QA arm moved freely by hand. I still checked to make sure it did a sweep when the ignition is turned on.

I went back to pulling fuel through with the mityvac. I can pull 25-30 inches of vacuum. It pulls fuel through pretty well but doesn't seem to drop on the gauge soon enough to make me think there is a serious leak in the fuel lines.

I also cranked on it quite a while between mityvac sessions. Finally I had my daughter come out and crank while I just watched it. The injector lines are still disconnected from the injectors. I can see a small "spit" of fuel into the inlet of the injector and maybe a drip or two coming off the injector with every pulse. Weird. Definitely not enough to run the engine. I'm honestly not sure what that tells me though. Maybe I have a bad pump? I don't know the history of the engine. It was supposed to be a running engine but maybe it was on it's last leg and sitting for a couple years in the shop finished it off? I don't know.

Last thing I did was pour a LITTLE bit of diesel in the intake and tried firing it. I thought maybe a little fuel would "jump start" it and get it going? I didn't put enough in to do anything. It didn't even fire. I'm scared to put too much in but I might try a bit more tomorrow if no one has any other ideas......

Thanks for the ideas so far guys!

Rob

I don't think Diesel in the intake will do anything. It doesn't evaporate fast enough. I've heard of gas on a rag in front of the intake. Never tried it.

There's starter spray but it's frowned on. Disable the glow plugs if you decide to try it. But if you aren't getting fuel at the injectors running on ether isn't going to do much.

How about pulling the plugs so it can turn over faster and save your starter and battery. Then crank it with the injector pipes really loose until you get fuel coming out.

With the injector lines loosened, cranking the engine should be soaking the engine bay in fuel if the pump was working properly.

Thanks for the comments.

New thought. I have had an fault code relating to coolant sensor (00522 - Engine Coolant Temperature Sensor (G62). I mentioned it in my first post. You were all probably thinking the same as me, "That is an easy fix, I can deal with it later. Let's get this started!" However, I looked into that more, thinking that I didn't know what else to do, I might as well fix it. I found this http://wiki.ross-tech.com/wiki/index.php/00522. It mentions “hard to start cold” as a symptom. That could be adding to my problem…… with this problem and not a fully bleed fuel system, maybe those two are combining to make it so difficult to start. I’ll pick up a new G62 sensor today and see what that does for me tonight. It's worth a shot....... I got nothing else to try.....

I had a similar no fuel at the injectors problem once that was because a rubber o-ring for the shutoff solenoid jammed the mechanism in the pump head. I removed the solenoid and it tested fine, but after hours of frustration I finally looked in the pump head and saw the jammed o-ring. Once that was removed, I had fuel at the injectors.

Thanks for the feedback Glenn1179. Are you talking about the oring with the blue arrow pointing at it in the image?

I installed a new coolant sensor. No more Fault Codes. That's all the good news I have.

It still won't start. I pulled the glow plugs and spun it for a long time. It still won't spray more than a couple drops out of the disconnected lines. I didn't pull fuel through the pump with the mityvac like I have before. The return line stayed pretty much empty. Unfortunately I didn't have help to turn the key so I wasn't able to watch inside the engine bay as it spun. Seems weird to me though that the return line stayed empty. Maybe I just have a bad pump?

I'm back to looking for a gas can and lighter......

Break down the fuel piping in sections and pressure test each section. You're getting air intrusion somewhere.

Yeah, that's what I was thinking. On the one I fixed, that rubber o-ring tore off and found its way down into the pump head, jamming things up.

Said he pulled a quart through the pump. Were you still getting air? When you removed the cover to check the QA was it full of fuel?

Could run it off an IV bottle to eliminate air as a possibility.

rcowan said:

.................................. It still won't spray more than a couple drops out of the disconnected lines. ....................

Click to expand...

He's got air intrusion, it should spray enough to make a mess. Easy problem, hard to find.

Thanks for all the comments.

Even a bad pump would still make a mess with open lines at the injectors? Is that what I'm hearing?

I can run an IV bottle right into the pump to see what happens. Any suggestions on something readily available to use as an IV bottle?

If the IV bottle causes the pump to work, it would make me feel better about chasing down a leak. It drove in the shop fine, with no fueling problems I'm aware. I just disconnected the lines at the pump and reconnected. Seems weird that I would have problems now..... However, maybe I had problems all along that I didn't realize and, with a purged system, it still ran.

(Actually, since I started having issues I have replaced the filter to pump lines (supply and return). They were easy.... and I had the same thought at first.)

One more question: The fuel shut off solenoid stops fuel from going to the injectors and return line or just injectors?

Thanks again everyone!!

Depending on what's bad in the pump, it could either make a mess or not.

I had one (a year-old reman) that suffered some sort of internal failure and became unable to build enough pressure to fire the injectors, so if you're seeing virtually no fuel coming out of the hardlines when cranking over, it's possible you have a similar failure.

The solenoid valve blocks fuel to the inlet of the high pressure plunger.

Quick and easy way would be to just run hoses into the top of a water bottle. Use your vacuum to pull on the return until you have a good prime then put the return back into the bottle. Maybe secure it with wire so it doesn't pop out when the motor starts. Idunno how hard the return flows.

Run an in-line filter to the pump.

Well, I gave it a Big Gulp.


I pulled a decent amount of fuel through with the Mityvac. Then I had my daughter turn it over while I watched the action..... No action. The fuel BARELY moved in the tubes. Not cool. Glow plugs are still out. It turns pretty quickly, it should have done something! Right?

I really think this pump must be done. Convince me I'm wrong or give me something else to try. Otherwise I'm just going to pull the AHU pump and put it on this engine. I'm disappointed because I had plans for this AFN after it's served it's purpose as a bandaid. Now I need to find a pump...... :-(

I can't say how fast fuel should move under those conditions. Could be the vanes in the pump are stuck.

Circulate some Power Service through it and let it soak before giving up?

Sure. What Power Service product are you talking about? I not familiar with their products.

PS Diesel Kleen? Diesel Purge is similar

After reading this: http://forums.tdiclub.com/showthread.php?t=45870, I'm thinking it might be worth checking the Pump case Pressure Regulator before pulling in the Power Service.

Couldn't hurt but don't get your hopes up. You'll probably find the retainer is out of place but pushing it in won't help. Even if it comes out in pieces the clearances in the hole are such that the plunger can't fall out until you unscrew it.

When in operation the pressure pushes it back up in its bore.