Pressure regulator (check valve) gets clogged several times

[speedbird1229]

Hi,

I'm new to this forum so Hello to all of you guys for the first time and I'm here from Estonia, Eastern Europe. My girlfriend is also an American cars fan and we got a 1985 K5 Blazer 6.2 Diesel for her in the beginning of this year. We have done quite a lot of work to this truck because it was in pretty untouched shape and maintained OK in Sweden for most of its lifetime but had been left forgotten for years before we finally bought it.

I have done gasoline engines most of the time and didn't know much about diesels. Now I've learned quite a bit with this 6.2 and I must say I love this engine because it's just such a nice classic diesel. I love the sound and the behaviour of it

Suddenly our Blazer just stalled and wouldn't run at all. It lost its power and we thought the injection pump is gone. Fortunately I found someone who was able to diagnose it must be the check valve or something clogging the return line. He was right - I removed the check valve from the pump and the glass ball was totally stuck. I was able to loosen it a bit but that original valve never really worked anymore. I got a used valve from a guy here and the glass ball was moving very well when I got it. The truck drove for about a week of daily usage and then lost its power again. I found that the other valve also got stuck and I spent quite a bit of time trying to loosen it. A lot of brake cleaner and WD-40 helped and I was able to get the truck running. A few more days of nicely running engine and again, the same issue! I found the valve to be stuck last night, cleaned it the same way and got it working again.

Is there some dirt getting out from the injection pump that disables the valve? I really don't want to remove the pump because it's quite a bit of work and otherwise the engine seems working really OK and I cannot find any dirt from the outlet of the injection pump where the check valve goes into.

I have a fuel filter installed right after the fuel tank before the optional electrical fuel pump and I ofcourse also use the GM original fuel filter under the hood which we replaced quite recently with an AC Delco filter.

Now I'm thinking that I should go to a hydraulics store and get some parts to make it possible to add a separate filter to the outlet of the injection pump before the check valve. I have a brand new check valve ready which I ordered some time ago from a military shop in eBay.

By the way, can such kind of check valves also be used on this 6.2 engine? http://www.ebay.com/itm/Fuel-Non-Re...es_EngineParts_SM&hash=item53ef11acab&vxp=mtr I guess we should know the pressure it holds...

 

[ak diesel driver]

That's usually a sign of a dieing IP.pump internals coming apart.

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[bison]

I wonder what kind of diesel fuel you use cause I am more inclined to believe it is fuel related.
I never have had a check valve seize up on an IP of a 6.2 in 17 years of using them.

 

[speedbird1229]

I was also thinking it could be fuel related. Well, I've tried fuel from different gas stations here but it is indeed the same fuel everybody uses. What kind of internals could cause such issues? I haven't noticed anything inside the valve or on the pump outlet.

 

[ak diesel driver]

I've seen a couple fail that way the seals are starting to fail. Cleaning the check ball was only a get me home fix.

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[WarWagon]

1985 should have had an updated ring in the governor assembly. Older years were known to come apart especially from alcohol (dry gas/water remover) use. You shouldn't use drygas on a diesel as you want the water to fall out of the fuel not blow the tips off the injectors and ruin the IP.

This check ball holds ~6 PSi in the IP. Sold on ebay from time to time as a fuel pressure regulator.

You have a screen in the inlet of the IP. Prior to this you have a fuel filter. So it is clear the debris is coming out of the IP. Likely the governor ring. It could also be (broken off) parts of the solenoids in the top cover.

You need to stop driving it as the risk of a runaway diesel is high. I suggest you find a rebuilt IP and also have the injectors rebuilt. A rebuilt IP will have a functioning timing advance where a used one may not. The DB2 IP is famous for the timing advance wearing out.

You could pull the top cover off the IP and take a look, but, you are at a rebuild point anyway. If you don't put the cover back on properly the engine is at WOT and will run away.

 

[uniquediesel]

Sounds like the Flex-ring is coming apart inside. This is on the governer assembly cage. You need to have the injection pump gone through and they'll install an EID assembly. Pumps back in the day when they were updated had a little metal tag on one of the three top cover bolts. The little tag will just have an embossed "E" on it, short for having an E.I.D.

J

 

[speedbird1229]

Hi guys,

I'm sorry I couldn't reply to this thread earlier but your help has been very useful. It could well be that the ring is coming apart inside. However, can someone please clarify how the risk of runaway on this engine is high with this pump issue? As far as I've understood runaways are usually caused due to oil leaking to the cylinders. I understand there is a possibility if the throttle control on the IP would let too much fuel in somehow but still, won't the fuel cutout solenoid stop the engine if the worst should happen?

It's just so stupid that the truck runs fine otherwise but now that the ring is coming apart I need to take the IP off and get a new one or have it fixed. I thought I could get a few more hundred miles at least out of it or so...

I'd really appreciate if someone explained this pump issue a bit further to me since I'm just a noob on the diesels. Thanks.

 

[ak diesel driver]

I've never seen on runaway because of the check ball, not saying it can't happen just never seen it.

 

[WarWagon]

If the governor fails the engine runs away. As in full fuel right now. If you ever leave it alone at idle this can happen. Coming to a stop sudden acceleration can ruin your and someone in your path's day. I am not clear if the engine shuts down with the key after a governor ring failure. What was the build date of your Blazer? Any tags on the side of the IP indicating the ring was replaced? Again 1985 should be updated, but, you may have a older/early 1985 build IP, replacement older than 1985 used IP, etc.

If you pull the top cover and put it back on wrong the metering valve is locked in full fuel with or without the key on. You will have to cut the air to stop the engine. Test the IP by putting 12v to it without turning the engine over and hearing a click. NO click means it wasn't put back on properly and is jammed at WOT.

What does a tow cost you? You will need to fix this eventually so weighing the breakdown inconvenience and towing vs. getting the IP rebuilt/repaired now is simply a cost decision. Add the risk of the engine running away when you least expect it doing engine damage, running people over etc. can't be measured. The same risk applies to the engine stalling - loss of power brakes, steering...

I have had the metering valve become sticky and stay shut after removing engine throttle causing a stall. Adjusting the idle up helped, but, the IP needed a rebuild.

The IP is a cakewalk to change. Finding a good IP is simply expensive.
Pull the intake.
Use a 5/8 crow foot for the bottom IP injector lines. The lines do not have to be removed from the injectors they will flex and bend enough to get out of the way.
Remove and replace 1/4" fuel lines with new. But do not attach to old IP yet...
Pull the oil fill tube off.
Get to the 3 IP gear drive bolts through the oil fill hole using a magnet on a socket - spin the engine from an alternator bolt backwards for each bolt. Do not drop these bolts or you will be pulling the timing cover to get them back out. That is a lot of work.
Take the 3 15MM nuts off the timing cover holding the IP.
DO NOT SPIN THE IP FOR GRINS!
Install the replacement making sure the driveshaft pin was in the same spot as the one that you removed. Otherwise it is real fun to line them up to the drive gear. This is why you don't spin the oil IP. Spin it all you want after the new IP is installed.
Line the IP up with the line on the top of the timing cover. You will have to time it by ear later if needed. A diesel shop that has antique tools can also do this better than by ear esp vs. an untrained ear.
Replace other items removed...

 

[speedbird1229]

Hi,

Thanks a lot for the detailed reply. Very useful information. I have a fella here locally who has had a few of these 6.2 trucks and has done basic rebuild for the IP's also. We will try to figure something out with him since my IP is working just fine not considering the possible governor problem.

We will take the IP off soon and look into it. Meanwhile, we discussed and we should order a rebuild seals kit to have ready when we have the pump off. I need to order it from USA and it takes a while to ship to Estonia. Can you point me to the right direction to get the proper kit? Does this one look like the proper one:

http://www.ebay.com/itm/Roosa-Maste...Parts_Accessories&hash=item338258d199&vxp=mtr

Or this? http://www.ebay.com/itm/GM-Ford-6-2...Parts_Accessories&hash=item233236d193&vxp=mtr

Or maybe some of you guys who have these parts ready or can get the best ones could help out a fellow old truck fan on the other side of the ocean and ship it to me if I pay by PayPal to you?

 

[speedbird1229]

Alright, done a lot of research on these issues and pumps. Since our vehicle is 1985 and according to the codes on the pump it should be indeed a 1985 pump:

DB2829-4425 14077168 1985 LD C/K Truck C/K DB2829-4502 Note 2 except (d)

I am assuming that our pump should already have the EID inside without the flex ring. However, there are still brownish particles coming out of the pump and I'm wondering whether there might be other seals causing these particles to appear.

There is like a white sticker on the top of the pump above the return line outlet and the information has worn off over the years. It seems like it could be a barcode sticker. Any idea what it could have been?