IP leaks fast but car runs great?

[odie]

Hey guys, new to the forum here...I found y'all thru a link someone posted on one of the Biodiesel forums.

Anyway, I have a Maxima diesel that is leaking fuel at a pretty fast rate. I can't locate the souce yet but it appears to be coming from somewhere off the IP. It's a pretty steady state, fast drip. But the car runs smooth and has no problem getting up to 70-80 on the highway. But anytime I am stopped, I leave a diesel puddle pretty quick.

Does this sound like the front shaft seal that I read some threads about or a more serious internal leak that needs rebuilding?

I find that it's real hard to pin-point the source of the leak. Lack of viewing space and light make it real difficult. I've checked the hosed and injector lines but don't seem to fine any evidence there.

Anyway, I'm so glad to be back into Maxima diesels. I foolishly let my old 82 go over 2 years ago and have been wanting her back ever since. Hopefully my new one will ease the pain...

[asavage]

If you remove the wye-shaped plastic splash pan under the front of the engine, you can look directly up at the front of the IP. If fuel is dripping from the IP's timing belt cover, chances are that the IP's front seal is the culprit. Matt found a source for this special seal that is ULSD and BD resistant.

If you find that the leak is from the top or rear, there are seals/gaskets that are needing replacement. The parts are cheap, but if you have to pull the IP, the labor is rather high and special tools not easily available are required.

It might be possible to replace the top cover gasket without IP removal, but I doubt that the distributor head seal can be replaced with it mounted in the car.

[odie]

I've removed the belly pan and tried degreasing the IP area as best possible. But still can't locate the source.

I'll probably have to steam clean the IP area as much as I can. The drip is from the rear of the IP. But the leak can be coming from anywhere and just creeping along the IP body to the lowest point before dripping off.

This is obviously going to be a long search.

Is there any damage possible if I continue to drive with the IP leaking? Or is this thing a time bomb on the verge of a total IP blowout?

[asavage]

You can drive forever with it leaking, though it's not the most ecologically sound thing to do. It will not hurt the IP or engine, though it may melt the undercoating (not a big deal in CC, I imagine).

If you have DIY car washes where you are, use that. It works very well. Be sure to let the temperature of the engine/IP equalize for a few minutes (I use 10) after cleaning, or IP internal damage is reputed to occur (hot IP, cooler water on it, reduced clearances for a while). We discussed this in a recent thread. Don't spray it off with the engine running!

After you're down to metal, drive it home, engine off, spray the area off with aerosol brake cleaner (any brand) then if you have compressed air, blow it off -- if no air, let it air dry for a good long while. Get a good flashlight or equivalent (ie do not try to use just daylight, esp. on a bright, sunny day: the contrast is too high to see anything) and have someone else start it up while you watch the top.

Chances are, you'll be able to spot at what level (vertically) liquid begins to appear. After that, it's Rinse-Lather-Repeat on the brake cleaner until you can pin it down. A mirror on a stick might be helpful, I found it so.

[odie]

hmmm, drive forever...I like that phrase...but wounder how applicable it is to an IP leak.

I would imagine that since the IP is sucking fuel from the tank, that the supply line is always under a slight vacuum and would not leak fuel but leak air.

After the IP initially pumps fuel for delivery, then the fuel is under pressure and at that point or later in the fuel delivery path would the leak be coming from.

I'm wondering if the leak remains or slowly gets worse, eventually fuel starvation to the injectors or any "higher" pressure pump in the IP body would eventually occur.

With this type IP, is there more than one actually fuel pump? A low pressure high volume type to supply the second higher pressure pump that feeds the injectors? Basically two pumps running off the same belt driven shaft?

It would be nice to keep be able to keep driving for a while until I can find the leak and plan to correct it. It could take a couple months if in need to locate seals or repair parts, or collect all the items needed to remove and re-install the IP, and then locate a diesel shop that will rebuild the IP.

Basically, I want to be 100% sure of my plan of action before I remove the IP, since it is such a precision operation to put it all back together and make it run correctly.

Too bad most diesel shops don't do the R&R of the IPs as well. Or do they?

The car runs great, just leaks. I'm kinda scared of trying to fix it and end up with a car I can't make run again. Seems to be a lot of specialized and unavailable or expensive tools to do this. At what point does the total cost to repair exceed the value of the car, or the value of my time instead of having a specialty shop do the whole thing?

[asavage]

With this type IP, is there more than one actually fuel pump? A low pressure high volume type to supply the second higher pressure pump that feeds the injectors? Basically two pumps running off the same belt driven shaft?

Yes, that's how the Bosch VE IPs are designed, and this is a Bosch-licensed VE pump.

At what point does the total cost to repair exceed the value of the car, or the value of my time instead of having a specialty shop do the whole thing?

Many diesel vehicles are in the JYs due to IP failure, sometimes as a direct result of "alternative fuel" experiments. The VE pump can develop a leak just running D2 though, that's fairly common. Access to the IP, getting it on and off the engine, timing it when reinstalling, all are chores.

Determine as best you can where the leak is specifically first before getting tied in a knot about the possible decisions.

[TheDieseliminator]

Yea I have the same issue with a leaking fuel injection pump and have had it for the past good 40,000 miles I've driven my car. And Al's right you won't wreck anything driving the car more with the leak from the injection pump. I've proven that, but still it's not the greatest thing to do as it gets under the car on the suspension and might possibly be considered a fire hazard. I've determined mine to be coming from the rear of the pump and is a steady leak enough to hinder my pretty good fuel mileage I was getting right after I put my car back on the road a year ago. At that time and for the next few months I was consistently getting 29-31 mpg with the car (combined city and highway driving). Averaging about 480 miles to a tankful and now a year later I swear I'm down to about 440-450 average. I hate this fuel injection pump leak and love efficiency, so it needs to be fixed soon but it's my only transportation right now. And I can't disassemble it to sit around for a month or two, let alone weeks because it drives me to work. And Al I remember you saying it's not cheap to get these pumps rebuilt, in the range of $800-1200 where I'd be hoping for $400-600. How much would it cost to have your local diesel injection shop reseal the injection pump with all new seals that are biodiesel and ULSD fuel resistant? I don't want to have the pump leak again just because this new ULSD fuel is less lubricative and eats up a non-Viton seal. Either way mine needs work too, haha.

Salvy

[glenlloyd]

If your IP is leaking from the rear...as is mine, the choices for the problem are few. It's either the distributor head o-ring, one or more of the delivery valve assemblies (or rather their seals), the pump stop solenoid or IP timing port plug seals.



In my case there is a drip from one of the delivery valves, not bad, but it's been that way for a while. In order to replace the seal however, I have to pull the lines and vacate the coolant hoses that I believe to be in the way.

I found that in this case using brake cleaner to clear and dry the area and then starting the car and watching the pump with a small mirror, I can see exactly which port is causing the problem. You may be able to troubleshoot your problem in this manner as well.

Good luck and keep us posted on what you find!

steve a

[odie]

finally got the nissan diesel forum to open up on my work computer.

Still chasing the leak. I've been spraying cleaner all over the pump and rinsing it. 20+ years of dirt, grease, oil, etc all over.

I read somewhere that diesel fuel is a great de-greaser. Spray it on and let it soak in. Or did they mean "bio-diesel" for cleaner?

If anything, I would have thought diesel would add to the problem of cleaning.

Anyway, I hope to have it clean enough soon so I can find the leak. I hope it's something repairable with the pump on the car. But that's just wishful thinking.

[Dr. Jones]

Hey this is just a swing in the dark but it is an easier fix then most. I have experience pretty heavy leaks coming from the plug travel check bolt (the bolt you remove to check the plunger travel in order to set the injection timing). Mine has a copper crush washer as a seal and since you have to remove three of the injector lines to get to it this will give a chance to tighten/check these also. That said, I would use my eyes to make sure that it was coming from this area first, I think I started the car and got underneath and looked up. I had a good pair of chemical splash goggles. And used a rag to dry the area and kept feeling around till I found the leak.

[odie]

the leak has long since almost dried up. Often it does not even drip. I'm wondering if it was just from sitting so long before I got it. Regular driving might have some effect on the seals keeping wet or lubed or something.

It don't make much sense but the more I drove it the less it leaked.

I bought some new IP shaft seals during the last group purchase but now seem to not need them. When I replace the IP belt I will have to think hard & long if I should even mess with the shaft seal...if it ain't broke don't mess with it???

[odie]

the leak has long since almost dried up. Often it does not even drip. I'm wondering if it was just from sitting so long before I got it. Regular driving might have some effect on the seals keeping wet or lubed or something.

It don't make much sense but the more I drove it the less it leaked.

I bought some new IP shaft seals during the last group purchase but now seem to not need them. When I replace the IP belt I will have to think hard & long if I should even mess with the shaft seal...if it ain't broke don't mess with it???

[dieseldorf]

Last year I resealed the IP myself with the rebuild kit from US Diesel. As of latest, they have $30.00 minimum ordering amount but take credit cards now. So I ordered 4 kits.
These are made in Italy and contain both shaft seals, the smaller and bigger ID. I do not know if these are Viton seals but since the EU is using the ULSD for years,that might be the case.

Lately I am re-sealing the IP from my Ford Escort Diesel (Mazda 2.0L RF Diesel Engine). The pump is similar to the LD28 but 4 cylinder. It was leaking a pint of fuel every minute through the throttle shaft. That job is somewhat more difficult as it involves the replacement of the throttle-shaft bushing. The shaft had at least 1/16" play. The old bushing must be machined out and the new pressed in. I did manage to buy the Bosch replacement bushing from Diesel Fuel Injection in Portland for $26.89
The pump cover comes off with no problems as seen here:



I hope that the machinist at my work place can do the job. Otherwise I have to find another machine shop. Last resort would be to return the bushing to Diesel Fuel Injection and let them do the job. They quoted me $150.00 to replace the bushing.

[asavage]

Do you feel that the wear is largely or entirely in the bushing?

I had the impression that, as in carburetors with throttle shaft wear, slop in the VE accelerator shaft area often had to be repaired by replacing both the bushing and the shaft.

[dieseldorf]

According to Diesel Fuel Injection and the Escort Diesel Forum, only the bushing needs to be replaced. The shaft is hardened steel the bushing is some copper alloy. The old bushing looks like copper.