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Diesel XJ having stalling problems.

DieselPioneer

NAXJA Forum User
Location
Florida
My Jeep is having stalling problems. I can be tooling down the road and all of a sudden I feel a loss of power. I give it more fuel to maintain till I finally get to full throttle and it then stalls shortly thereafter (all within a quarter mile). If I let off the throttle as soon as I feel the power loss it will run longer and if I just let it idle I think it would run indefinitely. I replaced all of the fuel lines. It is still having the problem. I believe it is air getting into the fuel line (but I am not sure). Maybe it is not sealing at the fuel filter assembly? It has that square GM push on filter. Maybe a leak within the fuel injection pump itself? Anyone else have this problem with their renault diesel? My next step is to put a piece of clear hose between the filter and injection pump to see if I can see any bubbles. I have been struggling with this intermittent problem for a while. Anyone else had this problem? Thanks for any help.
 
Thanks for the reply. There is no pump between the fuel tank and the injection pump. So, the whole fuel line is under a vacuum (even though slight) right up to the injection pump. The reason I thought a leak in the injection pump is maybe an o-ring is bad in the suction portion of the pump (again a slight vacuum) and drawing in air.
 
Leaking fuel lines or loose connections can adversely affect the performance of a diesel engine. If diesel engine does not start or run properly... it may be due to: in-operative glow plugs, restricted air or fuel flow, bad fuel flow, solenoid, contaminated fuel,injection pump problem, or low battery power. Most diesel engine problems are associated with the injection system.

Hope this helps.
 
BTW: If you are ever interested in selling your Diesel XJ... Please, keep me in mind. I'm in Tampa and would be willing to travel to get it. PM me anytime.
 
I was able to determine that air is leaking past the grommets in the filter canister filling the filter and fuel line with air. I wanted to post my findings for any others out there that have dealt with my issue. The factory fuel filter on my XJ is a Stanadyne filter assembly which was used by GM diesel vehicles for many years. The filter canister is box shaped and has four holes that have rubber gromets on them. The canister pushes onto four tubes that extend out from the permanently installed portion of the filter assembly (receiver). The canister is held in place by 2 spring clips one at the top and one at the bottom. These provide quite a bit of force as they are a pain to get on and off. The receiver has about 5 "standoffs" cast into its body. These keep the canister square with respect to the receiver and hold it away from the receiver at the right distance. Less distance may crush/deform the grommets on the canister with pressure from the spring clip. I temporarily fixed my problem by applying No. 2 Permatex to the grommets on the canister. A long term fix I believe is to file down the "standoffs" a LITTLE to allow a greater pressure on the grommets. Just use care to file them down the same amount.

Have fun,
Nelson
 
cher96,
I live in Valrico so am am not too far from you. I can't get rid of it, though! I like it too much! It would be nice however to have someone nearby to interact with about these Jeeps. Let me know when you find one. I can probably be of some help to you as well as I have gotten to know mine inside and out.

Nelson
 
check the gromments, o rings or other sealing surfaces before fileing away metal. over time the rubber sealing surfaces can wear down causing a faulty seal. if you can take the assembly off (and have another vehicle/ride) take it into NAPA and the guys there should be able to help you locate a suitable replacement for the sealing surfaces. be sure to lube the seals prior to install to prevent pinching, streaching or tearing
 
Thanks Stewie for the reply. That is good advice as I took the Stanadyne assembly off to get a better look at things and file down the "standoffs" (if needed). I was cleaning the receiver in a parts washer and noticed that when I put the parts cleaner hose up to the receiver fuel inlet not much cleaning fluid flowed through. I reversed the flow and all of a sudden I got good flow through. Evidently there was a blockage of some sort at the inlet. There is 90 deg bend right there where evidently sediment collects and it caused a blockage. This blockage caused a pretty good vacuum at the filter causing air to be drawn past the seals of the filter cannister. This problem has now been solved. A new problem has revealed itself. I suspect the blockage problem had been hiding this new problem. All of the fuel in the fuel line from the fuel injection pump and back drains back to the tank over a period of hours. And, I think it draws the fuel out of the injection pump as the vehicle is hard to start right away. I am watching the clear fuel lines tonight to see if I can tell where air is getting in.
 
Might need to add a check valve to your fuel line.
 
Joe,

Thanks for the reply. I actually did that, of sorts (great minds huh?). I installed a small manual valve in the fuel line that I close when I stop the engine and open when I start up. It is a temporary measure until I get things corrected. I think I have figured out my problem, at least to some extent. I believe the problem is the fuel injection pump drive shaft seal. Here are the symptoms: 1) When shut down, I can watch air bubbles entering the fuel line from the fuel injection pump, however slowly (hence the draining of the fuel line problem) 2) when running, I see no air entering the fuel injection pump from the fuel line, but, I see air bubbles exiting the pump in the fuel return line that goes back to the fuel tank 3) the engine is tending to run hot when I run the engine full throttle. I recently rebuilt a spare fuel injection I had which helped me understand my problem. The fuel pump within the injection pump is a small vane type pump just inside the housing from the injection pump drive pulley (this pump is the only fuel pump in the fuel system with the exception of the device in the fuel injection pump that supplies high pressure fuel to the injectors). There is a shaft seal between the two. If the seal is leaking, the pump draws in air across it mixing air with the fuel which results in less fuel being sent to the injectors and creats a lean fuel/air mixture in the cylinder making the engine run hotter (especially during a high fuel flow condition ie. full throttle). And, the return fuel that is sent back to the tank also has air in it also showing that somewhere air is getting into the pump. When the engine is shut down, air again is drawn past the seal due to the head pressure of the fuel in the fuel line which drains the line. If the Jeep had an electric fuel supply pump at the tank (like so many do) I would have never seen the problem. Some time back I had to replace the rotary head seal on the injection pump due to it leaking and I am sure the other seals need to be replaced as well. I will be installing my spare pump soon and hopfully that takes care of it. I appreciated the input from folks and wanted to share my struggles to help others. By the way, I got an excellent how-to video on the Bosch VE injection pump that was excellent! I was able to fully take apart, inspect, reseal and put back together my pump. I bought it on ebay. It was made by Rogue Power Industries.

Nelson
 
I installed my rebuilt pump. It solved my fuel draining back to the tank problem. I am still seeing air bubbles (sometimes quite a bit) in the fuel line from the filter but the pump does not seem to mind it. I guess the pump sorts the air from the fuel inside the pump body and sends the air back to the tank in the fuel return line. With the old pump I was getting air from the filter and air from the bad seals in the pump overwhelming the pump with air. It is running pretty well right now.
 
The saga continues: I teed the fuel pump return line back to the fuel pump inlet line putting much less flow through the fuel filter. This took care of a good deal of my air bubbles issue as I thought this may be attributing to my engine running hot (lean mixture). However, in reading a blog about this engine I was informed that my symptom, a slow continuous increase in temperature of the engine until overheating, suggested head gasket. I was also losing a little water but I wasn't sure where. A couple of the bloggers suggested retorquing the head gasket. I had my doubts but I tried it today. My overheating issue went away immediatly. I was able to actually get a turn on a couple of bolts. Some bolts did not move at all and some a little. I am not convinced it is a long term fix but I am happy for the moment. Some guys on the blog I read have done this several times to address their overheating issue. I guess combustion gasses leak out of the cylinder into the coolant area and displace the coolant. Till next chapter of the saga.

Nelson
 
I have been told by several diesel experts that diesel engines do not run hot when run lean, unlike gasoline engines.

In addition to retorquing the head bolts, you might try adding some of the brown color dry fiber pellets (I forget the brand name, it may be "Bars Leaks" ) that help seal small coolant leaks and head gasket leaks to your coolant.

I have used them for 30 years. A Chemical Engineer at Preston told me in 1995 that the OEM manufacturers have used, and added them to all new car radiators for about 80 years or more to make sure the cooling systems do not leak during the warranty period. If a small leak forms the fibers get stuck at the leak site, and the coolant drys up at the barrier, leaving a silicate (concrete) fiber seal at the leak point. The silicate is an acid neutralizer but also turns to a permanent solid (silica) at very hot leak spots like a small head gasket leak.

I may have retorque my SD22 (Nissan) diesel head bolts, after reading about your success with that trick, but mine passed a 10 minute head gasket leak test.

Mine does not overheat, but it also does not want to suck the coolant back into the radiator from the coolant overflow bottle (yes I know that sucks, LOL). I had a huge air problem in mine for 5 years, that I feared was the head gasket, but it turned out to be the water pump seal and water pump gasket on the suction side drawing in air . But it never leaked under pressure.

By the way, there is a diesel head gasket tester solution available that works with the typical "Block tester" rental kit from places like Advanced, AZ, and O'Rieleys. Part number 75730. Found at:

http://www.sjdiscounttools.com/lis-75730.html

There is a bulb on top of the block tester that you use to suck air out of the radiator and through the bubbler and fluid. 2 minute test will determine if there are combustion gasses in the radiator coolant. I tested mine for 10 minutes, with no color change, but I did not have it up to WOT on the freeway under a peak load, which is where an initial, small leak might start as the head pressures peak at WOT under heavy load.

In my case, I am just about convinced my problem is a radiator neck sealing problem, although I can not prove it, short of getting a new radiator. Or a very small leak in the oil cooler heat exchanger. So far I have no signs of leaks, into or out of the system. Just the annoying refusal of coolant to flow back into the radiator over night during cool down. Maybe it thinks it is a Renix closed system, LOL. But I may just retorque those head bolts for the hell of it.

In your case I would definately add some of those sealing pellets to help reseal that head gasket before it goes completely! I posted the part number for them here last year under in several threads. One of them was about snake oil fixes that actually work, IIRC.

I may have to track down that Bosch DVD you mentioned for fun some day. My Bosch is real interesting, it has a pneumatic over mechanical FI control on it. The SD22 is a naturally aspirated diesel. It operates the FIP on a throttle body plate differential vacuum combined with mechanical engine speed to control fuel rate flow.

Glad to hear you have that beast back on the road! Congrats!

Oh, and by the way, you have way too many posts here (only 43, LOL), especially for a 2005 joined up year.:laugh3:
 
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Thanks for you reply ECOMIKE. I appreciate the suggestions with the Bars Leak and the combustion gas tester. Good ideas! The Jeep has a flow-thru overflow bottle so any air in the coolant system gets worked out of the system pretty quickly. I have not had any overheating problems since I retorqued the head gasket. I have noticed that I am mysteriously losing a little coolant. I don't know if the head gasket sealed fully after the retorque or it is leaking again. I'll bet that if I retorque it again it will take care of that.
 
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