Injector trouble?

[TPringle]

I have a post in truck 911, dead truck in Mexico. My truck is a 1992 W250, 4x4, 12v, ext cab. Auto w/ 3. 54 gears. I may have messed up by having the injectors checked and cleaned (was done by a reputable firm). After a 3rd attempt on 2 leaking injectors, they told me that I should put teflon on the threads of the return line bolt (going into the injector). They look like they leaking from under the large nut that holds them into the head.



I am going to try what they suggested. If I end up having to get a set, do you have any recomendations? I have no knowledge on tips, brands, where to order, etc.



The truck is completly stock except for a gutted muffler. I dont want to up the power much beyond stock (then there goes the trans), but want to install something that will be efficient/economical.



I had the injectors checked because the economy had fallen from low 20's down to about 13. Idle speed has also dropped, but I dont know if that was a result of the injector problems. I had tried different things to correct, change all filters, clean the coolers/radiator and check the connections on the turbo/intercooler. No change. Power seemed off some, smoke seemed up, even after punishing it a few times. Tried injector cleaners, some used ATF, a little gasolione, u name it. Checked lift pump. Figured best place to start was the Injectors, since the system has about 100k on it. Truck has 350k. Any thoughts or suggestions?

 

[B.G. Smith]

Teflon is not a good sealant for diesel, it will seep through. I would be concerned about getting pieces of teflon in the fuel system. #2 Permatex will hold diesel in a threaded pipe line, I'm sure someone on here will have a better idea. Good luck. bgpi .

 

[Tippin Spotted Cow]

Can teflon hold up to the heat an pressure of the combustion chamber of a diesel engine?



At any rate, did you make sure they installed the copper washers for all the injectors, and torqued them correctly?

 

[JLEONARD]

If it's the same firm that suggested teflon that set up your injectors, I would doubt their work. As already said, teflon is not the wisest choice. That right there tells me they are not all that diesel savvy.

 

[cerberusiam]

Reputable is a stretch given what they are telling you. Dumber than a box of rocks comes to mind... ...





There are three sources that will put fuel around the lock down nut given all the lines are tight and not leaking:



1. Washers on the bottom of the injector not sealing either because they are bad or the bore was not clean enough



2. Those uclamps on the injector return line



3. A cracked injector





From what you said about having to file them, I would hope for the first 2 and suspect the last.



Idle quality and economy may not be the injectors. More often it is the pump that is causing it. I am sorry to say I have been the exact same route with generally the same sysmptoms and $1300 later it is fixed. Since the reputable shop is not looking that great I would hesitate to let them touch the pump, but... ...



I would not take it on a long run in less than ideal conditions without investigating more. If the IP eats itself you have a huge problem literally in the middle of no where.



Good luck and yell if you need more ideas.

 

[TPringle]

We found originally that one injector was leaking around the halves where they went together. I did find the shop (ok, USED to be reputable) damaged the face where the return lines went on. Now that seems to be where the leak is. I have attempted to clean it with a file, suspect I rounded it some, then used fine sandpaper over glass. Now, trying to find a copper or brass washer or have thought of trying rubber as a temp. I dont know if there is any pressure on the return line. I am doing all my own mechanical work, and have shop manual, so I know the torque is at least close. I fear I am stressing the small return line bolts, and fear breaking or stripping one.



I can change the pump, but figured the injectors were the best place to start.



Thanks for the help. To be continued... .

 

[cerberusiam]

Yeah, don't strip those little buggers or you will have a problem. There is not much pressure in the return line so a neoprene washer should work to seal it. You will need a washer on each side though as it is a banjo bolt.



Injectors are easier than pump but generally don't cause the issues you are seeing in these trucks. The HPCR trucks are another whole story.



I just had my pump rebuilt after only 60k miles. The internal vane pump went bad and spit metal thru the pump, injectors and relief valve. Cause all kinds of different problems.



Have another truck with the relief valve doing weird things and causing idle bounces, smoke, lack of smoke and power, etc.

 

[TPringle]

I "think" I may have the problem under control, that is with the leaking. I am not going to say it is fixed, tho. I didnt have any luck finding copper washers in Mexico. I am sure they exist, if I knew where to look. Out of desperation, I cleaned the washer, and applied a thin coat of solder, then used a file to smooth it, followed by fine sandpaper over glass. I still need to road test, but it seems the leak has subsided, or is so small that I cant tell. I will report back in once I road test for a couple of days. I did throw a few rubber O-rings in the truck just in case.



I will replace the injectors once I get out of Mexico (heck, it is easy now that I have practiced a few times). Does anyone know of someplace in McAllen, Tx that I can buy the injectors, or one of the TDR sponsors to have them shipped there? It has been reccomended that I try some 180 or 190 injectors. I am going after fuel efficency. A little extra power wouldnt upset me much when I need it. Wouldnt be any prob to add the Pyro & boost gauges.

 

[TPringle]

Road tested and seems "ok" overall. Not seeing any major leak, just may be a little damp around the area where the leak was, dont know if it is from the previous or is still leaking some. Anyway, should get me outta here. The only thing that still concerns me some is the drop in idle speed (it isnt stalling), and seems a little touchy coming off idle, but could be bouncing my foot from the rough roads down here. Gonna get in there and adjust it up where is sounds right and hook up and make the trip. All else seems ok. Gonna go injector and pump hunting once I get stateside. Thanks for the help and advice - got me going!

 

[dpuckett]

If you go on I-55 in MO, stop in and say hi. I'll take a look at it if I'm around. I also know a good injection shop in Jackson.



DP

 

[TPringle]

I made it! I got the truck, and trailer (of course) out of Mexico into the border area. I found a diesel injection shop down here that folks talk good about, and they are checking the injectors. I am investigating the 190hp injector tips. Waiting for the call with the estimate. I will run I55 going up. I even used to work in Cape (filled in for a fellow tv technician at that time). Thanks for the help! Not sure if this is the end of this story tho - still idles pretty low. Gonna see how the engine runs with the new injectors. To be continued ...

 

[cerberusiam]

Glad ya made it back with no trouble.



Just bite the bullet and do the 370 tips, you will be happy. :-laf

 

[TPringle]

I got the injectors back from the shop today. They not only fixed the idle problem but put the life back in that truck! I think the performance had been on the decline for some years, but wasnt drastic enough for me to really pay attention. It had begun to idle rough, and the word "slug" was an understatement. I had the shop put in a little hotter tip. They said they were 180 hp tips, and they did some other stuff in there too. Anyway, $800 later , I have my truck running again. The ide speed is back up to normal, and MUCH smoother, it accelerates smoother, and seems like I dont have to be on the go pedal quite as much to run the same speed as before. It is also quieter, the "rattle" seems more even, more uniform. Before it was really "rattely", and kind of rough. I am ready to head back into Mexico, and am curious to see if it will help the fuel economy. I will check in when I tally the results. Thanks for the help all!