within 100 psi on new is good, the springs will take a set and change in 5 to 10k then if they are reset they hold for a long time. Usually.
Lets talk injectors
- Thread starter Silver91Hatch
- Start date
Silver91Hatch
Full Access Member
Ok. I am going to diagnose which one is giving me a fit, remove and disassemble it for now. If I can fix it I will, if not I am going to install a spare 7.3L injector for the time being. The snow is a commin' and this rollback needs to be on the roads making some $$. I have sent the $$ to you Typ4 for a set of BB's and a retun line kit. When they get here I am going to install them in the 6.9 and go into total, rebuild/figure out how they work mode on the old ones.
Silver91Hatch
Full Access Member
DP
Silver91Hatch
Full Access Member
Ok. I loosened the injector lines one by one on the drivers side with the engine running about 1100 rpm and I noticed that on the third one back fuel was shooting out between the line and the nut, the others just oozed or leaked, the one that was shooting fuel was the one I had previously diagnosed by sound, feel and with a screwdriver to the big nut area, it sounded different. So instead of yanking one from my project truck I found that a local parts house had a reman one pretty cheap(not as cheap as the ones I ordered). So I poped the reman injector in for just until I get typ4's injectors. But as of now I am not hearing the tapping. I forgot my pop tester at work so I ripped into the old injector. The first thing I noticed is it was probably the original or a junkyard replacement. It is painted grey and has a date of 3-87 stamped into it. Also after looking really had it has a B stamped into a wrench flat. I also noticed that carbon/compression has been bypassing the copper washer. There was fuel up by the large threads where the injector screws into the head. So I locked it into the vise, (I know I should of tested it first but I was curious!) and took it apart. Unthreaded the lower portion and laid all of the parts out on a nice clean towel. There was nasty black material between the lower cap and the large nozzle. I took all of the parts to the parts washer and clean them. There were 5-6 shims various thicknesses ranging from about 1/8th inch to .010. After I cleaned all the shims, spring, and various other parts I reassembled it and I will see how it sprays and if it drips, etc Tuesday or when ever I can get back to work. We have 10" of snow here in central North Carolina and it has pretty much shut down the entire state, I know we are sissies but I'm not driving the 26ft beast with 5-6 inches of snow on the streets and a 1/2 inch layer of ice on stop the 35 mile one way to work in 15 degree weather.
Silver91Hatch
Full Access Member
Well. I drove it a little more yesterday and the noise is back. It sounds to me like its a bunch of different cylinders at different time. I did run it very low on fuel before all of this happened, so I think I will change the fuel filter and add a quart of ATF and see if it clears up before I install 8 new injectors. I would hate to trash up 8 new ones.
1994IDI
Registered User
Keep us posted. Good luck.
apextrans
What Log Book????
The ice on top of the snow is ok. It will offer some traction as it breaks & packs down into the snow unevenly. You just just don't want it UNDER the snow.....bad news.
Silver91Hatch
Full Access Member
Anyone have any ideas what the black stuff inside the injector is/was? I am wondering if I pulled something out of the tank or of something is getting in my fuel system causing these issues.
Silver91Hatch
Full Access Member
Ok, got the pop tester from work today and tested my injector that was removed from my truck. It pop-ed at 975-1000 psi and it pretty much shot a stream out into the bottle. I added an extra shim that I have laying around and it raised the pressure to 2400 psi but the spray pattern looked good, it atomized fuel really well. So I pulled the thinnest shim out but it only dropped the pressure to 2250. I think I am going to look for some more shims or see if I can buy some more shims to get the pressure correct and see if the spray pattern is good. It didn't leak at any pressures. My tester said something about a chatter test, what is that about? I noticed that after I raised the pressure it chattered when I was testing it. Is that a good sign or not? Thanks
A proper injector should produce a feeling in the pump handle that for lack of a better comparison, feels like the anti-lock breaks kicking in on an icy road to your foot on the brake. It should also produce a sort of high pitched squeal as it operates.
icanfixall
Official GMM hand model
Find an injrctor pump rebuild shop. They usually have the shims... A 1 thousands shim is what you looking for. Do not install this injector back in the motor unless all the other injectors pop at or near the same pressure. If others are poping at 1400 (which is the low factory limit) and the rebuilt one is opening at 2200 you will have a real big problem. The low cylinders will be timed alaike and the high pressure cylinder will be really retarded in timing... That wont run right and over time will hurt mileage and the motor...
Silver91Hatch
Full Access Member
I didn't hear a squeeling noise, but after I raised the pressure it def felt like the ABS was working. The fuel spray looked good to me(novice eyes in IDI). But the first test it was like shooting a pen stream out, not its like a spray from a spray gun, a little more concentrated in the middle but atomizing the outsides.
Silver91Hatch
Full Access Member
I will give my local shop a try. To get this injector to where I can take it apart and see whats going on I installed 1 "reman" Advance Auto (BWD) injector. It ran better, but after it is warm is sounds worse then before. My theory on that is the other 7 injectors are around 1000-1100 psi and the new on being arounf 1900 is throwing it off. I am trying to let if sit until I get my set of 8 from typ4, then I can tear down and play with the old ones.
Silver91Hatch
Full Access Member
Well I am striking out on shims. My local diesel pump/injector rebuilder just wanted to sell me injectors, not shims. If I can't find anything then I guess I will be salvage yard bound, grabbing all of the IDI injectors I can find for the shims.
Check with Piedmont Truck Center. I'll bet they can help or at least know where to send you. Joey Clewis is the operations manager and a knowledgeable guy.
