Injectors, help for a new guy

[nyford]

So as the truck sits this is the combo, 1989 motor.

265/70/19.5's, 4.11 gears, nv4500 with divorced 205 t-case. Motor stuff, timing adjustment, rotated star wheel, boost pin turned, 12 cm housing, 4" turbo back, cold side off a 92 plumbed through a 01 intercooler.

I think I got a couple of stuck injectors on the last tow home. Truck ran like crap, limited to 4th gear and drove by the egt guage. Rough idle, lots of smoke, grey at idle, black under load. backfiring through intake, checked the valve train and everythiing good, no fuel or water in oil. Still starts right up so thinking injector issue.

So, with that said, if I have to rebuild 2 injectors already, is it worth it to upgrade? Or leave alone for towing.

Towing about 10k 5th wheel camper, pulling a long hill it pull 30 psi boost, 1200 max egt. The way I got the pump tuned now I get smoke down low but it cleans up with rpm's. I wish I had no smoke to keep the camper clean....

Just wondering if more air is needed or the system can support more fuel. I am getting around 12-13 mpg towing.

I have read conflicting threads saying stock is fine, other are raving on 5x.012.

TIA

Matt

[Remps]

Is your pyrometer pre turbo? Definitely sounds like injector(s) are buggered. Sounds like your setup is maxed out fuel wise for towing, as far as boost and egt go. You could put some more fuel to it, but it won't be usable for towing. Personally, I wouldn't bother rebuilding 24 yr old injectors, I'd go with a injector in the 5x10 to 5x12 size, depending on your plans for the truck. There are 6 and 7 hole injector options as well. You could back off the smoke screw to raise the fuel pin, and tighten up the starwheel (counter-clockwise) to try and tune out some low end smoke. When shopping for new injectors, ask if the pop pressures are tested before they send them out the door.

[Diesel Dawg]

I would probably have the stock non i/c inj. rebuilt on my cores. I have heard of quality issues on aftermarket inj. lately and the non i/c ones make as much power as you can tow with anyway. I would also make sure they used bosch nozzles if they need replacing. I have a i/c motor and will probably go with 190 boschs because I want stock reliability. Just alittle shakey on aftermarket inj. now. JMO

[PToombs]

Matt, must be you made it home? 5x .012's are too big to tow with unless you add more turbo. They were too hot for my hybrid H1C with a 60mm wheel and 16cm exhaust housing. Even running empty I could hit 1200*.

[nyford]

Pyro is pre turbo.

Diesel shop just called me back on the injectors, they poped about 600 psi low and lots of carbon build up on the nozzle which erroded the body which effected the spray pattern. Quoted 97 per injector. Ouch....

Looks like I am injector shopping, glad it wasn't the pump.

I also just picked up a snow tow max which would help with the egt's.

I did make it home, thanks for the help Pete. Use 35 gallons to make it home roughly 4 hrs at 65 = 260/35 = 7.4 mpg the same as my old 460 motor in the truck lol...

What size was the cold side I got off of you, was that a stock 56 mm off a Dodge? It had a 4" inlet and the stock boost elbow for an intercooled truck.

[RCCUMMINS89]

Do you want to stay with the 9mm shank injector? Or is the newer 7mm shank ok with you?

You looking for stock power, or an upgrade?

[nyford]

I may have spoke to soon. Guys at the shop didn't think the 600 psi drop would cause the problems that I have. So got the injectors back and going to swap them into different cylinders and see if the problem travels with the injectors. Probably get to do that this weekend.

7mm are fine. Looking for a little more than stock for towing. See above

[PToombs]

Matt, I think it was the original from my '92 H1C, IIRC. That would make it a 56mm? I think?

[Ram360man]

What are they doing to the injectors for 600? Just got mine rebuilt with new nozzles for 390

[nyford]

Just the basics, new bodies and nozzles, lap them in and pop test and 7 to 9 mm bronze adapters.

They were going to charge me 50 just to pop test 2 of them and inspect them. When I got there, they charged me 24 so I don't know if the guy just likes pulling numbers out of thin air but sure looks like it would hurt there business. I will go else where from no one. 12 bucks just to pop test seems high.

[Sutter1stgen]

86$ will get your injectors pop tested out here in super expensive California. Hope this gives you a little comparison on prices.

[nyford]

Well swapped #5 & 6 with #3 & 4 and still have the problem with cylinder 5 & 6. So looks like the problem isn't with the injectors. Compression test tonight or tomorrow.