Should have left well enough alone!

[Brokedownmedic]

I just changed out injectors and glow plugs on my '98 Suburban. It was running okay but it had 118k and the mileage was falling off so, I thought it was about time. I also decided to put in a number nine resister to match the marine injectors. The resistor came from here. The rest came from Accurate Diesel. Everything looks good. No leaks. It idles ok with an occasional stumble. But, out on the highway is another story. It runs fine if you take it easy. It even runs fine at highway speeds. But put you foot in it and things are not so good. It stumbles badly and it even cut off when I kept my foot down on the floor. Then I got a 0251 code. It started back up and got me back home. So, what did I do wrong?
Ps. What does it mean when the wat to start light flashes 4 times after the truck starts? It was doing this before all this started.

1998 Suburban 118,000 miles. FSD heat synch, Stock exhaust, old style mechanical vacumn advance, K&N High flow Breather, Fire Package, 4WD.

[grancito]

Wait to start light means the glow plugs lit again, thats normal. Sounds like lack of fuel, you could have disturbed the OPS sensor and the lift pump is now not running, I did that when removing the intake manifold.

[Brokedownmedic]

Thanks. Short of a complete overhaul or a contortionist midget, does anyone know how to replace the OPS? I can barely see it much less get a wrench on it!

[grancito]

There is a special tool to remove it. In my case, on the side of the road, I ran a wire from the pump fuse on the fire wall to the windshield wiper plug so that it runs when the ignition is on, that's the way it will stay. But check to see if it is running.

[M123KT-450]

I just wired mine up to high amp flip switch . . .


Mike

[JD_countryboy]

Could ya fill out your signature, and your location? Im not sure what the 251 code is, but kinda sounds like noot gettin enough fuel from tank to ip. Check lift pump operation, like grancito said, and while makin sure its working, check for air bubbles in fuel. If air bubbles comming out also you have a leakin somewhere betwen tank and lift pump. seems as if lately theres a rusty/leaky fuel line bug goin around. common place to rust is top of tank sending unit, some with no sign except air in fuel, low fuel pressure at WOT, or under load.

[Brokedownmedic]

Thanks. Any idea where I can get one of those tools?

[Brokedownmedic]

Ok. I tried the Lift Pump suggestion. Thanks to all. I put a jug of fuel at the bleed off hose and opened it while running. The jug filled up. So, the lift pump is still running. Could all of this be happening because I screwed something up when I put the new #9 resister in the PMD? Maybe I got it in backwards or maybe it an aftermarket PMD that not compatible with that resister. This shade tree mechanic is scratching his head.

[grancito]

Nothing to do with the resistor. The code P0251 is IP fuel metering A fault, and has been cured by adding 2 stroke oil to the fuel.

[Brokedownmedic]

Nothing to do with the resistor. The code P0251 is IP fuel metering A fault, and has been cured by adding 2 stroke oil to the fuel.

I should have added that along with the Total Power, I add a pint of 2 stroke at each fill up.

[JD_countryboy]

did you see any air bubbles in the fuel? How big a jug, and how long did you have filter drain valve open? Did you replace fuel filter? and what kinda condition were the rubber lines in? could be restriction in the rubber line if its old and you flexed it.

[Brokedownmedic]

Thanks, I'll check all that. I've ordered another fuel filter. When it gets here, I'll do a fuel system check and flush and see if that clears anything. I'm also going to try another PMD just in case I screwed up something putting in the new resistor. Any other thoughts?

[3bals]

How far did you drive it after the work done? Any work on the fuel system lets air into it. Sometimes it take a few miles and starts to clear it out. I just went through this when I changed my fuel filter.

[Brokedownmedic]

How far did you drive it after the work done? Any work on the fuel system lets air into it. Sometimes it take a few miles and starts to clear it out. I just went through this when I changed my fuel filter.

I changed out my fuel filter and cleared out all the air from that. Then I swapped out the PMD with and old Stanadyne mounted on my FSD. After a bit of bucking and kicking at first as the last of the air cleared out, the old Suburban began to smooth out. No more stumbling. I'm still wondering if changing resistors on a Dtech PMD is the no no that got me in trouble to start with. I think I will write them. Thanks for all the help guys.