My Official OM617 Toyota Pickup Repower Thread

[OM617YOTA]

Well, the miss is still there.

I killed injectors one at a time while the engine was idling. Cyl's 1 and 2 being disconnected made no difference to the miss. Cylinder 3 reduced it's occurrence, 4 and 5 seemed to stop it entirely. Re-enabling all the injectors brought the miss back.

It's less of a miss and more of an improper injection, badly timed or something? When I kill an injector, there's no extra smoke or anything out the exhaust, just a skip and more shaking than usual. With this issue, there's a noticeable puff out the exhaust. Fuel is being injected, it's just not burning well.

Either way, I was able to effect it, which means I'm getting closer. Next attempt will be replacing the delivery valve crush washers for cylinders 3-4-5, as they haven't been touched yet.

Think it would hurt to drive this thing? I didn't notice any misfires while test driving it........

[funola]

I don't think you'll hurt it driving it. Shaving cream works better than soapy water. Do you have a clear line returning to tank (cigar hose)? 2" long 5/16 o.d. clear lexan tubing spliced in works great. If there are bubbles there, find and fix before doing anything else.

[OM617YOTA]

I have a clear line going from the IP to the return fitting on the fuel filter, and then standard black fuel line from there back to the tank. I haven't noticed any bubbles and I did check for them. I installed a new primer pump recently and would be both elated and peeved if sucking air from an improperly installed or faulty primer pump had been my issue all along. Tomorrow I'll check much more closely.

Thank you!

[Cadin]

(My cloth/rubber injector returns were beat and I put viton on them as well, so now I can check for air there too!)

[OM617YOTA]

Just a quick update.

I bypassed the stock EFI fuel filter that was still in place. Just cut the ends off the steel line, slipped fuel hose over it and double clamped it in place. I cut open the old EFI filter, it was full of a substance that resembled black mud.

I have air in the return lines from both my IP and injectors.

I read back over my notes here and off the forum, and noticed that I replaced the hand primer pump at the same time that I had the pump elements out. The primer pump I used was Febi, as that's all that the local Napa had. I see that Febi primer pumps are not well regarded on the forum. Took a look at my primer/lift pump and saw that it was wet with diesel. I wiped it away, went for a drive, and sure enough it's wet again with an obvious drop forming at the bottom. My thought was that if fuel can leak out when the engine isn't running, then it's probably sucking in air when the engine is running. I replaced the Febi pump with another one. Was improved for about a day, then same issue, missing and knocking and fuel drip.

Current plan is to contact my local Bosch fuel injection shop and order the DGK301 lift pump rebuild kit and a genuine Bosch primer pump. Really hoping that's it, I've stopped driving the truck due to the knocking and while I have other vehicles, they won't haul anything and it's pretty important that I get my truck back up ASAP.

I also have a toolbox on it now. Will switch to something under the bed eventually, but for now it's nice to get the tools, fluids, tarps, chains, etc out of the cab.

Thanks everyone, hope y'all had a good weekend.

[Stretch]

The hand primer pump is the first thing to check for leaks. I've heard that the Bosch ones aren't much better than the Febi ones...

...but I wouldn't buy febi on principle - so Bosch it is!

[Cadin]

Is it still knocking only at initial warm up?

I certainly have to run my glow plugs a little extra after I fire mine up. Mine has also been knocking from the onset.

What did your prechambers look like? I think the Bosche nozzles have a pilot jet and a main jet whilst the Monarks just have the main. (Feel free to correct me if I am confused!) Don't piloted injectors naturally run quieter, and would a non-piloted injector bring out any prechamber problems that were masked by the old injectors? Now I'm curious...

[OM617YOTA]

Thanks guys.

I'm thinking I'll go straight for the new manufactured old style primer from Monark. Bulletproof and well regarded, even if more expensive.

This last trip the knocking calmed down when warm but never went away, this is what prompted me to park the truck. I didn't check out my pre chambers, just cleaned the injector sealing surfaces well and reinstalled them. I have Monark nozzles installed.

[Cadin]

Oh, one last thing, you did screw down it all the way right when you were done right? (Bringing the pump up inside.) (It won't have the ability to pump.) This is required to fully close the pump mechanism per the FSM, otherwise even Mecedes says that it will leak (likely you already knew this!) Part of the ruggedness of many of these pumps is that they don't seal on the pumping gasket and the shaft rides on a "cushion" of fuel. The sealing gasket is on the top of the pumping plenum.

[OM617YOTA]

You mean screw the black outer shell of the primer pump down? I screwed the primer pump base in and tightened it against the crush washer with a wrench.

[Cadin]

I mean just twisting the pump body...my bad the Bosch style doesn't seem to do it...

I guess I was thinking of the original style pump...


And the original monark pump:
(MercSource).com/store/heavy-duty-monark-ultimate-hand-primer-pump

(They both screw shut/stopped.)

[OM617YOTA]

OK got you. I am definitely thinking of switching back to the old style.

[Cadin]

I'm even thinking about the Monark, looks rugged; maybe overkill, but with our rigs being pieces of equipment, maybe worth it. (Cheap insurance?)

[OM617YOTA]

I think eventually yes a Monark primer pump. For expediency, I'm going with Bosch this time around, and will be returning the failed Febi pumps.

I just ordered the lift pump rebuild kit and a genuine Bosch primer pump from the local Bosch service center. I also talked to their diesel injection expert and he gave me a few pointers and confirmed that air in the system could be causing all of my symptoms. I told him that I have air bubbles visible in the return lines from the injectors and the IP, he said oh yeah that's your problem right there.

Whew!

Parts should be in my hands tomorrow.

[Cadin]

Good News!