Air intrusion on 1990 7.3L f350 with banks turbo

[danda]

But the fuel doesn't drain back

thx for sharing that. It's been unclear to me how a leak in the return system would cause significant air intrusion in the primary. And it seems the answer is: it shouldn't, in isolation.

I wonder though if you have the line between fuel filter and injector #1 return cap, or deleted it? I plugged mine for now, just to eliminate that variable -- especially as mine has no check valve.

It makes sense to me that the real cause of my hard-start issue should be in the primary line. At this point, I believe the only thing I haven't eliminated/plugged is the heater element, but there is no leak at all in the fuel filter area running or sitting, so I don't see how air could be replacing fuel that is not escaping. I suppose I should delete it (or replace o-ring) just to eliminate the doubt though.

Have you ever taken the fuel filter off and checked how full the filter was first thing in the morning

no, I'll try it in the morning. Though I'm confident it will have dropped because the schrader valve dependably burps quite a bit of air after sitting overnight.

When I installed the elec fuel pump I was under the impression that it should purge the air and fix my hard-start issues, but it didn't seem to help at all. (At that point I still had the line between fuel filter and injector #1).

 

[danda]

Update:

I just tried a brand new cap from Badger Diesel, made in Germany, not China. It is the old/original style cap.

I also cut new hose and very carefully placed it to avoid putting stress on the o-rings.

Result:

STILL LEAKS OUT THE TOP. (of the cap, not nut)

At this point, the only thing I haven't replaced on injector #7 is the hard line.

Kinda pulling my hair out.

I am wondering if this could actually be a hard-line leak. If so, it would have to be leaking down through the threads rather than up out the top of the nut.

Does that sound plausible to anyone?

Anyone had this experience? if so, how did you fix it?

 

[danda]

Update:

I finally was able to get the injector #7 hard line removed. It attaches to the bottom of the IP, so I had to remove some other lines, and modify (with a grinder) a 5/8 half-moon wrench in order to reach the nut. After much swearing at international and ford, it is off.

Upon inspection of the nipple that attaches to injector #7, I find some pitting/cracks. Not all the way through, but enough that I believe fuel could leak by. Probably they could be sanded away, but it would take a fair amount of material off, and given the headache of removing and installing lines, I don't really want to mess with it, so I ordered a brand-new aftermarket line for $60. Hopefully it does the trick.

I have a set of re-man stanadyne injectors. I'm debating about installing them while waiting for the hard-line to arrive.

The engine runs well as-is but the exhaust smells a bit rich. I already put one of the reman injectors in at #7. Also, this engine/truck always seemed a bit weak to me, back when I used to haul a 37 ft 5th wheel around. With a banks turbo it would tow the trailer ok, but still going up a grade I'd have similar size rigs passing me.

So pros are:
* Maybe new injectors would fix the rich exhaust and provide more power.
* Since I already changed #7, it would make sense to do the entire set now.

cons are:
* I haven't pop tested the re-man injectors. Should probably do that, but I don't have a pop tester, so would need to buy, rent, or borrow from my cousin.
* it's kind of a big job. A full day if I'm lucky. And with my luck, new leaks will pop up.
* IP probably needs to be timed after. I don't have meter, and don't know how to do it.
* worried I might do a bunch of work and end up worse-off than now.

A possible plan of attack is to pop test the re-main injectors, install them (if ok) and then take it to a local diesel shop to time the IP. Hopefully they wouldn't charge too much for that. assuming they have the correct meter....

just thinking out loud...

 

[IDIBRONCO]

assuming they have the correct meter....

It's getting harder and harder to find a shop with a meter for timing our engines these days.

 

[Old Goat]

For what a shop would charge, you could just as well use the money and pick up one of the new one`s offered on E-Bay.

Shops today only want to look at the new stuff, not our old junk. They well tell you it is too complicated to work on or too old.

If they do "time" it, it will be by ear, and you can do that.

Goat

 

[Nero]

Isn't that the truth!

 

[Old Goat]

Here is a used one for $150

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New one for $300, $42 to ship. There were a bunch being sold a few months back for 1/2 of that.

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Keep checking, some others will show up.

Goat

 

[danda]

So what should I expect after replacing the injectors if I haven't re-timed the IP yet?

rough idle? exhaust smoke? poor mileage? not reaching full power?

but it should at least run.... right?

 

[IDIBRONCO]

rough idle?

Maybe, maybe not.

exhaust smoke?

Quite possibly.

poor mileage?

Yes.

not reaching full power?

Definitely.

but it should at least run.... right?

Right.

 

[danda]

Update:

I pulled the 7 remaining old injectors today. Copper washers came out with each one, so I was happy about that.

It turns out that the first one I pulled previously was in the best shape. Most all the rest had wet tips, even though the truck has been just sitting for about a week.

Also, there was a bit of carbon on the sides of some of them. Not too bad... they all came out easily. On some the copper washer is so black you can't even tell it is copper. And the tips are kinda grimy. I wonder if they weren't torqued down tight enough when installed, or maybe the seats not cleaned well.

Anyway, my thought is that the wetness indicates they were leaking into the cylinder. Perhaps this is the real cause of my hard-start situation.

Before installing the re-man injectors, I figured I would pop test them first to check pressure, pattern, leaks. And also the old ones for comparison. So I setup my brand new pop tester and .... nothing. I couldn't get the friggin thing to even prime. Contacted the seller and they said to return it. So it's at least 2 more days until a new one gets here. damn it.

Meanwhile I will wire brush out the bores. Anything else I should do while I'm at it? The glow plug harness wires seem functional but the clips are kinda loose on the plugs. I'm debating about replacing the harness or maybe just crimping the clips better.

Also, I want to replace the return line hose that goes to the back of the engine, or at least inspect the connection. Unfortunately, it is pretty well hidden behind/under the banks turbo and I'm too lazy and chicken to try removing the turbo just for a return line hose, which appears in good shape. Anyone else with a banks dealt with this?

 

[Big Bart]

Classic Diesel Designs has the glow plug harnesses. If it was me I would replace them as they are likely pretty rough if they have never been replaced.

 

[IDIBRONCO]

Also, I want to replace the return line hose that goes to the back of the engine, or at least inspect the connection. Unfortunately, it is pretty well hidden behind/under the banks turbo and I'm too lazy and chicken to try removing the turbo just for a return line hose, which appears in good shape. Anyone else with a banks dealt with this?

DO NOT remove the turbo to inspect or even replace the return line. There's nothing at all good about that idea. I don't remember if you plan to replace the return lines or not. At this point, it would be a good idea to replace them. the hoses are all old and have hardened. Once they are disturbed, they tend to leak. Russ, Conestoga Diesel, and Classic Diesel Designs all sell return line kits for a turbo application that do away with the crossover line at the back of the engine. That would be the best way to go.

 

[danda]

Update:

I received a new pop tester and was able to get it primed and working.

I started testing the rebuilt injectors I purchased and was not impressed. Well, one I had already installed before, so I didn't remove and test it.

I found 3 that seemed to be Ok that popped around 2000, held some pressure, and didn't leak.

Of the remaining 4, at least 2 popped over 3000. Most or all leaked considerably and lost pressure quickly.

Also, upon closer inspection I noticed that the injectors were a mixed bag. 7 are Stanadyne, but 1 is "Cav" from England like my old injectors. Manufacture dates are all over the place. Some say G, others E, one has E and G. Also someone has engraved/scratched "25x" into most of them. Maybe that is all fine so long as they are rebuilt well, but it didn't give me a good feeling. Oh, and also one injector was missing o-rings entirely and another has a broken o-ring. Not a good sign re quality control.

It would help if I had a brand new or "known good" injector to compare against. They could all be bad for all I know.

Today is the last day I can return them. I only paid $175 for all 8. So I'm debating whether to return, or hold onto them and perhaps rebuild myself.

I also pop tested 4 of my old injectors. They were popping around 1000 and dripping a lot. So the "new" injectors seem better than that.

I took one of the old ones apart. They are very simple. After cleaning and reassembly it was popping at about 2000. But it still leaked. I'm thinking the tip and/or needle needs replacement.

Anyone have links to resources on rebuilding these things?

 

[IDIBRONCO]

Unfortunately, you've just learned the hard way why cheap "reman" injectors aren't worth it. The letter codes mean nothing these days. They've all been rebuilt multiple times to the rebuilder's specs (or lack thereof). I would return them if it was me. Otherwise, I'd hold onto them for cores. If you want to rebuild them yourself I give you props. I certainly don't have the ambition to try.

 

[danda]

I went ahead and started a return on those reman injectors. Good thing I was able to test them today.

Yeah I wouldn't mind rebuilding my old ones, but afaict the biggest problem is that the nozzles are worn, hence the leaks. From what I've read, the only real fix for that is new nozzles, but I haven't found a good source for them.

So I may be looking at new injectors anyway, because yeah I'm quite leery of reman injectors now.

Or if anyone has a suggestion to fix leaky nozzles, I'd be keen to hear it.