Post injector swap issue...

[N.E fjord-by-fjord 2fiddy]

Just put a set of reman BB's in my 94 IDI T. I have what seems to be VERY low compression on one of my cylinders. If I start her below 20F, it actually misses for the first 5 seconds or so, then starts to get ignition after some revs. The problem isn't very obvious while driving, and there is VERY noticeable difference in power now, but when she idles... MAN. My headrests visibly vibrate to my 700rpm.

Anyway... My guess was that despite my best efforts, there was some crud that fell into the bore while removing the old injectors, and now one of my new one's is poorly seated and letting pressure get by on top. I was just asking on here before I go tear her apart all over again... Does this sound likely? If so, how in the heck would one clean out those bores? I was thinking I could "pipe cleaner" them out with some fuel, or additive with detergent, and then leave the bores open and crank my starter to blow them out...... But my IP would be off, so I don't want to mess up my timing at all. I know I could make a timing mark on the pump gear, but honestly, if there's a better way to go about cleaning out those bores that you guys know of, I'm very interested in hearing it.

That's if you even agree with me about what the issue is. If not, I'd love to know what anybody thinks is happening. Thanks!

(side question: any one know the OEM # for the brake line that goes from master to the proportioning valve? or even just the fitting types on the ends?)

 

[N.E fjord-by-fjord 2fiddy]

(i should clarify that the "VERY noticeable difference in power" was a comment about increased power from the BBs despite the one cylinder issue)

 

[crash-harris]

I used lots of PB Blaster and a 12 gauge tornado brush (woven stainless steel). I put it on a single section of cleaning rod and used a drill. I had so much carbon buildup that I destroyed 2 of them. A 16 or 10 gauge brush would probably be a better option, but Hoppe's doesn't seem to crimp then as well as the other brushes. I had to tighten it to the cleaning rod tight with 2 pairs of pliers and run the drill in reverse.

This worked great since none of my injector seats were scored or nicked. There is a special seat reamer tool for our injector seats, but they are rare and expensive. There are also a few $100 or so ramming kits available on ebay and amazon that have multiple head attachments for various makes and one brush kit for cleaning the boys and seats. I cheaped out due to finances.

When the carbon in my injector bores broke up, I made sure to pick out as much as I could and what I couldn't pick out got broken up into little bits and shoved into the precups. After priming the injector lines and reconnecting them, I spun the engine (GP's unplugged at the controller) a few more times to clear them out. Make site those seats are CLEAN.

 

[icanfixall]

Best I can do now with what you have posted is ask who did you purchase the rebuilt injectors from? Many cheapass ebay sellers offer "the best rebuilds" and the least cost.... Most if not all of the owners find out they got ripped off with poorly rebuilt injectors. Never buy a painted injector or injection pump from ebay. Those are ONLY tested. Then they paint them because that "looks like" a better rebuild than a dirty part sold to you. Makes sense too. Also did you time the engine after the injectors? If not I guarantee you are not timed correctly. Reason I can say that is the old injectors probably popping at a much lower pressure causing an advance timing. Now with a higher pop pressure the timing is towards the retarded side. Also how many miles are on the injection pump. Injectors and pumps generally run well for about 125,000 miles. some more and some less. They both degrade so slowly we can't feel the suttle change in power... But low and behold. Install a set of injectors and a pump and you feel like 2 more cylinders are added to your big V8 diesel. Sadly we are just getting back the power that has always been there but was lost because of worn out injection system.

 

[towcat]

if you suspect a injectore leaking compression at the seat, spray down where the injector screws into the head with penetrating oil and fire up the truck. go back under the hood and watch for bubbles between the injector and the head.

 

[Black dawg]

test those injectors if you have them out for any reason. The injector seat would have to leak quite badly to cause a rough idle.

 

[dunk]

I'm dealing with similar at the moment, but only a very slight miss and only when up to temp. I have an injector bore brush (https://store.snapon.com/Injector-Brushes-Brush-Injector-P635579.aspx) and seat cutter that I did not have previously so I plan to do a compression test, thoroughly clean bores and cut seaats if needed, and compression test again when done. I suspect I may have a double washer somewhere that has started leaking. Can the copper washers be reused? Probably cheap enough to get a new set or extras just to have. Source for these?

 

[Black dawg]

I'm dealing with similar at the moment, but only a very slight miss and only when up to temp. I have an injector bore brush (https://store.snapon.com/Injector-Brushes-Brush-Injector-P635579.aspx) and seat cutter that I did not have previously so I plan to do a compression test, thoroughly clean bores and cut seaats if needed, and compression test again when done. I suspect I may have a double washer somewhere that has started leaking. Can the copper washers be reused? Probably cheap enough to get a new set or extras just to have. Source for these?

My local hardware store has copper washers that work perfectly for these.

 

[N.E fjord-by-fjord 2fiddy]

if you suspect a injectore leaking compression at the seat, spray down where the injector screws into the head with penetrating oil and fire up the truck. go back under the hood and watch for bubbles between the injector and the head.

I did notice a little more anti-seize showing around #5... And that was the dirtiest bore. Lots of crap built up behind the GPC mount...

 

[N.E fjord-by-fjord 2fiddy]

Seller said pop tested, and BB is clearly stamped on all 8... Plus, not like I can mix em with my old G's that were running like crap. Haha.

That reminds me... Who's in the market for a rough looking set of G-codes for core?

 

[N.E fjord-by-fjord 2fiddy]

My motor mounts are probably pretty suspect as well, if the rest of the truck is any indicator. What I wouldn't give for unsalted roads...............

 

[dunk]

FWIW the injectors washers I believe are 8mmx16mmx2mm. Some old used ones measured slightly under ID, slightly over OD and a hair thinner. Could not find a standard size that was any closer than metric. No luck at hardware store and NAPA was useless, so ordered a bunch on Amazon cheap. Thinking since it's a pain to do I may just wait until I swap my ZF5 in. At that time I'll need to change turbo, and there won't be a more convenient time (as they come anyhow) to pull the engine to reseal it and do studs. The way my luck is that'll end up being a top end rebuild.

 

[Koch13351]

When my truck idled rough like you describe, it was from a loosened up rocker arm. Wasn't allowing the intake valve to open, therefor no/not enough air was getting into the cylinder, causing a miss. Same thing can be replicated by loosening an injector line, and since you did swap injectors, that leans toward an injector issue for sure.

I had quite the injector seat leak that went unnoticed until I washed my engine and saw the bubbles at the injector threads. Turned out to be a double washer in that bore, which was buried in carbon buildup and wasn't visible until I made myself a injector seat carbon cutter ream out of an old injector. It works very well at getting the seat damn near shiny, but doesn't cut into the metal. I'd take one of those old injectors and give it a shot. All I did was disassemble and gut the injector, thread the body and cap back together, grind the threads off with a flap disc, and cut grooves on the face of the cap. Stuck it in the bore and placed a 1" socket on it and twisted the socket clockwise by hand while pushing down.

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[N.E fjord-by-fjord 2fiddy]

^^^^ Pretty good use for one of my old G codes that no one wants. Haha.

 

[riotwarrior]

When my truck idled rough like you describe, it was from a loosened up rocker arm. Wasn't allowing the intake valve to open, therefor no/not enough air was getting into the cylinder, causing a miss. Same thing can be replicated by loosening an injector line, and since you did swap injectors, that leans toward an injector issue for sure.

I had quite the injector seat leak that went unnoticed until I washed my engine and saw the bubbles at the injector threads. Turned out to be a double washer in that bore, which was buried in carbon buildup and wasn't visible until I made myself a injector seat carbon cutter ream out of an old injector. It works very well at getting the seat damn near shiny, but doesn't cut into the metal. I'd take one of those old injectors and give it a shot. All I did was disassemble and gut the injector, thread the body and cap back together, grind the threads off with a flap disc, and cut grooves on the face of the cap. Stuck it in the bore and placed a 1" socket on it and twisted the socket clockwise by hand while pushing down.

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If u could figure some type of flats at socket flats to weld on so u could use an open emd wrench u could bore it completely through...attach a vacuum n suck out debris while cleanimg off seat....

Cool tool ya made there.