"Rebuilt" 6.9 idi with ARP studs - don't want to ruin this one too!!

[ConstantVigilance]

Want to begin by thanking everyone that has posted and answered... I've gleamed so much from this site and feel as if I've given nothing back. Very grateful for those that have answered my questions in the past, and who so selfishly and quickly respond to others... enough sappiness:

I think I ruined my last 7.3 idi. I say "THINK" because i was always having one problem or another, and from what I've researched, many of those problems could have come from low compression. I always had a lot of blowby in the other motor, but also had this lingering oil leak from the turbo's oil return line.

Long story short: Bought a "rebuilt" 6.9 idi with ARP head-studs. Prior to purchase, I was only able to watch a video of the motor running and while she's been installed (finally), I still haven't ran my own compression check. She seems to have just as much power (seems like more from fully stopped) as my 7.3. I worry about the MoosePump in this 6.9 (I'll be contacting them).

Some problems:
1) Upon removing one of the Injectors, I noticed some Black RTV on the threads. I thought it could be because the Injector had lost some thread, but it turns out its the Head side. I used a wrench while she was running and snugged her down.
-------My concern is: both oil and fuel where coming out, and after I snugged her down and drove her again, she leaks a little still.

2) When starting, she will only keep running if I feather the pedal: my 7.3 seemed to idle higher for a few minutes and than drop down on her own.

3) She turns over very easy. Especially compared to my 7.3. After initial install of the motor, it didn't take long to bleed the air enough to fire her up. (I run a high torque starter).
-------Maybe this is normal, and I'm just not used to a regular running engine. But it reminds me of when I removed all the GP's from an engine to check it's compression...

4) I had this problem with my other motor: she'll turn off when I break too hard. Even after I've been driving her around (trying to do that initial "break in period"). I don't use the engine harness to power my IP relay, I've installed my own relay with current from battery, and use a ring connector on both the cold idle and IP relay. NOTE: the cold idle relay still gets her juice from the harness.
------Can I run the cold idle relay to my own relay? or does it have to be the engine harness for sensor reasons? I guess my question is: how does the cold idle work?

5) She does not want to start back up after she's turned off when hot (I had this same problem with the 7.3, and through reading this site, suspected it was my new Moose Pump's relay - I'm not sure it isn't): I hit the breaks, she turns off, and will take a lot of cranking and pedal floored to get her to run again.

6) I burned up my glow-plugs... again. Yesterday was the 4th set of glow-plugs that I've gone through (even if I wasn't "in-between jobs" this would be killing me).
-------When I had the 7.3, I went through 3 sets. Originally I thought it was the controller, so, I did the GPC Bypass MOD. Then, I think I just ran the GP's too long when the motor was warm enough. But, I've only ran this 6.9 once before the plugs went. It's possible I guess, but don't recall, that I ran the plugs when the motor was warm... but i don't know if that, in-of-itself, would do it.
--------I will be looking today at the truck's GP's to see if I blew these out. I ran them for 10 seconds and than waited about 30 seconds and ran them for 7 seconds and she started. When she turned off with hard breaking, I didn't run the GP's.
--------Because I just finished installing this motor (and had all the fueling system unplugged), I expected it to hard start.

7) Downshifting into Second gear will grind if I'm not going around 20mph. Before, I could downshift at 30 or so... I'm not 100% sure on the speeds, but i know that with my 7.3, I could down shift much much sooner. I'm thinking its a clutch bleeding thing... she seems a little softer than before.

8) I've read the instructions on rebuilt motor break in. (( http://www.thedieselstop.com/contents/getitems.php3?Breaking in a Diesel Engine )) I know there are a lot of opinions concerning this, so many that my head was spinning.
-------My question is this: He says not to idle the truck for more than 5 minutes. But I'm having trouble getting my coolant fluids into the truck. When I let the truck cool down, the big radiator is full, but when I'm driving, you can hear the boiling water and steam shooting into the overflow tank. And she reads hot on the trucks thermostat (when I had my 7.3 in her, she ran very cool after a proper engine flush). To be fair, I haven't re-installed my fan yet... I'm keeping her between 30 and 50 mph. I'll install the fan today.

I've been working on this rig for about 2 years now. I have yet to shake out all the gremlins.
Thank you in advance.

 

[79jasper]

Glowplugs could be from too advanced timing.
Sounds like a new fuel system would Do it some good. I believe 90% or your issues/symptoms are fuel system related.

Sent from my SM-G892A using Tapatalk

 

[ConstantVigilance]

Thanks for the response.
Just before I ruined the 7.3, I installed a return line kit. I have all new fuel line from the hard line, up.
But, I've never done anything with hard lines...

The timing is defiantly something I need to look at. The new IP didn't have marks on it and I've not had it timed at a shop. I had no clue that advanced timing could ruin the GPs. I'm going to try and pull some timing today, see how she starts and runs.

I wish I understood timing a little better. It sounds like the advanced timing could be making the compression chamber super hot? would that effect hot starts too?

 

[TahoeTom]

Where to begin? The injectors seal at the copper washer so the threads should not have RTV. The cold idle is powered through a temperature sensor by the thermostat. Power is supplied until a set temperature is reached and the sender cuts the power. The plunger on the high idle is threaded and can be adjusted with a 1/4" wrench. Cold idle should be 750 or so and drop to 650 when sender reaches cutoff temperature. Have you checked timing?

Your cooling system may be getting combustion gas pressure from a head gasket leak.

 

[Mulochico]

I wish I understood timing a little better. It sounds like the advanced timing could be making the compression chamber super hot? would that effect hot starts too?

Where are you in "North California"? I am in Modesto and might be able to work out getting together to time your truck. You mentioned a "shop", biggest thing with these trucks is that there are almost no "shops" that know anything about these engines let alone how to time them properly. If it doesn't work out for us to get together to time it there is a timing registry thread and there should be someone on it who can help.

 

[ConstantVigilance]

Thank you for the response TahoeTom:
I think they put the RTV on it to seal the leak that I've just now observed. I'm wondering if there is a more reliable, or permanent fix. If the Injector seals at the washer, perhaps I can use white tape? or Maybe one of those thread making compounds? I don't recall the torque on those being that much.

I haven't checked timing. I'll look into renting the timing gadget today. If I can get her running reliably, perhaps I can take it in someplace.

 

[ConstantVigilance]

Thank you for the response Mulochico:

I appreciate the offer,,, really. I'm up by Chico. I'd be more than willing to make that drive down to you if I can get the oil leak under control.

 

[Mulochico]

Might be able to work something out as there a few things I want to check out up your way but it might be a few weeks. I work nights and am usually off Sunday and Monday nights so Sunday afternoon thru Monday could possibly work. Let me know if those days would work and we will see what works out. I am not above a good drive, my baby needs to blow off some soot occasionally.

 

[ConstantVigilance]

Absolutely! Not a lot going on in my life other than this pickup. If I havent been able to dial her in, I'll most definitely PM you. thank you for the offer.

 

[Sidewinded_idi]

Sounds like you need a new injection pump. The hot start sounds like the normal worn ip not starting when hot. Next time it does when your up to temp get out and dump about a full bottle of water on the ip head where all the lines connect to it and see if it fires right up.

 

[ConstantVigilance]

Thanks for the response Sidweinded: The pump is less than a year old, purchased from Conestoga Diesel. It's the Bull Moose.

It was doing this to me when I had my 7.3, and I called them and talked at length to a Service/Tech guy. He wanted me to check fuel pressure from my at-the-time mechanical pump. The pressure was low to none. (interestingly enough: I could fill a pint of fuel under the testing time, but when a gauge was put on her she wouldn't register enough fuel to even bleed the tester). I replaced the mechanical pump with the electric pump and the truck ran noticeably better.

But, still, after a long drive, she simply wouldn't start. I contributed this to low compression... but I simply don't know anymore.

 

[ConstantVigilance]

Looking for a way to seal up that Injector port:

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That's a video on how to use the permatex thread repair
I'm thinking about something that rebuilds the threads. Only problem would be preventing the compound from falling into the chamber.

 

[79jasper]

I would contact Mel again.
Theoretically, low compression would start easier warm than cold.

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[ConstantVigilance]

I think so too. I didn't know that about low compression. Thank you

 

[icanfixall]

Well you do have some issues there. I can't think of a reason for the engine to die just because you stopped too quickly. Now its proven that most if not all trucks have the broken off fuel suction lines in the tanks. So the last 1/4 tank of fuel can't be sucked out. so you "run out" when the dash gauge says 1/4 tank. Easy fix is to never allow that to happen.
About the rtv on the injector threads. Sadly that does nothing to seal any hot compression gas. ONLY the copper gasket on the bottom of the injector can seal off the gas escaping. If yours has been leaking it probably is cut so no amount to tightening it will help.Run it too long and you cut the seat in the cast iron head. then you need to cut in a new seat. Its not hard but most have never done it. Takes a special seat cleaning tool too. Please remove that injector and replace the copper gasket.Also never reuse any copper gasket.They work harden and take a "set" to the injector and the seat.
Timing can be easy but you need to listen to the cold and warmed up running engine. With the cold advance circuit entergised you will have more advance and the engine will sound like a power stroke. When that is not powered up your engine will sound much softer or quieter. Its hard to explain really.
What glow plugs are you ruining? If they are ANY TYPE other than Motorcraft Beru then you are not running a good quality plug. champion and autolites are horrible plugs not worth what they cost.