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Discussion Starter #1
Hi new to diesel place and new to diesel engines. I have a budget rat rod project I'm working on and have decided to go with a 6.2 for motor choice. I acquired it from a good friend it is a early 80s i believe 81 6.2 and chassis that was a known good motor that was started about a year ago. I got everything all plumbed up and ready to fire up bled out all the lines and ran the glow plugs for 8 to 10 seconds and it fired up but immediately revved way up. We where able to get it turned off with the key so all is well. I pulled the top cover off to inspect the rack and metering valve shaft all seems to move freely and seems to be clean. I am assuming that something is stuck inside maybe governor weights but as I said I really have no clue having no previous diesel experience. Any thoughts would be appreciated.
Thanks in advance
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Welcome to DieselPlace
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When you remove the top cover, you can't just sit it back on and expect it to be right, the trick is to place the cover forward of the location and slide it back then insert screws... the leaver has to engage in the right place.. to check, when you turn the key on you should hear the shutoff click, and if you place your hand on the cover you will feel the click... if it doesn't click it's not right... and the shout off cyl could be stuck as well, it can be checked with the cover off to see if it moves freely...
 

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Ive had air leaks in the fuel system cause some weird issues in the past. You may turn the idle screw down and see if that is part of it. Sounds like the shut off solenoid is working if you could cut it off with the key.
 
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Discussion Starter #6
Yep I correctly reinstalled the top cover after looking around inside. Just looking for ideas why it's revving so high at start up. Assuming something is stuck in pump from sitting. Hoping I can avoid pump removal and rebuild and or cleaning. Maybe let pump sit for a while with seafoam cleaner inside or maybe a couple hits with a hammer to pump could jar something that is stuck loose?
Idle screw is adjusted down almost all the way. It is up just enough to alow it to fire up. I did have a small leak in the return line and was told that a leak in return line would only cause an unstable rpm not full throttle runaway. I have repaired the return line but wanted to get an idea of what was happening before I try to start again for fear of an full blown diesel run away I have a steel pan to choke off air intake but just kinda gun shy to try to fire it again without really finding/solving the issue
 

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Discussion Starter #7
Yes that is correct shutoff is working I bench tested it and it is clicking while keying installed on pump
 

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Discussion Starter #9
I'm not sure where the idle spring is located but if it's under top cover I can pull it and post a pic in the morning when I get back to shop.Thanks
 

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If you mean the return spring on the throttle linkage, that is in good working order and linkage moves freely and springs back to idle nicely. But I will definitely post pic of inside top cover in the am. Thanks and sorry to anyone I don't understand what there asking like I say little to no diesel experience for me
 

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Wow, that is some clean diesel, completely clear. Awesome project BTW.
Nothing obvious, no signs of broken flex ring or weight cage rivets, you say the metering valve moves freely, it needs to be extremely free to work properly.
These min-max governors don't regulate speed very tightly, the low idle (MIN) spring is normally collapsed at anything much above low idle speed, and the MAX spring stays fully extended until atleast 4000RPM. So the governor between low idle speed and high idle is very loose. Air bubbles will make it erratic too.
 

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Discussion Starter #14
Thanks for the info. I do have one thing I'd like cleared up though the shut off valve in top cover is working correctly as we've talked about previously but the other valve in the top cover I believe is the cold start Solenoid that is part of the return line I do not have it hooked up to power nor did the previous owner would that make it rev high. I bench tested that Solenoid and can only suck air through it while it is energized. thanks
 

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The other solenoid is the HPCA, Housing Pressure Cold Advance. When energized, the plunger unseats the ball in the housing pressure regulator which dumps housing pressure and increases advance timing. It does not affect cranking fuel delivery or timing, only advances timing to warm the engine up faster.
 

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Discussion Starter #16
Ok thanks for the info again greatly appreciated. I think I will let it soak with some seafoam for a bit and give the pump a few wacks with a breaker bar maybe jar something inside loose that my be stuck and give her another try. Unless anyone has any other ideas. If still reving guess it's time to pull pump and have her gone through or find a known good used one. If I end up pulling pump any tips or tricks that I would need to know to make the process easier or ways I could mess it up. Lol
 

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Discussion Starter #17
Also if I do end up needing to pull pump is a rebuild something I could tackle on my own or is it very technical. I'm not afraid to pull some of my own hair out but also don't want to get way over my head if it's a total nightmare. Are parts available like in a rebuild kit? If I send it out what is a ball park for rebuild cost?
 

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You can purchase gasket kits online, sure, but to properly rebuild and recalibrate one does require some specialized tools and equipment. As far as injection pumps in general go, DB2s are pretty simple, but its far from being a DIY job. Rebuilds generally run $400-600 but that can vary by shop.
 

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Discussion Starter #19
Sounds good thanks again for the info. Will give her one more try and go from there Thanks
 

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Discussion Starter #20
I have the intake with the egr on top of intake would it be ok to remove the egr to be able to use a plate to cut off air in case of my run away issues or would removing egr alow more air to flow through making my risk of run away worse. Thanks again
 
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