m35a2 rebuilt fuel injector pump help

[168AR]

I just had my IP rebuilt and had my mechanic install it. When I drove the truck home it had low rpm. Then next morning I tried to start it and it wouldn't start until I pushed the pedal almost to the floor it then started but rpms were way over 1000. According to the mechanic once it got started & warmed up it idled fine. When I picked it up from the mechanic it started fine & idled fine due to it already being warmed up.

I have read several posts in regard to low rpms but I haven't found a post dealing with a rebuilt IP having problems starting. Can someone give me some guidance?

 

[country]

You may need to advance the timing a tooth or 2

 

[Floridianson]

We have had a hard starting because of a sticky fuel control. Did the mechanic spin up the IP? Did he use Viton O rings in the head? Was the FDC bypassed? Did you replace the old oil feed line with a new one? Might just need the main fuel brought up a tad. Anyone with a cheap tool set can take one apart and put it back together but in less you spin them up you will not know how it will perform. Would have been nice to talk to you before you took it any where as most problem we see here are just in the Head not the lower unit.

 

[rustystud]

We have had a hard starting because of a sticky fuel control. Did the mechanic spin up the IP? Did he use Viton O rings in the head? Was the FDC bypassed? Did you replace the old oil feed line with a new one? Might just need the main fuel brought up a tad. Anyone with a cheap tool set can take one apart and put it back together but in less you spin them up you will not know how it will perform. Would have been nice to talk to you before you took it any where as most problem we see here are just in the Head not the lower unit.

I would be surprised if the mechanic actually rebuilt the whole pump. You need some special tools to do that. I had some made for me when I was rebuilding mine. He probably just tore it down enough to see all was working OK, then put it back together. Like you said though, the Hydraulic Head is the problem 99% of the time. The 1% usually involves broken parts.

 

[gimpyrobb]

I wouldn't mess with the timing just yet. First, I'd try increasing the fuel delivery rate. If the FDC isnt bypassed, I'd do that first, that essentially turns up your fuel.

Also, I suggest installing a pyrometer. That will tell you when you have too much fuel. Too much, and you'll end up melting parts and ruining your motor.

 

[168AR]

My reason for a complete build was the IP was leaking bad and I had diesel in the oil. The mechanic who rebuilt the IP is federally certified Diesel pump mechanic that is all he does. He also does the rebuilds for duces at Idaho motor pool. He said the IP was in good shape except for seals & springs. The guy who installed it was a duece mechanic in the 80-90's but obviously has forgotton some things. I also had the injectors tested and they were bad so I had those rebuilt too.My FDC isn't bypassed at this time.

I will try moving the fuel up and see how that works. Where can I get a pyrometer and does it give a temp reading before the turbo or at the exhaust? Also where do I check the fuel psi for the IP. from what I've seen on SS the stock psi is 7psi and can be adjusted to 12psi?

I bought this 3 years ago from our rual fire department. It had sat for 3 years. It runs really good but the more I drive the more stuff needs worked on. For $2,000 I can't complain.

Thanks for all your help.

 

[gimpyrobb]

Lots of info in this link. I put mine in the manifold before the turbo.

The in-tank pump puts out 5-7psi, then the booster pump on the IP bumps that up to 60psi depending on rpm.

https://www.steelsoldiers.com/showthread.php?19089-Pyrometers&highlight=

 

[frank8003]

All your questions listed have been answered in this SS website.
Everybody here will help you, right after you help yourself.

Goto almost the top right of this site and put in there something you are interested in.
Insert "pyrometer" or "hydraulic head" or cluth or hard start of runaway or something like that.

Any problems write back.

 

[Floridianson]

Agree bypass the FDC first as it might only give you trouble later on as it can put fuel in engine oil.

 

[168AR]

I have watched videos on bypassing the FDC but none mention if you turn up the fuel as usual. Does this change with the bypass?

 

[gimpyrobb]

Yes.

The FDC limits the amount of fuel delivered to the injectors. When you bypass it, you will notice an increase in power.

 

[168AR]

What about the temp getting to high for the pistons? Do I still use the undjust at the baseof the FDC?.

 

[gimpyrobb]

Yes, but I'd try it out before you get too worried. As long as your not in 5th gear screaming up a mountain, you'll be fine till you install the pyro.

 

[168AR]

Thanks