m1008 Engine mystery

[mattm257]

My m1008 had a engine miss, and then the fuel shut off switch stopped working, so I took apart the injection pump and found it full of metal filings. Changed the pump with a high quality rebuild, new lines, new injectors, replaced the fuel filter base/filter, new golow plugs. Bleed the system out.
Engine runs awesome, no more mis, lots more power no more black smoke.

However still starts with what seems to be to much effort. Needs glow plugs almost all the time even when warm out. Starts easy when hot. Cannot understand what is causing the cold hard starts.

Also has a newer high torque starter, cranks fast.

Could this be a fuel drainback issue? any help greatly appreciated.

thanks

 

[tamecrow]

Is the cold advance solenoid working?

 

[dstang97]

If your GP "system" is stock and working correctly do exactly what the light says. They are pretty accurate unless you blow you GP card. So everything sounds fine to me

 

[notsosanestan]

Did u replace the lift pump?

 

[steved454]

a new lift pump made all the difference in mine.

 

[mattm257]

I will be replacing the lift pump, $23.00 and will post the outcome.

 

[mattm257]

Have replaced lift pump and no change. When cold even after cycling the plugs cranks over with nothing, not even a sputter, glow plugs cycle again and then cranks and fires. Cold advance is working. Is there a possibility of fuel drainback?

 

[notsosanestan]

Is the glass ball in the return fitting? Or u have a small air leak some where. You can disconnect the return line and put 10psi inti the return lines and listen for leaks works really good to bleed the lines when u need too also

 

[steved454]

On mine I had to cycle twice for mine to crank. Replaced Lift pump. It cranked right away, if it set for a day or a month but died right after and had to cyclte again to prime up the system. checked for leaks noticed that I had a leak at the injector pump. That explains the fact I had fuel in the rails past the IP and loseing prime from the IP to the filter. IP replaced now works great.

My guess is you have a leak somewhere. If the IP has not been replaced then I am sure there is some problem there, if not now then in the near future. also check the filter base they are prone to crank. If so they still had a few bases left at Saturn autoparts a month ago.

 

[BIG_RED]

Stock filter bases almost always leak on these things. I went spin on, no more problems. Haven't touched the filter unit since I put it in, money well spent. Mine is stanadyne FM100 system. Pricey ($120ish with shipping) but awesome. If it needs CRANKING to start, you have an air/fuel leak (air in fuel, fuel drainback, etc.). If it needs lots of time on the GLOWPLUGS to start, you have glowplug issues (too much resistance on GP resistor, they don't stay on properly - gp control card is shot, they are real dirty or something) or you might have low compression, or the timing advance fast idle solenoid system isn't working. (green wires on top of IP). Check that there is power to the green advance solenoid wires when the engine has just started and is cold. If not, you need a new temp sensor or wires. Temp sensor is on drivers side cylinder head towards front of engine. round thing with one wire to it, behind Power steering pump bracket, near frontmost glowplug. If I unhook this sensor, my engine starts poorly (more cranking than usual, have to hold part throttle to keep it running for first few seconds, etc.) There is another sensor on top of the passenger side cylinder head near the firewall, but i think it's just for an idiot light. Not sure about that, might want to check it too. Good luck!

 

[steved454]

been wanting to change to a spin on filter, yes I agree that is the way to go. have looked at alot of spin on filter bases, now when mine started leaking I will get the same one.

 

[BIG_RED]

I heard that GM used a filter that fits in the stanadyne FM100 base on the newer trucks with a 6.5 (like 1995+). That's why I chose it. Parts availability is important to me, cause I go all over the place. I bought 3 filters with the filter base over a year ago.. I still haven't replaced the one I originally put in. guess I won't need another one for a while. The FM100 is a modular set-up, so you can buy "accessories" for it. They have an electric fuel heater for it to use summer fuel in cold weather. I didn't put one in, because winter fuel up here is pretty good. (the original stanadyne model 80 "box filter" the truck came with usually has a heater). They also have a water sensor. You can wire it up to the truck's original filter sensor plugs and then the original idiot light will still work. It cost's like $80 though, so I opted for a "clear sight bowl". They don't offer it on the website, but if you ask for it they will look it up for you. It's basically a hockey-puck shaped clear plastic disk that goes on the bottom of the filter. You check it every so often, and if you see water in it, you drain it. It costs $36. I like it better than the idiot light. Less to go wrong, and cheaper. Plus, the bowl holds quite a bit of water, so even if you don't check it for a longg time, it'll keep the water out of your engine. (the original system didn't hold much water, so if your idiot light burnt out, you'd have water going in your engine pretty quick. And you wouldn't know until the truck started running poorly.) Good Luck!

 

[wallew]

This solved all sorts of starting issues for me.

It's a complete fuel filter block, including the backing plate (mine was leaking air) with two new sensors, a new fuel filter and a new mounting bracket.

Military Pickup Truck Fuel Filter CUCV NEW Chevy GMC: eBay Motors (item 390242173731 end time Oct-19-10 23:20:20 PDT)

Mine cost me less than $70 with shipping.

 

[mattm257]

what is the glass ball in the return fitting? where is it located? at the IP in the return line?

 

[JDToumanian]

I'd like to know where to check for the glass ball too.... I'm also going to replace my lift pump, I already bought a new one.

Where are the normal places to check the filter housing for leaks? Are there o-rings to check and replace? My M1009 cranks for about 8 seconds if it's sat for more than a few hours, even when still hot. I know it's an air leak, but the IP, fuel return lines and other fuel hoses are all new. I replaced the fuel filter too. So it's something else and I've been getting angry over it.....

Jon

 

[notsosanestan]

If you look at the return line its inside the small fittings connected to it. I didn't think mine had the glass ball at first its hard to see

 

[lindyp38]

thanks for this post...as mine is hard to start...and not starting right now.....

 

[91W350]

I am not sure where the problem lies in those original filter bases, but I suspect it is a product of the clamping force from the filter springs and the fact they hang unsupported by a bracket at the top. One of my M1009s was hard to start, replaced the lift pump as they are known to leak down. It fired right up for a few weeks, thought I had it whipped, then it slowly came back. It was requiring bleeding of the fuel block to get started, then once started it was good until it sat over night again. Finally it started actually puddling fuel and it was leaking from between the filter and base. A new base fixed mine. I had changed the filter before the lift pump, with the pump and once after installing the pump. Now she fires right off. I was really tempted to convert to the spin on filter system. Glen

 

[notsosanestan]

Also you should connect a clear hose for the return line and start it to see if there is bubbles

 

[86k10]

I had a hard start problem last year even in fairly warm weather. Checked for power on the glow plug spade to make sure power was getting there. It wasn't only 2 were working the other 6 had power at the connector but the spade was corroded enough to not let power through. Touched them all up with a small file and she starts like a new one even down around 0.