Injection Pump DOA

[79GLIDE]

Seems my injection pump has taken a dump.

My 1990 wouldn't even try to start yesterday. It was running fine when I parked it 2 weeks ago. Supposing it was a fuel problem, I cracked a few lines at the injectors and cranked, only a few air bubbles out. I spun the filter off and cranked again, nothing at the filter. So, I replaced the lift pump, restored fuel to the filter, and a good supply at the pump supply line. There was a lot of this. I checked the FSV and it responds when power is removed and applied. I bled air off the Schrader valve at the filter housing, and have fuel pumping out of the top of the injection pump at the return fitting when I crank the starter. My theory is that the lift pump was failing, starving the injection pump of fuel, resulting in seizure. Unless someone else has an idea, I'm guessing it's the injection pump.

Advice? Anybody have a take off sitting around they would be interested in parting with?

 

[icanfixall]

I don't think your injection pump is shot. No way could you crank it long enough without fuel to ruin it. Your starter would have died first. Bleeding the hard lines will take some effort. What you need to do is hold the throttle wide open and crank for around 15 to 20 seconds... No longer or you risk overheating the starter. I do this by jumping the fender solenoid and holding the throttle wide open with my hand. Leave all the hard lines tight to the injectors. Stop cranking and now loosen each line just about 1/2 turn. You will hear a hiss of air escaping or see fuel leak out because air has been compressed behind it in the lines. Tighten up and crank again with the throttle wide open. Holding the throttle wide open moves more air and fuel thru the system. These engines idle at a very low fuel need so it takes forever to bleed air out at the idle setting during cranking. Make sure your batteries are charged up. Grinding them down you end up with low volts and the starter draws more amps. that overheats the starter and will burn it down. A direct drive starter cranks slowly. A gear reduction starter will spin the engine so fast you can't count the startup rpm.

 

[93f250idi]

i dont think the ip is bad either, but if it is uhaul still has some on ebay for like $274

 

[Blind Driver2]

Everytime I read something like this, I always think that the engine isn't turning over fast enough.

 

[Compu Doc]

Turn the ignition on but do not crank After the truck for two minutes. After the two minutes get some ether and spray in the intake. Crank truck and see if it starts. Do not under any circumstances turn the ignition off before cranking with a little ether. Doing so will cause the glow plugs to cycle and you don't want them on when using ether. Keeping the ignition on for two minutes without cranking will ensure that they are not on. It may help to have someone crank while you spray the ether. If it attempts to start but does not run then your IP is probably bad.

 

[sle2115]

Turn the ignition on but do not crank After the truck for two minutes. After the two minutes get some ether and spray in the intake. Crank truck and see if it starts. Do not under any circumstances turn the ignition off before cranking with a little ether. Doing so will cause the glow plugs to cycle and you don't want them on when using ether. Keeping the ignition on for two minutes without cranking will ensure that they are not on. It may help to have someone crank while you spray the ether. If it attempts to start but does not run then your IP is probably bad.

I'm not sure about the earlier system, but the solid state system in my truck will continue to cycle off and on until started...I'm not sure I'd risk spraying ether in it. Unhook the gp's if you want to try ether.

 

['94IDITurbo7.3]

I'm not sure about the earlier system, but the solid state system in my truck will continue to cycle off and on until started...I'm not sure I'd risk spraying ether in it. Unhook the gp's if you want to try ether.

The 7.3L system continues to cycle on/off for up to two minutes.

 

[Cincinnati Guy]

Instead of waiting and hoping you dont mistakenly turn the key off, just simply disable the glow plugs where they will not come on at all during this testing period. I just think your going to need to do a lot more cranking, you have an air pocket somewhere.

(Slightly) loosen your fuel line to injector nuts and crank a little until you start seeing bubbles and or fuel. Oh BTW it helps to have a buddy crank while your under the hood, and once you start seeing the fuel bubbles start tightening back the lines. let the truck rest a few minutes then try starting again. It may start but it may be rough running just hit the schrader valve.

 

[Compu Doc]

I'm not sure about the earlier system, but the solid state system in my truck will continue to cycle off and on until started...I'm not sure I'd risk spraying ether in it. Unhook the gp's if you want to try ether.

I don't know what system your running but my 7.3 system does not cycle on and off until started. My volt meter starts off at about 13 volts with the key off then when I turn the key on it drops down to 12. After the glow plugs completely cycle the volt meter jumps back up to 13 and stays there. The glow plugs do not cycle and I am not talking about starting the truck.

How would the GP system know if the truck was running or not being the engine is mechanically driven without electronics.

I have done the start with ether I described in my OP with no ill effects doing it the way I described in my OP. Not only on my truck but another persons IDI as well and he did not have a volt meter.

 

[Blind Driver2]

You guys have some really weird GP circuits

The GPs cycle before then engine is started. Otherwise you can't start the engine cold. Mine never cycle more then 7 or 8 seconds even on the coldest days. When it's hot out, they don't cycle as long. Sometimes not at all.

Even if the engine starts without waiting for the WTS to go out, the GPs will still cycle as they don't know the engine is running.

 

['94IDITurbo7.3]

You guys have some really weird GP circuits

The GPs cycle before then engine is started. Otherwise you can't start the engine cold. Mine never cycle more then 7 or 8 seconds even on the coldest days. When it's hot out, they don't cycle as long. Sometimes not at all.

Even if the engine starts without waiting for the WTS to go out, the GPs will still cycle as they don't know the engine is running.

my friend it sounds like you have the odd GP system.

here is how mine works: on the first start of the day no matter what outside temps i turn the key to on & wait for the WTS to go out. usually stays on for about 10 sec. then light goes out and i start. if i don't start then i can here the relay clicking on and off and that makes my volt gauge move. that goes on for about 60-90 sec then power is turned off to the GP's so they don't burn up. from what i have learned on here that is how they are supposed to work.

 

[riotwarrior]

......Bleeding the hard lines will take some effort. What you need to do is hold the throttle wide open and crank for around 15 to 20 seconds... No longer or you risk overheating the starter. I do this by jumping the fender solenoid and holding the throttle wide open with my hand. Leave all the hard lines tight to the injectors. Stop cranking and now loosen each line just about 1/2 turn. You will hear a hiss of air escaping or see fuel leak out because air has been compressed behind it in the lines. Tighten up and crank again with the throttle wide open. Holding the throttle wide open moves more air and fuel thru the system. .....

Good info here Gary, thanks, I'll be attempting to fire the diesel pu with Turbo this weekend as such, this may be very helpfull for me Thanks! Thanks! Thanks!

 

[79GLIDE]

Thank you all! I charged the batteries all day cranked a couple cycles bleeding off air after each, and it fired right off. Cracked each line to relieve any additional air. I've got a complete set of new ZD-9's that are going in before winter. This site is fantastic. Thanks again.

 

[justinray]

I have the WTS, Clicky Relay for 5 Secs, Start... I don't know what y'all are talking about with this whole 90 second bs.. I'd buy a new gp circuit or something for sure.

 

[Compu Doc]

I have the WTS, Clicky Relay for 5 Secs, Start... I don't know what y'all are talking about with this whole 90 second bs.. I'd buy a new gp circuit or something for sure.

If your relay is clicking for 5 seconds you have some bad GP's. It may start ok now but wait till the winter time comes.