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94 7.3L IDI will not start

26K views 20 replies 6 participants last post by  gtspowerstroke 
#1 ·
I have a 1994 IDI factory turbo 4X4 Manual transmission.
Three days ago I parked my truck everything was normal, yesterday it will not start just cranks, no popping,no smoke, no trying to start, nothing but cranking over and over and over.
I live in central CA so cold weather is not the problem (100 degres)
Both batteries fully charged
after reading other threads most advice was a bad relay/glow plug controller, so i replaced both also replaced fuel filter and air filter I filled the filter with diesel. Still nothing but cranking, won't start, pop, snort, or anything. Today I pushed in the valve on top of fuel filter cranked it and fuel came out, so then I installed clear lines from filter to fuel rail(grey lines it is IDI) and from fuel rail to injector pump. Iused longer lines with a loop in them. Cranked it over fuel came into both lines but never filled them up. There are sites for adjusting injector pump but they state it is for preformance. Mine is not preforming at all. please do not give me advice like Dump your IDI and get a powerstroke.This is my truck and I love it, and do not have the money.
Any advice on adjusting, or tweaking, or repairs would be nice. I spent all my money on the selonid and controller. one glow plug bad #5 cylinder (drivers side front) did an ohm test on them all and checked wiring harness & connectors with a DC meter all ok Thanks
 
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#3 ·
did a flow & pressure check. Removed the top front spade from injector pump, removed valve core, installed tubing into a measuring cup. Pumped out 1/2cup in 10 sec.
So passed, pressure test 4lbs low end of the specs. I know you can turn up your pump, has anyone done this? Still pondering cracking the hard lines at the injectors, right now i have no leaks
 
#4 ·
I cracked the lines at the injectors and no fuel, i checked agin the fuel shutoff (FSS) jumped it and turned on key click click, back one also. So I removed it. Big T shaped crack in it. Anybody worked on the FSS? I will try to get a new one. Are there any fuel diagrams for IDI 7.3 on the web?
 
#6 ·
No Start

Sounds like you may have a leak in your lift pump. When you say you have fuel at the filter, does it have a good healthy spray at the shrader valve or does it just dribble out? It should spray pretty hard. I don't know the exact pressure it should make, but if the lift pump doesn't make enough pressure, the injector pump won't work at all. A bad lift pump will also allow the fuel to bleed out of the line between the lift pump and the fuel filter, making the engine extremely hard to start since it has to fill the line every time it sits a while. I have had 2 or 3 of these go bad on my 92 IDI.

Just another idea for ya, but I think your on the right track checking the FSS also.

And as far as turning up the pump, it generally involves removing the triangle shaped side cover on the pump and adjusting the allen screw a few flats. All this does is increase fuel flow at Wide Open Throttle, so I doubt turning the pump up will cure your current problem. But it sure makes bettsy move a lot better when it is running, I know, my fuel screw is bottomed out in my IDI.:woot::nod:

Good luck,

Pete
 
#8 ·
No start

I would guess the new FSS will probably fix your problem, but if not, you may have to have the injector pump tested. That may be a problem, depending on your local injection shop. The shop in my neck of the woods won't even test rotary style pumps because when they fail it damages their machine.

You can get rebuilt pumps for around 350 bucks if it comes to that.

Good luck
 
#10 ·
I would guess the new FSS will probably fix your problem, but if not, you may have to have the injector pump tested. That may be a problem, depending on your local injection shop. The shop in my neck of the woods won't even test rotary style pumps because when they fail it damages their machine.

You can get rebuilt pumps for around 350 bucks if it comes to that.

Good luck

Sounds to me like they just don't want to test them. Unless their stand is comletely different than the one at the shop I work at it won't do anything to the stand if the pump doesn't work.

manurehappens have you tried taking the top off the injection pump and checked to make sure the shut off solenoid is working? Cycle the key and it should move the arm back and forth.

You can also try cranking it with the top off. It will spill some fuel out so put a drip pan or something under it but that will bypass the shut off solenoid all together and let the metering valve open up. If still nothing it could just have a worn head and rotor. Also this will give you a chance to take a look in the pump to see if there is any junk in there. If it's the original pump it could have the original flex ring on the weight retainer which are known to go bad and come apart sending plastic pieces all through the pump.

On the test stand we run 5 psi to the pump so if you have at least that much it should have enough pressure.
 
#9 ·
Received New return hoses & plastic caps. I have a crossover hose (2 caps have a tee connector) New ones are 4ea straight conn. & 4ea elbow conn. no tee conn. mine are the new style with the conn. offset the plastic cap, not through the middle.
Should I use my two old caps w/ the tee conn. or use all new without the crossover, what is the difference?
 
#12 ·
Sweet! Glad to hear it's running again!
 
#13 ·
No start! Checked for air leaks and did not find any, removed the top cover from the IP, when the solenoid clicks in (run position) the metering valve will not open unless you apply full throttle. Then it opens verry slowly, so then I assembled everything turned the key and pushed the pedal all the way down waited 15 sec. and It started at full throttle, when I took my foot off the gas it died. I started her again this time I eased the RPMs down and the ol 7.3 idled right down. Starts everytime like this, But is the slow metering valve going to cause further problems, is there something I can do to speed up or free up the valve?
 
#14 ·
If the metering valve is sticking it needs to come apart and get cleaned and a new metering valve. At this point you are looking at a complete overhaul. If it's sticky as you describe it will die all the time if you back out of the throttle because it cuts the fuel back and once the rpm comes down to idle it can't react fast enough before it dies. If it sticks wide open then the engine could run away.
 
#15 ·
Every time I start it I have to push the pedal to the floor, then ease off the throttle until it hits the high idle solenoid (unless the engine is hot)and then everything seems ok.
I do not know the insides of the IP I am assuming that the metering valve is the one under the govenor cover that the shut off solenoid closes to shut fuel off to the engine, Driving test, the truck has a 5 speed manual trans. accelerates fine, no smoke, if driving and i depress the clutch she dies! If you take your foot off the pedal and let her slow down then depress clutch everything is ok. I have no idea what is going on here!
 
#16 ·
The metering valve is the valve toward the rear of the pump under the top cover. It's arm sits perpendicular to the truck. There is an arm that runs to the front of the pump to the governor which is what the shut off solenoid pushes to close the metering valve. If the metering valve gets sticky what happens is you let off the throttle and the governor closes the valve. Normally once the rpms reach low idle it will open the valve back up but because it's sticky it doesn't open fast enough and it kills the engine. Only way to get the metering valve out is to take the face cam and drive shaft out. To do this you have to recalibrate the pump to get the face cam back in the proper position. You need to replace the metering valve and/or lap it in so that it has smooth operation so you need to disassemble the pump so that you can do this and be able to clean the lapping compound out of the pump before reassembly. Or live with it dieing all the time. If you get lucky as it moves back and forth it might start to free up. But if there is some rust or something in there from it sitting for a long time it could just get worse.
 
#17 ·
If I rev her up to 1500- 2000 rpm and let off the gas pedal the rpm will just drop to 0 and she dies. I turned up the idle screw now idleing at about 800 rpm (just by the dash gauge) now when 1500 rpm or more there is a 50/50 chance she will still run, but she drops below idle speed, shudders, almost stalls then recovers to idle speed. If the air conditioner is on she stalls 80% of the time. I have heard about filling your filter with ATF before so I will get some and try that next.
well I might need a new Injector Pump, but not TODAY! I filled the filter with ATF started her turned her off and let it sit with the pump full of ATF. started again with no problems, took her on a drive, no stalling even with the AC on. When I had taken the govenor cover off to replace the FSS solenoid there was a little rust in the IP, and also in the bottom of fuel filter/water seperator (i guess my idiot light for water in fuel dosen't work). Now i will throw a bottle of diesel conditioner in each tank and hopefully burn up that water.
 
#18 ·
Good luck with it. It may fix it for awhile or it may come back once the ATF is flushed through.
 
#21 ·
That's just the shut off solenoid. It's not a safety switch. The single terminal on the side of the pump is the cold start solenoid. Those are the only two electronic parts on the pump.
 
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