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Problems with 7.3 diesel

2K views 29 replies 22 participants last post by  Don Nelson 
#1 ·
Backed out of drive and just died. Engine is full on oil. Hooked to scanner and no RPM while cranking, Replaced cam sensor and now have RPM's when cranking but no start. Replaced fuel regulator on high oil pressure pump, still won't run. Engine won't even fire on WD-40 or starting fluid. Scanner won't complete a KOEO self test either. Thanks in advance for any other ideas.
 
#4 ·
What year and model? There have been some significant changes over the years that could make it easier to diagnose. The injectors on most of these, work on a secondary high oil pressure system. Almost anything that inhibits the secondary oil pressure or the processor's reading of it could give trouble. If the Processor is unresponsive, I'd be looking at power and grounds first. There are some very specific diagnostic routines for these vehicles. A scan tool (NGS or WDS) can give a ton of information with the key in the "ON" position, through the data link. The KOEO and KOER test routines are different for most diesels when compared to a gasoline powered vehicle. You should look at the diesel section in a PCED manual for the appropriate year and follow the specific diagnostic routines for the concern. If you don't have one, check with Helm, inc. and see what they would get for a complete set of manuals for the vehicle. Either that, or have it towed to a qualified repair facility.
 
#8 ·
well you have joined into a group of people with engine problems. Its sad to say they have a 90% failure rate on their engines. I have had to remove several from school busses do to the oil branch tube that runs between the engine and transmisson. It connects to gallies in the cylinder heads that run the injectors. They were silver soldered. Once it cracks, the oil dumps directly into the oil pan. I recommend taking it to the best ( not neccessarly the closest) Ford truck dealer. They should cover the repair under warranty. Good luck. Don
 
#9 ·
Things to consider as possibles:

Fuel lift pump in tank has died...on Fords they do this often enough. You start the truck and use all the fuel in the lines before the engine starves itself out of fuel.

Solenoid on injection pump failing to energize or not getting signal....locate wiring diagram and use test lamp to verify.

Air leak somewhere between tank and injection pump...will always suck air before they draw fuel. You can plumb a standard low pressure electric fuel booster pump between tank and fuel filters...if you have an air leak...you will find it soon enough with fuel squirting around. My 97 cummins had a line that developed a pinhole and would suck air from time to time until I found it with the booster pump and fixed it.

Injection pump has failed....usually have some warning beforehand, but not always. This one requires some serious work and cash. Try others first.

I'm somewhat puzzled by no response from the starting fluid...I never saw a sound engine that I couldn't get a bark from ether. Sometimes I've had to run my combine on ether to get injection lines purged of air. Just don't load it all up before you turn the key....have it cranking over as you use the ether....it's best NOT to have the glow plugs cycling (just pull the wires) or the manifold heater element disabled.

Actually Silver S 007 said you need fuel and air....but you also need compression of that air or it won't run.

FWIW I do have more than a few diesels around....6 JD's, 1 IHC, 3 MF's, 1 Cat, 2 small Cummins, 1 BIG Cummins, 2 Case, and a Yanmar mower.

Find a farmer friend...he will get it started...or at least narrow your search.

Bob T.
 
#14 ·
Check the high pressure resivoir oil level.It has a plug on the top of it takes a 1/4 inch allen wrench to remove,located at the top of the timing cover.When you remove it the oil level should be about a half inch from top.Sometimes when you crank it extendedly such has in a no start the oil will empty out and cause this.You stated you had a scanner plugged in,does it monitor live data from sensors?if so look at your icp reading while cranking.MUST be over 500psi or will not start.If not aleast 500 psi check the engines base oil pressure,have seen many of these that the oil pumps get worn or the pressure regulator hangs and wont build oil pressure.The high pressure pump feeds off of low (or base)oil pressure.Let me know if this dont point you to problem and i will try to help. Don Cummins
 
#16 ·
My money says Mobear is right, happened to me. Even though it cranks, radio and lights work, if it drops below a certain amperage=no start condition.

Best Ford desiel site is thedieselstop. Looks like problems with the injector sleeves going out allowing fuel to enter cooling system, for engines over 100k. My bro-in-law just spent 2900 to fix, had to remove heads. Ouch!
 
#23 ·
You will probably have to register on this site, but it is no big deal. I guarantee you this - you will have an answer to your problem right away. Or if you want to go to the source, on Monday call Brian's Truck Shop. Their phone is 870-422-3675. Brian Thompson specializes in 7.3 Fords and is the go to guy on this site. He knows more about 7.3 's than anyone I know. And, everone on the above site will verify that. He is located about 30 miles south of Branson, Missouri in Lead Hill, Arkansas. There are not many things in life that are guaranteed, except death and taxes; but this is for sure - he will tell you what is wrong with your truck. Steve
 
#24 ·
Hi the 7.3 is a driect drive to the PT pump for injector if it didn't fire on ether the gear that drives the time and the pump and camshaft failed and this is why it won't fire and that why you can't get any reading on the code reader try opening the inspection hole in front of the PT pump to see if the gears are turning there are two scerws that hold the cover on that show you the timing marks are have someone crank the engine to see if it mark move if not the gear is broke and the front of the engine has to come apart and the gears replaced coming of the crank also the 7.3 is not a ford engine it is a international engine made for ford also if the engine doesn't crank and is frozen the value are hitting the piston don't try to push start it try trun it with a wrench from the crank pulley if it doesn't turn then that's probly the problem
 
#25 ·
Steve,, I had an appointment with Brian about 5 yrs ago,, was there on time, waited 3 hours, he never showed!! didn't call, or anything. Easy to get on the phone, but never saw him in person. No explanation when I finally did get him two days later. Too far to drive for a no show. Around Madison Wi. the place is Diesel Injection service.. Great guys and good with 7.3s. Paul
 
#26 ·
Paul - I was in the Springfield, Mo area a couple of weeks ago on business. One morning, I drove down to Brian's shop in Lead Hill. Nice shop. What a setup. I spent 30 minutes with him discussing my truck, which is an early model 99 F-350. I have had the tranny out 4 times in the last 15 months. And, the Ford dealer just keeps fixing it under warranty, since they rebuilt it to start with. Now I know what it will take to pull my trailer which weighs 15,000 pounds plus. He guarantees his trannys - unlimited for 5 years - and will repair it at his cost for up to 10 years, if you can get it there. But it's 4 grand to have him overhaul it. And I talked to him about upgrading the turbo to something a little bigger. Very knowledgeable and helpful. But, I can understand what you are saying. I got recommended by one of his customers, so I was treated OK. Do you have a phone number and contact name for Diesel Injection Service? I would like to get a 2nd opinion on this turbo upgrade. Thanks. Steve
 
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