Hello, I am a new member. After working on this truck for days and reading other posts on this forum I have decided it is time to make a post.

2001 F250 Super Duty 7.3 diesel (237,000 miles) 2WD

Problems:
Will not start without starting fluid.

Has a miss/hesitation at high RPM's

Backfires when you let off the fuel and then press it again like in a turn

After driving for a while the check engine light will come on and at a stop it will die or when you let off the pedal.

Had the codes checked and it came up P1211 & P1212

We have changed the Injector wiring harnesses, CPS, IPR, EBS (Exhaust Backpressure Sensor), & ICP. Also have changed all filters and the oil.

After the truck is started it will sit and idle perfect. It sounds great, just as it should.

I am really stumped bc it doesn't seem like an injector problem.

Any thoughts or ideas would be great as to what I might should check or do next.

Thanks Sean

 

Were all your push rods in place when you had the valve covers off?
Does the engine have a lot of blow by from the oil fill tube?
What is your fuel pressure under load.
What is your ICP and duty cycle when cranking?
Are your glow plugs new? How about the solenoid?

 

Push Rods were all in place.

There is very little blow by at the fill tube

What are the step to check the fuel pressure?

Also how do i check the ICP & Duty Cycle?

Glow plugs nor the solenoid are new. (I could be totally wrong, but I ruled the glow plugs out because it will not start when it is warmed up. It just turns over.)

The above might be some stupid questions to you guys. I know a little bit about mechanics but not a lot. I don't have the funds to take it to a shop so I'm trying to do it myself. Any direction would be very very appreciated.

Sean

 

Any ideas? I get very little register on the tach when cranking. The needle moves just a little. I have replace the ICP sensor and there is some oil in the plug after running it for a few days. What does that mean?

 

How bout the cam sensor ? Just a thought . I have seen hard starts and misfires from faulty cam sensors .

 

Already replaced it with a new one from ford dealer.

 

I moved this to the 7.3 specific forum for more assistance and ideas.

 

if it wont start when its warm that's not glow plug related, the glow plugs are there to assist the combustion in a cold engine.

it backfires? are you sure its a backfire? backfiring in a diesel is bad and usually results in broken parts... depending on how bad it could be anywhere from a blown compressor wheel in the turbo to a bent or broken connecting rod...

try this, when you first get it started when the engine is cold, reach up under the fenders and feel each of the exhaust ports for temperature. they should all warm up pretty evenly. if one is staying cooler than the others its because that cylinder isn't firing. feel the heads in the same manner.

you said you replaced the cam sensor, what about the crank sensor? those are a know failure and cause all kinds of rough running and stalling. no reading on the tachometer when cranking backs this up. get one from IH, not ford. the IH ones are better ive heard.

 

Next step, based on all you have already done, is to put an oil pressure gauge on the HPOP reservoir and find out if your Low Pressure Oil Pump (LPOP) has died on you (this is likely at your mileage). If you use a 0-100 gauge, you can use it to check your fuel pressure as well. Exact same fitting on the back of the fuel bowl by the drain lever. Pull the plug out of the top of the HPOP reservoir and take it with you to the store to find the right fitting/hose to connect to a gauge. I want to say I think it's #4 Oring boss.

You can use an IR thermo to try what 351 suggested above.

 

There is no "crank sensor" on this engine, so don't go looking for it to replace it.

The hall-effect device that determines when the Powertrain Control Module (PCM) fires each injector is called the Cam Position Sensor (CPS). The gray ones Ford currently sell are OK. Not the greatest (for the most-accurate timing), but no worse than what's available from IH.

BTW, stop using starting fluid (ether) in this engine! It's not good for 'em, AT ALL!

NickMike offers some good ideas for you, directly above. That P-1212 could indicate the HPOP reservoir is getting starved for oil by the LPOP, and thus not putting out enough high-pressure when the RPMs are higher, causing it to "stumble". It might also explain the "no-start" with warmer (thinner) oil.

If it turns out to be the problem, don't be afraid to tackle replacing the LPOP. With the right tools, it's relatively easy.

For that matter, despite all the naysayers thoughts on this diesel engine, it's relatively straight-forward to work on, though diagnosis is sometimes frustrating. Ask the guys who have the later-model ones!

Pop

 

huh, ive heard of both, didn't know there wasn't a crank sensor on the 7.3.. where does the tach read from then?

 

from my understanding the cam sensor is the crank sensor. if it has a hard time starting after sitting, i believe these have a "check valve" to prevent the oil in the hpop reservoir from draining back to the pan (someone else please verify or dismiss my theory). if my assumption is correct, then next time it sits for a while pull the little "fill" plug from the top of the reservoir and see if there is oil, if not, or if it looks low, take a very small funnel and add some to it, tighten down the plug and see how easy it starts.
if it starts right up, then the hpop reservoir is starving of oil. a simple and cheap test.

and i stress pop's words, NO STARTING FLUID. you have an intake heater wich can result in the fluid igniting in the intake (cool to watch from a distance) i almost wonder if excess fluid is partially responsible for the "backfire"

 

I think some may be confused about the CPS as it is low on the engine next to the crank shaft but it reads the various sized "dimples" on a separate gear that corresponds to the cam/piston position

 

The cam position sensor reads directly from the "windows", not "dimples", in the cam gear itself.

It discerns the presence or absence of proximate metal, and outputs (relatively) square wave pulses proportionate to that presence or absence.

Not all windows are the same size (though most are), and by keeping track of where the longer or shorter pulses are, the PCM knows which injector to fire, and when.

Pop

 

I used dimples as a figure of speech. How is the cam gear at the bottom of the engine? The cam shaft needs to be at the center of the valley. Or are you referring to a gear train that drives the cam shaft itself?