Hey everyone!

Last fall some of you may remember me posting about a friends truck that wouldn't start, and it was the fuel heater. It was a pretty easy diagnosis, especially when he told me he wasn't getting a WTS.

Well... I need your help again with the same truck. I think I know whats going on, but I'm looking just for more of a confirmation.

You guys know how it is, you read scenereos on here day in and day out, then when it comes down to actually doing it you second guess yourself. You reflect back on your training and wonder if it is what it looks like.

Anyways...

Have a 97 F-250, won't start. Getting a WTS light, fuse is good, his brother (who I don't believe knows anything about these engines) told him its the fuel pump. Checked in the bowl, and there was fuel. Tried checking for pressure but couldnt' get a reading. I was using a tire gauge, and I could get fuel to spray out, so I think thats all good.

Hooked my torque up to it, IPR jumps to 55% on crank, and ICP jumps to over 3500 PSI, and there is smoke out the tail pipe, but no fire. So that all appears good. Unplugged ICP and cranked again, still nothing.

Can hear the injectors buzzing.

There is oil in the ICP plug, but there is considerable oil in the valey (I double checked that its oil and not fuel). All this leads me to the conclusion that he blew an o-ring, specifically an IPR o-ring. I tried looking for the tin nut, but I cant see real well, and his engine is CRUSTY CRUSTY CRUSTY. Truck is at about 204K miles.

So how am I doing so far? Anything I missed?

 

Have you checked the glow plugs/relay? The smoke out the tail pipe says it is getting fuel. My 96 C&C won't start without working glow plugs on the first start of the day, even if it is 70 degrees out. Also my brother's superduty got so it wouldn't start without being plugged in, even with working glow plugs, no matter what the temp. Turn out the injectors were totally worn out. Something else to ponder.

 

I did not check glow plugs besides noting the relay came on. Which I know doesn't mean anything. Before I looked at it he tried ether and to no avail.

I'll add that the last time he was driving the truck he said it just shut off like someone turned the switch off. Couldn't be as simple as a CPS could it? If I recall the injectors won't fire with out the CPS right? And isn't his start up ipr considered off the chart for start up?

 

The PCM reads the CPS signal to determine what cylinder to fire. Without signal from the CPS-no start. (Correct me if any of this is wrong.)

One way to see if you've got signal from the CPS is to see if the tach moves when cranking. If the tach needle moves, the PCM is seeing a signal from the CPS.


Also, are there any good write-ups anywhere on the inner workings of the HPO system of these trucks? Specifically how the ICP, IPR and other components work with each other?
Thanks

 

I'm fairly certain thats all working. I'll check again when I have the chance.

What has me concerned is all the oil in the valley.

 

I do know however, that if that oil is coming from a leak in the HPO system, and isn't allowing the HPO Rails in the head to reach a minimum of 500 psi, the injectors won't fire.

But it seems we've already ruled that out since we have smoke out of the tailpipe and ICP reading higher than 500psi.

 

Bump bump. Anything?

Could it be idm? You can hear the injectors clicking when you turn it over. I feel like I'm missing somthing. I'll try and do some more reading. But I'm pretty much just shooting in the dark at this point.

 

Leave the glow plugs running for an extra 10-20 seconds, then crank. If that helps, then that suggests either a weak glow plug relay, or one or more bad glow plugs.

 

I just now read all of this.

First off, whoa, 3500 psi cranking is way too high. At WOT a stock tune will be lucky to hit 2650 psi.
That leads me to think IPR is stuck or the tin nut is loose/missing.

But then you say excessive oil in the valley. If its a HPO leak or HPOP reservoir leak there could be air in the HPO system. IDK what that would do to the ICP reading. It could explain smoke from the tailpipe without starting.

Also just because the GPR clicks doesn't mean its working.

Here's my suggestion:
1. Make sure the batteries are charged,
2. The oil is full on the dip stick, and
3. The HPOP reservoir is full.
4. Then jump the big terminals on the gpr for a good minute.
5. Try to start while watching the tach, and have someone watch for the oil leak.

Also you should be able to get a fuel pressure reading while someone is cranking it over.

Does it sputter like its trying to start?

 

Got it running! It was the CPS. It didn't exhibit symptoms of a CPS, at least I didn't think so. Thanks everyone!

 

I've heard of just one other one that acted like that. So I'd say that's one of the more rare types of failure, lol. I'm glad you got it going and helped your friend save money by not replacing the fuel pump.

 

Well when we changed the CPS, we got a lot more smoke than we did before. It didn't take off right away. Kinda like there was air in the hpop system like you said. But once it did take of it ran strong. It does have a stutter at 2500 rpm like it needs o rings, I told him that we should do injector o rings and ipr on rings and see where that leaves us. I'm not sure how long the truck had been sitting before all this either.

 

Yeah it surprised me as well. But I figured what do we have to loose? I knew that sensor in my glove box would come in handy. I had never changed one before this, they really are super easy. Definatly makes me feel more confident (and know what to look for if mine ever does this). He is going to get me a replacement sensor as payment, I told him to get 2 and throw one in his globe box!