In the past in very cold weather (high teens) if I didn't let the glow plugs go long enough it would crank a while and when I pressed the throttle I could here the change in the engine and it would blow white smoke out the tailpipe but it would stumble and finally fire. That seemed normal to me though, due to the temp and I wasn't very patience with the glow plugs.

Now this

It's happened twice now. The first time a few days ago the engine was cold but it was 90 degrees outside and I let the glow plugs go for probly 10 seconds. All it did was crank, pressing the throttle changed nothing, no smoke out the tail pipe. I gave the under hood area a once over and tried it again after another 10 seconds of glow plugs and it fired right up. I thought that was weird but oh well.

This morning was the second time. 100 degrees outside, I let the glow plugs go as longs as the light stayed on the dash (5-10 seconds) and it fired right up. I drove 10 miles to a convenience store. When I came out all it did was crank, pressing the throttle did nothing and no smoke out the tail pipe. I disconnected both batteries, connected a jumper between the disconnected negative cable and the positive post to drain anything that might have a capacitor for memory. Left it like that for five minutes, reconnected the batteries. Turned the key on for about 10 seconds, cranked it and it fired right up with about 1 second of crank time. I thought I could here a noise this time that I didn't here before, a buzzing or humming noise, was that the glow plug relay or the electric fuel pump, it sounded like it was coming from the glove box firewall area.

I'm thinking the problem is the electric fuel pump, since pushing the throttle while cranking changes nothing and it was warm the second time so glow plugs shouldn't have mattered.

Does the 7.3 need glow plugs even when hot?

Is there a relay that tells the electric fuel pump to come on when the key is on, should I here the fuel pump?

And no check engine light or codes.

Truck is stock except for AIS and straight piped. It did have a Superchips installed by previous owner but he removed that when I bought it 2 years ago.

 

Its important to let the glow plugs warm up in cold weather. Excessive cranking can be bad. The glow plugs stay on a little while past the wait to start light. You can hook up an led to the glow plug relay if you have one (instead of a Glow Plug Control Module)c That will tell you exactly when the glow plugs are on.

No smoke means no fuel.
I have my suspicions. Continue on down.

I've never heard of that method to clear memory. Doesn't mean its nkt valid though. Personally, I wouldn't do it as I don't know if it works. What does work is simply disconnecting both batteries for a few minutes.

That was the vacuum pump. Its for Esof 4x4 and HVAC.

I dont think so. Because of the way the injectors work, not getting oil causes them not to fire which causes a no crank issue. Fuel pumps generally fail gradually. A bad pump or relay won't work sometimes and not others in 99% of cases. More often fuel pump issues are low pressure/flow.

No. But its good practice to let them warm up a tad. I'm guilty of not doing this since where I live its 80* by 4AM.

Simple test. Turn the key on. You can hear the fuel bowl filling. You can open the fuel bowl drain valve to certify.

I believe this to be an oil system issue. Check oil levels. With no check engine light we can rule out a bad ICP sensor, but that wouldnt cause a no start anyway, not usually. Check the nut on the back of the IPR. A loose nut can cause a no start. As can a bad IPR.

If you can, look up ICP and IPR values with a monitoring tool. 500psi ICP is require tk start the engine. Checking fuel pressure wouldn't hurt just to be sure. The injectors use oil to fire the injectors. That is why it is so important in this case. Failure in the oil system means no firing injectors. Commonly the IPR (Injector Pressure Regulator) gets stuck and allows all of the oil to bypass, creating no pressure. Look up IPR rebuild and replacement if all else fails.

This is atypical of a CPS failure.

 

Trey, you ruled out a CPS failure. What led you in that direction? I'm curious because I had intermittent no start that was fixed when I replaced the CPS. Glock's symptoms don't match what I had exactly, so I am interested in hearing your thoughts on what can be very frustrating-not knowing if and when the engine will start. Larry

 

I didn't rule it out persay, just that its not the typical failure. Generally the CPS failure is caused by interference. However its possible that a bad sensor or weak hall sensor in the CPS is causing issues.

 

I had a similar thing happen a while back. Pull the electrical connection on the high pressure oil sensor, front top of drivers side head. If it has oil in the connection, clean the plug and replace the sensor. I did that and didn't have any more issues.
Can't say that's your problem but it's an easy check.

 

As far as the GPR Led I'm kicking myself because I usually have my Scangauge and can see the voltage drop when I turn the key on to see that the GPR is working but it's been in my wifes car for other issues.

I've got my Scangauge back and I'll put one of the settings on ICP so I can see what that reads also.

Thanks for the tips, I'll check the plug and sensor tonight.

And if it was a CPS wouldn't I still get fuel (just at the wrong time) and therefore smoke while cranking?

 

No. When a CPS goes bad it just stops working.

The reason I said the CPS failure is atypical of your symptoms is because generally an OEM sensor just kind of skips a beat causing the engine to stall, not continually fail to the point of a no crank.

 

So I just tried to start it again and only cranks, no fire. Voltage when I turn the key on is 12.4 and didn't change at all. So the GPR is not working. I jumpered the GPR and voltage dropped to 11.8, I let it sit like that for about a minute and still no start, only cranks. It's 90 outside and the engines only been off for a few hours so I still don't think the GPR is my only problem.

When I turned the key on the ICP was 0 while cranking the ICP is 166. I want to say when idling I've seen 500-600 and driving in the 1500-2500 range. There's no oil under or around the plug of the sensor.

Is there a way to test the CPS since I'm at work and would have to get a ride to get a new one.

 

O.K. so my Scangauge reads a couple hundred RPM when cranking so I'm thinking the CPS is good.

On the GPR I jumpered the drivers side large post to the front bumper side small post and I heard it click. I got in and turned the key on and voltage was still in the low 12's but I let it sit for 30 seconds and it fired right up so I'm thinking it's the GPR.

But................. I removed the jumper and let it idle for probably 5 minutes. I started to drive and it made it a hundred yards and died. As soon as the truck died relay #303 under the steering column started chattering as long as the key was on. I swapped it with another relay and it still chattered.

Relay 303 is (Injector driver module relay)

The truck would not start again.

I hooked my jumper back up to the GPR and when I turned the key on relay 303 was not chattering anymore and the truck started. I removed the jumper and drove it back to it's parking space and am hoping one of you guys can instill some hope in me that it's just the GPR but what does the (Injecter driver module relay) have to do with that.

 

That ICP reading is a worry. The PCM will not try to fire the injectors until the ICP reaches at least 500 PSI... 166 while cranking is a no-go. White smoke while cranking can indicate a "false" ICP reading of 500, which could be tested by pulling the ICP sensor plug and trying to start the truck without it.

That "relay 303" buzz makes the plot a little thicker - the wiring diagram says the IDM relay is K380 on a 2002 Superduty. I am unsure of what contacts you are shorting, but you may be introducing a short to the system, making the relay buzz. The IDM relay receives its ON signal from the PCM power relay. If the PCM relay contacts are "dirty", it can introduce a buzz and many other problems. Try replacing the PCM relay to see where that gets you.

 

I forgot to mention that once the truck started ICP read around 550. (On my Scangauge if that matters.)

What I had the jumper on was by my understanding manually engaging the Glow Plug Relay. I had one alligator clip on the hot post of the GPR and the other end of the alligator clip on one of the small posts on the GPR, not sure which one it was but it was the one that made it click like it engaged.

And the underdash 303 relay buzz was after I had disconnected the jumper and drove the truck, then after it died again the relay started buzzing.

And there is absolutely no smoke while cranking. If I disconnect the ICP plug should it smoke then or would that make it stop smoking if it already was.

Anybody want to by an 02' F350 haha.

 

Shorting the relay that way introduces backvoltage into the PCM, I don't know what can happen with this. I suggest you short the big posts directly to activate the glow plugs (it's a lot of juice, like jump-starting a car).

Pulling the ICP connector defaults the IPR to a higher pressure signal, and the PCM "thinks" it already has the correct pressure to start. You will get an SES light on the dash, but this is the prescribed method for testing the ICP sensor. If you get a lot of smoke and delayed/no start, this can point to a High Oil Pressure problem. If the truck fires right up and runs good, this points to the ICP sensor.

 

One of the small lugs (may have a red wire w/light green tracer) on the glow plug relay should have +12v any time the key is in the run or start position. The relay is activated by the PCM by grounding the other small lug (may have a purple wire w/orange tracer). So, with the key on, you should have continuity to battery positive on one of the small lugs constantly, and continuity to ground on the other small lug when the relay is commanded on by the PCM.

P.S. I say the wire "may be" those colors because my 2002 diagram doesn't list the colors, and my PC/ED is for a different year. Probably the same colors, but I don't know for sure . . .

 

I'd say you've identified the problem as the IPR. ICP to start is 500.

Try unplugging the ICP sensor as a last ditch effort and starting it like that. Otherwise consider a new or rebuilt IPR.
Good news is, I think you could get away with a rebuild.

 

Well, it's been starting the last few days. Which bothers me even more. I guess I'll just wait till it does it again. In the mean time I think I'll go ahead and do the GPR LED mod and new GPR and a new CPS since they're cheap, and keep the old ones as spares in case I find out it's something else.

And when you say it needs 500 ICP to start. Does yours read 500 while cranking? When I turn my key on it reads 0 and while cranking 100-200 and as soon as it fires 570 at idle.

At the same time IPR reads 14.9 with the key on and bounces around while cranking and 10-11 at idle.