Hi all, I have a 7.3 HD F250

It was running fine and then yesterday started "missing" going down the road and died. Would not restart.

Truck is fairly new to me, but had a CPS new in the packaging in the glove box and I replaced it (my code reader said this was the problem).

It had some insulation worn off of one of the pigtail wires, so I taped it up and got rid of the potential short.

Now, when I crank it won't start but I get lots of smoke. I get no codes when I scan it after trying to start.

I ran all the injector tests and stuff on my scanner and they all passed except for some sort of neutral relay on the transmission, which I'll tackle when it's running.

I unplugged the battery and got the code that the power was disconnected when I plug it back in, try to start and smoke but no running and no codes.

I unplugged the pressure sensor (ICP) just to see if it would start and still no start.

I looked at the HPOP reservoir (removed the torx bolt and checked for oil) and it's full.

Tested all the fuses on the driver-side of the engine compartment - all have contunitiy.

Dipstick shows good for oil level in the engine.

So - I'm getting smoke so I'm getting fuel - I don't know what else to check right now - I'm not sure how to test the IPR and even if it would show bad on a scan or not.

Any suggestions for further troubleshooting? I can't throw parts at it, so how do I further narrow down what could be wrong? The truck has been well maintained and is a one-owner, stored under a shelter buy from an estate sale, ~260K miles.

 

Sounds like a glow plug or relay problem. Try jumping the 2 large posts on the relay with a screw driver for 30 seconds then try to start it. If it fires up, the relay is probably bad.

 

Could be GP issue as stated. Plug it in for a few hours.

Batts. Cables. Starter.

 

Thanks y'all, charged overnight and still won't start, I've got the block heater plugged in and will try to start after an hour or so...

 

Glow plugs, starter, batteries, cables could explain not starting cold. Less likely to explain not restarting when hot, unless cranking is very slow. Running fine, then missing and dying would NOT be glow plugs, starter, etc. I'm suspecting that you have more than one issue.

Do you have tach when cranking? What brand is the "new" CPS? True Ford or International, not counterfeit or parts store? Parts store sensors have poor reputations on this site, with "bad out of the box" being reported. Did you replace the CPS before or after it died on the road? The chafed pigtail is the CPS connector?

The symptoms and their timing suggest a good look at the CPS and pigtail. Broken or otherwise damaged wire in the CPS harness (and not necessarily at the point of chafed insulation), grungy or damaged connector, "bad out of the box" CPS, or some combination of these. I would put a stink eye on the pigtail. If the pigtail is damaged, both CPS could be good. But I don't know if bad CPS system will let the engine fuel when cranking. I suspect not, since the cam position is needed to time injector firing.

You seem to be getting fuel. White smoke strongly suggests fueling, which suggests CPS and high pressure oil systems (injector controls and injector hydraulic power) are adequate. You may have fixed a CPS issue that shut you down on the road, and now have a separate cold-start issue, but it's good to confirm that CPS system really does seem fixed, and eliminate it from the possible causes.

Just for grins and giggles, when it died running, how full was the tank you were pulling from? If around 1/4 or lower, the "showerhead" on the pickup may have fallen off and you started sucking air. And maybe consider both tanks, since a failed tank selector valve could lie as to which tank you are pulling from. Both over 1/4 is good insurance during diagnosis. My experience running a tank dry (failed and lying tank selector valve) is that engine refires almost immediately once there is fuel in the tank. No need to crank for extended times to get enough fuel to the cylinders to start and run. OK, a bit rough for a while, but running and drivable. I suspect that enough white smoke to be noticeable should be enough fuel to start the engine, or engine at least tries to start.

Have you pulled the cover on the fuel bowl? Good clean fuel in bowl, not much slime, filter looks OK? Pressure regulator screen is clean?

My experience on missing cold starts is that if you crank-and-miss, it's best to quickly turn off, turn back to run, then walk away and let the glow plugs do their thing before trying to crank again. Repeated crank-and-miss just seems to stack up fuel in the cylinders and exhaust, make more smoke, and reduce chances of a successful start. Walk away for a longer time, then cycle glow plugs and let them on for a while before trying another crank. And the warmer you can get the engine, the better.

 

Thanks @paddler - I think the CPS is working (I get tach when cranking and plenty of smoke, so fuel seems to be flowing). It was motorcraft and not a knock-off. The chafed pigtail is the cps connector, but it seems to be behaving now.



It does crank and miss some now, and I agree that I have more than 1 issue. Now I'm looking at batteries.

I charged for a few hours (charger on passenger battery), cleaned the terminals and get 12.5 v on both batteries with no loads. I got 10.5 volts while cranking on both batteries (my wife turning the key).

It turns over and tries to catch and does not, and smokes quite a bit after about 20-30 seconds.

I have the block heater plugged in now, and will try jumping it with another truck I've got that has a brand new oversized battery in it and we'll see what happens after a few hours (so block heater for ~4 hours and jumping with a running 800 ccv battery hooked up to the passenger side).

I get 12v on my big terminals on my GPR, I'm not sure how the small terminals should act, or how to test the actual glow plugs.

Front tank is almost full (over 3/4) with new diesel. Rear tank is over 1/4. I'm pretty sure the tank selector on the front tank is right because it was about 1/4 and I filled it up and the gauge followed.

I'll pull the fuel filter cover and have a look if it's still not working after this, the HPOP is full of oil and the amount of smoke I get says it's unlikely to be fuel (IMO)

 

One quick-and-dirty test for general glow plug and relay operation... When cold, turn key to accessory. Look at volt gage. Turn key to Run. You should get Wait to Start and glow plugs should turn on. The volt gage should drop quite a bit with glow plugs on. If gage doesn't drop, something is wrong (dead plugs, connectors / wiring, relay, whatever sets "engine is cold, turn on glow plugs" versus "engine is warm and doesn't need glow plugs". Even a few working plugs are enough to cause a notable drop on the volt gage, so this check really only tells "totally not working". Long ago, I had glow plug issues resulting in dicey cold starts, it was either 3 failed / 5 working or 3 working / 5 failed, but still dropped the volt gage while the working plugs were on.

Looks like you are going through a good, careful diagnostic process. I concur that at this point, fuel, including tanks, HPOP, CPS and related are not likely to be problems. Anything in the filter bowl is unlikely to be a problem, but it's an easy check just to make sure.

I personally do not like to lay on starter for more than about 5 seconds. My experience suggests that if engine doesn't fire after that, I'm basically flooding it. Exception might be if I have reason to suspect air in fuel lines (HPOP also, but I have no experience with that), but white smoke would be my sign that enough air is gone to try a "normal" start.

One question... what cranking speed are you getting when you crank? Too slow, and heat may leak out of cylinders faster than compression can generate it. Many folks have noted here that they thought they were getting OK cranking speed, until they fixed cables/batteries/starter and got reminded of what healthy cranking speed really is. Slowly deteriorating system can be hard to recognize.

 

OK - got an update - here are a couple of videos:

https://photos.app.goo.gl/Y7YG538A4A9DhZubA

Basically, still trying to run and ran a little bit the very first time I started it.

This is with the heater plugged in and jumped off of my running F150.

Seems like it might be fuel after all (even with all the smoke) - it'll barely idle but won't increase rpms when I hit the gas.

Will check the fuel bowl/filter/screen later, but that's where we are.

 

Could be that extended cranking is dumping enough fuel to smoke, but not enough per revolution to ignite and maintain rpm. White smoke indicates getting at least some fuel, but doesn't tell if its enough to run well. I also jumped to the conclusion of "if white smoke, it's getting enough fuel to run". That's USUALLY the case in a no-start condition, but white smoke doesn't definitively tell that.

Fuel pressure test when cranking will be the next diagnostic. And a good peak into the filter bowl...

 

From the videos, it sounds like rpms are strong. I would agree with getting a fuel pressure reading. It sounds like it has low fuel pressure when it is running. I would suggest fixing the CPS wiring. If it was chaffed pretty bad, electrical tape won’t really fix it.

 

I'm going to order a fuel pressure gauge and hook it up to the schrader valve on the fuel bowl.

I'll also pull the fuel filter and check that out, not exactly sure what I'm looking for but will take some pics and see if anything obviously looks funky.

More to come in a day or two when my gauge gets here...

 

More information - pictures updated here https://photos.app.goo.gl/Y7YG538A4A9DhZubA:

- I took off my fuel filter and looked, pics show what I found - Seems OK to me, the screen is not too bad on the return? I did not drain the bowl, this is what was in it
- I tested my glow plug relay, had voltage on the big terminals and took a picture, I had some voltage on the small terminals but before I could take the pic I felt the relay cycle off (this was with the key on)
- I re-ran my fault check and got an intermittent CPS fault, I guess I need to address the pigtail now where the insulation was bare, I guess taping it up is no good.
- I get 2 ICP Pressure readings on my scanner - "Injector Control Pressure 1 and 2 - those are 2.156 MPa and 1.933 MPa after a few seconds of cranking, don't know if that's good or not b/c I'm not sure how that converts to PSI. Google says the 2.156 is about 312 PSI? That's not enough, but I didn't crank it for very long.

That's all I've got for now, got a fuel gauge coming to test the pressure on the fuel bowl during cranking, I'll post that when I have it.

My question is how the hell do I get to the wires to be able to solder them on the CPS? I can really only get one hand in the location, and even if I unclip it I can't really pull it up on top of the engine to work on, can I? How can I re-solder when these wires are so hard to get to?

 

pull CPS up to top of engine, there is a clip on WP IIRC that holds the wire

 

Got to get my alternator bracket off to get the CPS up, it won't come past the bracket and is stuck now. What fun.

Question about that bracket here - basically it's just 4 bolts right? I've got the alternator off, just removing the bracket and don't want a surprise here...

https://www.ford-trucks.com/forums/1...l#post21386471

 

So you have basically a 30 year old truck...

Pop the fan off and belt drive, fix it. Yes, you probably should do idlers and tensioner while there. Clean behind it ALL, the alt grounds to bracket, clean batt neg to block while access is easy.

Hint - oven cleaner is killer degreaser.