Slow crank after possible overheat

[Luke_IDI]

I’ve been asked to take a look at a 7.3 Powerstroke that the owners recently purchased. They report that the truck (van chassis box truck) ran great for them on an initial test drive, then on the way home lost power and died. They noted white smoke in the engine bay and coming out of the oil fill when opened (unclear whether this was coolant or fuel). The truck shut down shortly after the oil/temp warning light came on. Gauges are not working so they suspect an overheat as they saw coolant bubbling back up toward overflow bottle. They drained the radiator, got two gallons of coolant out. No signs of oil in coolant. Changed oil. No milkshake, but they say it was on the sludgy/thick side. The maintenance on this truck does not appear to have been the best.
I immediately notice that the truck cranks very slowly. Two brand new batteries. Voltage stays above 10v while cranking. Compression sounds fairly even, just very slow, like a low battery struggling to start, or a struggling starter. Engine turns easily by hand.

Also drained a bit of diesel out of the bottom of the tank. The fuel was pretty well bright yellow. Smells like diesel though.

I intend to do a compression test to assess overall mechanical health after this breakdown, about which I have very little real info. But I need to get the crank speed up first.

Any theories as to why this thing may have started fine for a test drive, and now has this slow crank issue? More than coincidence?

A friend has a starter I can borrow out of a running 7.3. If removing the belt doesn’t speed things up, I will try swapping in that starter as a test. Hopefully that will speed the crank up to normal and we can get a decent picture of compression.

Any advice on other things to check is appreciated. I will update this thread as more diagnostic info is obtained!

 

[Rdnck84_03]

On the powerstroke battery cables and starter are always my first suspect for a slow crank condition.

If I remember correctly your need a minimum of 10.5 volts while cranking or the idm will not fire the injectors.

James

 

[Luke_IDI]

On the powerstroke battery cables and starter are always my first suspect for a slow crank condition.

If I remember correctly your need a minimum of 10.5 volts while cranking or the idm will not fire the injectors.

James

Thanks for that. 10.5 volts. I will monitor carefully. After cleaning all battery connections, voltage while cranking went from low 9s (maybe high 8s) to low 10s. However, still losing connection to the computer while cranking on my crappy scan tool. Better ELM327 coming tomorrow and hopefully my crappy laptop will run FORScan well enough to get some good data. Will also check for voltage drop across starter cables.

 

[Rdnck84_03]

If you have a different pair of batteries, would probably be worth while to try them. Even if the batteries test good means nothing for starting a 7.3 powerstroke, these truck are hell on batteries.

James

 

[lotzagoodstuff]

What year Powerstroke?

Here’s a long shot, but worth looking into. Although it sounds like it could have overheated, keep in mind that the early valve cover harnesses are pretty notorious for failure (ask me how I know). If you have the early version with two plugs on each valve cover, or perhaps aftermarket replacements with the newer single plugs (Doorman brand is commonly pointed out as failure prone) I would inspect and measure the glow plug circuits at the valve covers. I know you are chasing a described overheat, but the reported smoke could have been electrical related. Glow plug shortage could be draining your measured voltage.

Lastly, if it did overheat, and I think the description points that way, I would start with the HPOP as it’s possible that it is not making pressure. Check the oil level and any blockage in the reservoir, then try to measure pressure.

Lastly, you sound pretty electronic savvy. Pulling codes are mandatory on Powerstrokes. If it’s sensor related, codes will point you in the right direction.

You’re a good friend for helping out some friends who need your help with a new rig in question. Good luck to you in your quest to revive the new Powderchoke.

 

[Luke_IDI]

What year Powerstroke?

Here’s a long shot, but worth looking into. Although it sounds like it could have overheated, keep in mind that the early valve cover harnesses are pretty notorious for failure (ask me how I know). If you have the early version with two plugs on each valve cover, or perhaps aftermarket replacements with the newer single plugs (Doorman brand is commonly pointed out as failure prone) I would inspect and measure the glow plug circuits at the valve covers. I know you are chasing a described overheat, but the reported smoke could have been electrical related. Glow plug shortage could be draining your measured voltage.

Lastly, if it did overheat, and I think the description points that way, I would start with the HPOP as it’s possible that it is not making pressure. Check the oil level and any blockage in the reservoir, then try to measure pressure.

Lastly, you sound pretty electronic savvy. Pulling codes are mandatory on Powerstrokes. If it’s sensor related, codes will point you in the right direction.

You’re a good friend for helping out some friends who need your help with a new rig in question. Good luck to you in your quest to revive the new Powderchoke.

Thanks for the suggestions. The glow plugs appear to be wired to a manual switch on this truck, so it should be easy to eliminate those as a power draw. Valve covers are off in preparation for a compression test so I can verify at the glow plugs that the switch does indeed control them.

Unfortunately I didn’t see any codes when I hooked up a scanner—batteries had been removed for charging due to the slow crank.

The battery terminals were in a pretty bad state yesterday. Got them all clamping tight onto the batteries and saw some small improvement in the crank speed. I’m going to do a voltage drop test across the main battery cables to the starter and verify there are no issues there. I’m trying to avoid putting any time/money into permanent repairs until we’re convinced there’s decent compression, but if these terminals are causing a problem with the crank speed, they’ll have to be fixed before anything else can be known.

 

[Diesel D]

On the powerstroke battery cables and starter are always my first suspect for a slow crank condition.

If I remember correctly your need a minimum of 10.5 volts while cranking or the idm will not fire the injectors.

James

.....what about the batteries?....those are always my FIRST suspect in diagnosing a slow crank....

 

[Luke_IDI]

.....what about the batteries?....those are always my FIRST suspect in diagnosing a slow crank....

Certainly….these are supposedly brand new: 2 NAPA group 65s with 8/23 sticker. Dropping to mid-10 volts during crank. We didn’t personally purchase these from NAPA though—the seller threw them in with the truck.

Just did a voltage drop test, not seeing any significant drops over the starter cables: .3v or so while cranking.

Just about to drop a known good starter in and see what happens. I have been wanting to avoid spending on a new starter in case we have compression problems.

 

[Rdnck84_03]

I immediately notice that the truck cranks very slowly. Two brand new batteries. Voltage stays above 10v while cranking.

.....what about the batteries?....those are always my FIRST suspect in diagnosing a slow crank....

This comment was the only reason that wasn't my first suspect also.

If you have a different pair of batteries, would probably be worth while to try them. Even if the batteries test good means nothing for starting a 7.3 powerstroke, these truck are hell on batteries.

James

I did also recommend trying a different set of batteries.

James

 

[Luke_IDI]

Swapped the starter with a known good one. Cranking speed now sounds excellent, so the starter is condemned. This evidently completely unrelated to the breakdown on the way home. Time to figure out the cause of the no start .

I should add that the crankcase smells like gear oil.

 

[Rdnck84_03]

Does the oil look good or seem overly thick or thin? Since the injectors are oil pressurized the oil condition can cause some issues.

If you think the oil condition is good, I would put a scanner on it and see how much pressure the HPOP is producing during cranking.

I'm not sure how familiar you are with the powerstroke platform but just to be sure. A generics obd2 scanner won't even pull codes on these.

James

 

[Luke_IDI]

Does the oil look good or seem overly thick or thin? Since the injectors are oil pressurized the oil condition can cause some issues.

If you think the oil condition is good, I would put a scanner on it and see how much pressure the HPOP is producing during cranking.

I'm not sure how familiar you are with the powerstroke platform but just to be sure. A generics obd2 scanner won't even pull codes on these.

James

The owners described the oil as overly thick, drained and replaced with fresh 15w40. We will be hooking up to it with FORScan as soon as a suitable laptop and ELM327 can be assembled. Now that we’ve got a healthy crank, this should be much more in the realm of a normal Powerstroke no-start diagnosis. HPOP pressure is first on the list. I’m not super familiar with Powerstrokes—this will be the first one I have worked on. But I have read about them a fair amount. I am familiar with the basics of the system, but there are probably plenty of details I could stand to be alerted to. Like the fact that you can’t pull codes with a generic scanner—good to know! However, I do know that FORScan or similar is necessary to monitor data.

Does anyone have any thoughts on why the diesel drained from the tank was bright yellow?

 

[Rdnck84_03]

I believe the forscan should also be able to read the codes. I'm not sure on that as I have never used it myself. I have a snap-on scanner.

I am not really sure about the bright yellow fuel. What color is the new bio fuel? I have never used any of it so I have no experience with it.

James

 

[Luke_IDI]

It may be biodiesel. I will post back results using FORScan. I plan to check Injection Control Pressure and check ICP sensor by unplugging if not enough oil pressure. I have read that it is common to have to replace IPR valve after the engine gets hot, so if there are any ICP issues I may start there.

As another added part of the problem, I thought I would check voltage at the glow plugs as the valve covers are already off, and there is an unlabeled non-factory switch on the dash with an indicator light that one might think would control the glow plugs manually. I could not detect any voltage at the glow plugs with this on or with the key on.

I understand the glow plugs, pcm, and fuel bowl heater are on the same fuse circuit (fuse 22) on the trucks. This is an E-450 platform. The fuse diagram mentions PCM power but does not mention glow plugs. Are those circuits related in the van chassis?

 

[Rdnck84_03]

I know the fuel bowl heater and the pcm are both on the same fuse. Not sure if the glow plugs are fused.

Does the wait to start light come on when the key is cycled on?

James