99 F-250 7.3, 4x4, Manual

I've done a bunch of searching but I'm new to diesels and there seems to be a bunch of acronyms and testing methods that I'm having a hard time understanding what posters are saying in a lot of posts.

So, having a intermittent no-start issue, no issues in the morning if I plugged it in, but after sitting at work all day, sometimes it took some cranking to get started. After it warms up, it will start back up no problem.

Checked ICP, had oil inside connector, so I replaced it with a Motorcraft sensor. It took a lot of cranking to get it to fire up after the sensor swap, charged batteries, a lot more cranking and it finally fires up. I forgot to plug it in last night so it didnt want to fire up this morning, sprayed some starting fluid to get it going, ran just fine. Got fuel, started back up just fine. Sat at work all day(25-30F), crank and no start. Pulled the P1280 again. Unplugged the ICP and charged up batteries(I cranked on it quite a bit) and it fires up. Could I have gotten a bad sensor? I still have the one I took out but it was leaking so I don't think any valueable info would be gained by putting that one back in, since it seems to be doing the same as the new sensor.

Looked through the troubleshooting flowchart and it seems that it boils down to a sticking IPR. How do I test that? It seems like the people having issues with the ICP or IPR are also having problems with idling, but mine idles and runs great, no issues once it actually starts.

Batteries are about 2 years old, have not tested glow plug relay or glow plugs. I see mention of testing duty cycle of the IPR, I have a bluetooth OBDII and TorquePro but I dont think it works with diesel codes.

What info would be helpful to troubleshoot further?

 

If you plug it in and it starts, it is most likely glow plug related. Usually the GPR. Cross the two big posts for 60 seconds and see what happens. Or just have someone turn the key on when cold and time the amount of time it takes for the glow plug relay to click. In that temperature it should really stay on the full two minutes. If it clicks shortly after you turn the key on it's most likely bad. Mine was.

 

Need to STOP USING STARTING FLUID. If you do and a glow plug does get hot you can have enough of a bang to do damage.

Like Chet said it sounds glow plug related

If your glow plugs are good then the procedure Chet gave you of jumping across the large contacts on the GPR for 30 to 40 seconds before starting will result in a good start.

You can ohm the glow plugs from the connectors at each valve cover. Should read about 1 ohm or less for each.

 

I think these guys have you on the right path. Bridge the big terminals on the GPR with a screwdriver. Ya got two batteries pushing amperage so do not touch anything else.

If the GPR is bad a common upgrade is a Stancor relay, see this link.

Also inspect the wiring to the ICP, it can get beat up over time. Or maybe still have oil in it, hit it with brake clean.

 

I'm planning on testing the relay and plugs this afternoon.

Would that still cause the low pressure code on the ICP? Is it possible the ICP wasnt causing the start issue, it was bad(leaking oil) but maybe not causing a problem yet? Does the Wait to Start light timing have a connection to how long the glow plugs stay on, as in, is it on as long as the plugs are energized?

Sorry for all the questions, just trying to wrap my head around how everything works on a diesel vs a gas engine.

 

Keep asking those questions - we all do and it's the best problem solving technique out there.

Its possible the ICP was still working, especially given your warmed up running, but just a matter of time before it fails, given the oil in the connector - good to eliminate the obvious.

The wait to start light does not directly link to how long the glow plugs are energized. It just tells you the cycle has started. The actual time on is dependent on oil temp, I believe. [LINK]

I used an Innova monitor plugged into the cig lighter as an easy way to see when my glow plugs were engaged or not. A pretty significant dip in voltage when they are energized.

 

Did you clear the code after changing the ICP sensor and it came back? Motorcraft sensors are usually reliable. Could still be a fault in the connection/wiring causing the code.

I'd first confirm my oil level is correct. Then I'd look closely at system voltage under the following conditions:

1. before starting
2. at key on/engine off
3. 2 minutes after key on/engine off
4. under cranking
5. with engine running shortly after startup
6. with engine running after glow plugs have cycled off

 

Being you said when you plugged it in it would start, leads us to believe it is in the glow plug system. ICP would not be effected when plugged in. You could away's unplug the ICP if that was the problem and it should start. Wait to start light has nothing to do with how long the glow plugs are on. I told you about the click! Or jump the two big post on the relay and see if that helps. This should only be done in an emergency. The problem should be fixed. If the relay is good you probably have two or more bad glow plugs. In that case change them all.

 

Glow plug relay is powering up the other terminal with Key On, so I would say it is good. Is there a fuse for the Glow Plugs themselves? Something that could block the power from the relay to the plugs?

Voltage drops about 1-1.5v when the relay is on, I forgot to plug it in this morning and tried cycling the glow plugs a few times, checking the voltage while doing so, but couldn't get it to start at all. Forgot to try to unplug the ICP this time, but that did work the other day when it was acting up after work.

 

How long did you wait before testing the other lug? Some times they work for a short period of time then click off. That's why I told you to time it. If it is cold, and engine oil is cold it could stay on for a period of two minutes. Mine did that but just wasn't on long enough. On the other point, if you have two or more bad glow plugs it won't start either when cold.
Did you jump the lugs for a minute or more and see if it starts?

 

Sooooo... the voltage was... ???

 

1. I cranked on it to see if I was going to be lucky and it would start so I could get to work so I drained the batteries a bit. Charged up for 20 mins, voltage was 13.1
2. 10.5ish
3. 13ish
4. Was reading voltage through OBD port, wont give reading during cranking
5. N/A
6. N/A

Was in a bit of a rush, having to get to work, and since it didnt start had to drop the wife off and steal her car. I was planning on checking again tonight for better results, although I left it plugged in

 

Well, the 10.5ish indicates there is a serious draw, hopefully that's the glow plugs . If you watch that voltage, it will tell you how long they are staying on for. But they should have no less than 10.8v. Are you ever getting smoke from the tailpipe during cranking? As others have mentioned, jumping the GPR is a simple test that is almost foolproof, it takes almost no time, and cuts to the chase. If that ISN'T the problem, you haven't wasted much time.

The 13.1 and 13ish - was that with the charger connected and running? The reason I ask is that #3 is very high for batteries that just saw 2 minutes of glow plug draw on a cold morning. If it was 13+v after waiting for 2 minutes, I'd suspect they didn't get nearly a full cycle - or if they did, I want to make sure I buy the same batteries you have next time. If it's just recently off the charger, or still on it, that isn't giving us a good baseline on battery health. Glow plugs pull a ton of amps, they need healthy batteries. And there's a lot of stuff downstream in the start cycle that needs proper voltage as well.

You mentioned that you have an OBDII reader and Torque Pro - if you have the Ford PIDs set up in TP, you should be able to read ICP and pulse width (depends on the reader).

Unfortunately, with the age/mileage of some of our trucks, it isn't always just one thing that causes a problem - old injectors, a couple tired glow plugs, a battery cable with some interior corrosion, UVCH with a bad connection, several moderately deteriorated things can add up to a no-start.

Still interested in your oil level, viscosity, and condition. Also very interested to see if pulling the plug on the ICP lets it start every time...

 

Pickup had 248k miles
Battery voltage12.8v just off charger
12.7v to hot side solenoid
Difference of .2v when energized, across posts of solenoid
10.6v key on
12.3v after glow plugs cycled off
Long time to crank 20-30 sec
12v engine running
14.7v after a minute of running
Oil in middle of hashmarks, Rotella T6 5w-40, about 3,500 miles on oil
No smoke on start up usually, unless it takes abnormally long to start, then there might be a little while smoke, it smoked a bunch after I replaced the ICP and it didn't want to start.
I looked through the service records and PO replaced glow plugs and solenoid 24k/2.5 yrs ago, batteries about 2yrs old
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Sounds like the GP system and the batteries are healthy...

You mentioned service records...are those the original injectors? At your mileage if they're originals its certainly possible they just really don't like that cold oil anymore...5w40syn or not...