My 02 7.3 4x4 Ex will crank but won't start once the weather is under 40 degrees unless I use heavy duty jump boxes and I am talking about putting one on each and recharging multiple times. I replaced the 2 Lead Acid Interstate batteries that came with it with 2 AGM Interstate batteries thinking that was the culprit. Starts just fine during warmer weather.

I also end up needing to trickle charge the batteries for a few days after a failed start as well.

I can tell you that when it is cold and it tries to start up but won't I sometimes see smoke arising from towards the firewall even though it hasn't started which I would imagine is the result of excessive heat. It really can't be anything else since the vehicle hasn't started IMO. No smell of fuel or anything.

So what can be causing this?

I run 15w-40 conventional oil FWIW.

I know that the typical "check your grounds" types of posts might come up which can be valid but often become unsupported when the harder questions need to be asked.

Any ideas as to what is going on? On a few vehicles that I have owned the end resolution has been to replace the starter and I have seen some videos on Youtube mentioning that there are different starter types to compensate for this.

There are no Forscan codes and it passes the Buzz Test. Driver's side UVCH replaced with OEM. New DTC IDM as well.

Any advice here?

Thanks.

 

Glow plug relay. Power only on one terminal with key in forward position. I need to understand the circuit better but leaning towards a defective relay....HOPEFULLY!

 

my glow plugs are working, but had the same issue right at 40*F when I got the truck.
it had dino 15w40, whatever the Kenworth truck stop uses.

I changed to 5w40 synthetic, and a new high speed geared starter.
plus I keep a Battery Tender on it 24/7/365 unless it is on the road.

yesterday, at 9*F I needed to move it away from the very old Oak tree, because we had a prediction of two inches of ICE, and we loose tree limbs every time....

I have a DVM in the Power Port, Key On, watch the DVM until it starts back up from 11.5ish, about 2/10s of a volt.
that signals the Glow Plugs are OFF.

it took twice as long to start, but it did and got it away from the tree.

 

Thanks for the feedback. I just tried it with 100% charged batteries and 32 degrees ambient in the garage and it did not want to even attempt to turn over. I am going to run the block heater for 6 hours in an attempt to see if it is glow plug related.

I went to use Forscan Lite on my head unit for the glow plug test but I could not even get that test started as it needs to be running to spit out codes unfortunately.

Another bummer is that I just realized that the 2002+ have a glow plug module and I none of the Youtube videos seem to take that into consideration for troubleshooting.

In the end, the large gauge wire is not energized. The smaller wire in the front goes to 12VDC when the key is turned to ignition but the smaller wire facing the firewall also goes to 12VDC so the relay is not energized.

EDIT: The Glow Plug Relay does not appear to exist on the 2002+ 7.3. What I have been testing is the heated air intake relay which physically looks like the GPR. What a waste of time so far.

 

Looks like mine has CA emissions. I don't see a GPR. I see a GPM. Can anyone confirm that this might be the case as well as further help?

This thread seems to confirm this...

https://www.ford-trucks.com/forums/1...ce=chatgpt.com

Thanks.

 

from what I have read, all 2002 Excursions are California with glow plug control module, not a relay.
I use a DVM plugged into the power port and watch it when I turn the Key On.

if the glow plugs are working, the volts will drop immediately, from 13.3 ( on a battery tender )
to 11.5ish

I watch that DVM until I see the volts start to creep up, from the 11.5 mark to 11.7
or 2/10ths of a volt from whatever your battery reads...
( for me, this is to keep the MechMan 340A alternator from burning up the glow plugs,
it hits 14.8 volts the instant the engine fires up. )

then I hit the starter switch....

i have newish, high speed, gear reduction starter that spins fast,
and also 5w40 full synthetic oil.

it whirls over pretty good, 200 rpm plus in warm weather,
yesterday in 9*F temps, it was slower, but it fired right up without the block heater ON.

 

My 2001 has a glow plug module, gently remove and check both green and black square plugs at the module. Sometimes connectors can be burnt. Here is a thread I scanned through that will give you a bit of direction. The smoke issue from the firewall sounds strange, but possibly caused by worn up pipe donut gaskets. One of the posted pics identifies the AIH relay (Air Intake Heater), and the GPCM (Glow Plug Control Module).



https://www.ford-trucks.com/forums/1...questions.html

 

Hey i would start by checking the vitals. Rpm, batt voltage ipr, ipc, ipcv and injpw with forscan preferably. This will show that the pcm is trying to start the truck. If its not, its not a glowplug issue. Need 400+ icp, need generally better than 10v while cranking, need better than 100 rpm, and youll see injpw if the truck is trying to fire. I feel like the truck should be sputtering at 40*f if its injecting fuel, and would eventually fire off. It would be considered a long crank though, and without glow plugs, it wouldnt fire right off. My truck would eventually start at those temps without glowplugs.

The gpcm works similar to a gpr. It has an activate signal from the pcm, and then sends voltage to the plugs. My whole system was dead when i bought the truck. Gpcm will throw codes for any gp that are bad, and it will throw a code if the gpcm doesnt work. Aftermarket glow plugs and bad uvch was probably what lead to the gpcm's demise in my case.

Check the battery cables. Very common they go bad. Use a ohm meter, visual isnt good enough. I just replaced the ends on mine. The passenger positive terminal was almost entirely rotted inside, and that has the main power line for all the electronics.

 

Thanks so far. I don't think this is a glow plug issue at this time. I did the KOER glow plug test in Forscan Lite and it passed. There were also no glow plug DTCs. Maybe I should ohm out the connectors to the glow plugs just to be sure but even if those are bad it seems like there are other improvements that I can make based upon the other posts I see here.

The starter cranks very slow even with the new AGM batteries being 100% charged and gives up trying like weak batteries if it doesn't catch within about 5 seconds.

After plugging it in for a few hours I was able to get it to start just prior to those 5 seconds that I have to crank the starter. The starter turned over pretty slow during the process.

I did observe something odd during the process though. The vehicle exhibits a "fast idle" a few seconds after starting which I have experienced in many a vehicle when cold. However, the fast idle can be stopped simply by blipping the fuel pedal. However, if it is left in that high idle state, the alternator is not doing much if any charging. It drops down to the high 12.x volt range until I blip the fuel pedal and then it goes back into the 14.x range and doesn't fall back down again. Maybe that is normal behavior.

For those of you who replaced battery cables did you replace the battery cables or just the terminals? I have replaced the terminals on many a vehicle but I feel like that is a can of worms beyond the scope in the post but suffice it to say that I have had issues with poor fit and more wire exposed to oxidation, etc. after doing that.

Thanks.

 

All Excrusions have the GPCM versus the GPR except for some very early models...the wife's 2000 Excursion has one and I wish it had a GPR. As aforementioned they will set a CEL for just about anything abnormal about the system. What I've found relative to cold weather no start on my 2000 F350 that stays in the driveway, is several things which helped. When I installed the 6.7L starter that rolls the engine over much faster, it helped start my F350 with temperatures in the 30's, when it wouldn't at temperatures in the mid 40's. Then I went in and did several things, but most importantly I shimmed the injectors to bring them back to the factory .004" clearance and drilled out the aluminum spacers between the solenoids and injector bodies. This will allow the oil to drain out of the armature area and allow much better cold starts. The last cold spell we had last year got down into the low 20's here and the truck fired right up. It will be in the low 20's again here in the morning and we will see what happens, but I suspect it will fire up.

I also suspect the smoke you're seeing back there in the firewall area is leaking up-pipes. Do you see any black areas there on the firewall?

 

Thanks so much folks. I will check for black areas on the firewall as well. I think that I am going to go with the DB Electric high speed gear reduction starter (Chinesium Denso) and see how it goes for starters (no pun intended). I had the same issue on my EZ30R Subaru Tribeca and that starter spins like lightning bolts and has lasted for years. Seems like it might be a combination of things and I am willing to bet that this move will not hurt at all. I bet it can only help. I will try the other suggestions if needed and keep this thread in mind for when I need to check into key areas and/or have more time.

 

I made an error in my post, it should have ended with:


Obviously, Battery condition and cable condition is critical along with a starter that spins fast.

 

Check your battery cables, especially your main frame ground. Your starter could be weak, and/or your cable connections could be poor as mentioned. Sounds like you may not be building oil pressure when cold and the starter does not crank fast enough versus warmed oil from the engine block heater being used. High Idle is part of the PCM program, as well as the exhaust back pressure valve. Both operate in cold conditions if everything is still intact. Tapping my brake pedal while in park will also return my idle to normal from high when it's cold. Not sure on the ambient temp requirements, but mine will enter high idle after several minutes of regular idle, whereas my exhaust back pressure valve is fairly quick to actuate during cold temps.

 

Thanks guys for the additional details. I do think it's a bit odd that the alternator does not charge while it's in that high idle mode. I appreciate the thoughts on the LPOP or low oil pressure scenario here.

 

I think that I am also going to use Torque Pro to keep an eye on these values. The GUI is a bit more friendly than FS and has the built in Powerstroke values which are pretty awesome.