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Alternatively one could disconnect the PCM ground off of the GPR and attach a ground on a dash mounted momentary switch and convert the glow plugs to manual only.
I could send you some short-time/voltage sense stuff along with making the wait to start indicator much more realistic.
I was super proud of myself for moving Beyond Octane from the shipping box at home to the glove box of my truck, when I had the chance to go home for Thanksgiving. Wow, such progress! So I only have 3 more feet to go before it is in!
I'm actually very excited about it. My two other vehicles are down though, and I have not been home to fix them. So I haven't wanted to experiment with the truck while it was serving it's mission critical role as my sole means of transportation.
It was one thing playing around with a PCM to spare. But with only one working PCM, and only one working vehicle, and no time to work on anything personal... that last three feet of the journey looms like a mental hurdle of FOFU. (Fear of **** Up)
Let me ask this, once the glow plugs have turned off (be it 120 seconds, or 30 seconds) are they off for good until the next complete off-on cycle of the key? Let me be a bit more clear. Say I jump in the truck and turn the key to on which lights the glow plugs for X amount of time. After X has come and gone the glow plugs turn off. Will they turn back on at any point of the start-run cycle after turning off?
Yes... AS LONG AS THE KEY REMAINS ON for the entire waiting period before cranking, and not turned off prior to cranking, then glow plugs will not come back on again for that ignition cycle.
Well, now you have me wishing I had stuck to the OEM 110 Amp alternator, but there is no going back now. So my choices are the following.
1. Ditch the new Quick Start 160 Amp alternator and eat the $300 I spent on it, not including the cost of another 110 Amp alternator.
2. Gamble and let the 160 Amp alternator ride the wave and hope for the best.
3. Get new MotorCraft glow plugs (along with the Stancor relay and LED light mod) and hope for the best.
4. Find a solution to the "over heating" of the glow plugs issue being caused by the high output alternator.
Would a 110 Amp alternator with brand new AGM batteries (like I just installed) produce 14.3 volts directly after the truck starts as well, or would there be a delay like there is when the electrical system is older.
For example, AndyM posted the below information in my other thread.
Originally Posted by andym
Interesting. Mine goes like this:
12.7 when I open the door and get in
11.2 WTS
10.1 cranking
12.1 idling
14.2 glow plugs turn off after ~2 min
Is this delay in raising the voltage from 12.1 to 14.2 only because the 110 Amp alternator is installed on his truck opposed to the 160+ Amp?
I will be the first to tell you that I don't know enough about this stuff to have an expert or even and experienced opinion, but I can come up with some crazy ideas from time to time.
What about a delayed relay of some sort? This probably wouldn't work, but I installed a delayed relay timer for a camera to come on after 1 minute instead of instantly when I start the truck.
528T delay timer relay
If there was something similar to this that would do the same thing, but for the ground side of the GPR circuit, and breaking the connection instead of making the connection.
I'm open to ideas here, but really just wish I had bought the Bosch 110 Amp alternator on Amazon at this point.
In the post above, I mentioned not knowing the PCM glow plug cooking / timing recipe, only the ingredients. Not knowing makes timing the KOEO mitigation more or less guess work.
However, the following graph might offer some assistance making an educated guess...
This graph maps the glow plug on time at 12 volts. It doesn't map the glow plug on time at 14.4 volts. It doesn't map how much time it takes for the EOT to climb to any given temperature following engine start. And if an engine block heater is used, well, that would effect the EOT starting point on the X axis of this graph as well. So we are chasing a dynamic, moving target by trying to "time" KOEO.
Speaking of which... block heater. A fifth mitigation. Elevating ECT will elevate EOT which will reduce glow plug on time overall, and thus reduce glow plug on time with engine running.
For some guesswork might be acceptable, but for people like me it is not. I might be OK with guesswork if it was once in a while or a rare occasion thing, but not starting a cold truck every time.
I am committed to finding a good solution for this, but think we will have to call upon the FTE brain trust/community to help us out.
I was hopeful that waiting for the GPR light to go out would not prompt them to come back on again when going from run to start to run, but that does not appear to be the case.
For some guesswork might be acceptable, but for people like me it is not. I might be OK with guesswork if it was once in a while or a rare occasion thing, but not starting a cold truck every time.
I am committed to finding a good solution for this, but think we will have to call upon the FTE brain trust/community to help us out.
I was hopeful that waiting for the GPR light to go out would not prompt them to come back on again when going from run to start to run, but that does not appear to be the case.
What didn't you like about the thought of a momentary manually operated system? I forget who initially stated that they have that.
For some guesswork might be acceptable, but for people like me it is not. I might be OK with guesswork if it was once in a while or a rare occasion thing, but not starting a cold truck every time.
To your point, note also the non linearity of the graph, in particular observe the precipitous drop in Y axis GP on time when viewed between 20 to 50 degrees F on the X axis. The 35 degree F temperature that you report your cold morning starts occur in is smack dab in the middle of that steep and slippery slope between 20 and 50, making your GP on time rapidly dynamic and less predictable without an informational training aide like the indicator light you plan on doing.
I've prepared a few more slides to emphasize the issue.
The main text is directly from the glow plug manufacturer. I super imposed the notations in red, green, and sometimes black (for dimensional data on the differences in glow plug generations). Too often, we read something referring to a code or part number, and are not sure if it applies to us or our situation or not. That is why I super imposed the additional information... to answer naturally occurring questions before they are even asked.
12.7 when I open the door and get in
11.2 WTS
10.1 cranking
12.1 idling
14.2 glow plugs turn off after ~2 min
Originally Posted by Sous
Is this delay in raising the voltage from 12.1 to 14.2 only because the 110 Amp alternator is installed on his truck opposed to the 160+ Amp?
Undoubtedly. The 110A alternator is only rated at 50 amps maximum at idle.
If this alternator in real life is actually only generating 45 amps at idle, which is only a 10% deduct from its maximum rating at that rpm... and...
If the glow plugs are only drawing half of their maximum rated current, which is 16.5 amps per glow plug multiplied by 8 and then divided in half, amounting to 66 amps current draw...
Then we already have a 21 amp current deficient... demand that the alternator is not capable of meeting with the engine at idle.
And, we haven't even considered the current demand of the batteries that are in immediate need of a recharge after having just been depleted of stored energy from cranking the engine as well as powering the glow plugs initially solo... so add whatever amps the batteries are looking to receive...
Plus, whatever the electrical needs of the truck itself are... add those amps to the current demand too.
The PIE relationship between current and voltage is operative here... When there is a limited amount of power generating capacity to meet the current demand, voltage will drop.
That voltage drop was what Ford was banking on, to get away with otherwise inappropriately continuing to use the old style, NON afterglow capable glow plugs in the 7.3L, even while Beru by that time had developed a three stage glow plug that was afterglow rated following engine start. Ford chose to save that new glow plug for the 6.0L and beyond, and solve the 7.3L issue by downgrading the stock alternator, and adding a second alternator option for those who needed more electrical capacity, while sentencing everyone else with single alternators to a lifetime of electrical system misery beyond the 3yr/36K warranty.
AndyM's reported voltages at the different stages of start up are exactly as originally designed.
Those who grew tired of electrical system misery upgraded their alternators to high amp units, and enjoyed the tangible benefits having enough electrical power generation capacity to actually keep the batteries maintained.
When an alternator can produce 100 amps of current just off idle, there is no current deficit. The 66 amp and declining glow plug draw is entirely taken care of, along with the 5 to 25 amp battery replenishing current, as well as the 10 amps of truck running current. All handled, so there is no voltage dip. No deficiency in power. No brown out. Full voltage is available up to the limit of the regulator.
That only happens on the 110A unit after the major load of the glow plugs is turned off.
Here is my idea if you think it is a problem, This will allow you to disable the glowplugs. May also work and a anti theft LOL.
Add a relay after the GPR that is on a switch on the dash. "Position 1" = connected working normally. "Position 2" = no power from GPR will make it to the glow plugs. Leave in "Position 1" start truck switch to "Position 2" to protect glow plugs.
Brandon, I am thinking this may be the only viable solution, or a variant of that.
I could get a switch and install it in line with the GPR ground/PCM connection or position 3 noted below.
As you said, this would allow me to control when the GPR was providing power to the glow plugs. Although, I would probably shut the glow plugs off with the ground switch before starting the truck in order to keep the afterglow to a minimum.
This is one possibility, but there may be others out there. Let's keep beating our heads against the wall and see if we can come up with something.
Brandon, I am thinking this may be the only viable solution, or a variant of that.
I could get a switch and install it in line with the GPR ground/PCM connection or position 3 noted below.
As you said, this would allow me to control when the GPR was providing power to the glow plugs. Although, I would probably shut the glow plugs off with the ground switch before starting the truck in order to keep the afterglow to a minimum.
This is one possibility, but there may be others out there. Let's keep beating our heads against the wall and see if we can come up with something.
I like that better. I did not think of just interrupting the signal. No need for an additional relay.
12-19-2017, 11:50 AM
