Grid heaters
 

Truck is having an issue cycling the grid heaters this year. The self check doesn't show up in the dash anymore but if I unplug the intake heater and force the heaters to turn on for a complete cycle the light comes on.


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Air Intake Sensor go bad?

Kinda what I was thinking, but none of the lights in the information center light up like they used to... Idk maybe I'm thinking of my parents old 93 that they all lit up momentarily when keyed on. I also know it's gotta be pretty much freezing out before they'll pre heat and it was 37 when I fired it up this morning. Even at 37 they'd cycle on and off while warming up.


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Yea mine kicks on if it gets below 40. As far as the lights, mine are MIA so I couldnt tell ya. Good Luck!

The lights don't bother me, more along the lines of if them not working is a sign of a module being toast, hence why they don't function unless the system is sent into a fault


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They should cycle if it gets below 60 outside.

If that's the case then they've been screwed up for years lol. I figured with the KSB and dynamic timing of the VE the grids weren't needed until a lower temp because of the timing properties. I don't think the P7100's cycle until 50's


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I know mine is kinda finnicky, sometimes they cycle for about 2 seconds and kick off and my truck runs like crap for a few minutes unless I cycle the heater a few times before starting, other times it runs much longer. Is there a good, safe, and somewhat easy way to make them run longer like off of a switch or something? Even the 7 seconds or so that it runs when its doing good isn't always long enough to make it do well when its down in those deep negatives like the -30s that it was some mornings last year here. I don't know if its healthy for them to run any longer but from what I understand they are, I don't think it would do damage to have them cycle a little longer??

The last thing I did to eliminate the PCM in the 1st Gen was wire the grids to a manual switch. It's a push/hold switch on the bottom left of the dash that always works. I don't need a light on the dash to tell me what the grids may or may not be doing. The colder it is the longer I heat them, up to about 12 seconds max. 6-8 secs works down to around freezing, more the colder it gets.

I definitely like that idea... is there a way to do that without eliminating the rest of the PCM?

I don't see why not. As far as controlling the grids is concerned, the PCM is just a timer switch for either one or both heaters, depending on the signal it sees from the intake temp sensor.

I've been contemplating a 3 way switch that still utilizes the PCM as a timer but fools it into thinking it's much colder out than it really is


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So would you just have to find the wire that comes off of the PCM that goes to the relay that kicks on the grid and cut it and take it to a switch? I haven't gotten into the electrical system yet at all but is that right?

You should think about re wiring the truck I did mine this summer and before I did the speedometer didn't work and the truck would just shut off and dash lights didn't work. Old wiring is the main culprit of a car BQ

if I was a little better at wiring I would probably just do the whole thing, but right now it all works (except my trailering tail lights) and I don't have the time to take on anything that's not necessary, and its like 5 degrees outside and it currently transmission-less and thats my first thing I need to get taken care of.

Someday i might tackle that one.

No, just disconnect the stock grid relay triggers and connect your own manual trigger switch. Extremely simple. The hardest part is running new wires to it and mounting the switch.

I was going to but a resistor in line to fool the PCM that it's colder out than it really is at a certain switch position. I'm going to replace the intake temp sensor before anything


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Maybe even a high idle solenoid for one of the 3 positions


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You're over thinking this. You don't Need alot of complexity to get some heat in the intake for cold starting. The grid system is more complex than it needs to be stock. That's what started this thread in the first place wasn't it?

where are these wires I would need to find? I don't know anything about the grid system to be frank.

90% of my truck is ran off toggle switches. Im not a big fan of wiring either. As far as the grids go just run power to a momentary toggle then to the heater and hold it as long as you want them to run and you should be good.

Heaters work, just not at the desired or ideal temp. That's what spawned all of this. I know what you're saying but i'd like to figure out why the temps are off and maintain the factory system since on cold start with the engine running the heaters continue to cycle. Push button like you said is bullet proof and simple. I just would like to preserve the after start up cycling without havin to push the button myself.


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My IAT sensor was replaced with a water/meth injection nozzle a couple years ago.

I disliked the headlight dimming post-start grid cycle. I think all that does is reduce exhaust emissions for the first couple minutes after cold start. Function almost always trumps form for me.

Understandable, my truck does some funky things on cold start up. KSB is screwy lol. It'll pick up and drop rpm, idle low so on and so fowarth. Randomly... Lol. Perfectly warm idle is ideal.


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My KSB is also manually switched. The only time I use it is for a minute or 2 on fast idle (also manual throttle cable controlled!) to reduce the white smoke after cold start. I'm pretty sure both those "features" (KSB and post-start grid cycle) were never expected to be anything more than primitive pollution controls.

Makes sense, KSB advances timing for your normal "operation" so in a dead state the retardation aids in cold starting. Although I've heard between the two intercooled and non, the KSB works opposite, one works with juice and the other in the absence of battery power. So I'd have to determine if to wire the truck up if I'd cut power or supply power for the pump to advance.


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You Have That Exactly Backwards...
 

The KSB has absolutely nothing to do with starting. It only advances timing (either in the presence of absence of voltage, depending on the version) when the "other" IAT sensor tells it to, and it cannot physically do anything until after the engine starts.

I understand that, that it works off of vane pressure from the pump, but if the presence of fuel pressure is kept from the advance piston until the KSB is energized leaving the pump at base timing, wouldn't that mean the pump is retarded in relation to KSB hot; fuel pressure present.


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No. and if by "hot" you mean 68F, then I guess it depends on how long it takes your intake to reach 68F. That's when a properly functioning IAT sensor tuns it off.

It closes off the pump's internal pressure regulator bleed port. Pump pressure increases and moves the advance piston against its spring. Then the piston rotates the cam ring so the rollers hit the lobes sooner, advancing timing.

None of that can happen until after the engine is running. Base timing is what it is. Most people who have tuned their VE's much have already advanced the timing beyond what makes the 6-8 degree KSB effect even noticeable.

I do like the after starting grid cycling, there are some times my truck doesn't do it and it takes much longer to start running nice and smokeless when it doesn't run. I hate the white smoke after starting and I don't know if everybody's trucks do it as bad as mine but mine looks like im burning a haystack for about a minute after startup but it goes away much quicker when the grid cycles. It just looks trashy in the parking lot for one thing, and I don't like it looking like that for so long.

I wonder if there's a way I can hook up the push switch, to make it run when the grid doesn't fully cycle but leave it to run the stock way if it does function right and/or after startup?

I may not be getting my logic across clearly because a lot of what you say sounds like what I've already said. Atleast to me. Im sure the air dog and M&H timing spacer has a little to do with the factory function being "off" to say the least lol


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Could be, but did not seem like it to me. I keyed on the part about the KSB having something to do with starting:
There's no "retardation." Like I said, base timing is what it is. And the KSB has nothing to do with starting. It's a post-start pollution control device. That's all I'm saying. :hellox:

Gotcha, and I was simply trying to say base timing is "retarded" compared to when the KSB is doing it's job, I understand that the KSB only advances, does not retard.


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