AutoAfterglow Timer. Diagnose & Discuss alternative

[moose60]

The dealership wants a bunch of money for this little box. If any of you junkyard hounds come across one, I would love to buy it off of 'ya. Any suggestions about other possible sources or alternatives are welcomed.
Byron

[asavage]

I've got a spare, but it's . . . a spare, and I don't want to part with it. I'd be willing to loan it for a while though, if you want to see if your symptom changes with a different one. For a short time, I could loan you TWO of them, as the one in service is being stripped for a transplant and the GP controller is pulled, probably won't be needed for a couple of months at least.

Back in May, member "Dave S" in Oregon bought an aftermarket one:

am installing a glow plug relay/timer system from "Fourthgen" a firm on Ebay that has stuff made in India. Fairly cheap, about $40 or so, plus 10-12 for freight. Includes timer, relay, mounting plate, and a glow plug light.

Relay is a knock-off of the Datsun unit, looks identical, will see how well it functions.
[ . . . ]
The "Fourthgen" GP unit has a temp sensor included. A block of aluminum, with a bolt hole to attach to the engine block.

Maybe Dave will pipe up and tell us how it's worked out.

[moose60]

Al,
The loan sounds pretty good, and Dave S's experience sounds heartening (perhaps). The dealer wants $185.
I have also been looking into the Mercedes fastglow controllers. These puppies use fast glowplugs and afterglow for three minutes (!). I think that the SD 22 is intended to afterglow for about 30 sec. on a cold start up. Is that about accurate? Any info on the Merc setup? I've been doing some reading, Mercedes made a kit to convert older cars to the newer system. Many of the folks who have switched love the speed of the new setup, and claim smoother running right after startup (vs. the old system, which may not have any afterglow at all).
Byron

[redmondjp]

Moose,

I switched over to the ultra-fast setup w/up to a 3-minute afterglow on my '81 Rabbit D (Bosch dual-coil glow plugs and controller) and I can't say enough good things about it. The original 'slow' glow plugs took up to 30 seconds to heat up (1970s). The later 'fast' glow plugs (1980s) took 15-20 seconds. Now, I can fire up in 4-6 seconds (at 55-45 deg. F)--almost as fast as the late-model VW TDIs (no delay at all unless below 40 deg. F). And the afterglow definitely helps to minimize smoke at cold startup.

I would love to switch my Datsun over to this setup, but haven't spent any time on it. I did pull all of my plugs and power-tested them in a bench vice last night. IIRC they were the NGK Y112TS ones. When clamped in the vice, they took 15-20 seconds before becoming bright red (which doesn't seem very fast to me--the ones in my VW are supposed to hit maximum temperature in 8 seconds or less). But they are all working, so I will continue to search for the intermittent missing I am experiencing on at least one cylinder during cold startup (I think many of us have had this same issue).

[moose60]

Redmond,
Thanks for the info on the fast glow system. How much did the whole swap cost you? I'm guessing that the Merc to VW swap is probably a little easier than a Merc to Nissan because both use Bosch components.
I think that I would need: new plugs, controller, some wiring harness bits from the Merc. Would I need a different coolant temp sensor?
Does that sound about right?

Byron

[moose60]

Thanks for the info guys. I've got a solution for now.
Byron

[glenlloyd]

Anyone have more specifics on the Merc super-fast system?

thanks
steve a

[83_maxima]

Anyone have more specifics on the Merc super-fast system?

thanks
steve a

I'd be interested to know more about this as well.

[moose60]

My understanding of the merc fast system is that the mysterious black box contains a GP controller, heavy duty relay and an ambient air temp sensor, which the computer bases its pre-glow times upon. The fast system also incorporates about three minutes of afterglow.

Sounds great eh?

Except that you will need to find some MB electrical connectors (part of a wiring harness) to connect the merc relay to power/ignition wire etc.

These things also use an individual wire to feed each GP.

Mercedes (or Bosch?) makes a kit to update older slow-glow mercs to fast glow. The kit contains (IIRC) the controller, GPs, and the wores for the GPs. Not much else (like the connectors we will need to get power into the box).

[philip]

The dealership wants a bunch of money for this little box. If any of you junkyard hounds come across one, I would love to buy it off of 'ya. Any suggestions about other possible sources or alternatives are welcomed.
Byron

Are your REALLY SURE the problem (whatever the problem is) can be blamed on the AutoAfterGlow Controller?

I see the box contains the same minature relay found in the DPC. If the contacts have fried ... wire in a new relay ... and external one. I repaired two DPCs this way for $5 each. Sold one, am using the other.

[moose60]

Eveybody-
Sorry, most of the info in my last post is contained earlier in this thread.

Philip-
I'm pretty sure that it's the after glow timer. The afterglow timing is determined by engine RPM on my truck. The coolant temp sensor has no effect. If I can keep the RPM at idle, without raising the engine speed at all, I can get it to after glow about 25 seconds. Any increase in engine speed reduces AG time, down to 2-3 seconds. I'm just listening for the thunk of the relay. I have wired in a momentary on switch to power the relay to reliably extend the after glow times to 20 sec.

I can now start on B100 down to 25 deg F (not well) and 40 deg. with minimal smoke/missing.

Even around 60 deg. starting in the morning the truck will start great, but begin to misfire within 5 seconds of the second relay thunk. The second relay thunk typically occurs within 3-5 sec of start up. If I an SUPER anal about just barely keeping it running (maybe 400 RPM) I can keep the relay on for about 10 seconds.


Through all of this, the initial pre-glow has always been the max time. The glow light will always stay on for 35-40 sec. I have not timed it, but I have timed the after glow cycle.

[philip]

Eveybody-
Sorry, most of the info in my last post is contained earlier in this thread.

Philip-
I'm pretty sure that it's the after glow timer. The afterglow timing is determined by engine RPM on my truck.

The truck is a 1982 KC / SD22 ... right?

There is no rpm signal generator .... anywhere. Temperature, lapsed time, ignition key position are your variables.

The coolant temp sensor has no effect.

There's one problem right there.

If I can keep the RPM at idle, without raising the engine speed at all, I can get it to after glow about 25 seconds. Any increase in engine speed reduces AG time, down to 2-3 seconds. I'm just listening for the thunk of the relay. I have wired in a momentary on switch to power the relay to reliably extend the after glow times to 20 sec.

Then it sounds to me like engine vibration and/or rising system voltage is affecting the AutoAfterGlow Controller in an undesireable way.

Even around 60 deg. starting in the morning the truck will start great, but begin to misfire within 5 seconds of the second relay thunk. The second relay thunk typically occurs within 3-5 sec of start up. If I an SUPER anal about just barely keeping it running (maybe 400 RPM) I can keep the relay on for about 10 seconds.

There is no "second relay" in the Type-I (SD22) system. There are two relays in the Type-II system found on SD25 trucks.

If you wait for the duty relay to "thunk" off and then start the engine ... moving the key switch from ON to START to ON resets the AutoAfterGlow timer for another 30 seconds. Seems this is what you mean, correct me if I'm wrong.

Through all of this, the initial pre-glow has always been the max time. The glow light will always stay on for 35-40 sec. I have not timed it, but I have timed the after glow cycle.

Hot or Cold, the preglow is always 35-45 seconds? Then your temperature input is faulty or the AutoAfterGlow controller is faulty.

[moose60]

Philip,

Of course there is no RPM signal. It is a voltage issue, I absolutely agree.

If you wait for the duty relay to "thunk" off and then start the engine ... moving the key switch from ON to START to ON resets the AutoAfterGlow timer for another 30 seconds. Seems this is what you mean, correct me if I'm wrong.

Exactly. I know that there is no second relay. But there is a second relay clunk when the afterglow cycle is over. I hear one thunk immediately before I start the truck, then another sometime (5-25 sec.) later.

Hot or Cold, the preglow is always 35-45 seconds? Then your temperature input is faulty or the AutoAfterGlow controller is faulty.

Temp input seems to vary the temp sender's resistance according to coolant temp. I tested it. Thus the AGT is kaput

[asavage]

I see the box contains the same minature relay found in the DPC.

You've had it apart? I'm impressed: I've got one on the workbench and am still working out how to get the terminals disassociated with either the PCB (they're staked, I'm thinking Dremel on the staked portions) or the black cover (tougher problem than it first looked: melted in place?).

I was seriously considering a horizontal cut of the case, making it a "lid".

Can you share how you accomplished the GPC disassembly?

[asavage]

These things also use an individual wire to feed each GP.

Mercedes (or Bosch?) makes a kit to update older slow-glow mercs to fast glow. The kit contains (IIRC) the controller, GPs, and the wires for the GPs.

This is true: the eariler, series-wired loop-style glow plugs used in the 300D series and earlier diesel models . . .


. . . can be updated to the parallel-wired pencil-style GPs used in later MBs. Rusty's got the kit for $95.

Kit Includes: 4 Glow plugs, 0 250 201 044; 1 Control Unit - 0 281 003 005, 1 Service Kit = 1 235 345 001 - Nut; 0 332 002 156 - Relay; 0 354 010 001 - Fuse Holder; 1 904 520 017 - Fuse; "ADD 1 extra glow plug for 5 cylinders"

Bosch has superseded the glow control relay to a new glow plug kit which includes a new controller and 4 glow plugs. This new controller allows the glow plugs to continue functioning up to 3 minutes after the vehicle has been started, providing a smoother engine start up and less exhaust smoke. It is important to keep this in mind when testing the glow circuit func- tionality. For vehicles with 5 cylinders, 1 additional glow plug is required (0 250 201 039).

However, I don't think the kit takes you to "ultra-fast", as redmondjp mentions. It's a lot faster than the series system that had recurrent problems with carbon shorting the loops to ground in the precombustion chambers, requiring perodic reaming of the GP aperture -- there are special tools specifically for this:




but I don't think the newer system is in the 3-8 second range either.