glow plug circuit problemo

Discuss (and cuss) the Nissan LD-series OHC Six diesel engine, popularly available in the US in 1981-83 Datsun/Nissan Maxima Sedans & Wagons.

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goglio704
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#76

Post by goglio704 » 13 years ago

Should I pursue the above further? Personally, I get kinda irked when people wont even ballpark something for me, but I am willing to continue.

I'm not sure what it would cost, but this could be done with a small 12 VDC Programmable Logic Controller. One problem would be coming up with an inexpensive temperature sender that would produce a 0 to 10 VDC analog signal for use by the PLC. Thermistors are cheap, but not linear and the calculations needed to get useful temperature data from a thermistor curve are beyond the capability of the controller in question. A thermocouple or RTD could be fed to a temperature transmitter, but this could get bulky and expensive in a hurry. Thinking out loud, feel free to join in...
Matt B.

83 Maxima Sedan, LD28, 5 speed, white, 130k miles. My original Maxima.
83 Maxima Sedan converted from gasser, LD28, 5 speed, 2 tone blue, 230k miles
82 Maxima Sedan, LD28, 3 speed auto, 2 tone Gray/Silver, 140k miles
81 810 Sedan, LD28, 3 speed auto, rust, rust, and more rust!

2005 Jeep Liberty CRD

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asavage
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#77

Post by asavage » 13 years ago

goglio704 wrote:Should I pursue the above further?
I'm not interested, because it's all proprietary. Thanks for the legwork. I liked the idea that someone had done up an interface for poking values in.

I'm not keen on using a PLC, but one of the small microcontrollers + interface for I/O might be cost-effective. Using analog I/O and a lookup table for mapped values, I think that would be straightforward. But I've never really liked PLCs all that much -- the couple I've worked with and had to create ladder logic programs for.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

goglio704
Posts:726
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Location:East Tennessee

#78

Post by goglio704 » 13 years ago

IMO, one of the problems with glow plug control is that you are never monitoring actual glow plug temperature, but rather coolant temperature. If you could monitor actual glow plug temperature and used some form of solid state switching on the power, a PID temperature controller might be a good answer. I wonder if a 7th glowplug in a well that had similar thermal properties to the prechamber could work?
Matt B.

83 Maxima Sedan, LD28, 5 speed, white, 130k miles. My original Maxima.
83 Maxima Sedan converted from gasser, LD28, 5 speed, 2 tone blue, 230k miles
82 Maxima Sedan, LD28, 3 speed auto, 2 tone Gray/Silver, 140k miles
81 810 Sedan, LD28, 3 speed auto, rust, rust, and more rust!

2005 Jeep Liberty CRD

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asavage
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#79

Post by asavage » 13 years ago

The Ford/IH IDI engines (1984-93) reportedly monitor current draw (or voltage rise) and cycle the plugs based at least in part on that data.

Lose a GP, system of GPs doesn't draw enough current, GPC thinks the plugs are hotter than they are and shuts them down too soon.

glenlloyd
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#80

Post by glenlloyd » 13 years ago

So let me pose this question.

Do you really need to install an additional relay to manualy activate the glow plug circuit once the controller has cut power?

Based on the wiring schematic for the OE system, the #1 relay energizes via the controller, allowing current to pass to the glow plug bus bar.

If one were to reapply power to the #1 relay via a momentary switch mounted in the dash would there be a problem or damage to the controller?

Would it be safer to simply run another #1 relay, energized by the dash switch, tapping into the existing wiring from the first #1 relay?

I found both spade connectors at the water temp sensor completely worthless and in need of replacement. Unfortunately the temperature here now is not conducive to testing the system adequately, it's too warm.

TIA
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!

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asavage
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#81

Post by asavage » 13 years ago

Welcome back, Steve. It's been months since you posted. I wondered where you'd gotten off to.
glenlloyd wrote:Do you really need to install an additional relay to manualy activate the glow plug circuit once the controller has cut power?

If one were to reapply power to the #1 relay via a momentary switch mounted in the dash would there be a problem or damage to the controller?
No, and no. Go ahead and do it. It's what I'm going to do.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

glenlloyd
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#82

Post by glenlloyd » 13 years ago

Thanks for the tip Al. Didn't think that it would actually cause any problems but for the sake of the controller I thought I would ask anyway. Sometimes I study those wiring diagrams and think I'm right and the next thing you know it doesn't make any sense anymore.

As I mentioned, the problem could be solved with the new connections to the water temp sensor, but since the discussion has often centered around inadequate glow times I think the added manual control will be beneficial.

It has been a while since I've posted. Much has changed, little good and a lot bad, but I won't get into that here, it's just life I guess.

steve a
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!

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