glow plug circuit problemo

[Carimbo]

Believe you can "fool" the fastglow system into energizing by temporarily disconnecting one of the two butt connectors at the temp control sensor (the passenger-side one of the two sensors). This could help isolate to a faulty/intermittent temp sensor. If it starts easily that way, you've found your problem.

[goglio704]

Carimbo- neat idea!

I have not tried this but unless the glow plug control is more sophisticated than I think it is this should work because if you look at the specs on the sensor higher resistance equals colder temp. By opening the circuit you would introduce infinite resistance and the control should respond as if the car is infinitely cold. The only problem would be if the control checks to see if there is a circuit present on the temp sensor, but I doubt it is that complex. An expansion of your idea would be this: by adding a fixed resistor in series with the temp sensor it should be possible to fool the system into thinking the car is colder than it is across the whole range. In this way you could tweak it in. Full range on the sensor is about 3000 ohm and about 120 degrees F. If you added 300 ohms of resistance to the circuit the control should act like it is 10% or 12 degrees colder. At some point I'll try this and post results.

P.S. I just thought of something. If somebody tries this they need to be careful, fast glow plugs usually have a limit on how long they can run continuously without burning out. I'm thinking no more than 20 seconds. Years ago I went to manual control of the plugs on a GM diesel. I deliberately ran a plug to destruction with it out of the engine and I think it died at about 20 seconds. It might take a little longer with the plug in the engine because the head would soak up some of the heat. I know in that GM a plug which failed from being run to long would bulge and be a cast iron nightmare to remove from the head. Anybody had this happen on a Nissan?

[Carimbo]

Matt B.,

In fact I have used this method (temp. disconnect one of the temp sensor wires) to force the GPs to ignite; did not need to use resistors, did not fry the GPs. Of course quickly reconnected the wire-- as soon as the car started and I ran to the front to reconnect-- abt. 7 secs.

I had shut down the car in WVO mode; intending to run into the house to get the kid's backpack, the phone rang, got distracted, by the time I went to start the car it wouldn't. Engine not warm enough to ignite the WVO, yet still too warm to energize glow circuit. Battery starting to wear down. Nighttime soon coming, absolutely did not want to leave her like that overnite. Quickly checked the FSM diagram of the glow circuit, figured it was worth a try. Identified the sensor, pulled the wire, VROOOOM! Started first try, ran to front and reconnected the wire.

Have heard about mushrooming GP tips, hope to never have to deal with the problem.

[goglio704]

Definitely a handy trick to have in the back of your mind and easy to do in a pinch. Thanks for the tip. The resistor thing is just an idea for a way to calibrate the glow plug controller to match the starting characteristics of a particular car/fuel combination. Both of my cars are hard to start warm and a couple of other members have also mentioned having trouble warm starting their car. It also sounds like we have separately arrived at the same sort of workaround (listening for the relay, recycling the key, etc.) but adding some resistance to the circuit might let the system operate the way it was intended. Both of my cars vary the glow plug cycle according to the temp, but they both seem to be too conservative in their use of the plugs.

[glenlloyd]

I suspect that the sensor is the problem, but I won't know for certain until I take a reading in a little while.

If you want a "loaner", I've got two spares. One's already pulled.

I took a cold reading and it's way off, max of 5.25, no wonder the glow plugs aren't heating.

I have a theory. I'm looking at the '83 Owner's Manual (because it's here, and the '82 is out in the car where it's raining like rain is going out of style, so hard that the wagon is literally in a lake of water right now!) and the "Instruments & Controls" page is 17. Number 6 is "Illumination control rheostat".



I'm betting that your button is just to the left of it. If so, what you're seeing in the illustration isn't a button but a raised area for an option that wasn't offered in the US. I'm guessing foglights or rear foglights (latter available in Europe on many cars). I guess I should buy that damned Canadian Maxima Owners Manual (in French!) that that guy on eBay has been trying to sell for six months -- but he wants a lot for it. I'm guessing that in the Canadian version, there may be a real control there.

But in the US version, there's nothing (IIRC).

That's very likely, manufacturers often use the same images and just id those things that apply to the model for that country. I wouldn't doubt it at all. Funny that my owner would have chosen that spot for his "button"!

I checked with the dealer on the water temperature sensor, $40, special order, prepay, and a week for delivery..it has to come from California!

Also, the new copper bus bar is complete and installed. I have pictures but still without a diskette drive so I can't post them. The nice thing about the new bus bar is because of the way it attaches to the glow plug it hangs lower than the original and requires fewer bends. I'm making another one with larger copper, I think 4 gauge.

Pictures soon...I promise!

SA

SA

[diesel-man]

Looking at the picture on page one of this thread, if you look at the solenoid that is just above the object that is circled on the lefthand side of the picture.........That is the solenoid that energizes the glow plugs. It has two (like) 10 guage wires, one comes from the glow plug relay (from memory) and the other goes directly to the glow plug buss bar. There is a small green wire that has a male/female connector (also to the solenoid) If you put power to the solenoid side of the green wire you will hear it make contact. I have a couple cars that I wired a switch inside to manually energize the glow plugs like when it is half warm and it just cranks but won't run.

Another common problem is the Glow plug controller (1981 is on the kick panel, 82&83 is under the passengers seat.) It is supposed to energize the glow plugs for the first so many seconds and then drop the voltage down for another 10+ seconds. It really needs it all, but that box is Mucho Denero, hence a little help from a switch. I recommend a 3 position switch so that you must actually hold it on so that it doesn't happen by accident.

Warning: A little will do ya, or you'll fry the glow plugs. Same with either, just a little to get it woke up, or else it's starter drive time.

[asavage]

LAnother common problem is the Glow plug controller (1981 is on the kick panel, 82&83 is under the passengers seat.)

While you are the one with all the rigs, the '82 FSM shows it still on the left kick panel.

that box is Mucho Denero, hence a little help from a switch. I recommend a 3 position switch so that you must actually hold it on so that it doesn't happen by accident.

Do the Fast Glow Controllers really go bad?

I played electronics bench tech for a few years, if I get a spare GP controller, I'll have to take it apart. The things that go bad over time are solder joints and electrolytic caps, and I bet that thing's just filled with both . If it's not potted, I can probably fix it. But a manual system and judicious use of the switch may be easier for those of us who can count to ten without taking off our shoes

Warning: A little will do ya, or you'll fry the glow plugs. Same with either, just a little to get it woke up, or else it's starter drive time.

I have to violently disagree with any non-diagnostic use of ether on a diesel that has glow plugs that are active. If you have to use ether, disconnect the GP system at the relay (where it's easiest). Warm/hot GPs + ether = broken pistons. It's not theory, it's fact.

Fortunately, the LD28 is an easy starting rig. But I'm probably going to go with a spring-center batwing switch + indicator as a bypass to the GP controller, as I've got a new temp sensor and still have trouble with warm starts. Cold starts are fine, hot starts are fine, but in-between is not fine.

[asavage]

If you want a "loaner", I've got two spares. One's already pulled.

I took a cold reading and it's way off, max of 5.25, no wonder the glow plugs aren't heating.

I checked with the dealer on the water temperature sensor, $40, special order, prepay, and a week for delivery..it has to come from California!

Yeah, when I got mine, I had to order it too. I can put a used one in the mail for a lot less than that, unless you really want new.

Also, the new copper bus bar is complete and installed. I have pictures but still without a diskette drive so I can't post them. The nice thing about the new bus bar is because of the way it attaches to the glow plug it hangs lower than the original and requires fewer bends. I'm making another one with larger copper, I think 4 gauge.

You'll have to go into production!
Reminds me of the guy who's selling "crank scraper kits" on eBay for the L24/L26/L28/LD28. When he first started selling them, his pic links were bad in such a way that he could see them but noone else could. I did some very light tech supt via email with him, and he offered me one for free . I politely declined.

1) My pan doesn't leak, has never been off, and I'll need a damned good reason to pull it;

2) The LD28 doesn't normally rev a whole lot, so the amount of HP "lost" by oil "whipping" around against the rotating parts is miniscule;

3) Hey, don'cha think Nissan engineers figured on the oil mist providing some of the cooling and lubrication of the lowers of the cylinders? You think that if a static piece of sheet steel in the crankcase could pick them up 5HP, that they wouldn't do it?

No, I'm not interested in a "crank scraper" for my LD28. Now, on my Corvair . . . it's a whole different story.

[diesel-man]

Do the Fast Glow Controllers really go bad?

I might be a mechanic, but don't consider myself to be able to say: If I can't fix it you should've never broke it. I check the GP buss bar and there is power there until the second portion of the Glow starts, and then there is nothing. I change the Fast Glow control box under the seat, and now it works.... I check the old box on a car that did work, and now it doesn't. That is all I know. The '82FSM shows it on the kick panel. I have no idea what month it changed. I have a couple 81's and the rear calipers are different as is the A/C mounting bracket. I have 18 yrs of experience w/Maxi's, (12/87) yet don't know all that much. Sometimes people are going to bring something up and I remember a solution I came up with over ten yrs ago.

I bought a Maxi that had a weird electrical problem that a Nissan mechanic could not figure out, (that is why it came up for sale) but after a month I solved it. When putting the car in reverse it would blow a fuse (I think to the transmission, 10 yrs ago) After the fuse would blow, the car would not crank, so I put a circuit breaker in place of the fuse until I figured it out. It turned out it had a chafed wire in the wire loom on one of the starter bolts.

I had a customer's Maxi have problems with the intermittant wipers and something else?, it was the time control box inside the passengers doorpost.

My nephew broke a crankshaft (front six inches). No idea to the question anybody is thinking. When one plays with enough of 'em, some crazy things will pop up.

spring-center batwing switch

Actually that is what I have, but did not explain it well.

If the glow plugs don't work all of a sudden, check the fuse link @ the positive battery cable.

One Maxi wagon I bought had a little extra diesel "knock" (compression ignition noise) than any of the others and was also the only car in the fleet to use oil. It would sop up a quart every thousand miles. I'm sure that someone twisted the injection pump a smidgen. It isn't a problem now that I flipped it end over end back in '98. (hit from the rear on the Interstate) Came from York, PA a helicopter mechanic was going off to the first Gulf War.

I only use ether when it is really cold and it already won't start. (If it is half warmed up, don't even think about ether) A little is cheaper than a lot. USE AT YOUR OWN PERIL! Yep, it is the wrong thing to do, so is speeding and taking medicine if you don't need it. Supposedly that is why Doctors prescribe medicine because they are supposed to know how much is too much, and if you need it at all. After a couple starter drives over the years, about a half second spray seems to be about right at 10 degrees. A Maxi has a precombustion chamber and I am remembering that the glow plug is in there, where a different type of diesel might have the glow plug in the main combustion chamber? I would think that that would would be a bad combination with ether. I have a couple cars that are really great starting, and a couple that are on the hard side. It also reminds me of the 5 blind men and the elephant. The short side of the story is: that they are all correct about what an elephant looks like, yet each describes the elephant in a vastly different way.

Anyhow, I'm sure the Amish talk to each other at a barn raising about the best way to "handle" their horse. Be it far from me to convince someone to operate their Maxi in a different way. These are only my observations over 18 yrs and a dozen different Maxi diesels (25 in the family including parts cars) Still willing to learn... Pop is still learning about cars @78 (we both work together)

I'll probably remember some other oddball solutions I came up with later on. Hope my mistakes help somebody.

[asavage]

Do the Fast Glow Controllers really go bad?

I check the GP buss bar and there is power there until the second portion of the Glow starts, and then there is nothing. I change the Fast Glow control box under the seat, and now it works.... I check the old box on a car that did work, and now it doesn't. That is all I know.

Perfect: a known-bad GPC. If it's useless to you, and I pay shipping, would you be agreeable to sending me a bad one?

I had a customer's Maxi have problems with the intermittant wipers and something else?, it was the time control box inside the passengers doorpost.

I've got the glovebox out of mine (had to replace the A/C TXV last year, and want to replace the radio with another one here, and I don't drive the car much so . . . ) and I looked at the packaging of the time control module and thought to myself, "hope I never have to take THAT out!".

If the glow plugs don't work all of a sudden, check the fuse link @ the positive battery cable.

Glad you reminded me. When I sold mine, a couple of months later the fellow calls me up, says it won't start. Long story short, it was that link. The 3/8" spade connector was totally de-tensioned. I swapped in a nice length of 10ga and never looked back.

Lister diesels (IDI stationary engines) are IDI and have no GP. Early ones have variable compression ratio. You turn a valve to "high compression" to start, and can leave it there up to 1/3 load. Above that, you're supposed to turn the valve to "low compression".

These are only my observations over 18 yrs and a dozen different Maxi diesels (25 in the family including parts cars) . . . I'll probably remember some other oddball solutions I came up with later on. Hope my mistakes help somebody.

Of our group, you seem to have the most "depth", and I am looking forward to more of your observations (and anecdotes)!

[oldmax82]

Hello:

Sorry to enter this discussion so late but I am having cold start problems too and think it is a glow plug. My 82 maxima wagon starts well when the temp is above 60ish. Once started it runs and starts fine the rest of the day. I have started putting a drop light next to the engine to keep it warm at night in the garage. I will be pulling the glow plug bus this weekend and I hope to find it is simply a bad glow plug or two which is causing the problem.

This is my first diesel and I have a question. My Crown service manuel says always replace glow plugs as a set. Others have told me only replace the bad one. Any feed back on these two notions? I have seen autolite plugs on-line in a pack of 4 for $8.18 each. Schucks auto has them for $10 each and I can order one at a time.

Glen: My dashboard has a plastic knockout between the dashlight rheostat and the cubby next to the driver side door. My owners manual does not show it to be used for anything. However, if I were going to wire around the OEM glow plug circuit that is exactly where I would put a spring loaded button to activate the glow plugs.

Thanks,
Terry

[diesel-man]

Terry:
The Scottish in me intends to say one at a time. History has taught me that I will end up going back in there, thinking that it is a corroded terminal on the aluminum buss bar (yet I clean it and even use Neverseaze). I have tested each glow plug (out of the head) with a test wire to the battery, and have concluded that I can "make" each glow plug work, but have found over the years that a good one will heat up in like 2 seconds, usually less, with minimal effort. The more times you have to "stick" it to the battery (while testing it) to make it work, the more unreliable it is. I notice that the good ones in the bunch will have a small curl of smoke come off of it, in less than a second. It seems that a car that has a good set of glow plugs is fine year after year, while the other car that gives problems...year after year. They are like children... they have personality now, some good, some bad.

If you put in the switch, just keep in mind why you are using it. To activate the switch you are overriding the system to make the glowplugs heat more. They don't like that, and will fail if you get too happy with your switch. Only use the switch in that weird situation when it is half warm and for whatever reason the Fast Glow system thinks that you don't need any GP, but yet it just cranks and cranks, that is when you give it a little boot in the pants there.
Welcome to the board!

[glenlloyd]

I have used the Autolite plugs in other applications and never had a problem with them. Others have mentioned in the past (not on this forum) that they don't like them. Personally I can't say anything bad...yet. My car has five Autolite plugs and one "other" (brand unknown). I think the people that worked on this car before I bought it left the remaining older plug in 1) maybe because it worked or 2) because the threaded stem is longer and allowed the connectors to be attached. That's one thing I did notice about the Autolite, you have to split the attaching wires up if you want to use them, you can't attach both the bus bar and the wires at a single plug, the threaded stem isn't long enough.

I'll have pictures of the new copper bus bar online tomorrow sometime. I am rather pleased with the way it turned out.

PS - I have a set of the Autolite in my Golf right now and that baby has started down at zero degrees with only two heatings, so I can't say bad things about the Autolite plugs. It may have started with only one heating, but when it's that cold I run the heat plugs twice at least.

SA

[asavage]

In the Ford Diesel forum, Autolites are nearly universally panned as the bottom of the barrel. Several people have had them ballon when they get overheated. Granted, overheating is not supposed to be a normal situation, but if you have a bad GP controller (Ford and GM's early GP controllers often fail in the ON mode), the Autolites fail such than the head has to come off. That's why they aren't the first choice.

I don't like Champion GPs either, and I generally buy NGK, and if they're unavailable, I'll use Bosch too.

IP timing that is too advanced can degrade GPs too.

[goglio704]

I have found some info which may explain some of the glow plug problems we all seem to have experienced to some degree. I am not proclaiming any of what I am about to say as carved in stone fact, but I think it warrants closer scrutiny. I don't think the original glow plugs in these cars are simple dumb heaters like I was used to in GM's and others. My white (100k) car recently picked up a miss on cold starts that would clear up fairly soon after start. Dead glow plug - found one with no continuity. Need to find a replacement plug. Pretty sure my plugs are factory - they have the little datsun/nissan symbol stamped in them. I was leaning strongly toward NGK and couldn't figure out why they are three times the price - till I found this. http://www.ngk.de/Sheathed_type_glow_plugs.691.0.html I believe the original plugs are of this self regualating type. I pulled one the other plugs and powered it with twelve volts through an ammeter. Initialy the plug was pulling 4.5 amps and then this tapered to 3 and then 2 and then 1.5. The plug never really got too hot to touch - I don't consider this plug good either. Apparently the self regulating feature deteriorates with age. I've got 2 new NGK's on order (Y204RS) and I'll put one of them through the same test and see what happens. The good news is that these self regulating plugs should be hard to fry. The bad news is they seem to be about 30 bucks a pop. I wouldn't mind using a cheaper "dumb" plug, but I don't want to risk having to pull the head to get a bulged one out.