6v or 12 v glow plugs?

[rogerh]

My recently-purchased 1993 L300 (P35W Jasper automatic 4D56) came with a single manual 12v glow plug by-pass but ancient-looking 6v glow plugs. The by-pass wiring is rather poor so I planned to replace it along with new glow plugs. (I haven't examined the 6v plugs closely but the van is a bit slow to start and produces a large cloud of black smoke on start-up so I'm guessing not all are working OK.)

Should I stick with both the 6v and 12v relays (and if so, does that require 6v plugs?) or move to a single 12v system? I'm thinking NGK CY57 for 12v plugs but not sure which 6v would be suitable. I thought maybe NGK Y-115T1 but some places list them as 12v. (Below: existing wiring to single momentary switch and glow plugs, showing green tops.)

Thanks for any suggestions to this, my first post!

 

[sk66]

You should not be triggering both relays at the same time.

The 115T1 is 12v; the 115R1 is 6v. But you are unlikely to find either (discontinued)... 6v plugs are hard to come by; if you can't find OEM (or suitable) 6v ceramic tipped plugs I would switch to a manual 12v system.

The CY57 has been discontinued and replaced with the CZ257.

 

[rogerh]

I did wonder about the two relays being linked. That's what I inherited. Is it likely that will have burnt out one or more of the 6v plugs?

The L300 Quick Glow Dual Bypass kit you offer – does that work with 12v plugs or only with 6v ones?

 

[sk66]

I did wonder about the two relays being linked. That's what I inherited. Is it likely that will have burnt out one or more of the 6v plugs?

Not likely to burn out the plugs with the relays if they are original ceramic type... running the two relays in parallel is just redundant/pointless/wasteful. With ceramics you are just shortening their life at worst. If the plugs are replacement metal tips it's possible to cause them to blow by applying 12v to 6v plugs for too long; or even by applying 12v to 12v plugs if they are not a self regulating type.

The L300 Quick Glow Dual Bypass kit you offer – does that work with 12v plugs or only with 6v ones?

There's no point in sending 6v to 12v glow plugs; it won't do anything but waste battery. Better to just convert it into a single relay 12v system and leave the second relay as a spare.

 

[rogerh]

Thanks. I've just disconnected the bypass and reinstated the original wiring. It starts OK with not too much smoke (although it's pretty mild over here now).

 

[sk66]

Thanks. I've just disconnected the bypass and reinstated the original wiring. It starts OK with not too much smoke (although it's pretty mild over here now).

I would probably keep the manual bypass connection to the 12v relay in parallel to be able to give it a little help in colder weather.

 

[rogerh]

I would probably keep the manual bypass connection to the 12v relay in parallel to be able to give it a little help in colder weather.

OK.

I found a set of NGK 115R1 plugs but see they are metal body, not ceramic.

 

[sk66]

OK.

I found a set of NGK 115R1 plugs but see they are metal body, not ceramic.

I would not be replacing the OEM glow plugs if they are working satisfactorily. Very few non-OEM plugs work with the OEM controller at all (I think it's just luck if they do).
If you go away from OEM/6v ceramic I would just go directly to a 12V manual conversion. The OEM plugs are still available... but pretty pricey.

 

[DeliKit]

The OEM plugs are still available... but pretty pricey.

Just FYI, I picked up a set of OEM 6V ceramic glow plugs from Amayama, cost me just over $250 for the set of for, including FedEx Shipping (I steered clear of EMS International shipping which would’ve been slightly cheaper, but I’ve read elsewhere on the forum of issues with EMS). I received my glow plugs in 2 weeks (to California) and my van (a 1990) really likes them! Previously I tried the HKT brand but even though the folks I bought them from (Good Karrma) sold them as like-OEM replacements, my van didn’t agree (they didn’t stay on near long enough, was really noticeable compared to my old and new OEM plugs). My old glow plugs were ancient too, but otherwise my 6V system works fine even at near freezing temperatures (now that I’ve learned to also give my van the right amount of fuel starting up)!

I chose the cheaper of the two Japanese warehouses at this link:

Mitsubishi MD092392 GLOW PLUG

Mitsubishi MD092392 GLOW PLUG. New & genuine Japanese car parts. Fast shipping. Low prices. Request a quote from Amayama Trading Co. online.

www.amayama.com

 

[rogerh]

Just FYI, I picked up a set of OEM 6V ceramic glow plugs from Amayama, cost me just over $250 for the set of for, including FedEx Shipping (I steered clear of EMS International shipping which would’ve been slightly cheaper, but I’ve read elsewhere on the forum of issues with EMS). I received my glow plugs in 2 weeks (to California) and my van (a 1990) really likes them! Previously I tried the HKT brand but even though the folks I bought them from (Good Karrma) sold them as like-OEM replacements, my van didn’t agree (they didn’t stay on near long enough, was really noticeable compared to my old and new OEM plugs). My old glow plugs were ancient too, but otherwise my 6V system works fine even at near freezing temperatures (now that I’ve learned to also give my van the right amount of fuel starting up)!

I chose the cheaper of the two Japanese warehouses at this link:

Mitsubishi MD092392 GLOW PLUG

Mitsubishi MD092392 GLOW PLUG. New & genuine Japanese car parts. Fast shipping. Low prices. Request a quote from Amayama Trading Co. online.

www.amayama.com

Thanks. I'll check those out. Some time I'll take mine out and see if they're all working OK.