To glow or not to glow.

Does your Mitsubishi L300 make a strange noise? Need wheel alignment specs?
Green1
Posts: 3257
Joined: Wed Jul 19, 2006 9:18 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: 1994 L400 Royal Exceed PF8W
Location: Calgary Alberta Canada
Contact:

Re: To glow or not to glow.

Post by Green1 » Fri Jun 04, 2010 8:38 pm

Erebus wrote: In about Feb of this year, it started doing:
*When the engine is stone cold, glow plug circuit works completely normal
*when not fully warmed up, circuit works normal, either 2 clicks a few seconds apart, or 2 clicks very close together
*when fully warm, and it has sat for 5-10 minutes, no clicks at all. Given it is hot, it starts just fine.

Any theories?
I *think* that's the way it's supposed to work... when fully warm the temperature sensor sees that there is no need for the plugs, and tells the glow controller not to use them.

User avatar
mararmeisto
Posts: 3275
Joined: Wed Sep 19, 2007 10:00 am
Vehicle: 2013 Toyota Tacoma
Location: Dartmouth, NS

Re: To glow or not to glow.

Post by mararmeisto » Fri Jun 04, 2010 9:43 pm

@Erebus - what's you've described is a properly functioning glow circuit. When the engine is warm there's no waiting for the glow circuit because it's already turned off by the ECU via the glow controller.
JPL
I still miss my '94 Pajero!

drrod
Posts: 167
Joined: Thu Jun 19, 2008 9:19 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: 93 Exceed
Location: Calgary, Alberta

Re: To glow or not to glow.

Post by drrod » Fri Jun 04, 2010 9:58 pm

So all this talk about glow plug function has got me wondering. Here is what ours does:
- first cycle takes abou 5 secs.
- second cycle (turning the key off and on) is almost instant between the 2 clicks. This is regardless of how cold it is.
- the control unit continues to click several times even after the engine starts.
- even with the engine warm, the first cycle is about the 5 sec range.
- The van starts as soon as you hit the starter, regardless of how cold it is if we cycle the plugs once or twice (and it has been plugged in when really cold).
- We never cycle the plugs more than twice regardless of how cold. I didn't think it necessary because the second cycle was so short.

Since it has always started so good, I have not really thought much about it.
Should I be concerned about the conrol unit? The multiple clicks after startup has me a bit worried now.
Probably overthinking this but any thoughts would be appreciated.
Thanks
Rod

User avatar
Erebus
Posts: 1367
Joined: Mon May 28, 2007 7:55 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: 1992 Super Exceed
Location: Edmonton, Alberta
Location: Edmonton (was Calgary until 2017), Alberta, Canada
Contact:

Re: To glow or not to glow.

Post by Erebus » Mon Jun 07, 2010 5:16 am

drrod wrote:So all this talk about glow plug function has got me wondering. Here is what ours does:
{snip}
Since it has always started so good, I have not really thought much about it.
Should I be concerned about the conrol unit? The multiple clicks after startup has me a bit worried now.
What you describe is how mine used to work. Multiple clicks after startup is normal.

Further to the description of how mine is acting. The other day, when engine fully warmed up, the 2 clicks came about 1 second apart. That's how it always used to be. Then the next time I started, about 20 minutes later, no clicks at all. It's the no clicks that is relatively new. Before I ALWAYS got clicks.
Image "I could be just around the corner from heaven, or a mile from hell." -- Jackson Browne, "The road and the sky".

drrod
Posts: 167
Joined: Thu Jun 19, 2008 9:19 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: 93 Exceed
Location: Calgary, Alberta

Re: To glow or not to glow.

Post by drrod » Mon Jun 07, 2010 8:11 am

Ours will always have a noticeable (ie. seconds) gap between clicks on the first cycle. This happens even if the engine is fully warmed up. I usually wait for the cycle to complete before starting the van, not because it is easier to start, but I am thinking that there something, somewhere, in the system, that would be damaged if I didn't. I know that is probably not true but it starts and runs so good that I don't want to screw anything up.
From reading, it sounds like a faulty temp sensor. The only thing going against that is how well the van starts, even at 40 below after one 5 sec cycle and one very short cycle. I am a big fan of "if it ain't broke, don't fix it" club so I haven't done anything about it for almost 2 years.
Rod

Blackberry
Posts: 98
Joined: Fri Feb 29, 2008 1:45 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: '92 Exceed P35W
Location: Victoria

Re: To glow or not to glow.

Post by Blackberry » Mon Jun 14, 2010 4:11 pm

My '92 L300 had been starting fine/immediately after 2nd click (say 7 seconds after 1st when temp 5c) but seemed to belch too much whitish/greyish/blueish smoke for a minute or so upon cold start. It looked like it was coming out of the tail-pipe in irregular bursts, so I thought, hmm, maybe one or 2 GPs are going/not heating uniformly. So I was travelling in SE Asia and I bought some aftermarket glow plugs. The GPs in the van were OEM Mitsu green-tops with 6.2v stamped on them. I've scoured the i-net high & low to figure out exactly which glow system my van has and all info eventually led to: OEM part number MD092392 for the dual-voltage glow system found in 02/91-06/93 4D56T engines. I believe this system uses 2 relays as well (there's a ton more detailed info about this on the mdocuk site than on ours, BTW...and, apparantly, this "super quick start" dual-voltage glow system is problematic - which might explain why it was so short-lived). So anyway these aftermarket (HKT knock-off's, part# CP-06) had 6.2v stamped on them and even had MD092392 stamped on the box so I figured they had to be the correct ones. I put them in and nada... no initial clicky/no current/no starty. I'd bought a box of 10 so I put another set of 4 in, just in case...same non-result. So I checked the resistance on them and it was slightly over 1 ohm. I checked the resistance on the OEMs and it was below 1 ohm - can't remember exactly what but .25-.8 ohn range rings a bell. So I think there must be some kind of feedback to the ECU that doesn't happen if the resistance is too high. According to the mdocuk site there's many aftermarket GPs that are supposed to be MD092392-compatible but that don't work. They've had success with one brand, so I've bought a set from them but have yet to try them. Before I do I'll pull the ECU to have a close look/sniff to see if anything is cooked...which could even possibly be why it didn't like the aftermarket GPs with such a slightly higher resistance. I also changed my temp sensor but that had no effect on the blue smoke (and when I got the old one out and tested it, the resistance was within spec).

Post Reply

Return to “L300 Technical”