Glow Plug System QSSI

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barrieri
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Isuzu vehicle(s): Gemini

Glow Plug System QSSI

Postby barrieri » Sat Jan 12, 2019 6:28 am

Dear members,

So I have this Isuzu Gemini 1500LT diesel which I have purchased very recently in December. The car is in an immaculate condition, however there is one problem. When the engine is cold it takes up a lot of time to start, followed by a good amount of white smoke from the tail pipe. After looking into the problem I noticed that the dashboard glow plug light stays on for around 4seconds when I turn the key on, which I think is normal for the QSSI system.

Then checked with a multimeter the voltage going onto the glow plugs. When the key is turned on, the voltage on the glow plugs rise to 5V for 1 second maximum and goes back to zero. Whilst I crank the engine, the glow plugs get 5V continuous. When the engine starts, the voltage on the glow plugs go back to zero.

I am thinking that this is not the expected operation of the QSSI system. The engine takes very long cranking to start. Glow plugs are all good with a resistance of 1 Ohm. I also checked the thermo switch which seems to be good. High resistance with cold engine and continuity with warm engine.

I would truly appreciate if you guys can help in this. I do not wish to bypass the system, as the car is in its original condition and wish to keep it this way.

Thanks in Advance.

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JoeIsuzu
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Re: Glow Plug System QSSI

Postby JoeIsuzu » Sat Jan 12, 2019 10:06 am

We never got a "QSSI" system in the US, but it sounds like it might be the same as our QOS. What model year is this?

Jack

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Halden
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Re: Glow Plug System QSSI

Postby Halden » Sat Jan 12, 2019 10:50 am

JoeIsuzu wrote:We never got a "QSSI" system in the US, but it sounds like it might be the same as our QOS. What model year is this?

Jack


Quick Start Silent Idle. The plugs come on at low voltage at a certain RPM to smooth and quiet engine noise. The 84 imarks had that here in the US.

Honestly I would just bypass the system with a push button.

I can upload a scan from the FSM if you'd like for trouble shooting. Though it may not be quite the same as in Europe
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

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JoeIsuzu
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Re: Glow Plug System QSSI

Postby JoeIsuzu » Sat Jan 12, 2019 12:03 pm

Ok, we never got anything called QSSI here on P'ups (that I'm aware of). :D

Jack

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Halden
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Re: Glow Plug System QSSI

Postby Halden » Sat Jan 12, 2019 12:15 pm

JoeIsuzu wrote:Ok, we never got anything called QSSI here on P'ups (that I'm aware of). :D

Jack


I think it also was referred to as UQOS - Ultra Quick On Start.
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

barrieri
Regular Member
Posts: 5
Joined: Thu Jan 10, 2019 2:52 pm
Location: Malta
Isuzu vehicle(s): Gemini

Re: Glow Plug System QSSI

Postby barrieri » Sat Jan 12, 2019 4:24 pm

Now I got confused. If I'm not mistaken it is called 'QSSI'. What I do know for sure is that it follows the circuit in the below link.

I've diagnosed the circuit and it seems that everything works as it should. What I cannot check is the controller. So I wished to hear some opinions before going ahead and purchasing a controller (if I find any).

http://repairguide.autozone.com/znetrgs ... 1da08f.gif

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JoeIsuzu
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Re: Glow Plug System QSSI

Postby JoeIsuzu » Sat Jan 12, 2019 6:51 pm

barrieri wrote:Now I got confused. If I'm not mistaken it is called 'QSSI'.
Sure, but since that wasn't ever offered in the P'up, we wouldn't be as familiar with it as the QOS in the P'up. Even so, some general tips would probably apply.

The symptoms you're describing sound much like what I've experienced with my QOS-equipped P'up. Mine was simply a fouled electrical connector plug between the engine and the main harness. After cleaning, my trouble went away. I added some electrical "grease" to protect it from corrosion.

Jack

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Halden
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Re: Glow Plug System QSSI

Postby Halden » Mon Jan 14, 2019 9:55 am

Is your controller currently plugged in?
You probably won't be able to find a new controller. I am not meaning to be a Debbie Downer here, but if you try cleaning connections up and that isn't working I would just bypass everything with a switch to the relay. It will save you a lot of time and headaches.
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

barrieri
Regular Member
Posts: 5
Joined: Thu Jan 10, 2019 2:52 pm
Location: Malta
Isuzu vehicle(s): Gemini

Re: Glow Plug System QSSI

Postby barrieri » Thu Jan 17, 2019 12:45 pm

So I took the controller out today to see if something is visibly wrong and it seems I was wrong about the QSSI. In fact it is an QOS system as given in the photos.

In order to get the engine starting I tried to track the wires of the relay being operated from the controller. I powered on the relay manually however it seems that when I did this I was getting around 10V on the glow plugs. I am worried about this as it seems that when the controller powers on the heaters for the very very short time <1second, the voltage does not go up more than 6V. My worry is that if I'll continue to power up the relay manually, I'll burn the glow plugs (which by the way are new).

Any ideas whether the 10V are good or not ? I might be tempted to think that the 6V that I'm seeing in the short time the controller powers the glow plug is because the power up - power down is so fast that the multimeter is not fast enough to read the 10V.

Thanks
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puttputtinpup
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Re: Glow Plug System QSSI

Postby puttputtinpup » Thu Jan 17, 2019 1:20 pm

I'd double check each glow plugs to see if they're all good. Having just one plug burned out will cycle off the glow cycle prematurely to protect the rest of the plugs.

The way I used to do it is remove the bus bar from all the plugs. All but one I think (if the same as the c223) you'll just need to loosen the nut on the plugs and the bar slides off. One has to have the nut completely off.

Before digging in, check the bus bar for loose wires. If it's the same system are the c223, there should be a couple of little wires at the back end. Those send resistance and voltage values back to the controller. In that harness the holds those wires and wiring from the thermostat cover sensors, there should be a connector in the harness that those pass through. On the Pup, it's up against the firewall. Idk about the Imark. Clean it up good especially if the glow plugs check out okay.

Then take my meter set on ohms and simply check for continuity from ground to the center post. If one shows no continuity, I'd just replace them all. And be sure if this system has the drop down resistor (small alum box) that all plugs are marked 5v.

Before all that, you could double check all connection plugs to relays, clean up the fusible link connections real good. I've taken connectors apart and pinched the female ends down a bit for a tighter fit on the blade. Connector at the drop dn resistor is another spot to check too.