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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Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

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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Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

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: 4
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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Joined: Thu Aug 19, 2004 9:11 am
Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

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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Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

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