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I recently bought a Jinma 284 with a Quanchai QC385T engine. The wiring has been cobbled up by a previous owner, and in tracing wires I found there was a Chinese made relay under the dash that had been partly disconnected. There are several wires with circuit numbers I can’t identify, some of which appear to have been originally connected to the relay.
These wires are: #71 from starter battery terminal to relay, #72 (white) connected to relay output, #74 (green) connected to terminal 2 on the key switch, #76 (red/white stripe) connected to a unknown device on the intake, #77 (yellow) connected to terminal 4 on key switch. The glow plugs and another unknown device on the manifold are connected by unmarked wires which appear to have been originally connected to the relay output, but now are connected direct to key terminal 3
Does anyone know what these devices are or what these circuit numbers identify?
Any help will be much appreciated.
Thanks,
Erik
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I have the same tractor / engine combination. That is a manifold pre heater. It is designed to spray fuel into the manifold and heat/ignite it while the glow plug circuit is energized. (I don’t know if mine works or not but left it hooked up). What I did do was take the wire from the key switch going to the glow plugs and run it to the signal post on a solenoid, and running full battery power to the glow plugs through a circuit breaker, then through the solenoid. That gives the glow plugs full power which the factory setup cannot provide, as well as saves the key switch from premature failure due to excess current running through it.
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Thanks for the information. Did your 284 have a large mechanical relay under the right side of the dash? Keno Tractors ID’d it as a glow plug relay; it is a Chinese “ALAE” brand 12v volt 90 amp relay. The wires associated with the relay appear factory installed into the wiring harness wrap. I removed and tested it and the relay works fine, so I don’t know why it was disconnected and the wiring modified.
Erik
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I have a quanchi engine a 495 I think. it has neither a glow plugs or manifold heater it starts at 20 degrees no problem. but that is not your engine. maybe it was disconnected because somebody did not know what it is or seen that it was creating a big draw on the battery and alt. and thought it was bad. I kinda find it curious that it has both unless the relay puts fuel in the system then the glow plugs light it off ,but then why would it need to be rated a 90 amps ? do you think maybe the relay heater kinda preheats the fuel for the glow plugs. I will be watching this post.
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I’m interested in what size wires are plugged into this 90 amp relay, I’m guessing 18 gauge :negative: I think it’s time I put a meter on this thing and find out what it’s drawing and if it’s even doing anything :scratch: I’ve seen the larger engines start easier in cold weather with most brands, better engineering, more compression, or better thermal dynamics with a larger mass? My little engine needs the glow plugs to start at 20 unless I’ve had the block heater plugged in, that much I know .
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The type of engine has a lot to do with how it starts in colder weather. This is even true of older vs. newer Caterpillar engines. The Indirect Injection (IDI) engines are notoriously cold blooded, and need all the help they can get in extremely cold conditions, whereas the Direct Injection (DI) need very little, if any, help at all. Quanchi may have different combustion chamber configurations for different model engines.
Here is info on the flame start system by Borg Warner (same principle).
Account deleted.
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Thanks for the info; when the rain lets up a bit I will get back under the dash and try to trace the remaining mystery wires down.
So far, the remaining unidentified circuit numbers are:
#72 (white) from glow plug relay power out to harness under dash.
#74 (green) from ignition switch terminal #2
#77 (yellow) from ignition switch terminal #4
Once the wires are traced I will post a list of where they terminate.
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