Retro fit engine from a Golf GTI to a 1.9

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Ukjamie82
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Retro fit engine from a Golf GTI to a 1.9

Post by Ukjamie82 »

ImageImageGood morning all

I am in the throws of retro fitting a 1.9 water cooled engine from a 1.8 Golf GTI , reason , ecu failed and could not find a replacement.

Engine is now in but in their wisdom the wiring colurs on the plugs in the rear are different.

so the question is , will they just swap straight over or will i need to have an electrician out to sort ?

Pictures below. for context its the main white plugs , i know one is for the rear light clusters and there are extra there which i need to remove as the ECU loom was spliced into it.

Many thanks.

Having a closer look now i may need to change the loom , fortunately i have a donor van although this still doesn't look straight forward.

 
Last edited by Ukjamie82 on 03 Sep 2025, 05:56, edited 1 time in total.
1984 - Tin Top VW T25 - 1.9 - 5 Speed

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Ukjamie82
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Re: Retro fit engine from a Golf GTI to a 1.9

Post by Ukjamie82 »

to add the original van is 1984 and the engine is from a 1990 model

Thanks again
1984 - Tin Top VW T25 - 1.9 - 5 Speed

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Aidan
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Re: Retro fit engine from a Golf GTI to a 1.9

Post by Aidan »

wiring diagrams are in Bentley or downloadable from SyncroSport of Sir Adventure websites, since they basically follow DIN standard they aren't to different, later engine will have DOPS, early dash won't, otherwise should be pretty much the same

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Robsey
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Re: Retro fit engine from a Golf GTI to a 1.9

Post by Robsey »

Agreed - the VWs all share the same wire colours and context.

One of the barrel connectors is for the rear lights.

The other is for the ignition, ground and instrument sensors.

I am sure there are many posts on these two connectors.

I do note one two-pin connector has a missing / snapped wire.
1983 Tin Top with a poorly DF and 4 speed DT box.
1987 Electrics and a DJ engine.
Maybe one day I might get it finished

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Robsey
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Re: Retro fit engine from a Golf GTI to a 1.9

Post by Robsey »

Sensor wires to gauges etc.

Connector T7a
Pin 1 = blue / black - 0.3 bar oil pressure switch.
Pin 2 = yellow / red - gauge temperature sender.
Pin 3 = blue / green - coolant shortage sender
Pin 4 = brown - ground wire
Pin 5 = green - tacho / rev counter signal
Pin 6 = red / black starter signal wire for control modules.
Pin 7 = yellow = 0.9 bar -DOPs pressure switch.

__________________

Rear Lighting Wires.

Connector T7

Pin 1 = black / white - left turn signal
Pin 2 = black / green - right turn signal
Pin 3 = black / red - brake lights
Pin 4 = black / blue - reverse lights
Pin 5 = grey / black - left tail lights
Pin 6 = grey / red - right tail lights
Pin 7 = brown - ground wire.

Other wires -
Grey / Green - number plate lights

Black - ignition live.

Red - battery live (usually) although manifold heater may have a heavy red wire, but is ignition live.

Blue - alternator [D+] charge light for the dash.
1983 Tin Top with a poorly DF and 4 speed DT box.
1987 Electrics and a DJ engine.
Maybe one day I might get it finished

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Ukjamie82
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Re: Retro fit engine from a Golf GTI to a 1.9

Post by Ukjamie82 »

Thanks for the advice ,





 
1984 - Tin Top VW T25 - 1.9 - 5 Speed

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