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wyatt152013 James Brooks
Monrovia, MD, USA   USA
Hi, I have a 1981 Triumph tr8 with fuel injection and I just got this and there is a wiring issue. Someone has spliced into the first purple wire coming from the power resistor unit mounted to firewall for the fuel injector system and connected it to the w/y wire from the starter. When I disconnect the wire the vehicle will not run and when connected it runs so it was bypassing a problem but I can't figure it out. Hope someone can give me a starting post .

Thanks

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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1502729 by wyatt152013 Hi, I have a 1981 Triumph tr8 with fuel injection and I just got this and there is a wiring issue. Someone has spliced into the first purple wire coming from the power resistor unit mounted to firewall for the fuel injector system and connected it to the w/y wire from the starter. When I disconnect the wire the vehicle will not run and when connected it runs so it was bypassing a problem but I can't figure it out. Hope someone can give me a starting post .

Thanks

The Purple and Red Wires to the resistor pack (item 136 in the image) supply power to the injectors, and the ground side of the injectors is switched by the ECM. The power is ordinarily supplied through a relay in the combo pack (item 115 in the image), so that the injectors are only 'hot' while the engine is cranking or running.

If the relay in the combo pack failed, then to get the injectors to fire it would be necessary to supply another source of switched +12 to the resistors/injectors. It turns out that the purple wire will supply power to all injectors via the resistor pack and thus can be used to supply power to all the injectors..

I can only assume that a relay in the combo relay pack failed, and since finding a replacement is akin to hunting for a unicorn, this was the DPOs solution.

If you can find a combo pack replacement, then you are probably back in business and can remove the errant wire permanently. Otherwise you will need to leave the wire in place, or open and repair the combo pack fault. If you do repair the combo pack, document it so that others may learn from your experience.

Addendum: I realized after posting the above that you have the later car with no combo pack. However, the above is still correct except that the relays are separate units with a separate diode pack instead of being integrated into a single package. So I repeat my claim - a relay most likely failed and no longer supplies power to the injectors. replace the offending relay and you will probably be back in business.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore



Edited 1 time(s). Last edit at 2017-12-14 06:55 PM by Darth V8R.


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wyatt152013 James Brooks
Monrovia, MD, USA   USA
Thanks I will do what you advised.

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