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Old grandmother's trick to enrich obd1 injection ...😂

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If you want to add a turbo to your car, or you have put on a more aggressive cam and increased the gas pressure is no longer enough to enrich your engine ...

It is necessary to falsify the reading of the water temperature sensor with a potentiometer of 5000 ohms ...

Then use an adjustable pressure switch (1 to 20) psi to regulate the start of the system connected in series with a relay switch ... Make sure that it is well connected on the reverse side of the polarity, so that when the relay clicks, it sends the distorted signal from the potentiometer to the ecu and when it is not in contact, it sends the signal from the temperature sensor to the ecu ... To continue to have a good cold start...

So from there you can adjust how much boost you want to enrich the air-fuel mixture ... And how much you want to enrich it ... It's almost linear, it doubles the gasoline air mixture ...

You can even do internships with another pressure swith and another potentiometer ...

If you want to use bigger injectors and you have an air flow meter, tighten the spring inside the box and calibrate it so that it is not too rich before the boost...

Here we can go quite far with 50$ of electronic product ...😂

Attached Files

Not something I would recommend as "quite far" may be to the end of the street...

IMO, this sort of barbarity should have died off in the eighties - there are many problems it will cause, and overlooks the point that the injectors have a limited capacity, as does the fuel pump and the rest of the fuel supply assemblage. Some modern electronics management will also log the change in parameters and self-correct and so reduce, or even cancel out, the changes made.

There was a similarly primitive version where a fifth injector would be installed in the inlet tract with a pressure switch to activate it when a threshhold pressure was reached.

Pay the money to do it properly, or pay the money to do it wrongly, replace the engine, AND then the money it would have initially cost anyway.

I certainly wouldn't recommend anyone else do it, but I have a certain attraction to sloppy tweaks like this or bias resistor arrangements for air flow meters to tweak an old shitbox with minor modifications, fully are there is significant potential for failure if something goes wrong. Provided there was some headroom in the fuel system with a two or three Hobbs switches on an old turbo setup you could make it relatively progressive.

Yet it was reliable, I drove a year with this digifant2 injection (vw jetta 1992 1.8 8valves) ...

Subsequently I installed a digifant1 (vw corado 1991 1.8 8 valves supercharge) with map sensor, I also tampered with it to be able to run 16 psi of boost ...

This photo is from 2001, it was a $ 2000 turbo scrap class kit ...

I did 14.30 @ 102 mph with an engine that originally had 90 hp

With everything that is being done today as an alternative, it is of course that I do not recommend that ...