Bosch diesel resistor cheat mod

[lanciamatt]

Not sure if anyone or everyone knows about this, but there is a really cheap mod you can do to bosch 1.3.1 diesel management. This system is fitted to quite alot of cars like land-rover 300tdi, vw golf, rover 220td, to list just a few. Its also fitted to my lancia thema turbo ds,. Basically you fit a 1kohm variable resistor into 2 wires going to the fuel pump. (on 300tdi it's pin 6+7). I finished this today and the results are remarkable, more power better response, obviously you can go overkill and cause damage. But if you set it sensibly all will be fine. 

[320touring]

It's a fairly common mod I think - usually called the Evry Mod ?

Seems to work well, but you can do similar on VAG lumps by remapping it using a cable - nae wiring needed, plus the ability for MOAR BOOZT:)

[lanciamatt]

Ye evry mod in vw circles. I'm going to remove the egr valve and fit a exhaust temp sensor, just so I can keep eye on things. 

[320touring]

Fancy:)

 

I think it works by using the resistance to make the pump think the engine/fuel is colder, so it pumps more?

[lanciamatt]

Not sure about colder, unless I've read it wrong, think it's tricks the ecu into thinking it's delivering less fuel, so it opens the injectors for longer,thus more fuel enters cylinder,so more power. It works better than just increasing boost for instance on a petrol turbo, as this can cause lean running a melt a piston. Diesels don't generally have throttle body's, so if you increase fuel you naturally increase air intake too. And the waist gate still opens as normal 

[bigfella2]

Another way of achieving this or similar is the 'hammer mod' used quite heavily on be circles. Slacken the bolts on the upper part of the injection pump and 'hammer' or in reality tap the upper part of the pump a tiny amount to up the IQ or injection quantity. Higher IQ  = more power, but if you over do it, it'll run like shit, or make the pump leak.

[Dave_Q]

Bodgery IMO, nothing wrong with it as such but why bother using x% more fuel everywhere when remapping is accessible and not even much more expensive on most of these lumps?

The resistor goes across the fuel temp sensor, there is a correction for fuel density vs temperature so if you trick it into thinking the fuel is hot it lobs more in (at all times) to compensate.

[lanciamatt]

Remapping on these age cars involves stripping ecu and removing chip and getting it updated, then resoldering back in. Probably better results, but resistor cost 2 quid. People wire in a switch so it can be turned back to stock. I'm going to hay on wye tomorrow in it so shall get a clearer inclin on what if any difference it's made to the MPG. 

[Lacquer Peel]

How does the ECU open the injectors for longer? The injectors are mechanical.

[sutty2006]

You got me all excited until mentioning electronics came up. My fuel pump only needs a few spare volts to keep the stop solenoid open 

[bigfella2]

2 hours ago, Lacquer Peel said:

How does the ECU open the injectors for longer? The injectors are mechanical.

If you increase the amount of fuel injected through an injector, the duration it takes to inject the fuel is longer, or the amount of time the injector is open, this is ok to a certain extent but at the extremes you get high egt's and black smoke.

[Dave_Q]

The adjustment is in the pump, longer duration (VP44 style mechanical pump with electronic control)

[beko1987]

Just takes a 10mm spanner and a screwdriver in a 1.9xud! Can turn the clouds up or down then

[Dirk Diggler]

From experience works well on mech vag tdis and savage on the Volvo / Audi 2.4; smokez like you wouldnt believe though

 

[hpi_matrix]

Done this on my 300Tdi, seems to make the pedal go funny but it is good for blasting people with soot.