Fuelsystem upgrade

[hagedevoogd]

I've problems with the fuel/injection system of my 350i from 1987. After my winterstop it refuse to idle and run properly. I've checked and measured the whole system on defaults and the only thing I've discovered is, that my throttle position sensor is working the otherway around from approx. 4.5V to 0.3 V instead from 0.3 to 4.5V. If I swap the green (earth) and yellow (current) wire, then it works properly, but the engine goes even worse. I have the idea, that my ECU gives far to much fuel. Sofar I didn't check my injectors because at high rev's it functions ok. When the engine gets hot it runs better, although my idle gets to high or suddenly drops down and stops.

Does anyone recognize these problems and knows how to solve them? Or is there a good substitute/upgrade for this very oldfashioned airflapsystem?

Please let me know and thanks for your help.

Hage de Voogd
Netherlands

Edited by hagedevoogd on Monday 3rd April 12:53

[350zwelgje]

Coolant temperature sensor is notorious.
If not ok then the ECU cannot fuel the engine correctly.
Quick test I normally do to exclude this, is to take the connector off and short it (by this the ECU gets a signal that the engine is warm)
If engine runs ok, you found the issue. Replacements are available at land rover dealers.
If possible buy one that is brass and not partly plastic...

Other standard issue is false air entering after the AFM, is the hose to the plenum ok? Etc.

Flapper EFI is not too bad, but you need to know the system.
Running mine for over 15 years and until now only a coolant sensor and a re-soldering of the ECU required.
This resoldering can often also cure issues if all the sensors are ok.
There is a resistor pack on one of the wings for all injectors. Plug(s) seated ok? No corrosion on the connections?

Rob

[adam quantrill]

Yeah it will never run right with the throttle pot reversed.

Sounds like a bodge up to hide something else - I agree the CTS is a good place to start.

[The Hatter]

I fought problems with the flapper system for a few years so decided to ditch it all for a Megasquirt system. It then took me a couple of years to get the Megasquirt system to run properly. It's not a turn-key solution, but now it's sorted it runs superbly - but I'd only recommend it if you're afflicted to compulsive fiddling and you're willing to learn all about ECUs, wiring and engine tuning.