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LH2.4 install, fuel pump won't run

DennisvdB

DennisvdB

New member
Joined
Mar 13, 2011
Location
The Netherlands
Installed LH2.4 in my '76 244. When the ignition is on, the main fuel pump will start very briefly, but runs a bit rough. Also stops immediately afterwards. Cranking the engine won't help it start either.

Measured the pins on the EZK, everything seems ok except for 2 pins.
(on this schematic: http://volvowiringdiagrams.com/volvo/LH 2.4/LH2.4 ECU Pin Out.jpg)

-number 5: Signal ground; Signal ground on intake manifold for control module electronics.

0v on this one, it should read "Ubat" (?)

-number 18: Injectors control; Grounded when the injectors are to open.

Measured 12V here, where it should read around 190-200mV

The 2 ground terminals on the intake manifold are connected as they should be.

What is necessary for LH2.4 to get the engine running? And mainly to keep the main fuel pump running? As said, injectors won't work as well (measured it), but if it's a cause or effect of a failing pump I'm not sure about.
 
Ill try:
Ubat= Battery voltage (12.2-12.8 etc.)
If you're testing a ground pin to chassis ground with the connector in plugged in, you're testing the voltage drop through the ground wire to chassis. It should be close to 0V.
You will get B+ (as we say) at the injector ground side with key on engine off. Idling, it would presumably read an average, hopefully the spec you gave.

Edit: The fuel pump primes for a second when key on. RPM from coil (-) trips the fuel pump relay as long as the car is running.
 
I thought turning the pumps on briefly upon turning the key to the II position to prime the fuel lines and then not again until running was a feature of LH 2.4. At this point in time this is hearsay. I have no reference to back my claim.
 
Try using a remote starter switch.
I had a similar problem, it turned out that the wiring to the ignition switch was different.
 
poulson01 said:
Ill try:
Ubat= Battery voltage (12.2-12.8 etc.)
If you're testing a ground pin to chassis ground with the connector in plugged in, you're testing the voltage drop through the ground wire to chassis. It should be close to 0V.
You will get B+ (as we say) at the injector ground side with key on engine off. Idling, it would presumably read an average, hopefully the spec you gave.

Edit: The fuel pump primes for a second when key on. RPM from coil (-) trips the fuel pump relay as long as the car is running.
Click to expand...

But what about the injectors not opening? We measured it with cranking engine, but no reading. Wired a direct ground from battery to intake ground but still nothing.

edit: oh yes, Buchka mod installed, don't think that would be anything different than with regular coil setup?
 
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