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MG MGF Technical - Not Firing

My 1996 MGF 1.8 not firing for No.2 + 3 cylinders causing smell and white smoke form the exhaust.
Dist. cap, rotor arm and leads are new and when the engine is on can not hear any motor movement noise from No. 2 + 3 injectors as the No. 1 + 4 had.
What can I do?
D Cho

This seems a good input
It seems the ECU drive or associated wiring providing the earth has failed. Easy to find if you have or can borrow a scope.

The four fuel injectors are fitted between the pressurised fuel rail and inlet manifold. Each injector comprises a solenoid operated needle valve and a specially designed nozzle to ensure good fuel atomisation. The injectors are controlled in grouped mode with 2 & 3 being grouped and 1 & 4 being grouped, with the injectors in each group being operated alternatively. The ECM determines when to operate the injectors based on the signal it receives from the crankshaft position sensor. The ECM provides an earth signal for the period the injectors are required to be open, the injector solenoids are energised and fuel is sprayed into the inlet manifold onto the back of the inlet valves. The ECM carefully meters the amount of fuel injected by adjusting the injector opening period (pulse width). During cranking, when the engine speed is below approximately 400 rev/min, the ECM increases the injector pulse width to aid starting. The amount of increase depends upon engine coolant temperature. To prevent flooding, the ECM periodically inhibits the operation of the injectors
Stan Best

Thanks for your details information, I might have difficulty in borrowing a scope but sure will try. In my serive manual where I can find the diagram for this layout? If a scope is not available how can I check? Today I took the injectors out and went to a shop and have them clean once it is returned I will put them back and check the things you mentioned above. Really apprecaited your help. I am far away in HK and not much help can get from here.
D Cho

http://www.mgfcar.de/schedules/sb8.jpg

http://www.mgfcar.de/schedules/sb9.jpg

I have the manual for the TF, but the F schematics are here on the famous "Dierter's site". You can see clearly where the injectors are "electrically Common" . A testlight or meter may help if you dont have a scope. You should be able to see 12v at both end of the injectors that are not working, and with the engine running it should drop at the end being earthed. With a meter you can measure the resistance of the injectors. If one has gone short circuit the other will not work. You can do this before putting them back in. With this info an auto electrician could check for you.
Stan Best

More useful info on MEMS here.

http://www.mgfregister.org/forum/viewtopic.php?f=8&t=4885&p=39197&hilit=mems#p39197
Stan Best

Good advise
:)
not to forget another source @ "Dieter's site"

MEMS side connector (1996 MGF 1.8 88kW)
http://www.mgfcar.de/mems1.9/mems1.9.htm
and how it is from inside
http://www.mgfcar.de/mems1.9/index.htm
Dieter

Thanks for all the help and I will try it out and let you guys know the outcome.
D Cho

The injectors are OK, could it be the ECU?
How can I identify it is the ECU giving me problem?
D Cho

Hi , Do a compression test on 2 and 3 cylinders it may be a gasket problem between the cylinders and could be passing coolant into the exhaust
e holloway

>How can I identify it is the ECU giving me problem?

Either with *testbook* diagnose computer, wherein it woun't show _output_ signal failures.
Or the easiest would be to change your engine ECU _and_ the immobilizer ECU against another proved working one.

Both needs to be changed cause this both ECU's talk to each other and the immobilizer code is programmed into the ECU with *Testbook*
Dieter

Can anyone tell me where I can find the (testbook) connector
D Cho

After checking the votage of pin 23 (yellow/red) from the ECU
voltage = Ignition on 12.xx V
Engine on 2 - 3 V
BUT
N0 1 + 4 injectors when engine on 12 V (no up and down)

So can I be sure that is the ECU giving out problem?





D Cho

This thread was discussed between 17/02/2011 and 22/02/2011

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