Loss of power

[redmaestro]

My 2L Efi has started loosing power at low speeds :-s. I was taking my girlfriend home after work last night, and as we pulled away from a roundabout I had no power at all! About a second later, power came back then went again. This stop/starting of power only lasted about 5 seconds and then was fine.

I looked through the forums last night, and a chap (sorry, can't remember your name) had a similar problem. Turns out he also had a faulty temp sensor which seemed to be causing it. Mine is working fine, so not sure where to go from here.

Any ideas?

Redm

[G Force]

Hi Redm a couple of possibilities spring to mind. Could be a bad connection at the crank sensor, remove the crank sensor plug and check the pins are not backed out of the plug, then peel back the rubber boot and check for breaks in the wires.

Could be faulty plug leads, can you remember how the rev counter was behaving?

Gary:)

[redmaestro]

Hi again GForce!! I'm not sure where the crank sensor is, but its worth a try. I replaced the dizzy cap, rotor arm and leads last year when she was misfiring.

I havent noticed the revs, but its approx 2000rpm. Interesting thing I spotted yesterday; when this was happening I had my foot lightly on the accelerator and watched the rev counter. It rose to 2000rpm then fell to about 1000rpm, then rose again (as quick as that). This happened 4-5 times then I had power again.

[G Force]

I had my foot lightly on the accelerator and watched the rev counter. It rose to 2000rpm then fell to about 1000rpm, then rose again (as quick as that). This happened 4-5 times then I had power again.

Hi I this may or may not be directly related to the problem or just a coincidence, but that would indicate the throttle pot setting is wrong and causing the surging, I think I remember going through the setting procedure with you but if you need me to post it again I am happy to.

The crank sensor is on the gearbox adapter plate down the back of the engine about half way down.

[G Force]

The throttle potentiometer setting on the Maestro and Montego 2.0EFI with Lucas hot wire fuel injection is a very important setting and is crucial to the correct running of the engine.

To set the throttle potentiometer you will need a suitable multi–meter and an allen key or angled pozi–drive screwdriver.

There are three wires going to the potentiometer from the fuel injection ECU The harness wires are coloured as followed: pink with black trace, pink with purple trace and a third which varies from model to model and is either green with red trace or green with yellow trace.

With the ignition switched on and the throttle potentiometer harness connected push the probe of the black wire of the multi – meter into the pink and black wire of the vehicle harness throttle potentiometer connector. Then push the probe of the red with of the multi–meter into the green and red wire of the vehicle harness throttle potentiometer connector. If your harness has a different colour wire always remember that the pink and purple wire is never connected into with the meter.

With the multi – meter set to the mv setting measure the voltage reading. The reading should be 325mv +/-10mv with the throttle fully closed. If the reading is incorrect then the two screws holding the throttle potentiometer to the throttle body can be loosened enough to move the potentiometer to obtain the correct reading. Take care as when the screws are re tightened the setting can alter. Open and close the throttle butterfly a few times to ensure the reading stays constant when the butterfly is closed. I find that sometimes it is easier not to loosen the screws of the potentiometer and just tap the potentiometer body gently with the handle of a screwdriver to obtain the correct reading, obviously sometimes loosening the screws is the only option if more force would be needed.

Cheers Gary:)

[redmaestro]

I've just come back from the supermarket and it was still doing it - no juddering this time but loss of power for 1-2 secs.

I think i'll check this crank sensor thingy first. I've had the car for about 4yrs and never had this problem.

[Dave]

Check the temperature sender aswell - that failed on mine, causing major loss of power, but left the idle smooth and sounding okay.

It's on the back of the head, on the left hand side as you look into the engine bay.

Dave