Thread: Fuel Pump & Coil

Bigmac,It would be much more helpful if you told us what the symptoms were along with all relevant info , eg model, mileage, any modifications, under what circumstances does the problem occur eg hot, cold?

What is the problem,eg no start, miss at light revs, high revs , light load heavy load etc etc.
Maybe less fun but more productive.
My answer without any further info about the fuel pump is that the car doesn't go and you do not hear a noise from around the tank.
Regards Philip A

Philip,

It is a series 1 1/2, disco 1. It is constantly missing and surging, not holding and idle. I have checked - the MAF, the Idle Air Valve, anthe TPS, Distributor cap and air gap, plugs replaced and so have the leads, replaced the fuel filter and cleaned all the hoses to and from the plenum chamber. The fuel pump whirs when I switch the car on, and stops after a few seconds as per normal. The only things left to check are the fuel pump (starting from the back working forwards) fuel temp sender, water temp sender, black box on side of dizzy and coil, hence the question. The reson I did not speicfy any symptoms is specifically to preclude any - it's the IAC, TPS, MAF type responses. The other possible answer is a short somewhere in the engine loom.

Thanks in advance.

Greg

Well, I would start from the front seeing the fuel pump whirs.. My only real experience with a dud fuel pump that didn't simply stop was a blocked inlet through a hole in the pickup filter. In this case it went perfectly for a while eg 10 minutes then became soggier and soggier until it would not take a poofteenth throttle. Switch off and it was perfect again for 10 minutes.
First
What colour are the plugs ? Grey with black tips or sooty all over? if sooty all over look for richness caused by the water temp sensor( the one with 2 wires) The fuel temp sensor has far less effect only compensating for hot fuel.
Check the TPS by placing a mythical analogue multi meter into the signal wire and check for a smooth progression from .3V or whatever to 4.9 with no backsliding.
How old are the plugs, leads, dizzy cap and rotor? To eliminate them I would buy new ones unless you recently have and if you recently have chuck away the "Bosch" or whatever rotor and fit a fabulously expensive Lucas.

My understanding from this forum but no personal experience is that the amplifier usually dies in the heat and if hot if you pour water over them they recover , just like Pommy football players.
Try that and spend all your money and if it doesn't work we will all scratch our heads. And ponder on what work you have done immediately prior to the problem starting.

Regadrs Philip A

When I get one that sounds like that I usually do this:

Lucas ignition amplifier replacement by Bosch 024

Seems to work for me 9 times out of 10. Basically the Lucas ignition amp is known to go half dead instead of totally quitting.

Thank you all, my Thursday is now full on...

Greg

Having just replied to a tach query in another thread, you have to remember any missing ignition pulses will also cause a loss of injector signal. This is probably why the weak ignition pulse causes so much trouble. The ignition coil negative is connected to the ECU via the white/black stripe wire, then to a resistor and a white/blue stripe wire after that.

My ignition coil went about two weeks ago.

Symptoms were difficult to idle, hard to start, missing at low speeds.

Diagnosis was easy: Arc out the HT lead to earth and see the colour of the spark. Mine was orange which is a sure sign the coil is on the way out.

HTH

Ok all, just an update, am in the middle of replacing the BIM with a bosch 024. Got wet and wild here so not able to complete it until tomorrow (fingers crossed) so I will let everyone know how it goes when it happens. Just a quick question, why is a bosch gt40r coil a no go?

Cheers

Greg