Advice pls...little problem.
Discussion
My car let me down tonight, but I did manage to get home.
Starting off on my little hoon, the car coughed and hesitated once, then normal progress and normal running until after about 5 miles the engine died suddenly, ignition ok... turning the engine, but wouldn't fire.
I called my mate up the road (who I was on my way to visit), and had a quick look under the bonnet for anything obvious...pipe/wire off, etc. All looked ok.
So, 15 minutes or so have elapsed and I try again, foot held down on throttle, and she roars into life.
Drove her home with mate following, no problems and parked her up.
When this sort of thing happens, first thing I do is think about what has changed in the last day or two.
Well, yesterday I drove a troublefree 20 miles to have my exhaust replaced.
The new one didn't fit, so the old one was put back on until next week.
I then drove to a garage and put in 15 quidsworth of Tesco 99 (first time I've bought the stuff).
I then had another troublefree journey home until the last junction before my house where...she cut out and I had to re-start.
I'm wondering whether this could be fuel pump/wiring related ?
Any suggestions please, bearing in mind that I just about understand what an earth is.
Starting off on my little hoon, the car coughed and hesitated once, then normal progress and normal running until after about 5 miles the engine died suddenly, ignition ok... turning the engine, but wouldn't fire.
I called my mate up the road (who I was on my way to visit), and had a quick look under the bonnet for anything obvious...pipe/wire off, etc. All looked ok.
So, 15 minutes or so have elapsed and I try again, foot held down on throttle, and she roars into life.
Drove her home with mate following, no problems and parked her up.
When this sort of thing happens, first thing I do is think about what has changed in the last day or two.
Well, yesterday I drove a troublefree 20 miles to have my exhaust replaced.
The new one didn't fit, so the old one was put back on until next week.
I then drove to a garage and put in 15 quidsworth of Tesco 99 (first time I've bought the stuff).
I then had another troublefree journey home until the last junction before my house where...she cut out and I had to re-start.
I'm wondering whether this could be fuel pump/wiring related ?
Any suggestions please, bearing in mind that I just about understand what an earth is.
Haha...no, there's at least a third full of fuel.
The engine was hardly even warm tonight, which is why I at first thought the initial hiccup was because of a COLD engine.
Doesn't seem to be related to how long she's been running either.
I don't think it's a hot starting issue.
Fuel filter ?
The engine was hardly even warm tonight, which is why I at first thought the initial hiccup was because of a COLD engine.
Doesn't seem to be related to how long she's been running either.
I don't think it's a hot starting issue.
Fuel filter ?
Edited by grahamw48 on Sunday 25th April 23:55
grahamw48 said:
Fuel filter ?
Fuel starvation on a V8 usually leads to a spluttering halt, not a sudden one.Also, foot held down on an injection engine probably doesn't help unless you already have pools of fuel lying around the inlet tracts. Otherwise you're better off letting the ECU sort out the fuel requirements. You can't force it to do what it doesn't want to, unlike a carb...
Keep driving, see if you note a pattern, could be something thermally intermittent (temp sensor, coil, ignition amp. top of my list).
Edited by Wedg1e on Monday 26th April 00:14
When my ignition amp went it was gradual. Over around 30 miles or so, got to the point where I knew it would not make it up a hill so pulled over and got low loaded to BBWF.
When the throttle pot drifted it went quite quickly. Over fueling and flooded. Reset throttle pot all OK. (Low loaded home and the breakdown guy did not speak for three hours. Happy chap.)
Other running issues have had me wire out the pump wire (piggy back to the pump) to a convenient place. I can pop a lamp across it to see if its getting juice. Quick and easy once its in, take the lamp out when it is not required but it proves the supply.
When the throttle pot drifted it went quite quickly. Over fueling and flooded. Reset throttle pot all OK. (Low loaded home and the breakdown guy did not speak for three hours. Happy chap.)
Other running issues have had me wire out the pump wire (piggy back to the pump) to a convenient place. I can pop a lamp across it to see if its getting juice. Quick and easy once its in, take the lamp out when it is not required but it proves the supply.
True, the ignition amp can be intermittent too.
Depending on how sudden the cut-out is, it could also be the dreaded engine temp sensor - especially if accompanied by clouds of black soot from the exhaust. These commonly fail intermittently and when the engine is in the warming-up phase.
Depending on how sudden the cut-out is, it could also be the dreaded engine temp sensor - especially if accompanied by clouds of black soot from the exhaust. These commonly fail intermittently and when the engine is in the warming-up phase.
Just an idea, happened to me a few years ago, Car kept cutting out every now and then, only thing I had done was a few days before I had two new tyres put on the back.
The nice tyre fitter had jacked the car up and caught the petrol pump wire which was secured on a chassis tube, The wire then being nearly cut decided to work or not sometimes.
The Second AA callout found it, and a mate fixed it.
The nice tyre fitter had jacked the car up and caught the petrol pump wire which was secured on a chassis tube, The wire then being nearly cut decided to work or not sometimes.
The Second AA callout found it, and a mate fixed it.
As luck would have it the 400SX has started cutting out when I get home, tonight was particularly bad. The temp sensor seemed OK (and shorting it didn't make any difference) so I changed the ignition amp - this seemed to do the trick.
The one I put on was an old Lucas one I had which is 20 years old - the one I took off was an Intermotor one that has lasted two whole years. Yet another raving endorsement for Intermotor - NOT!
The one I put on was an old Lucas one I had which is 20 years old - the one I took off was an Intermotor one that has lasted two whole years. Yet another raving endorsement for Intermotor - NOT!
the one I took off was an Intermotor one that has lasted two whole years. Yet another raving endorsement for Intermotor - NOT!
[/quote]
2 years for an Intermotor one.........I've had two in the past, one was duff straight out of the box, replacement lasted less than 2 weeks! Numerous dizzy caps and a coil all had short lives......thank god for the Emerald now!
[/quote]
2 years for an Intermotor one.........I've had two in the past, one was duff straight out of the box, replacement lasted less than 2 weeks! Numerous dizzy caps and a coil all had short lives......thank god for the Emerald now!
Some interesting ideas there ,thanks guys.
I had a QUICK( because I don't really know what I'm doing
)rummage under the bonnet again this evening.
I was looking for loose wires, bad connections, etc, and familiarising myself with what is what and where.
I've identified the ignition amp, and checked the connections to it, which seem sound, also wiring to the silver coffin shaped box attached to the passenger side inner wing. A couple of earths from that were a bit slack, so tightened them.
HT leads are quite new and all correctly attached. Coil terminal leads and king lead ok.
No other wires obviously loose, broken or dangling.
I had a look at the fuel pump wiring,and it seemed pretty well located, but I'd have to take a wheel off and jack her up to do a proper inspection.
As she's going to up on a ramp this weekend (at TVR specialist), thought I'd leave that until then.
I was meaning to ask if it was an idea to disconnect the cold start thingmebob...seem to remember people having suggested that. Is it the brown connector attached to a small housing at the passenger side front of the engine ?
Does anyone know where 'proper' Lucas parts can be sourced , such as the ignition amp ?
Never seen such a clean motor, incidentally, but I know the wiring does suffer with heat and age.
Many thanks.
I had a QUICK( because I don't really know what I'm doing
)rummage under the bonnet again this evening.I was looking for loose wires, bad connections, etc, and familiarising myself with what is what and where.
I've identified the ignition amp, and checked the connections to it, which seem sound, also wiring to the silver coffin shaped box attached to the passenger side inner wing. A couple of earths from that were a bit slack, so tightened them.
HT leads are quite new and all correctly attached. Coil terminal leads and king lead ok.
No other wires obviously loose, broken or dangling.
I had a look at the fuel pump wiring,and it seemed pretty well located, but I'd have to take a wheel off and jack her up to do a proper inspection.
As she's going to up on a ramp this weekend (at TVR specialist), thought I'd leave that until then.
I was meaning to ask if it was an idea to disconnect the cold start thingmebob...seem to remember people having suggested that. Is it the brown connector attached to a small housing at the passenger side front of the engine ?
Does anyone know where 'proper' Lucas parts can be sourced , such as the ignition amp ?
Never seen such a clean motor, incidentally, but I know the wiring does suffer with heat and age.
Many thanks.
All the cars that are fixed with a replacement amplifier indicate a possible solution for Graham too, but it might not be? So! Seen hereabouts previously, perhaps a crude LT ignition test to see what component might be faulty?
Intermittent Ignition, Low Tension Fault Finder
Rig up two 4/5 watt 12 volt bulbs (or better still, 2V, 15mA LED's + 680 ohm resistors) on test leads into the cabin and connect one between coil +ve and earth and the other to coil -ve and earth. Mark the bulbs POS and NEG. Beware cables dont foul hot/moving parts.
Start the engine and observe:
POS sensing the ignition input voltage is permanantly on,
AND
NEG sensing the pulsed voltage across the Ignition Amplifier flickers in sympathy with engine rpm, or is dimly lit (LED's flicker better).
Now drive the car and have a helper note what happens when the engine mis-behaves.
If POS and NEG go out together there is an open circuit interruption of the 12 v feed such as a faulty wire/ignition switch,
OR
A short on the same circuit due to burned insulation.
If NEG comes full on the Ignition Amplifier (due to excess internal heat) or its associated wiring/earth has failed in open circuit mode,
OR
The pulsed input (ie Hall Effect or Reluctor) to the amplifier from the dizzy has failed or the associated wiring is faulty/shorting to earth,
OR
The Coil has failed in a short circuit mode (unlikely cos it would surely kill the amplifier methinks?)
If NEG goes out the Ignition Amplifier has temporarily failed in short circuit mode due to excess internal heat,
OR
the local wiring is shorting to earth,
OR
The coil has failed in open circuit mode due to insulation breakdown or internal heat
If POS stays lit and NEG show signs of flickering instability not sympathetic with engine rpm, then the Ignition Amplifier or its connections are on the blink.
If nothing else, it saves buying replacement components speculatively.
Intermittent Ignition, Low Tension Fault Finder
Rig up two 4/5 watt 12 volt bulbs (or better still, 2V, 15mA LED's + 680 ohm resistors) on test leads into the cabin and connect one between coil +ve and earth and the other to coil -ve and earth. Mark the bulbs POS and NEG. Beware cables dont foul hot/moving parts.
Start the engine and observe:
POS sensing the ignition input voltage is permanantly on,
AND
NEG sensing the pulsed voltage across the Ignition Amplifier flickers in sympathy with engine rpm, or is dimly lit (LED's flicker better).
Now drive the car and have a helper note what happens when the engine mis-behaves.
If POS and NEG go out together there is an open circuit interruption of the 12 v feed such as a faulty wire/ignition switch,
OR
A short on the same circuit due to burned insulation.
If NEG comes full on the Ignition Amplifier (due to excess internal heat) or its associated wiring/earth has failed in open circuit mode,
OR
The pulsed input (ie Hall Effect or Reluctor) to the amplifier from the dizzy has failed or the associated wiring is faulty/shorting to earth,
OR
The Coil has failed in a short circuit mode (unlikely cos it would surely kill the amplifier methinks?)
If NEG goes out the Ignition Amplifier has temporarily failed in short circuit mode due to excess internal heat,
OR
the local wiring is shorting to earth,
OR
The coil has failed in open circuit mode due to insulation breakdown or internal heat
If POS stays lit and NEG show signs of flickering instability not sympathetic with engine rpm, then the Ignition Amplifier or its connections are on the blink.
If nothing else, it saves buying replacement components speculatively.
Thanks for the guidance.
I will hopefully have a go at that testing procedure, depending how busy I am at work this week, otherwise I'll ask the garage to do it at the weekend.
Oh, and 'johntom' asked me about fuel pump priming noise.
There has never been ANY fuel pump noise (when starting for instance) with this car. She does always start perfectly and rapidly though.
I did find that surprising, as my 400SE had a definite initial whine to add to the starting up of a Spitfire effect.
Presumably their fuelling system is slightly different ? The 400 was a hotwire.
I will hopefully have a go at that testing procedure, depending how busy I am at work this week, otherwise I'll ask the garage to do it at the weekend.
Oh, and 'johntom' asked me about fuel pump priming noise.
There has never been ANY fuel pump noise (when starting for instance) with this car. She does always start perfectly and rapidly though.
I did find that surprising, as my 400SE had a definite initial whine to add to the starting up of a Spitfire effect.
Presumably their fuelling system is slightly different ? The 400 was a hotwire.
Your car is of the flapper type if there is no noise of fuel pump priming on ignition. Take the air filter off and poke ya fingers into the air flow meter and move the butterfly flap, With the ignition on, you should here the fuel pump running. If it doesn't, then there is a problem with the pump/wiring.
The pump only pumps when the engine is cranked over, unlike the hotwire cars that pressurise the system when the ignition is switched on
The pump only pumps when the engine is cranked over, unlike the hotwire cars that pressurise the system when the ignition is switched on
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