Running problems with Lucas L (flapper 4CU) injection system

[esprits1v8]

I have just brought a TVR (wedge 350i)
It is not running very well, does not tickover (hunting and stalling)
does not rev very well did not like going over 2500rpm most of the time
sometimes would rev ok

has had an auto electrician test it and all sensors are working, diagnosed as faulty ecu plug or ecu
ecu plug has been cut off and spade ends fitted, was told this fixed the problem

however it has not fixed the problem, still the same!

I have now replaced the ecu plug wiring and changed the ecu (been told these were working) yes you guessed it no difference!!!

HELP!!!!

[SuperV8]

I would check all your injectors.

I found 2 of mine were stuck closed and another 2 which had a very feeble flow.

These injectors are getting on a bit now and if they have been sat for a while with fuel in the fuel can solidify and stick them shut.

You can make a simple test bench up using a compressor and pulsing the injectors but only with 3v NOT 12v. You should also feel them click when they open, if you can't feel them probabbly stuck.

I also found 2 injector connectors not connecting, a little tweek with a screwdriver and hey presto.

Tom.

[esprits1v8]

all spark plugs are a nice tan colour? would that not mean its running with the right amount of fuel?

[esprits1v8]

the car will rev freely when standing still, but when driven splutters and has loss of power just over 2500rpm
Have changed every sensor, and checked all pipe work, new plugs, ht leads etc, etc,
The only thing left is the fuel? or unless the replacement ECU is dodgy as well?

[softdash3.9]

Have you changed the fuel filter? might be restricting fuel flow

[esprits1v8]

I have not, but the previous owner did along with new pump.....

[softdash3.9]

Correct way round?

I know it sounds stupid, but......

[ramon alban]

Hello Rob, Just been reviewing your other threads on various forums on this subject and came across your last post on the V8 forum dated 10 December. The one where you said

checked all pipe work, no blocks or leaks, crankcase breather was blocked so cleaned it out, made no difference.
Checked the distributor cap and rotor arm, they are poor surprised they were not changed when HT leads got changed?
Tried the other used ones I got with the spare system, no difference.

Changed the AFM, Bingo did change it, the hunting on tickover has gone and revs a little better, took it for a drive, engine is still cold and is holding back like it has too much choke?

The key point being highlighted as you see.

Was this true? Is it still true?

If so, then it suggests that the thermostat is stuck wide open and the engine is simply unable to reach an efficient running temperature and, particularly in the recent very cold weather, the temperature sensor is telling the ECU to keep the mixture artificially rich, hence giving you the impression that as you say

it is holding back like it has too much choke?

Which, if the thermostat is stuck open, is exactly what is happening.

Check the thermostat and replace if necessary with an 88 degree C item.

[esprits1v8]

Hello Rob, Just been reviewing your other threads on various forums on this subject and came across your last post on the V8 forum dated 10 December. The one where you said

checked all pipe work, no blocks or leaks, crankcase breather was blocked so cleaned it out, made no difference.
Checked the distributor cap and rotor arm, they are poor surprised they were not changed when HT leads got changed?
Tried the other used ones I got with the spare system, no difference.

Changed the AFM, Bingo did change it, the hunting on tickover has gone and revs a little better, took it for a drive, engine is still cold and is holding back like it has too much choke?

The key point being highlighted as you see.

Was this true? Is it still true?

If so, then it suggests that the thermostat is stuck wide open and the engine is simply unable to reach an efficient running temperature and, particularly in the recent very cold weather, the temperature sensor is telling the ECU to keep the mixture artificially rich, hence giving you the impression that as you say

it is holding back like it has too much choke?

Which, if the thermostat is stuck open, is exactly what is happening.

Check the thermostat and replace if necessary with an 88 degree C item.

but the engine is getting hot? when I take it for a run the temp is going to 90 degrees, so I dont think it can be the problem?

[esprits1v8]

I would check all your injectors.

I found 2 of mine were stuck closed and another 2 which had a very feeble flow.

These injectors are getting on a bit now and if they have been sat for a while with fuel in the fuel can solidify and stick them shut.

You can make a simple test bench up using a compressor and pulsing the injectors but only with 3v NOT 12v. You should also feel them click when they open, if you can't feel them probabbly stuck.

I also found 2 injector connectors not connecting, a little tweek with a screwdriver and hey presto.

Tom.

could I take out the complete injector rail, but each injector in a jar and zap each one with 3volts? or is it simple to make a test bed? I have a compressor, thanks

[ramon alban]

I extracted this from my web pages article on Efi injectors.

Home Workshop Injector Maintenance

• All the components needed for injector overhaul can be sourced from a local injection specialist or from Burlen Fuel Systems (Tel: 01722 412500 begin_of_the_skype_highlighting              01722 412500      end_of_the_skype_highlighting) under the following Burlen part numbers and description (1998 prices). The same items are also available on the SU carb web pages.

• BFB103Q10 Filter Baskets 10 off £5.00

• BPC13Q10 Pintle Caps 10 off £2.50

• ABF407 Fuel Injection Hose 2.0 mtr X 7.6 mm £13.40

• BHC1214 Hose Clamps 12-14mm 100 off £14.50
Packing and First Class Post £1.95 all + vat

• Cleanliness is a key factor particularly as there is the possibility of metal debris whilst removing the old hoses.

• Cut off the swaged hose collar at a sharp angle using suitable snips or a very fine junior hacksaw blade and discard the old fuel hose

• Cut off the old pintle caps with a sharp blade being careful not to mark the body of the filter.

• Clean all around the area where the pintle cap fits with fine wire wool and metal polish.

• Clean up the body of the injector and the area where the manifold rubber seals fit with a wire brush, wire wool and polish.

• Blow off any debris and wash the injector in a container of clean “Panel Wipe”.

• Last in this sequence, pull out the old injector filter using a wood screw or small "easy-out" gently screwed into the open end of the filter, bathe the injector again and blow away any more debris with a 100 psi airline.

• Access to an ultrasonic cleaner may significantly improve the cleaning process and if thought necessary such equipment is readily available at low cost on popular auction sites.

• Press a new filter into place using a drill press or vice, protecting the pintle end of the injector with suitable hole in a hardwood block.

• Press on a new pintle cap using a small hardwood block with another small hole to protect the pintle end, ensuring the cap starts off upright to prevent uneven fit.

• It’s probably best to think this next part through and make up a rig meeting the following requirements.

• Temporarily connect a 6” length of hose to the input end of the injector with a hose clip, and connect a 3 volt supply to the injector connector using a switch to pulse the injector on and off.

• Note: It’s possible to use a 12 volt supply but the injector must be protected by a 6 ohm resistor wired in series with the supply and switch.

• Pour a small quantity (about one fluid ounce) of Panel Wipe into the open end of the hose and connect a 30 psi compressed air source securely to the hose sufficient to withstand the pressure.

• Ensure there is suitable lighting to the rig so that one may clearly see the resulting spray pattern.

• Pulse the injector coil briefly with the switch and observe an orderly conical spray pattern with no dribbling.

• Pulse the injector several times and see that the above is repeatable with a clean start and finish to each pulse.

• If the spray pattern is disorderly or dribbles then the injector is probably still contaminated, damaged (or blocked) and should be replaced.

• Complete the above for all the injectors.

• Cut new hose lengths for each injector and ensure there is no rubber debris contaminating the hose interior.

• Couple the new hose to each injector using the appropriate hose clips.

• Assemble the injector hoses to the fuel rail using similar clips.

• Ensure that the hose clip screws are facing in a convenient direction to provide easy access for screwdriver tightening in their final position.

• Fit the other various hose lengths to the fuel rail and the job is complete.

[esprits1v8]

Thank you Ramon, I will clean them ASAP, I was planning to empty the fuel tank today and clean the swirl pot, filters and check the pump but its raining!

today it is running real bad, will not tick over, stalls and just will not rev clean? took it for a short drive and its horrible, lumpy,flat spots and missing.

because its running at its worst today and because its wet would that make it more likely to be a wiring loom connection fault?