Running problems with Lucas L (flapper 4CU) injection system
Discussion
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!!!!
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!!!!
I have posted the problem on a few sites and had a massive amount of help! thanks, the car was Gerry Attrick`s car, and I will try and start to check everything ASAP, I have a complete flapper system to rob parts from so will be changing bits out soon, the cold weather is not helping!
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? will go for a drive latter and see how she goes! stuck baby sitting!
Thanks
Rob
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? will go for a drive latter and see how she goes! stuck baby sitting!
Thanks
Rob
yes had loads of hassle with intermotor parts in the past!
well took it for a longer run and its no different apart from tickover is working now, its not stalling and the tickover is not hunting.
The problem now is it just does not rev cleanly, missing, and feels like its a carb with the choke full on when it should be off......
Will look into getting a new rotor arm and distributor cap, it would be great to try parts that are known to work, as using parts that could still be faulty is not going to help! and the problem is many people will sell parts known to be faulty on ebay etc, as its easy money for junk.
well took it for a longer run and its no different apart from tickover is working now, its not stalling and the tickover is not hunting.
The problem now is it just does not rev cleanly, missing, and feels like its a carb with the choke full on when it should be off......
Will look into getting a new rotor arm and distributor cap, it would be great to try parts that are known to work, as using parts that could still be faulty is not going to help! and the problem is many people will sell parts known to be faulty on ebay etc, as its easy money for junk.
adam quantrill said:
No-one has specifically mentioned the engine temperature sensor - it's worth taking the plug off and shorting it out, after it's a bit warmed up. If it runs much better then there's your culprit!
Also I was emailing Ramon (HJ2) the other day about the ignition module - he pointed out when changing it you MUST use some thermal paste on the back, or else it will start to overheat and go bad.
Ok Will give it a go, thanks for the tip about the thermal paste, cheersAlso I was emailing Ramon (HJ2) the other day about the ignition module - he pointed out when changing it you MUST use some thermal paste on the back, or else it will start to overheat and go bad.
changed TPS........... yes you guessed it no difference!
changed the thermal time switch.......yes you guessed it no difference!
changed the temp sender..........yes you guessed it no difference! (looked like a brand new one I took out?)
engine would not run with this disconnected? and ran very poor if I shorted the wires? like Adam suggested?
changed the thermal time switch.......yes you guessed it no difference!
changed the temp sender..........yes you guessed it no difference! (looked like a brand new one I took out?)
engine would not run with this disconnected? and ran very poor if I shorted the wires? like Adam suggested?
honestjohntoo said:
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
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 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.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?
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.
adam quantrill said:
s1v8esprit said:
changed the temp sender..........yes you guessed it no difference! (looked like a brand new one I took out?)
engine would not run with this disconnected? and ran very poor if I shorted the wires? like Adam suggested?
That's very interesting!engine would not run with this disconnected? and ran very poor if I shorted the wires? like Adam suggested?
Normally you only need the enrichment when it's quite cold (you did warm it up a bit first, right?) and when you short this out then the engine runs a bit leaner, but should run fine.
The fact that it runs worse make me start to think the fuel is already on the lean side? And then the rough running at 3500+ is the same reason?
So - how about checking the AFR when driving? I dunno if you can get a lambda sensor that can work up the tailpipe? Also check the usual reasons for poor fuelling:
Hardly any fuel in tank (!)
Bad Fuel Pressure Regulator - check the fuel pressure
Vacuum pipe to fuel regulator split
Failing pump
Blocked fuel filter(s)
Flapper getting a bit gummed up
Air leaks
Throttle pot totally open circuit or no voltage to pot
honestjohntoo said:
B-Reight said:
Ramon, i don't think this could be true, from my experimentation with the L-jet ECUs it would appear that the enrichment %age is only significant under 40degrees C coolant temp. Over that value there was no discernable enrichment.
I think you are right because of placing the emphasis on the word "significant". The sensor chart bears out the change from 40 to 100 degrees accounts for only about 1000 ohms in a total resistance change from nearly 10,000 ohms very cold, down to approx 200 ohms at full temperature. Coolant Temperature Sensor Chart
-10°C......9100-9300
0°C........5700-5900
20°C.......2400-2600
40°C.......1100-1300
60°C.......500-700
80°C.......300-400
100°C......150-200
and whilst the temperature/resistance curve is non linear, the ECU enrichment circuits will be linear as far as their response to the input resistance is concerned and that final 10% change whilst being "small" does not exactly qualify as "no discernable enrichment".
Indeed continually driving with enriched mixture will feel like a choked engine. Even the reported plug colour seems to bear that out for an engine/system that normally runs a bit on the weak side with normal plug colour, in my experience, a bit lighter than reported.
Now its all academic, but before the information came in that the engine does indeed get up to temperature the sufferer actually says "took it for a drive, engine is still cold and is holding back like it has too much choke?"
Also following the progress of the reportage on three threads over two different forums is not bringing in any cohesive actions.
My own solution from the getgo would be in the simple "back to basics" test programs suggested earlier. On the other hand, sooner or later the scattergun approach to component replacement will eventually bring about an answer even if that answer is total disenchantment and moving on to a different marque.
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.
I was hoping to drain the fuel tank and check the filters and pump today but its raining. Now because its running at its worst today and because its wet would that make it more likely to be a wiring loom connection fault?
I was hoping to drain the fuel tank and check the filters and pump today but its raining. Now because its running at its worst today and because its wet would that make it more likely to be a wiring loom connection fault?
honestjohntoo said:
s1v8esprit said:
so could I not try bypassing the temp sensor with a resistor at the ECU end of the loom? just in case I have a faulty connection or wiring?
Yes indeed, 200 ohms will make the fuelling correct for normal running temperature, if you have access to the wiring at the ECU, or you could simply carry out the test process for the CTS as detailed here: http://www.vintagemodelairplane.com/pages/Rover_Te...
and in the manu of course.
Apologies if I'm wrong but you seem to be reluctant to do any suggested testing - just wanna replace components randomly and in hope?
These have been changed, and it made no difference? I have not been randomly changing parts? I have a complete system for spares, its quicker just to change the parts as to test them again just in case the parts have intermittent faults? I have been changing parts in order of what is most likely at fault.
I have a fuel pressure gauge on order and will be going back to basics starting with the fuel, I had hoped to have fixed it by changing the parts that I had, but this has been a tricky problem as the results have changed and not been consistent......other than it drives real crappy.
adam quantrill said:
What is the history of the spare parts system you are robbing bits from? Was it from a good runner? For it is quite possible that you have replaced your ECU with another one, with a different fault.
Damp and running worse suggests the ignition isn't pukka, but as HJ2 says, there may be more than one fault present.
Now it is dark go outside and run it, in the dark, and check for arcing.
What is the spark like at the end of the king lead, and then at the end of each lead in turn, weak, or nice and fat? (You'll need to poke a well-grounded screwdriver up the shrouds for the last test)
Then, are all the leads connected up in the correct firing order?
was told it was all good, bottom end went in water (off roading) and knackered the bottom end so the bloke sold all the bits off the car and scrapped it.Damp and running worse suggests the ignition isn't pukka, but as HJ2 says, there may be more than one fault present.
Now it is dark go outside and run it, in the dark, and check for arcing.
What is the spark like at the end of the king lead, and then at the end of each lead in turn, weak, or nice and fat? (You'll need to poke a well-grounded screwdriver up the shrouds for the last test)
Then, are all the leads connected up in the correct firing order?
right just ran it in the dark, no arcing and still running crap! have now got a 3rd ECU and has made no change. Tried the bypass of the temp sender with a 320 ohms resistor (all I could find) engine very hard to start and will not run, really does not like it at all? is this not a clue?
will check condition of spark tomorrow, too cold and wet now, and double check firing order but can not see that being wrong as at times it has run ok?
adam quantrill said:
Yes it should be running leaner with the 320 ohm resistor in - if cold the engine temp sensor will be in the 1k ohm + value with the weather we've been having lately.
If all the components have been replaced with good ones then the wiring loom needs checking. If (for example) the air meter isn't feeding back a good value via the wiring, then you could end up running lean.
Maybe if you take off the ECU multiplug and check each wire one at a time for continuity all the way to the corresponding pin on the other end, e.g. air meter, throttle pot, etc.
Then (with all the engine bits disconnected) check for shorts between the various wires at the ECU multiplug. Some are grounds so should be shorted.
yes good idea, the whole injection loom could be dodgy! the auto electrician who done the checks could have been lazy and not checked the loom properly?If all the components have been replaced with good ones then the wiring loom needs checking. If (for example) the air meter isn't feeding back a good value via the wiring, then you could end up running lean.
Maybe if you take off the ECU multiplug and check each wire one at a time for continuity all the way to the corresponding pin on the other end, e.g. air meter, throttle pot, etc.
Then (with all the engine bits disconnected) check for shorts between the various wires at the ECU multiplug. Some are grounds so should be shorted.
I have a complete loom so I will check this as its easy to do than on the car, and if it checks out ok will swap it over, (I have swapped every thing else!) still going to check the fuel setup first. Hopefully have it sussed soon.
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