Discussion
having studied my rolling road fueling graphs (well ok actually after having them explained to me by different people Gary Carzy Horses RR/Jules/Mike from Dyno Dynamics/Euean Torque V8) it appears the car is running both lean and rich.....
At about 3600 rpm it's running lean, and the general concenus of opinion is to get a higher rated fuel regulator...... any idea what pressure one I should have on the car, and what I should up it to0 (I was advised yesterday but brain like a seive try to absorb technicalities of it all)
Then at about 4800 rpm it looks to be over fueling ....... it was suggested either airflow meter or ecu .... unfortunalty I didn't have time to put on OE airflow meter kindly offered by Euean of Torque V8 to eliminate or confirm....
Ohh and what should my AFR reading be in the ideal world considering all is perfect.
At about 3600 rpm it's running lean, and the general concenus of opinion is to get a higher rated fuel regulator...... any idea what pressure one I should have on the car, and what I should up it to0 (I was advised yesterday but brain like a seive try to absorb technicalities of it all)
Then at about 4800 rpm it looks to be over fueling ....... it was suggested either airflow meter or ecu .... unfortunalty I didn't have time to put on OE airflow meter kindly offered by Euean of Torque V8 to eliminate or confirm....
Ohh and what should my AFR reading be in the ideal world considering all is perfect.
Edited by Hoover. on Tuesday 17th August 07:48
Looking at the Graph I don't think a higher fuel pressure would do you any good if anything it would make the car run richer. The ideal air fuel ratio you want is around 12.5-1 across the range, TVR's do tend to lean off at higher rpm but in theory should stay constant at WOT. I would sugest you may have an air flow problem. I would start by checking all the sensors that send readings to the ECU ie throttle pot, AFM, Lambda, temp sensors etc. This can be done with a simple multimeter at the ecu if you have the bible it gives you some good info on electrical testing.
I also have a fuelling problem on mine (also found at the Growl) but mine is going the opasite way its running lean and gets even leaner as the rpm picks up.
Graph here
Mark (blitzracing) has helped me a lot with this problem i'm sure he will be along soon to point you in the right direction aswell
Chris
I also have a fuelling problem on mine (also found at the Growl) but mine is going the opasite way its running lean and gets even leaner as the rpm picks up.
Graph here
Mark (blitzracing) has helped me a lot with this problem i'm sure he will be along soon to point you in the right direction aswell
Chris
You need to remember the graph here relates to the roller test when it's foot to the floor so it's not representative of real world part throttle driving.... mine was well rich on the rollers but in normal driving, even giving it plenty, the on dash AFR guage is showing much more sensible readings (the guage was very close to the lambda monitor on the RR too, which was reassuring
Hoover. said:
Mines a pre-cat and doesn't have lamba sensors.......... at the car stinks of petrol fumes as well as behind, regulary spitting flames out....
cool 
I will post my graph up later, had a great time at BSG
Thanks to Eann for lending me an air flow meter (didn`t work but at least i know) and Hoover for spotting my missfire
Mine suddenly started doing the same as Chris' graph when i was on track (AFR alarm went off and i backed off). Checked the usaul suspects...ignition, AFM, Lambdas and Regulator etc. to no effect, replaced the fuel filter near the pump and it was much improved. Replaced the old pump with a Bosch 044 unit and the problem went completely away for me.
As for the op, I wouldn't suspect the regulator or pump/filter, as it is running rich at high rpm's which is where i would expect it to lean off if they were at fault.
You're off Lambda, so i would suspect either the WOT fuel map (what ecu are you running? any mods since it was last mapped/set up?). or the air intake is getting restricted (collapsed pipe?).
One other thing to look at is the fuel rail pressure, If you have upped the rail pressure from when it was mapped at, it will run much richer. The garage tried to bodge my lean fueling by tweaking my regulator from 38psi to 45ps1 this created a 20% overfueling issue when i finally track my problem down to the fuel pump failing.
Another thought what injectors you running, and how old are they? If you over pressure std injectors it will have a negative effect on the spray pattern especially if they getting a bit tired, and you wont get as good a burn. this will make the AFR reading rich (does the car feel down on power?)
As for the op, I wouldn't suspect the regulator or pump/filter, as it is running rich at high rpm's which is where i would expect it to lean off if they were at fault.
You're off Lambda, so i would suspect either the WOT fuel map (what ecu are you running? any mods since it was last mapped/set up?). or the air intake is getting restricted (collapsed pipe?).
One other thing to look at is the fuel rail pressure, If you have upped the rail pressure from when it was mapped at, it will run much richer. The garage tried to bodge my lean fueling by tweaking my regulator from 38psi to 45ps1 this created a 20% overfueling issue when i finally track my problem down to the fuel pump failing.
Another thought what injectors you running, and how old are they? If you over pressure std injectors it will have a negative effect on the spray pattern especially if they getting a bit tired, and you wont get as good a burn. this will make the AFR reading rich (does the car feel down on power?)
Edited by Bluebottle on Tuesday 17th August 08:43
Fuel pump, filters were all changed a year or so ago.
Aftermarket new injectors fitted about 3 years ago... supplied by Rob Robertson as an alternative to the Bosch.
As for induction got the ACT induction kit + trumpets + Powers Isolator......
Think I might see if I can get another AFM and see that makes a difference.....
As it's running TVR's chip I can't see that much can be done with that...... probably if AFM makes no difference it's time to give MA some of my wonga to sort out a fueling map.
Editted to say done some further reading now I've found away to search specific forums google........ off to play with AFM and see if that is out of tolerance and see if it can be bought back in line.
Aftermarket new injectors fitted about 3 years ago... supplied by Rob Robertson as an alternative to the Bosch.
As for induction got the ACT induction kit + trumpets + Powers Isolator......
Think I might see if I can get another AFM and see that makes a difference.....
As it's running TVR's chip I can't see that much can be done with that...... probably if AFM makes no difference it's time to give MA some of my wonga to sort out a fueling map.
Editted to say done some further reading now I've found away to search specific forums google........ off to play with AFM and see if that is out of tolerance and see if it can be bought back in line.
Edited by Hoover. on Tuesday 17th August 20:02
If you're running aftermarket injectors and a few other mods on a bog std TVR chip...Unless it has run correctly in the past with those mods, I would be looking at the WOT map as your most likely suspect.
ETA AFM will have no effect on WOT above 3.5k rpm as that is ecu map controlled
ETA AFM will have no effect on WOT above 3.5k rpm as that is ecu map controlled
Edited by Bluebottle on Tuesday 17th August 20:21
The AFM output is critical to get the correct fuelling on the not catalysts map, as it has by far the biggest influence on the amount of fuel supplied. The AFM is very sensitive to small changes in airflow at low speed, but becomes less and less sensitive as the airflow goes up and getting sensible reading at near WOT can be difficult to say the least on the road, I have to bench test them with a 2.5kw gargen vac' and that still wont reach the peak airflow of a 5ltr car. As you dont have the Lambda probes any inaccuracies in AFM output cant be compensated for by the ECU so inacurate AFM output will show up as wrong fuelling and at low speed if the AFM output is out by even 10's of millivolts the fuelling will be wrong. This may not be the only cause of this odd fuelling, and its odd to be lean then rich' it would tend to show that the AFM output would be to high at near full power, and low and lower airflows, which is not a fault Ive seen on the Lucas 5AM or 3AM. From what Ive seen so far they tend to overfuel at low speed when the electronics fail, or as already stated there is a tendency for the bigger engine cars to run lean at full power. The problem here is the AFM and fuel map was never designed for 6000 rpm or 280+ BHP, so the AFM output simply flat lines at near 5 volts peak before the car is at peak airflow so the extra fuel needed has to be mapped against the RPM and throttle pot only, which is a major drawback in accuracy terms.
Mark Adams did this bit on testing the AFM which is pretty good:
Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.
Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).
Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.
Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine).
The next test is full load, and as with the fuel pressure test it will require use of a rolling road or a steep hill in the same manner. Under full load the voltage should rise to 4.45 Volts (3.5 Litre engine) to 4.95 Volts (5.0 Litre engine).
On this injection system, the idle CO mixture adjuster is provided on the airflow meter. It is located in a boss on the top of the airflow meter, pointing towards the engine. Leaving the multimeter negative probe in the Red/Black wire, move the positive probe to the Blue/Red wire.
Now turn on the ignition but do not start the engine. Observe the voltage. The normal adjustment range is between 0.0 and 3.6 Volts, with the higher Voltages producing higher idle CO values. There are approximately 20 turns of the adjuster screw to cover the entire range.
Annoyingly, the adjustment may be clockwise or anticlockwise to increase the value, and this varies from meter to meter! For this reason it is always preferable to have the multimeter connected in this manner when adjusting idle CO, so that you see can something is actually happening.
Typical Voltages that would be found at this point are between 0.9 to 1.4 Volts for non-catalyst cars. This Voltage is always factory pre-set to 1.8 Volts for catalyst vehicles. A value near to 3.5 Volts will generally produce an idle CO value of 9-10%. These Voltages may be used as safe initial values particularly if no CO measuring equipment is available.
Mark Adams did this bit on testing the AFM which is pretty good:
Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.
Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).
Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.
Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine).
The next test is full load, and as with the fuel pressure test it will require use of a rolling road or a steep hill in the same manner. Under full load the voltage should rise to 4.45 Volts (3.5 Litre engine) to 4.95 Volts (5.0 Litre engine).
On this injection system, the idle CO mixture adjuster is provided on the airflow meter. It is located in a boss on the top of the airflow meter, pointing towards the engine. Leaving the multimeter negative probe in the Red/Black wire, move the positive probe to the Blue/Red wire.
Now turn on the ignition but do not start the engine. Observe the voltage. The normal adjustment range is between 0.0 and 3.6 Volts, with the higher Voltages producing higher idle CO values. There are approximately 20 turns of the adjuster screw to cover the entire range.
Annoyingly, the adjustment may be clockwise or anticlockwise to increase the value, and this varies from meter to meter! For this reason it is always preferable to have the multimeter connected in this manner when adjusting idle CO, so that you see can something is actually happening.
Typical Voltages that would be found at this point are between 0.9 to 1.4 Volts for non-catalyst cars. This Voltage is always factory pre-set to 1.8 Volts for catalyst vehicles. A value near to 3.5 Volts will generally produce an idle CO value of 9-10%. These Voltages may be used as safe initial values particularly if no CO measuring equipment is available.
SILICONE KID said:
Is this OK before and after the Mega squirt.332.3bhp
Naughty Naughty, you know this is NOT a simple case of bad Mark Adams mapping and should not be marked as such, something else was way out or faulty for the fueling to be that bad on a 14CUX. Edited by SILICONE KID on Friday 20th August 23:06
SILICONE KID said:
Nothing naughty about that !It was a best guess map which we all know as a total waste of time .Im sure Mark would of got the same or close figures as the Meagasquirt set up .My point is that a best guess map is a no no .
I'm glad you qualified that, as I was starting to think going to MA would be a waste of time if that's his result on the fueling front.I still dont hold to that one that a best guess can be that bad. Ive tried the TVR 3.9, 4.5, 5ltr, an Adams 4.2, an Adams Tornado, and a JE engineering modified 3.9 all on my car, and they all maintained Lambda below 3400 rpm as the ECU is so flexible (12.35:1 AF). At no point does your map show this unless you held it flat out from 2000 rpm in whatever gear you where using and it ran open loop all the way, and my experiance of Rolling roads is you feed the power in progressively, you dont just stamp on the throttle to start with, but please correct me if this was the case?
I have a best guess from MA, through Tim at ACT, ( told him what mods I had done)and I'm well chuffed with the overall performance. Tick over is perfect without adjustment, no shunting, and it now revs sooo much better.
Thumbs up to MA. Just wish the man was more contactable, bit like trying to get hold of
Lord Lucan !!
R
Thumbs up to MA. Just wish the man was more contactable, bit like trying to get hold of
Lord Lucan !!
R
Blitzracing.I have just had a chat with Kevin at AutoTech reagarding having the program installed in to my laptop.I mentioned your query regarding the fueling AF .He said the its in closed loop all the time with the (wide) band lambdas working all the time set at 10% each way.Its means nothing to me but you will have a idea . I have two wide band lambdas 1 working each bank .Does this explain why the dyno does not show what you have been talking about..You have to admit that my engine gives a good 55bhp more than a factory engine .Thanks To V8 Developments and The Megasquirt.
http://www.dyno-tech.co.uk/
http://www.dyno-tech.co.uk/
Edited by SILICONE KID on Monday 23 August 13:18
Thats fair enough, I gather the megasquirt can be set to run whatever air fuel ratio you want to map it to as it uses wide band sensors, so the megasquirt graph would appear to show a slightly leaner mixture to start with under lighter load, getting progressively richer as you need more power, its pretty spot on. Its the 14CUX plot that all over the place, its should have been holding at around 14.35:1 in its closed loop area using its narrow band sensors, which is either less than 3/4 throttle, or 3400 rpm, and then it should switch fairly sharply to around 12.5:1 as it goes open loop above these settings. Even with bad mapping Id expect to see it start somewhere near correct as the ECU has an ability to trim the mixture by 20%, which is a pretty massive amount to bring it into range. Your plot is so far out, I think the ECU would have been in a fault condition as it could not control the mixture, so it should have been throwing a fault code to go with it.
Hoover. said:
having studied my rolling road fueling graphs (well ok actually after having them explained to me by different people Gary Carzy Horses RR/Jules/Mike from Dyno Dynamics/Euean Torque V8) it appears the car is running both lean and rich.....
At about 3600 rpm it's running lean, and the general concenus of opinion is to get a higher rated fuel regulator...... any idea what pressure one I should have on the car, and what I should up it to0 (I was advised yesterday but brain like a seive try to absorb technicalities of it all)
Then at about 4800 rpm it looks to be over fueling ....... it was suggested either airflow meter or ecu .... unfortunalty I didn't have time to put on OE airflow meter kindly offered by Euean of Torque V8 to eliminate or confirm....
Ohh and what should my AFR reading be in the ideal world considering all is perfect.
something we found later that day is that some cars were not making full throttle - (the ecu has a full thottle map)At about 3600 rpm it's running lean, and the general concenus of opinion is to get a higher rated fuel regulator...... any idea what pressure one I should have on the car, and what I should up it to0 (I was advised yesterday but brain like a seive try to absorb technicalities of it all)
Then at about 4800 rpm it looks to be over fueling ....... it was suggested either airflow meter or ecu .... unfortunalty I didn't have time to put on OE airflow meter kindly offered by Euean of Torque V8 to eliminate or confirm....
Ohh and what should my AFR reading be in the ideal world considering all is perfect.
Edited by Hoover. on Tuesday 17th August 07:48
get somebody to put thier foot at full throttle and see if the linkage will move any more
the other thing we suggested was a new mass air flow meter - did you manage to get a new one fitted ?
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