Rich and rough
Discussion
No, its not the new name for French and Saunders, but a description of how the Griff is running.
I've just got back from Le Mans and I'm not certain if I have a problem specifically so I'm looking for an opinion (not that we are ever short of that on here eh!)
Before we left I had the battery disconnected while I worked on the indicators, so I was living with the usual high revs and slow to drop revs as the ECU re-learns its stuff.
Only I was travelling with an old car with a max of 55mph which basically meant I ran most of the way barely touching the throttle - because tickover was at 2100rpm - so I'm not sure what the hell the ECU might have made of it.
On the way back I started to suspect the car was running badly. Nothing I could put my finger on, it just didn't sound right. There is no obvious misfire, but its running very rich, is maybe slightly down on power and nothing obvious when I stick my head under the bonnet.
I had a blast on the A43 and was told we are belching out black smoke on hard acceleration.
Now I'm convinced its running roughly.
I've already
swapped the dizzy cap
checked/cleaned the rotor arm
checked the plug leads are seated OK
checked the air filter is OK and have no obvious leaks in the induction system
disconnected the battery to reset the ECU (again)
I have Moroso leads and was able to just grab them without getting a zap, so they seem OK but I have a spare set of Magnecours I can swap to.
I doubt its related but just in case;-
I filled on at Portsmouth in Tesco using their 99 rated fuel.
I filled at Arnage using 97 rated
Brimmed from half a tank again at Portsmouth using 99 rated fuel on the way back.
As I said, I doubt this is a contributor, the car should be happy with 99 rated fuel. But you never know.
I'll take the plugs out tonight, but I'm pretty certain I’ll find they are sooted up.
Is it possible the ECU is just being screwy because of the odd driving style after the reset so I should just clean the plugs and give it a blast?
I've just got back from Le Mans and I'm not certain if I have a problem specifically so I'm looking for an opinion (not that we are ever short of that on here eh!)
Before we left I had the battery disconnected while I worked on the indicators, so I was living with the usual high revs and slow to drop revs as the ECU re-learns its stuff.
Only I was travelling with an old car with a max of 55mph which basically meant I ran most of the way barely touching the throttle - because tickover was at 2100rpm - so I'm not sure what the hell the ECU might have made of it.
On the way back I started to suspect the car was running badly. Nothing I could put my finger on, it just didn't sound right. There is no obvious misfire, but its running very rich, is maybe slightly down on power and nothing obvious when I stick my head under the bonnet.
I had a blast on the A43 and was told we are belching out black smoke on hard acceleration.
Now I'm convinced its running roughly.
I've already
swapped the dizzy cap
checked/cleaned the rotor arm
checked the plug leads are seated OK
checked the air filter is OK and have no obvious leaks in the induction system
disconnected the battery to reset the ECU (again)
I have Moroso leads and was able to just grab them without getting a zap, so they seem OK but I have a spare set of Magnecours I can swap to.
I doubt its related but just in case;-
I filled on at Portsmouth in Tesco using their 99 rated fuel.
I filled at Arnage using 97 rated
Brimmed from half a tank again at Portsmouth using 99 rated fuel on the way back.
As I said, I doubt this is a contributor, the car should be happy with 99 rated fuel. But you never know.
I'll take the plugs out tonight, but I'm pretty certain I’ll find they are sooted up.
Is it possible the ECU is just being screwy because of the odd driving style after the reset so I should just clean the plugs and give it a blast?
My one has similar sounding problems and I just can't sus out what is causing it.
It holds back from around 1,800 rpm and then surges, it's as if the spark is momentarily cutting out or the fuel is suffering some thing similar. It feels down on power as well.
Fuel filter has been changed along with dizzy cap, leads new ish rotor arm and air filter. About a year ago the alternator and battery weren't which gave similar running and a big loss in power. But both of these are new.
A rolling road has been suggested as the only way to find out what is causing it, any decent firms in the Essex , east London area ?
It holds back from around 1,800 rpm and then surges, it's as if the spark is momentarily cutting out or the fuel is suffering some thing similar. It feels down on power as well.
Fuel filter has been changed along with dizzy cap, leads new ish rotor arm and air filter. About a year ago the alternator and battery weren't which gave similar running and a big loss in power. But both of these are new.
A rolling road has been suggested as the only way to find out what is causing it, any decent firms in the Essex , east London area ?
Hi,
I would check the Lambda sensors, does anyone near you have an ECUMATE as this will give you a really good idea of what is going on (or wrong!)
http://ecumate.com/shop/product_info.php/cPath/22/...
Regards
Steve
I would check the Lambda sensors, does anyone near you have an ECUMATE as this will give you a really good idea of what is going on (or wrong!)
http://ecumate.com/shop/product_info.php/cPath/22/...
Regards
Steve
Good advice on the ECUmate Steve.
I should have said I have a 92 pre-cat 4.3 so don't have lambda sensors.
Plugs are out and as suspected they are sooty
Initial investigations lead me to believe the AFM is the problem. But with the plugs out I have only been able to check the first phase of what it does and it's reading 0.7 volts and slowly dropping to 0.36 over about 5-10 seconds.
I have a mate locally who I can pinch the AFM from to test with. I'll see him and cross check mine and his, see how different they are.
I should have said I have a 92 pre-cat 4.3 so don't have lambda sensors.
Plugs are out and as suspected they are sooty
Initial investigations lead me to believe the AFM is the problem. But with the plugs out I have only been able to check the first phase of what it does and it's reading 0.7 volts and slowly dropping to 0.36 over about 5-10 seconds.
I have a mate locally who I can pinch the AFM from to test with. I'll see him and cross check mine and his, see how different they are.
Barreti said:
Good advice on the ECUmate Steve.
I should have said I have a 92 pre-cat 4.3 so don't have lambda sensors.
Plugs are out and as suspected they are sooty
Initial investigations lead me to believe the AFM is the problem. But with the plugs out I have only been able to check the first phase of what it does and it's reading 0.7 volts and slowly dropping to 0.36 over about 5-10 seconds.
I have a mate locally who I can pinch the AFM from to test with. I'll see him and cross check mine and his, see how different they are.
I've got an ECUmate if you want to borrow it.I should have said I have a 92 pre-cat 4.3 so don't have lambda sensors.
Plugs are out and as suspected they are sooty
Initial investigations lead me to believe the AFM is the problem. But with the plugs out I have only been able to check the first phase of what it does and it's reading 0.7 volts and slowly dropping to 0.36 over about 5-10 seconds.
I have a mate locally who I can pinch the AFM from to test with. I'll see him and cross check mine and his, see how different they are.
You can then help me use it.
FFG
The AFM reading you took is typical of a failing AFM as the intitial settle period is far too long. This is what it should look like (1 second per division). Ther trace shows ignition on (big spike- short period ignition only- start- then idle on a 3.9- your idle voltage will be just a bit higher.
Being a precat the ECU has no leaning facility, as it has no lambda feedback. The idle mixture (up to 2400 rpm or so) is set by the screw on the side of the AFM.
Being a precat the ECU has no leaning facility, as it has no lambda feedback. The idle mixture (up to 2400 rpm or so) is set by the screw on the side of the AFM.
Well its about time I bought an ECUMate so one is on order.
I really want a RoverGauge too, but daren't get near that level of diagnostics or I'll be forever tinkering. Its bad enough now while I only have spanners!
FFG, thanks for your kind offer Paul. I'll figure out the ECUMate works while I check this out and will be more than happy to give you a run through at the Growl.
I've arranged to go to a mates tonight who has a Chim.
Unfortunately the bolt holding his AFM is spinning the so-called captive nut inside the wing, so we can't just swap the AFM over, but we will measure both side-by-side and see what we get.
I'll update this post later.
Blitzracing, your information about how to test the AFM is invaluable. Thanks for taking the time to post it. I'm sure I'm not the only one who has used it.
Thank you.
I really want a RoverGauge too, but daren't get near that level of diagnostics or I'll be forever tinkering. Its bad enough now while I only have spanners!
FFG, thanks for your kind offer Paul. I'll figure out the ECUMate works while I check this out and will be more than happy to give you a run through at the Growl.
I've arranged to go to a mates tonight who has a Chim.
Unfortunately the bolt holding his AFM is spinning the so-called captive nut inside the wing, so we can't just swap the AFM over, but we will measure both side-by-side and see what we get.
I'll update this post later.
Blitzracing, your information about how to test the AFM is invaluable. Thanks for taking the time to post it. I'm sure I'm not the only one who has used it.
Thank you.
Barreti said:
Well its about time I bought an ECUMate so one is on order.
I really want a RoverGauge too, but daren't get near that level of diagnostics or I'll be forever tinkering. Its bad enough now while I only have spanners!
FFG, thanks for your kind offer Paul. I'll figure out the ECUMate works while I check this out and will be more than happy to give you a run through at the Growl.
I've arranged to go to a mates tonight who has a Chim.
Unfortunately the bolt holding his AFM is spinning the so-called captive nut inside the wing, so we can't just swap the AFM over, but we will measure both side-by-side and see what we get.
I'll update this post later.
Blitzracing, your information about how to test the AFM is invaluable. Thanks for taking the time to post it. I'm sure I'm not the only one who has used it.
Thank you.
Yes you can I really want a RoverGauge too, but daren't get near that level of diagnostics or I'll be forever tinkering. Its bad enough now while I only have spanners!
FFG, thanks for your kind offer Paul. I'll figure out the ECUMate works while I check this out and will be more than happy to give you a run through at the Growl.
I've arranged to go to a mates tonight who has a Chim.
Unfortunately the bolt holding his AFM is spinning the so-called captive nut inside the wing, so we can't just swap the AFM over, but we will measure both side-by-side and see what we get.
I'll update this post later.
Blitzracing, your information about how to test the AFM is invaluable. Thanks for taking the time to post it. I'm sure I'm not the only one who has used it.
Thank you.
just un-clip the extension housing you wont be disturbing anything 
I got stuck at work tonight so didn't get chance to get to my mates, however I did get the plugs cleaned and back in so I could do the static tests blitzracing posted.
I have a 5AM unit with the code 270050 on it.
I ran a few tests, first of all just turning on the ignition
I found it always does the same thing
When ignition is switched on it indicates 0.75volts dropping to 0.50 volts in 7 seconds and settling at 0.36volts after 20 seconds
I repeated this 5 times ad got the same results every time.
On starting the engine I measured this
Here is how Blitzracing says it should read
Suggesting the AFM is barfed I think
I'll see what happens when I fit Paul's spare tomorrow night.
I have a 5AM unit with the code 270050 on it.
I ran a few tests, first of all just turning on the ignition
I found it always does the same thing
When ignition is switched on it indicates 0.75volts dropping to 0.50 volts in 7 seconds and settling at 0.36volts after 20 seconds
I repeated this 5 times ad got the same results every time.
On starting the engine I measured this
| Revs | run1 Volts | run2 Volts |
|---|---|---|
| 2000 | 2.00 | 2.00 |
| 1800 | 1.97 | 1.92 |
| 1500 | 1.75 | 1.81 |
| 1100 | 1.68 | 1.69 |
Here is how Blitzracing says it should read
blitzracing said:
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).
So not conclusive on the 'started engine' tests but it is certainly odd at 'Ignition on' 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).
Suggesting the AFM is barfed I think
I'll see what happens when I fit Paul's spare tomorrow night.
Edited by Barreti on Thursday 27th June 00:24
Edited by Barreti on Thursday 27th June 00:26
A quick update for those of you who kindly offered help and advice.
The main thing is the car seems to be running fine again.
As yet though I haven't figured out the cause
I've removed and cleaned the plugs which were very sooty but with brown tips.
Cleaned the stepper motor which wasn't too cruddy but not exactly clean either.
Swapped the AFM to Pauls nice shiney refurbished one.
Disconnected the AFM to Air filter pipe
Cleaned the AFM harness plug with contact cleaner.
This weekend I'll get new plugs, rotor arm, fuel filter and swap them.
I can't rule out one odd thing I've found which is the stepper has screwed in nice and tight exactly 1/2 turn out from where it was.
And I'm also not certain if I've actually fixed it or just made it all nice and clean and it will run rought as a bears ass when it soots up again.
Now I have to slowly reconnect things to see if it starts running terribly again, and drive it.
So it seems I will be at the Growl this weekend after all
The main thing is the car seems to be running fine again.
As yet though I haven't figured out the cause
I've removed and cleaned the plugs which were very sooty but with brown tips.
Cleaned the stepper motor which wasn't too cruddy but not exactly clean either.
Swapped the AFM to Pauls nice shiney refurbished one.
Disconnected the AFM to Air filter pipe
Cleaned the AFM harness plug with contact cleaner.
This weekend I'll get new plugs, rotor arm, fuel filter and swap them.
I can't rule out one odd thing I've found which is the stepper has screwed in nice and tight exactly 1/2 turn out from where it was.
And I'm also not certain if I've actually fixed it or just made it all nice and clean and it will run rought as a bears ass when it soots up again.
Now I have to slowly reconnect things to see if it starts running terribly again, and drive it.
So it seems I will be at the Growl this weekend after all
Barreti said:
A quick update for those of you who kindly offered help and advice.
The main thing is the car seems to be running fine again.
As yet though I haven't figured out the cause
I've removed and cleaned the plugs which were very sooty but with brown tips.
Cleaned the stepper motor which wasn't too cruddy but not exactly clean either.
Swapped the AFM to Pauls nice shiney refurbished one.
Disconnected the AFM to Air filter pipe
Cleaned the AFM harness plug with contact cleaner.
This weekend I'll get new plugs, rotor arm, fuel filter and swap them.
I can't rule out one odd thing I've found which is the stepper has screwed in nice and tight exactly 1/2 turn out from where it was.
And I'm also not certain if I've actually fixed it or just made it all nice and clean and it will run rought as a bears ass when it soots up again.
Now I have to slowly reconnect things to see if it starts running terribly again, and drive it.
So it seems I will be at the Growl this weekend after all
Look forward to your AFM comparison tests. Seem likely it was the AFM? Make certain your new Rotor arm is not a Chinese repro. Hang on to your old one, or send it to me. Hope.The main thing is the car seems to be running fine again.
As yet though I haven't figured out the cause
I've removed and cleaned the plugs which were very sooty but with brown tips.
Cleaned the stepper motor which wasn't too cruddy but not exactly clean either.
Swapped the AFM to Pauls nice shiney refurbished one.
Disconnected the AFM to Air filter pipe
Cleaned the AFM harness plug with contact cleaner.
This weekend I'll get new plugs, rotor arm, fuel filter and swap them.
I can't rule out one odd thing I've found which is the stepper has screwed in nice and tight exactly 1/2 turn out from where it was.
And I'm also not certain if I've actually fixed it or just made it all nice and clean and it will run rought as a bears ass when it soots up again.
Now I have to slowly reconnect things to see if it starts running terribly again, and drive it.
So it seems I will be at the Growl this weekend after all
FlipFlopGriff said:
I may have sorted my rough running/stalling issue. The engine earth strap was almost through which may have also contributed to my one bank of injectors randomly dropping out. Changed it and it seems to be running well for now - touch wood.
FFG
What you then need to ask yourself is what has the starter motor - ground return been using? FFG
I have seen many a melted throttle cable due to loosing engine grounds (non TVR) 
Barreti said:
I got stuck at work tonight so didn't get chance to get to my mates, however I did get the plugs cleaned and back in so I could do the static tests blitzracing posted.
I have a 5AM unit with the code 270050 on it.
I ran a few tests, first of all just turning on the ignition
I found it always does the same thing
When ignition is switched on it indicates 0.75volts dropping to 0.50 volts in 7 seconds and settling at 0.36volts after 20 seconds
I repeated this 5 times ad got the same results every time.
On starting the engine I measured this
Here is how Blitzracing says it should read
Suggesting the AFM is barfed I think
I'll see what happens when I fit Paul's spare tomorrow night.
\I have a 5AM unit with the code 270050 on it.
I ran a few tests, first of all just turning on the ignition
I found it always does the same thing
When ignition is switched on it indicates 0.75volts dropping to 0.50 volts in 7 seconds and settling at 0.36volts after 20 seconds
I repeated this 5 times ad got the same results every time.
On starting the engine I measured this
| Revs | run1 Volts | run2 Volts |
|---|---|---|
| 2000 | 2.00 | 2.00 |
| 1800 | 1.97 | 1.92 |
| 1500 | 1.75 | 1.81 |
| 1100 | 1.68 | 1.69 |
Here is how Blitzracing says it should read
blitzracing said:
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).
So not conclusive on the 'started engine' tests but it is certainly odd at 'Ignition on' 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).
Suggesting the AFM is barfed I think
I'll see what happens when I fit Paul's spare tomorrow night.
Edited by Barreti on Thursday 27th June 00:24
Edited by Barreti on Thursday 27th June 00:26
Baretti or Blitzracing
Would it be possible to PM me (or post here) the full process for testing the AFM, where to connect the test equipment etc? It could be useful for others.
Many thanks
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