Uneven running is slightly worse with the lights on!

[lancelin]

Hello, I have a Griff 500 with the canems conversion! The car is great while driving above 2000rpm. Unfortunately while driving in slow traffic and changing gear there is a slight hesitation after reengaging the clutch again and applying throttle. No matter how hard I try with different amounts of throttle and clutch combinations it’s not always easy to make the process smooth. There is a slight transmission clunk when it happens. Its like there is a delay between the throttle opening and the engine responding. The problem is only slight but it still detracts from the whole driving experience. There is also some very small shunting while letting the car slow down in the gear especially in 2nd. My first thoughts are it’s a mechanical problem but after switching on the headlights the problem is noticeably worse!!!! Uneven running below 2000rpm is the most complained about problem and has been covered in many posts but I haven’t heard of headlights influencing it. Just wondering if anyone else has noticed this. I’ll be checking electrics at the weekend for ground loops etc but I wonder if it’s still a mapping issue and the load on the engine in closed loop mode is altered with the lights on and the mapping is different. The other thought is the revs need to be held up a bit more after lifting off – how can this be altered with canems software? I’m a bit fussy BUT life is all about continuous improvement!

[Steve_D]

I don't know the inner workings of the Canems system but any others I have come across have settings to compensate for volt drop. It may be that these settings have not been configured/enabled.
Would also be worth checking that your alternator is in good health.

Steve

[lancelin]

Thanks Steve, I'll check the canems settings. I have a new upgraded alternator! I even tried running the car without the alternator for a short distance to see if alternator electrical noise was causing it.

[FarmyardPants]

How does it idle? Does the idle speed drop when the lights are switched on? Sounds like poor/lack of spark at low revs/volts. I would check the HT leads are clicked on, plug gaps aren't too big and battery is good. The clunk could be diff or diff bushes?

[lancelin]

The idle stays the same with lights on and off. I have a new battery. Yes, the clunk is a bit of transmission slack. I have a device for measuring spark performance but the canems system uses coil packs which should give better sparks.

[Classic Chim]

Throttle pot sensor might be slow to respond. As they get older there known to cause signal faults especially on very light throttle settings.

You could do with asking CHIMP ON GAS on the Chimaera forum as there’s not a lot he doesn’t know about the Canams system.

I have Mbe and with a new Dif shunt is eradicated
Mbe alone removed most of the shunt but still there similar to what your symptoms are.
The new Dif has removed that transmission slack so completing the job.

[ChimpOnGas]

lancelin said:

Hello, I have a Griff 500 with the canems conversion! The car is great while driving above 2000rpm. Unfortunately while driving in slow traffic and changing gear there is a slight hesitation after reengaging the clutch again and applying throttle. No matter how hard I try with different amounts of throttle and clutch combinations it’s not always easy to make the process smooth. There is a slight transmission clunk when it happens. Its like there is a delay between the throttle opening and the engine responding. The problem is only slight but it still detracts from the whole driving experience. There is also some very small shunting while letting the car slow down in the gear especially in 2nd. My first thoughts are it’s a mechanical problem but after switching on the headlights the problem is noticeably worse!!!! Uneven running below 2000rpm is the most complained about problem and has been covered in many posts but I haven’t heard of headlights influencing it. Just wondering if anyone else has noticed this. I’ll be checking electrics at the weekend for ground loops etc but I wonder if it’s still a mapping issue and the load on the engine in closed loop mode is altered with the lights on and the mapping is different. The other thought is the revs need to be held up a bit more after lifting off – how can this be altered with canems software? I’m a bit fussy BUT life is all about continuous improvement!

Start by saving your current map so you can always go back to it if you get in a muddle.


PWM Valve Idle Control

1. Slow down your PWM idle valve control

2. Reduce the % correction

3. Raise the 'permit duty below' %


Spark Scatter Idle Control

1. Activate this feature

2. Experiment with the settings to find out what works best on your car.


Keep in mind in all cases, less is more

It's way more complex than the above, if you're going to get into mapping be prepared to invest a lot of time learning and get ready to make things worse before you make them better.

Also remember every element you change will in turn influence something else, so you can end up chasing your tail if you're not disciplined and structured in your approach.

If in doubt, seek the help of a professional.

[Classic Chim]

Lloyd’s are the specialists who know every inch of the Canams. They might have an answer for the problem getting worse when lights are on.
Worth a call I’d have thought.

[lancelin]

Thanks a lot for the info. I’ll have a play at the weekend and let you know how I get on. I was thinking the idle valve could be adjusted to help. Thanks Dave. Really pleased I have an original Bosch part and not the cheap aftermarket one that was originally fitted - this part failed and caused erratic idle.

Might invest in some engine mapping literature. Failing all this I’ll fit an electric motor!!!!! Imagine a hybrid TVR! I suspect Dave is already thinking about it. Petrol, lpg and electric.

[lancelin]

Well, I’ve been playing with the idle valve settings and it has made a difference. I think its super sensitive to the parameters chimp outlined. The car is almost a pleasure to drive in slow traffic!