K series misfire
Discussion
I have a steady part throttle misfire off idle to around 3k rpm.
I've swapped out all the ign components (HT leads, king lead, dizzy cap, rotor arm, plugs).
What would people suggest is the next port of call?
thoughts:
1) crank posn sensor - apparantly either likely to let the engine run or won't, so not the 1st thing to swap out. (the crank posn sensor is well away from any HT sources, or anywhere that could interfere with the signal)
2) TPS
3) check for air leaks on the inlet side - although this is most likely to be more evident at idle and the idle is rock solid.
4) MAP sensor (not sure whether emerald uses this)
5) Could it be worth putting new fuel in it? After approx 3k rpm, when the car was mapped, it ran cleanly up to 8k rpm, and gave full power....
6) check the earths? Any recommended way of doing this?
7) any other suggestions?
Is it worth getting the car on a krypton type machine/oscilloscope to check the firing voltages and display the ign traces?
This is bugging me now!!! Can anyone suggest a good auto electrician/garage who may be able to help? i.e. someone who can diagnose the problem rather than swap out endless parts, as I can do this myself!
I've made the following list to work through:
Connections
• Poor alternator connection (at alternator)
• Throttles balanced
• ECU ground (to battery)
• Contacts on HT leads
• Crank sensor
• Bent pin in grey loom plug
• TPS
• Leaks in TBs
• Bad earth (loose bolt / bad connection) (chassis side & starter connections)
• Connection to injectors
• Voltage across battery (BC: #15555)
• Dry joint in loom
• Timing belt loose
• MRFU
• Wiring loom – loose joint
• Alternator to starter cable
• Screening around crank sensor signal / proximity to HT lead
• Main HT lead to coil (plugged in OK?)
Parts
• HT leads
• Old petrol
• Dizzy Cap
• Coil
• Plugs (champion RC6YCC)
• TPS
• MFRU
I've swapped out all the ign components (HT leads, king lead, dizzy cap, rotor arm, plugs).
What would people suggest is the next port of call?
thoughts:
1) crank posn sensor - apparantly either likely to let the engine run or won't, so not the 1st thing to swap out. (the crank posn sensor is well away from any HT sources, or anywhere that could interfere with the signal)
2) TPS
3) check for air leaks on the inlet side - although this is most likely to be more evident at idle and the idle is rock solid.
4) MAP sensor (not sure whether emerald uses this)
5) Could it be worth putting new fuel in it? After approx 3k rpm, when the car was mapped, it ran cleanly up to 8k rpm, and gave full power....
6) check the earths? Any recommended way of doing this?
7) any other suggestions?
Is it worth getting the car on a krypton type machine/oscilloscope to check the firing voltages and display the ign traces?
This is bugging me now!!! Can anyone suggest a good auto electrician/garage who may be able to help? i.e. someone who can diagnose the problem rather than swap out endless parts, as I can do this myself!
I've made the following list to work through:
Connections
• Poor alternator connection (at alternator)
• Throttles balanced
• ECU ground (to battery)
• Contacts on HT leads
• Crank sensor
• Bent pin in grey loom plug
• TPS
• Leaks in TBs
• Bad earth (loose bolt / bad connection) (chassis side & starter connections)
• Connection to injectors
• Voltage across battery (BC: #15555)
• Dry joint in loom
• Timing belt loose
• MRFU
• Wiring loom – loose joint
• Alternator to starter cable
• Screening around crank sensor signal / proximity to HT lead
• Main HT lead to coil (plugged in OK?)
Parts
• HT leads
• Old petrol
• Dizzy Cap
• Coil
• Plugs (champion RC6YCC)
• TPS
• MFRU
Hi
On my car,R300 with TB's, it misses every time after it's been washed. It drives me mad!
I have eventually drilled it down to the multiplug under the TB's that seems to get wet on washing. I just liberally spray it with WD 40 & all is OK.
Appreciate this might not be your problem but might be worth a try?
On my car,R300 with TB's, it misses every time after it's been washed. It drives me mad!
I have eventually drilled it down to the multiplug under the TB's that seems to get wet on washing. I just liberally spray it with WD 40 & all is OK.
Appreciate this might not be your problem but might be worth a try?
BertBert said:
does the K3 not give any hints? Can you monitor it when running?
Bert
In theory yes, but in practice, I cannot see anywhere in MS vista where I can manage the port settings to allow me to see serial ports via a USB adapter, so can't 'see' the K3 via my laptop at the moment!Bert
I understand poor connections to the coolant sensor can cause a misfire with the MBE ECUs, so might be worth checking this too....although why this should cause a problem I've never really understood, too rich maybe.
(I ended up replacing the loom to resolve an occasional misfire, after replacing most of the ignition system first. I've read before that R400 race teams were told to change the looms every season by Caterham)
(I ended up replacing the loom to resolve an occasional misfire, after replacing most of the ignition system first. I've read before that R400 race teams were told to change the looms every season by Caterham)
bse said:
I understand poor connections to the coolant sensor can cause a misfire with the MBE ECUs, so might be worth checking this too....although why this should cause a problem I've never really understood, too rich maybe.
(I ended up replacing the loom to resolve an occasional misfire, after replacing most of the ignition system first. I've read before that R400 race teams were told to change the looms every season by Caterham)
If anything due to the popping, etc, I'm assuming it's running too lean, which isn't normally a condition of a duff water temp sender.(I ended up replacing the loom to resolve an occasional misfire, after replacing most of the ignition system first. I've read before that R400 race teams were told to change the looms every season by Caterham)
I'm radiply coming to the conclusion that a new engine loom may be the way forward.
Does anyone have any recommendations for a custom loom maufacturer, who can supply an engine side loom cheaper than our friends in dartford? No "support caterham cars posts" in response to this please.
I think you'll struggle to find anyone to make one cheaper than CC will sell you one, unless you do it yourself. A few specialists will sell you a loom of significantly better quality (i.e. Tony James) but at a price. I made mine and the hardest bit was sourcing the connectors & pins...but doing it yourself means you can use better materials reducing the weight and taking out any redundant wiring you may have, it's just time consuming.
Problem solved.
The solenoid in the injector was duff at certain pulse widths. At idle it was OK, and at higher duty cycles was also OK. On an ANSU machine, the spray pattern, etc was OK. Even when on the 9 cycle program found on most machines (designed to simulate various rpm) the mains current applied didn't replicate the problem.
Using an interupter box (plugs between the OEM injector harness and the injector itself), which showed the pulse width, you could see the current going to the injector was OK, and when increasing the fuelling (group firing mode) the mis went away until the fuel increased to the point where the other 3 cylinders were too rich.
This is the first case of this Dave Walker (Emerald) has seen in 15 years. A swap out with another (good) injector, solved the problem....
Dave identified the problem in about 30 mins, with no parts swap outs. Massive
The solenoid in the injector was duff at certain pulse widths. At idle it was OK, and at higher duty cycles was also OK. On an ANSU machine, the spray pattern, etc was OK. Even when on the 9 cycle program found on most machines (designed to simulate various rpm) the mains current applied didn't replicate the problem.
Using an interupter box (plugs between the OEM injector harness and the injector itself), which showed the pulse width, you could see the current going to the injector was OK, and when increasing the fuelling (group firing mode) the mis went away until the fuel increased to the point where the other 3 cylinders were too rich.
This is the first case of this Dave Walker (Emerald) has seen in 15 years. A swap out with another (good) injector, solved the problem....
Dave identified the problem in about 30 mins, with no parts swap outs. Massive
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