Kangaroo Griff
Discussion
Just tried mine without vacuum attached, didn't make any difference. Think I need to consult Dom and Jamie again.
It's strange, when my car's had a little work done on the engine, it seems to be alot better i.e. smoother, then after a couple of hundred miles or so, the hunting comes back. Like you say, bloody annoying.
It's strange, when my car's had a little work done on the engine, it seems to be alot better i.e. smoother, then after a couple of hundred miles or so, the hunting comes back. Like you say, bloody annoying.
if popping the advance cures it, suggests the timing is out - slightly.
posibly a worn dizzy (internal weights)
or maybe the one way valve (the disc in the vacuum pipe is the wrong way round)
but big injectors and peaky (powerful) cams can make the car more shunty in anycase, the tune (M adams)needs to be softer and more even to help, this can be done on the rollers one the engine has bedded in for a while. was it chipped on the rollers or has it got a 500 base map, or a "hot 500" base map
...or carbs will cure it
posibly a worn dizzy (internal weights)
or maybe the one way valve (the disc in the vacuum pipe is the wrong way round)
but big injectors and peaky (powerful) cams can make the car more shunty in anycase, the tune (M adams)needs to be softer and more even to help, this can be done on the rollers one the engine has bedded in for a while. was it chipped on the rollers or has it got a 500 base map, or a "hot 500" base map
...or carbs will cure it
I seem to have narrowed this problem down (on my car at least & with help from a trip to Rob at V8 developments) to the lamda sensors.
Before the symptoms were just as described, Rob changed a tune resistor on the ECU loom to take the lamdas out of circuit and hey presto problem solved.
Over the next 3000 to 4000 miles the car just seemed to run better and better especially at low speeds, so much so that I decided to refit the old tune resistor to try and protect the catalytic convertors. After approx 300 miles the jerking is back!!
I spoke to Mark Adams about the problem (back before LeMans trip) and from our discussions I think the only solution maybe to remap the chip on a rolling road.
Its a big expense and I am unsure whether the end result will justify the cost (especially as my old Volvo has just expired with ironically an ECU failure and have had to buy a new car). I need to speak with Mark again and get an idea of how successful the remapping is likely to be in solving this problem.
Before the symptoms were just as described, Rob changed a tune resistor on the ECU loom to take the lamdas out of circuit and hey presto problem solved.
Over the next 3000 to 4000 miles the car just seemed to run better and better especially at low speeds, so much so that I decided to refit the old tune resistor to try and protect the catalytic convertors. After approx 300 miles the jerking is back!!
I spoke to Mark Adams about the problem (back before LeMans trip) and from our discussions I think the only solution maybe to remap the chip on a rolling road.
Its a big expense and I am unsure whether the end result will justify the cost (especially as my old Volvo has just expired with ironically an ECU failure and have had to buy a new car). I need to speak with Mark again and get an idea of how successful the remapping is likely to be in solving this problem.
wixer said:
Just tried mine without vacuum attached, didn't make any difference. Think I need to consult Dom and Jamie again.
It's strange, when my car's had a little work done on the engine, it seems to be alot better i.e. smoother, then after a couple of hundred miles or so, the hunting comes back. Like you say, bloody annoying.
Same here, after putting the engine back in with new plugs, leads, cap etc it ran very smooth.
After 100 miles the old shunting at low revs is starting to come back.
Same here too.
It seems OK after some fettling but soon comes back - anything up to around 2,000 revs at consant speed seems like there is a misfire. I have a tune resistor to replace but does this fook up the cats as I though it was replacement for the existing (possibly knackered) item.
Taraka upgrade (4,000 miles ago) with cleaned injectors (500 miles ago).
It's at the point where the car is not enjoyable - so have to keep booting it to get the smile back.
FFG
It seems OK after some fettling but soon comes back - anything up to around 2,000 revs at consant speed seems like there is a misfire. I have a tune resistor to replace but does this fook up the cats as I though it was replacement for the existing (possibly knackered) item.
Taraka upgrade (4,000 miles ago) with cleaned injectors (500 miles ago).
It's at the point where the car is not enjoyable - so have to keep booting it to get the smile back.
FFG
I first started this thread after a very annoying kangaroo drive into work. On the journey home however, the little devil exhibited completely different symptoms - It simply wouldn't tick over; it wasn't erratic, it just kept trying to tick over at about 3-400 rpm. The other bizarre circumstance was that the volt meter registered a constant 0.75 volt higher reading than normal (this was independant of load eg when the fans were on or off). This suggests that something wasn't drawing the usual current. That same evening I took her out again and she behaved herself impeccably. I think my missus may have diagnosed the problem when she pointed out that the car was left out in heavy rain the day before and damp got into something electronic.
Stepper moter has been suggested above but I fitted a new one a couple of months ago.
I suspect that damp gets into the Lambda connectors underneath the chassis which in turn confuses the ECU which maybe needs resetting by switching the engine off? I dunno.
Stepper moter has been suggested above but I fitted a new one a couple of months ago.
I suspect that damp gets into the Lambda connectors underneath the chassis which in turn confuses the ECU which maybe needs resetting by switching the engine off? I dunno.
This seems a common problem, mine has exibited similar symptoms a few times.
I changed the leads, cap, rotor and plugs and everything was fine for a while (200 miles), then it came back!!
An emission check showed that the lambda reading was high, so they were changed and every thing was ok for 200 miles.
Then it came back !!!
I have changed the fuel pressure regulator and now it has done the last 1200 miles running great? and on the plugs that i took out and cleaned the last time it started running bad.
I think i found my problem? time will tell, good luck everyone
I changed the leads, cap, rotor and plugs and everything was fine for a while (200 miles), then it came back!!
An emission check showed that the lambda reading was high, so they were changed and every thing was ok for 200 miles.
Then it came back !!!
I have changed the fuel pressure regulator and now it has done the last 1200 miles running great? and on the plugs that i took out and cleaned the last time it started running bad.
I think i found my problem? time will tell, good luck everyone
Chim thread along very similar lines:
www.pistonheads.com/gassing/topic.asp?t=198177&f=8&h=0
Can't beleive so many people are suffering almost idenbtical problems - is there an inherent fault somewhere?
I've got the Griff today and it is a bitch below around 2k revs at constant or slowing speed. Makes you look like a c**t who can't drive.
Hopefully we can all have a chat at the Growl.
FFG
www.pistonheads.com/gassing/topic.asp?t=198177&f=8&h=0
Can't beleive so many people are suffering almost idenbtical problems - is there an inherent fault somewhere?
I've got the Griff today and it is a bitch below around 2k revs at constant or slowing speed. Makes you look like a c**t who can't drive.
Hopefully we can all have a chat at the Growl.
FFG
FlipFlopGriff said:
Chim thread along very similar lines:
<a href="www.pistonheads.com/gassing/topic.asp?t=198177&f=8&h=0">www.pistonheads.com/gassing/topic.asp?t=198177&f=8&h=0</a>
Can't beleive so many people are suffering almost idenbtical problems - is there an inherent fault somewhere?
I've got the Griff today and it is a bitch below around 2k revs at constant or slowing speed. Makes you look like a c**t who can't drive.
Hopefully we can all have a chat at the Growl.
FFG
Mine was the same today. A right pain in the arse on the M25 car park
It's nice to know that so many of you are having the same problems, I'll just put it down to one of its "undocumented features" and learn to live with it
The main problem today was that it was raining, so couldn't get the roof off or the windows open
How do those of you without A/C cope! mine was misting up like crazy without the aircon
With it, it was fine, just a bit chilly
>> Edited by geoffvalenti on Friday 19th August 18:35
Had another fiddle around yesterday and have made some improvements to the hunting. I swapped my Magnecors back to standard leads, reset the throttle pot (it was registering 0.36V) to 0.33V and checked the voltage across the airflow meter. It was 2.55V and I believe it should be 1.8V. Anyway, took the car out after these adjustments and it has smoothed it out. Think I'll put the OE coil back on this morning and see if that makes any difference.
wixer said:
checked the voltage across the airflow meter. It was 2.55V and I believe it should be 1.8V.
Where did you measure this? I got a varied reading of 1.77v - 3.3v for the air flow signal (blue with green trace wire), varying with engine speed (ie air flow), and a lowly value of 0.005v for the CO trim (blue with red trace wire). This value can't be right! Where did you get the 1.8v value from? RPI say 1-1.5 for the CO trim, bible doesn't seem to give a value, just saying 0.3v - 0.6v at 'rest' (idle? off?) - but I'm assuming this is the air flow signal not the (fixed value) CO trim as it it also desribed as 'rising with revs'. Can anybody help me make sense of the afm voltages please?!!
Measured my AFM at rest with the ignition on and battery voltage across the alternator @ 12.65v
Here is what I got:
-between red/blk and blue/green and I get .0312v
-between red/blk and blue/red I get .007v
Mine is 5L Pre-Serp 1994, runs Ok with a minor "feature" below 1500 at the moment.
Phil FYI.
My tune resister (standard as far as I know) is marked as 3.7K ohms and measures 3.9K on a meter.
Here is what I got:
-between red/blk and blue/green and I get .0312v
-between red/blk and blue/red I get .007v
Mine is 5L Pre-Serp 1994, runs Ok with a minor "feature" below 1500 at the moment.
Phil FYI.
My tune resister (standard as far as I know) is marked as 3.7K ohms and measures 3.9K on a meter.
griffter said:
checked the voltage across the airflow meter. It was 2.55V and I believe it should be 1.8V.
Where did you measure this? I got a varied reading of 1.77v - 3.3v for the air flow signal (blue with green trace wire), varying with engine speed (ie air flow), and a lowly value of 0.005v for the CO trim (blue with red trace wire). This value can't be right! Where did you get the 1.8v value from? RPI say 1-1.5 for the CO trim, bible doesn't seem to give a value, just saying 0.3v - 0.6v at 'rest' (idle? off?) - but I'm assuming this is the air flow signal not the (fixed value) CO trim as it it also desribed as 'rising with revs'. Can anybody help me make sense of the afm voltages please?!!
I measured the CO trim reading(ignition on). Got the info off RPI's site, 1.8V, measured warm, which I took to meaning just after switching engine off. Anyway it made no difference to the running and didn't eleminate the hunting but I have found the cure. It's the tune resistor. Whilst at the Griff Growl yesterday, myself and FFG, swapped our tune resistors for one he got from Mod Wise. Problem went away I could actually get my car to drive below 1500RPM smoothly. As a double check, I've put the old resistor back in and the hunting returned. Paul also found that his car was far better on the Mod Wise resistor. I sort of understand what the tune resistor does but is there anyone out there who could go into it in more detail??
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