Resetting the distributor
Discussion
Hi I removed my distributor on my 2.9 S2, to try and trace an oil leak at the back of the V, having carefully scratched dist and block to mark position.
While it was out I decided to put a pop mark on the edge of the block where the scratch was to make it easier to see when I came to put it back together. Centre pop in place - tap - and a section of the raised lip where the dizzy hole has been spot faced breaks off taking my scratch mark with it! Can’t find the piece. I replaced the dist with the rotor lined up by eye on No 1 and then turned it back and forth until it seems to run ok.
I disconnected the throttle pot and used a strobe to set the spark to 12deg BTDC, with tickover approx 900, (I tried disconnecting the idle control valve as well but tick-over became so rough it was impossible to set the timing mark in one place - so I had to reconnect it, and I was surprised that even with the throttle pot disconnected the timing still advanced when the engine was revved as I thought the “limp home mode” had fixed timing).
When the throttle pot is reconnected the timing at tickover drops back to 9deg BTDC.
The engine runs and pulls well but seems to have lost a bit of the aggressive edge to the acceleration.
Can anyone suggest what I may have done wrong.
I have found a number of postings which suggest that setting the timing is a big issue as the ECU tries to correct it giving spurious results using a strobe, and the bible says it should be done by a specialist using exhaust gas analysis, but surely it cant be that difficult to get the dizzy back in the right place.
PS. Getting to the dist clamp bolt is a bit tricky isn’t it
While it was out I decided to put a pop mark on the edge of the block where the scratch was to make it easier to see when I came to put it back together. Centre pop in place - tap - and a section of the raised lip where the dizzy hole has been spot faced breaks off taking my scratch mark with it! Can’t find the piece. I replaced the dist with the rotor lined up by eye on No 1 and then turned it back and forth until it seems to run ok.
I disconnected the throttle pot and used a strobe to set the spark to 12deg BTDC, with tickover approx 900, (I tried disconnecting the idle control valve as well but tick-over became so rough it was impossible to set the timing mark in one place - so I had to reconnect it, and I was surprised that even with the throttle pot disconnected the timing still advanced when the engine was revved as I thought the “limp home mode” had fixed timing).
When the throttle pot is reconnected the timing at tickover drops back to 9deg BTDC.
The engine runs and pulls well but seems to have lost a bit of the aggressive edge to the acceleration.
Can anyone suggest what I may have done wrong.
I have found a number of postings which suggest that setting the timing is a big issue as the ECU tries to correct it giving spurious results using a strobe, and the bible says it should be done by a specialist using exhaust gas analysis, but surely it cant be that difficult to get the dizzy back in the right place.
PS. Getting to the dist clamp bolt is a bit tricky isn’t it
hi your distributor problem has helped me fix my emission problem setting the distributor is in the bible strait forward. but will need to go on a gas emission tester turning distributor until correct reading is made i have tried for months to get my emissions right after setting the timing to the timing marks i only twiged when i read your post and set it up at mot center today we learn new things every day
hi do not know the answer but i set distributor static line up timing marks on the pully setup distributor as said in the book page 81 on. turn distributor with ignition on when you hear or see a spark nip it up timing should be near enough to run engine to have the gas anliser set fine ajustment
william weir said:
hi your distributor problem has helped me fix my emission problem setting the distributor is in the bible strait forward. but will need to go on a gas emission tester turning distributor until correct reading is made i have tried for months to get my emissions right after setting the timing to the timing marks i only twiged when i read your post and set it up at mot center today we learn new things every day
Slightly confused by this, surely the only control of the fueling is by adjustment of the AFMs. I checked my timing by strobe and it was correct, then adjusted the AFMs to the correct CO. It was a bit tricky as the diy Gunson meter is affected by the volt drop when the fan cuts in. Can't see how you an get the fueling right by adjusting the timing. Anybody out there to enlighten us?I am glad it worked for William but I can’t see how it is possible to set the ignition timing by measuring emissions. Do you turn the dist until you get minimum emissions, or until emissions are at mid point in the range?
Ideally I would like to set the ECU to service mode but I don’t have a fault reader and my local garage couldn’t get theirs to talk to my ECU.
I found that unplugging the throttle pot lets you set the ignition timing close enough for the car to be fully usable but the ECU still tries to fiddle with the timing while you are setting it, and stops you being very accurate, and in my case the car seemed a little less eager on acceleration afterward.
I found a diary post by Deadpineapple where he suggested cutting the spout (spark out) lead to the distributor to set the base timing (and fitting a connector).
As this wire (blue/red, second one down from the top on the distributor connector plug , from ECU pin 36) is screened I was reluctant to cut it. But by removing the red locking strip it is possible to pull this one connector out of the plug, a bit of tape round the bare end and put the plug back in the dizzy. Start the engine again and the timing mark is dead steady under the strobe and doesn’t change with revs or temperature.
Found that 12deg BTDC set with the throttle pot disconnected = 6 deg BTDC with spout disconnected
Reset it to exactly 12 deg BTDC. Put the spout connector back in the plug (its a bit of a fiddle getting it back through the rubber seal in the back but it will go). And off for a test drive. Spot on and all the acceleration is back. Problem solved.
Ideally I would like to set the ECU to service mode but I don’t have a fault reader and my local garage couldn’t get theirs to talk to my ECU.
I found that unplugging the throttle pot lets you set the ignition timing close enough for the car to be fully usable but the ECU still tries to fiddle with the timing while you are setting it, and stops you being very accurate, and in my case the car seemed a little less eager on acceleration afterward.
I found a diary post by Deadpineapple where he suggested cutting the spout (spark out) lead to the distributor to set the base timing (and fitting a connector).
As this wire (blue/red, second one down from the top on the distributor connector plug , from ECU pin 36) is screened I was reluctant to cut it. But by removing the red locking strip it is possible to pull this one connector out of the plug, a bit of tape round the bare end and put the plug back in the dizzy. Start the engine again and the timing mark is dead steady under the strobe and doesn’t change with revs or temperature.
Found that 12deg BTDC set with the throttle pot disconnected = 6 deg BTDC with spout disconnected
Reset it to exactly 12 deg BTDC. Put the spout connector back in the plug (its a bit of a fiddle getting it back through the rubber seal in the back but it will go). And off for a test drive. Spot on and all the acceleration is back. Problem solved.
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