Couple of "niggles" on my 280i
Discussion
I have a nice 280i wedge that is almost spot on now and 99.9% of the time is brilliant.
Still have 2 weird things going on.
1) When I overtake on a sharp bend (more often on a left hand bend like the exit of a roundabout) mostly when changing from 1st to 2nd (normally overtaking some numpty doing about 5mph!) the engine seems to pick up very briefly (when changing into 2nd, its fine all the way through 1st) and then die (total loss of power like no ingition or no fuel at all) only to recover less than half a second later (time enough for the front of the car to drop from accelerating to just crusing) then it is fine (usually back on a straight bit of road by then too).
Is it a combination of the 2 G forces? Cornering and accelerating? thats causing something to not be happy? maybe its a problem with an earth or similar to the engine? or could it be fuel or oil slop causing the engine issues? It might be something to do the the cange of gear de-tourquing and re-tourquing the drive train, engine etc?
Its not a major problem just annoying/embarrasing when it happens.
2) Dash Electrics/battery/alternator?.... First really noticed this at the classic Le Mans (stuck in traffic in hot weather) initially looked like overheating but took a while to sus what was going on. The temperature gauge rises and the car starts to cough/splutter will not run smoothly at tick over but will at slightly higher revs.
We eventually sused that the reason was that sat in traffic with brake lights/indicators/electric fan etc running the battery voltage was dropping and that made ALL the dash gagues overread slightly (even affects the electronic speedo!). If you put the brakes on or use the indicators you can see the battery voltage (on the dash gauge) going up/down accordingly. over a prolonged period (normally minutes) with the engine only on tickover the battery starts to drop (alternator not turning fast enough to provide a decent charge under 1000 rpm?)and that causes the engine to run rough when the volts are low enough cause issues with the ignition amp.
We have replaced the altenator and put the viscous fan back on, and this has improved things (the battery voltage recovers quicker) but not cured them, it only seems to be things that are related to the dash that cause the problem (indicators/brake lights and sidelights/dashlights) I'm wondering if i have a wiring fault in the dash area (maybe something akin to a short?) that causes these things to draw more current than they should.
Anyone seen similar problems? is it possible they are related? (i'm not convinced they are) it doesn't stop the car being used and there is no evidence of any extra heat in the dash area (as would be the case with a short) we're looking at beefing up the earths to the dash in case its an earthing issue.
Any input/help gratefully received and sorry for the long post.
Norman
Still have 2 weird things going on.
1) When I overtake on a sharp bend (more often on a left hand bend like the exit of a roundabout) mostly when changing from 1st to 2nd (normally overtaking some numpty doing about 5mph!) the engine seems to pick up very briefly (when changing into 2nd, its fine all the way through 1st) and then die (total loss of power like no ingition or no fuel at all) only to recover less than half a second later (time enough for the front of the car to drop from accelerating to just crusing) then it is fine (usually back on a straight bit of road by then too).
Is it a combination of the 2 G forces? Cornering and accelerating? thats causing something to not be happy? maybe its a problem with an earth or similar to the engine? or could it be fuel or oil slop causing the engine issues? It might be something to do the the cange of gear de-tourquing and re-tourquing the drive train, engine etc?
Its not a major problem just annoying/embarrasing when it happens.
2) Dash Electrics/battery/alternator?.... First really noticed this at the classic Le Mans (stuck in traffic in hot weather) initially looked like overheating but took a while to sus what was going on. The temperature gauge rises and the car starts to cough/splutter will not run smoothly at tick over but will at slightly higher revs.
We eventually sused that the reason was that sat in traffic with brake lights/indicators/electric fan etc running the battery voltage was dropping and that made ALL the dash gagues overread slightly (even affects the electronic speedo!). If you put the brakes on or use the indicators you can see the battery voltage (on the dash gauge) going up/down accordingly. over a prolonged period (normally minutes) with the engine only on tickover the battery starts to drop (alternator not turning fast enough to provide a decent charge under 1000 rpm?)and that causes the engine to run rough when the volts are low enough cause issues with the ignition amp.
We have replaced the altenator and put the viscous fan back on, and this has improved things (the battery voltage recovers quicker) but not cured them, it only seems to be things that are related to the dash that cause the problem (indicators/brake lights and sidelights/dashlights) I'm wondering if i have a wiring fault in the dash area (maybe something akin to a short?) that causes these things to draw more current than they should.
Anyone seen similar problems? is it possible they are related? (i'm not convinced they are) it doesn't stop the car being used and there is no evidence of any extra heat in the dash area (as would be the case with a short) we're looking at beefing up the earths to the dash in case its an earthing issue.
Any input/help gratefully received and sorry for the long post.
Norman
Number 1.
I would replace the dist cap and rotor, unless of course they are new. They are inexpensive and will eliminate them as the problem.
If it continues then the fuel system requires attention. Swirl pot filter etc. Two tanks of gas with Techron will not do any harm
Number 2.
How old is your battery? Charge it , leave for one hour, them give it a load test. If the Battery passes test then those grounds need to be checked. The hi tec way is to mega them to less than .5 ohm, but most like me, just clean 'um up and apply a bit of dielectric grease.
I would replace the dist cap and rotor, unless of course they are new. They are inexpensive and will eliminate them as the problem.
If it continues then the fuel system requires attention. Swirl pot filter etc. Two tanks of gas with Techron will not do any harm
Number 2.
How old is your battery? Charge it , leave for one hour, them give it a load test. If the Battery passes test then those grounds need to be checked. The hi tec way is to mega them to less than .5 ohm, but most like me, just clean 'um up and apply a bit of dielectric grease.
I think the dist/rotor are new (engine just having been put back in recently) but will double check.
I might run some cleaner etc down the fuel system and we are having to take it apart over winter anyway (sender not working) so will clean up and replace all the filters.
Had my Local MDC check the battery and checks out fine with 400+ cranking amps.
Gonna run some new grounds to the dash and clean up the old and see what that does.
I take your poimt ed but thats no fun...lol Its never made the car "unsafe" for overtaking just annoys me! Lets face it TVRs have plenty of spare ooomph anyway.
I did wonder if it might be the leads to the alternator being a bit High resistance too? Might have to see how easy it is to replace them as well.
Thanks for the input so far guys.
I might run some cleaner etc down the fuel system and we are having to take it apart over winter anyway (sender not working) so will clean up and replace all the filters.
Had my Local MDC check the battery and checks out fine with 400+ cranking amps.
Gonna run some new grounds to the dash and clean up the old and see what that does.
I take your poimt ed but thats no fun...lol Its never made the car "unsafe" for overtaking just annoys me! Lets face it TVRs have plenty of spare ooomph anyway.
I did wonder if it might be the leads to the alternator being a bit High resistance too? Might have to see how easy it is to replace them as well.
Thanks for the input so far guys.
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