Cold running & Random issues
Discussion
Been having a read through loads of posts on here covering various idle and running issues.
Hoping for some pointers on this one :-)
Here goes -
Wedge will start everytime with no real issue beside it runs lumpy when cold and needs some throttle to keep it going until warm otherwise keeps stalling.
Started the other day in garage and once warm i.e. above 80 on temp gauge ticked over good and reved freely with no issues. Tickover seemed high at 1200 ish so tightened tickover screw on top of plenum half a turn, revs dropped to 1000 ish.
Once fans come on and draw current revs drop and struggles to tickover again, only way i have stopped it cutting out is if the tickover is set to 1200 - drops to 1000 with fans on.
Managed to get out for a good hoon the other day and tickover seems to randomly change between 1500 & 900 or less.
Also if i accelerate slowly she pulls fine through the rev range but if i give her full throttle she splutters then starts pulling.
If held at constant speed 1/4 throttle @ 1500 - 2000 rpm she runs lumpy.
Once driving in this colder weather temperature gauge stays low (Up to 60 deg)
Seems to drive better at higher temps i.e. sat in garage and warm reving freely.
On last drive while at full throttle climbing a hill she died completely - No power but no ignition lights etc on, this happened a couple of times on run out but only for a split second then came back to life and pulled again.
New leads, dizzy and coil. Checked plugs and one seemed dark & black - changed and ran better.
Is it worth checking throttle pentometer voltage / setting? Checked butterfly position and set to 0.002" with feeler.
Other thoughts were temp sensors as not running at higher tickover when cold.
Sorry for all the info above but thought i would put it all down and see what anyone thinks.
Any thoughts etc would be greatly appreciated.
Hoping for some pointers on this one :-)
Here goes -
Wedge will start everytime with no real issue beside it runs lumpy when cold and needs some throttle to keep it going until warm otherwise keeps stalling.
Started the other day in garage and once warm i.e. above 80 on temp gauge ticked over good and reved freely with no issues. Tickover seemed high at 1200 ish so tightened tickover screw on top of plenum half a turn, revs dropped to 1000 ish.
Once fans come on and draw current revs drop and struggles to tickover again, only way i have stopped it cutting out is if the tickover is set to 1200 - drops to 1000 with fans on.
Managed to get out for a good hoon the other day and tickover seems to randomly change between 1500 & 900 or less.
Also if i accelerate slowly she pulls fine through the rev range but if i give her full throttle she splutters then starts pulling.
If held at constant speed 1/4 throttle @ 1500 - 2000 rpm she runs lumpy.
Once driving in this colder weather temperature gauge stays low (Up to 60 deg)
Seems to drive better at higher temps i.e. sat in garage and warm reving freely.
On last drive while at full throttle climbing a hill she died completely - No power but no ignition lights etc on, this happened a couple of times on run out but only for a split second then came back to life and pulled again.
New leads, dizzy and coil. Checked plugs and one seemed dark & black - changed and ran better.
Is it worth checking throttle pentometer voltage / setting? Checked butterfly position and set to 0.002" with feeler.
Other thoughts were temp sensors as not running at higher tickover when cold.
Sorry for all the info above but thought i would put it all down and see what anyone thinks.
Any thoughts etc would be greatly appreciated.
Hi Mate..Im afraid I'm not that experienced with the V8 workings yet but is the cold start connected?..Are the battery connections good and tight?...I had a bit of a random flat spot after driving for a while and the car would cut out and then catch again..I cleaned the AFM body internally and connections and also gave the Pivot that the flap moves on a small squirt of WD after cleaning and gently worked it back and forth until it was smooth..Might be worth testing the TPS and also the ignition amp could maybe be giving some weird running issues?..Is the connector plug on the ballast resistor secure?...Ziga
Temperature sensor could be faulty..
Have you changed the rotor arm..Is it a Lucas?...
ben420se said:
Started the other day in garage and once warm i.e. above 80 on temp gauge ticked over good and reved freely with no issues. Tickover seemed high at 1200 ish so tightened tickover screw on top of plenum half a turn, revs dropped to 1000 ish.
Once fans come on and draw current revs drop and struggles to tickover again, only way i have stopped it cutting out is if the tickover is set to 1200 - drops to 1000 with fans on.
Once driving in this colder weather temperature gauge stays low (Up to 60 deg)
New leads, dizzy and coil. Checked plugs and one seemed dark & black - changed and ran better.
Was the tick over still high after it had warmed up?...Once fans come on and draw current revs drop and struggles to tickover again, only way i have stopped it cutting out is if the tickover is set to 1200 - drops to 1000 with fans on.
Once driving in this colder weather temperature gauge stays low (Up to 60 deg)
New leads, dizzy and coil. Checked plugs and one seemed dark & black - changed and ran better.
Temperature sensor could be faulty..
Have you changed the rotor arm..Is it a Lucas?...
Edited by mrzigazaga on Sunday 5th January 13:57
I would check the basics first, honestjohn has an excellent diagnosis guide online, he has several threads on here so worth having a look.
Personally I would start by checking the throttle pot, make sure the idle setting is correct and with a voltmeter measure the voltage as you open the throttle, any jumps or spikes and it will need replacing. It's probably something really simple, usually is.
Personally I would start by checking the throttle pot, make sure the idle setting is correct and with a voltmeter measure the voltage as you open the throttle, any jumps or spikes and it will need replacing. It's probably something really simple, usually is.
Thanks for the replies much appreciated.
Battery connections are good and secure
AFM connections dont look bad, i had problems before with her cutting out and found the connection was loose, flap is smooth and feels good.
I have taken the TPS off and found broken insulation in the pic below!
Tickover still high after warmed up it never changes, would have thought it would be higher when cold and slower when warm i.e 1200 cold and 900 warm.
Rotor arm ok and lucas
Where abouts is the ignition amp and how would i test it along with ballast resistor?
Will have a look at TPS idle voltage and also clean increase to full throttle.
Battery connections are good and secure
AFM connections dont look bad, i had problems before with her cutting out and found the connection was loose, flap is smooth and feels good.
I have taken the TPS off and found broken insulation in the pic below!
Tickover still high after warmed up it never changes, would have thought it would be higher when cold and slower when warm i.e 1200 cold and 900 warm.
Rotor arm ok and lucas
Where abouts is the ignition amp and how would i test it along with ballast resistor?
Will have a look at TPS idle voltage and also clean increase to full throttle.
A useful thread: http://www.pistonheads.com/gassing/topic.asp?h=20&...
Edited by jindle on Sunday 5th January 15:30
Been here in the past and it was the throttle potentiometer. Then 6 months later started again and it was the airflow meter, 12 months later similar thing and it was the ecu. I had also replaced dissy cap, plugs, leads, coil and a little thing on the side of the distributor but cant remember what its called. I have been told in the past to disconnect the cold start injector as its not required and can also cause problems. So as you can see its not always straight forward. Biggest problems with all of these is lack of use and short journeys they just dont like it. They need to be used and abused!
Hi Ben, that old flapper system probably needs a good going over. Also it has a very wild cam installed (makes peak power at 6500 rpm!!!! ) so setting up the idle is always going to be a challenge. Good luck with it... the one I should have kept. 
Could always do you a deal.........
http://www.pistonheads.com/classifieds/used-cars/t...
Could always do you a deal.........
http://www.pistonheads.com/classifieds/used-cars/t...
Had a look at the throttle pentometer voltage today inline with the wedge epistles guide but the voltage seemed to be working backwards (Unless im missing something)!
Taken the unit off the car but still connected - Voltage read 4.28 which is close to ECU control voltage (Yellow & Green wire) OK
When turning it by hand against spring mechanism - Voltage reads from 4.28 to Zero (Yellow & Red wire)!
Put it back on car and checked voltage
- throttle closed = 2.66 volts (Had to turn unit slightly on spring to fit in screws so guess that why voltage reduced slightly to that off the car.
- throttle fully open = 0.26 volts (Surely that's working backwards to what is stated in the wedge epistles!!)
Cant be right or would not run surely!! Or am i being a muppet :-)
Taken the unit off the car but still connected - Voltage read 4.28 which is close to ECU control voltage (Yellow & Green wire) OK
When turning it by hand against spring mechanism - Voltage reads from 4.28 to Zero (Yellow & Red wire)!
Put it back on car and checked voltage
- throttle closed = 2.66 volts (Had to turn unit slightly on spring to fit in screws so guess that why voltage reduced slightly to that off the car.
- throttle fully open = 0.26 volts (Surely that's working backwards to what is stated in the wedge epistles!!)
Cant be right or would not run surely!! Or am i being a muppet :-)
It will run in its current setup but idle is rough and random missing under load or part throttle.
Thought i would start with this as butterfly position has been adjusted to 0.002" clearance plus comments about checking clean voltage increase during increasing throttle.
Just seems strange the voltage reduces to zero instead of increasing as wedge epistles state. ECU surely cant be reading this if that is the case voltage reduction would cause fuel starvation at high throttle positions due to low voltage!!
Thought i would start with this as butterfly position has been adjusted to 0.002" clearance plus comments about checking clean voltage increase during increasing throttle.
Just seems strange the voltage reduces to zero instead of increasing as wedge epistles state. ECU surely cant be reading this if that is the case voltage reduction would cause fuel starvation at high throttle positions due to low voltage!!
That's certainly not right http://www.actproducts.co.uk/2011/lucas-14cux-fuel...
It should be .32 to .34v at idle and 4.5 ish at full open throttle, follow the link above for the wiring and check
It should be .32 to .34v at idle and 4.5 ish at full open throttle, follow the link above for the wiring and check
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