Running lean, the story so far...

[gmw9666]

QBee said:

IIRC the early cars with the LT77 box & GKN diff don't have one. The speedo box only came in with the T5 box & BTR diff.

A quick google and this is the best image I can find..........does look like the early ones have a sender from the gearbox.....pics courtesy of Barkychoc back in 2010

So I'm now thinking how on earth is my speedo working ok but the ECU reading ZERO

Edited by gmw9666 on Tuesday 20th October 19:22

[gmw9666]

and thank you Spend for your 2008 post

"The speed sensor on the box is only used by the Lucas Efi ECU. The sensor for your speedo is above the nose of the diff, driven by a crowned wheel at the end of the prop shaft"

that answers my speedo vs ecu question

Time to break out the multimeter again to test me thinks / clean up the connector under the car etc

[gmw9666]

Ok, sit rep from last nights multi meter activity

car jacked up and on axle stands
ecu unplugged
voltmeter attached to pin 6 and a good ground
spin the wheels and watch the voltmeter

it "should" flick between 0 and 12v as the sender pulses so I read...... but zippo, just read 0v

now I have to get dirty and shrink my hands to get at the sender / connector which is just in front of the exhaust plate (has anyone done it from above?)

So net net if this is not giving a signal to the ECU the fuel map will remain in idle map mode from what I've read......does that sound right?

I also disconnected the speed transducer on the gear box to force an error message on the RoverGauge but nothing, no error

The only thing that happened when I started the car was the lambda's read 0 in both short and long trim, ie like they were not working

Edited by gmw9666 on Wednesday 21st October 15:00

[gmw9666]

Further update......jack jacked up higher, tested the transducer connector and its definitely getting 12v on ignition but with the rear wheels being turned whilst in gear there is no voltage pulse on brown output wire of the transducer

Perhaps I'm chasing ghosts here as the car drives fine lol

[gmw9666]

davep said:

With a road speed signal of 0 Vdc or 0 mph the ECU assumes the car is stationary and will only enter idle mode when the throttle pot voltage goes below its lower threshold point. This may cause stalling. I would of expected a Road Speed Sensor error code to be set but this isn't happening.

It looks like your speed transducer is faulty, getting a new one could be a problem.

Yup, no reading of speed and no error being flagged......I even disconnect the transducer and ran the car (its on stands so just 2k rpm in 2nd gear) and it still didn't flag an error code

The gearbox mounted transducers are about 35 quid from rimmers (they offer different sizes) or a cheap 20 quid ebay option.

Next step me thinks is to remove the existing unit and test it on the bench......if still shot I can then replace with the correct size / tooth version. Its not going to break the bank.....however its a right pain to get too and I think I need to drop the exhaust grrrr

[gmw9666]

davep said:

It'll more than likely require a 20 teeth orange, and 4 or 8 pulse; good luck with that. If it was me since the speedo isn't effected and the car comes down to idle OK I wouldn't bother.

does it not tell the ECU to change maps?......

[gmw9666]

davep said:

Your RoverGauge screenshots show you are consistently running the correct map, Map 5, and not Map 0, Limp Home Map. Map 0 is used when the ECU doesn't have a tune resistor connected or the resistance value is too high and under certain fault conditions. You have no fault error codes so Map 5 it is.

Well that's saved me a job.......cheers dave lol

[gmw9666]

Well its been a while so thought I'd report back as the old girl is now all fixed and running sweet

Had recently been to see Joolz up in Chesterfield to take a look at my "lean" running first spotted on the Neil Garner Event rolling road and to see if there is anything wrong (2nd opinion) and if so look for a solution

I'm pleased to report back a problem was indeed found. The AFM I had on the car was giving the wrong voltages hence causing it to run lean. Joolz swapped the AFM for a good known one he had on the shelf which fixed the issue then set about working his magic throughout the rev range on the fuel map. Wrote me a new chip, installed, and bobs your uncle.

Net net I've now got perfect fuelling giving 257bhp @ 5000rpm and just a shade over 300ftlb @ 3750rpm ish which is pretty much bang on for a healthy 430 so really really pleased..........the driving / power / delivery feels so much sharper and more punchy, and low gear / low speed crawling is also super smooooooooth

I wasn't chasing numbers on this, just wanted a safe and strong unit..........so in short I'm one happy chappy here

Better find myself my next project now the 430 is all done lol

Edited by gmw9666 on Wednesday 2nd December 17:58