Throttle Pot Re-Setting

[Ballistic Banana]

After recently Changing my Plenum to a larger one .
I need to reset the throttle pot. I have read up in the bible and also Badgered Tim from Act (sorry Tim) and thought I would ask on here as to not keep bothering Him.

I have replaced as it was on the old Plenum.
I have the normal 3 wires going into the POT, Red( or brown in my case) Green and Blue.

I believe you have to check the voltage between the Brown and Green on the Pot.
With the Ignition on you should get around 33mV with the throttle closed and as you open it it should smoothly go up to around 4.5 Volts.

Problem is that I am getting this reading the other way round starting at 4.5 volts and going down to 34mVolts.
The Pot is on the right way up and I believe I am testing the correct wires. so I trifle confused.
Engine runs Ok but havent tried it under load yet?? which I am wreary of doing.

Any help Ideas gratefully recieved.

BB

[joospeed]

I'm sure it's blue and green when i test them ..

[Ballistic Banana]

Ah didnt check them yet tried blue and Brown got sweet didly

Will go and check them to

Cheers Mr Joospeed

BB

[2 sheds]

Hey BB don't mind you asking me, after all you have increased my bank balance on the od occasion
Yes you must have wired it in reverse, it will still run ok but run leaner as you open the throttle.
Tim

[Ballistic Banana]

Thanks Tim

I havent unwired anything. Unscrewed from old Plenum, then screwed back on New one. Never unplugged at the connector. So someone else must have wired them wrong. Cant see the colours very well the otherside of the connector to double check but will investigate later. Unfortunatly I have kust been called into work oh weel it pays your bills Tim

Thanks

BB

[johno]

Ballistic Banana said:

After recently Changing my Plenum to a larger one .

No you haven't ..... a larger throttle butterfly perhaps, but not a larger plenum.

Further engine components lessons and mechanical understanding will be given during a long weekend to France in .... err ..... June !

[HarryW]

BB are you running a standard chip , only ask as 0.33v from the TP is right for tick over/idle position, but I thought on full throttle the pot has to reach at least 4.6V to give it full load enrichment . Could be wrong on that though do a search, ask someone that knows .
btw is it a bigger plenum you have or just the bigger throttle bodied 'standard' one

Harry

[Ballistic Banana]

johno said:

Ballistic Banana said: After recently Changing my Plenum to a larger one . No you haven't ..... a larger throttle butterfly perhaps, but not a larger plenum. Further engine components lessons and mechanical understanding will be given during a long weekend to France in .... err ..... June !

SmartArse I new what I meant.. awaiting patiently for Drunken Lesson on Engine components and on how to sit on a French Maxers bonnet to gain maximium wheelspin along with a drunken 57 old English Father

Have you picked the Soar arse up yet?

BB

[Ballistic Banana]

HarryW said:

BB are you running a standard chip , only ask as 0.33v from the TP is right for tick over/idle position, but I thought on full throttle the pot has to reach at least 4.6V to give it full load enrichment . Could be wrong on that though do a search, ask someone that knows . btw is it a bigger plenum you have or just the bigger throttle bodied 'standard' one Harry

Hi Harry,

Yes Standard chip for now ( until get funds for MA chip and RR)
Your right from 33mv(throttle closed)smoothly scaling up to around 4.5 volts is correct ( thought I wrote them figures earlier in thread)

BB

[HarryW]

Ballistic Banana said:

HarryW said: BB are you running a standard chip , only ask as 0.33v from the TP is right for tick over/idle position, but I thought on full throttle the pot has to reach at least 4.6V to give it full load enrichment . Could be wrong on that though do a search, ask someone that knows . btw is it a bigger plenum you have or just the bigger throttle bodied 'standard' one Harry Hi Harry, Yes Standard chip for now ( until get funds for MA chip and RR) Your right from 33mv(throttle closed)smoothly scaling up to around 4.5 volts is correct ( thought I wrote them figures earlier in thread) BB

BB I realise you wrote them earlier in the thread I was commenting on the figures youu gave . Saying that yes the low end is right, but IMHO the top end may be a bit low and that may not, for the standard ECU chip, invoke full power enrichment at full throttle. As i understood it to be triggered by a voltage in excess of 4.6V.

Harry

[Ballistic Banana]

Hi Harry,

Right, after now testing on my Blue and green wires I am getting 37mV and then smoothly going up to 4.68V. which seems better, I cant adjust the pot to ge it lower that 37mv its right at the end of the lots on the Pot.
I am using a Fluke Digitial Multimeter which I know have a marginal error so ,hopefully that will do nicely. do you think so?

BB

[GreenV8S]

It isn't always obvious which part is out of alignment. For example I had to cut slots in mine to get enough adjustment to set the idle voltage on the new throttle body. If you can't *quite* get the right voltage it may be worth cleaning up the slots on the throttle pot. Alternatively the problem could be that the idle stop on the throttle spindle is set too high for some reason. You may find that by winding the idle stop down, and winding the base idle adjuster up to compensate, will bring the idle position far enough back to get the right voltage. Having watched an expert set the throttle pot up I now appreciate that it is *extremely* sensitive to being set too low, if you go below 300 mv the ECU seems to throw its toys out of the pram and assume the pot is b*ggered. So do check and recheck that you still get the right reading after you've rattled the throttle around a bit.

[Ballistic Banana]

I holes for the screws/adjustment on my pot. well they are holes and not slots so no wonder I couldnt adjust it by much. I have since filled them out to give a bit more play of which I have good figures now.
I am not sure this is the original pot as it doesnt have the slots and the wire colours have varied from what people have suggested to test over.
I didnt touch the idle stop.but thanks for the pointer
Was going to take it out for a Blat, looks to busy around here and Salt lorrys are out

BB

Edited to Add, been out for a blat and all seems ok,

Thanks Guys :thumbsup:

BB

>> Edited by Ballistic Banana on Saturday 15th January 12:25

[dickymint]

Balistic - IMHO you ought not to assume the throttle cable stop is adjusted correctly. Check that the gap (top and bottom)of the butterfly plate is set correctly - It should be 0.002"-0.005" not fully closed (well thats what it should be on my Wedges).
Make a note of the original gap in case it goes breasts up!

[johno]

Ballistic Banana said:

Have you picked the Soar arse up yet?

BB[/quote]

Yes .... had a swift run to and from Norfolk at the weekend, have fitted the AP brakes and am now retiring it for the rest of the greasy season to complete a variety of jobs that need doing. Not like me I know, but too much to do and although I have done 30,000 miles in the car, I don;t need to risk it this winter having not had it for nearly 8 months last year ...

Apart from a get together in February which I'll let you know about, and yes I did take photo's of the brakes work for the site.