Ignition system setting up

[martym]

Been read alot of old posts, cooling system-ignition sys etc, great reading!
I resently set my timing to 12 degrees as stated for an S2. There is a slight bit of hesitation when you rev her up, am wondering if this is the norm ??? regards throttle pot adjustment, read when most adjust it increases revs! on doing this, would then retarding ignition timing counter act increased revs ?
Or am I thinking rubbish ?
Also Flow meters, how do these control air-mixture (or not if this is case) ? Does winding screws in richen or weaken ?

[Gerald-TVR]

Hi Martin

Look here hesitation might be the 'J' shaped slot

[martym]

Gerald-TVR said:

Hi Martin

Look here hesitation might be the 'J' shaped slot

cheers for that, but mine has straight slot

[martym]

Thought my post would have generated a little tech feed back..... ?

[TJC46]

Hi martin im sure someone will come along with more detailed tech info pretty soon, as for the air flow meters mine was a 2.9 s3 1990 there were 2 no adjusting screws but i dont know if screwed in or out weakened or enriched, but be careful i had an mot failure on emissions and found that these 2 screws were unbalanced, one was slightly undone more than the other, i screwed them both all the way in and then undone each a turn at a time until the desired emission levels were attained, this was done at the mot testing station the guy was very helpful he seemed to have a genuine interest in T.V,R the car seemed to be running better after this but to be honest it was running ok beforehand. mine also had a very slight hold when you pressed the accelerator, i think there is some mod you can have done to the throttle linkage to eradicate this, Tom.:

[tozerman]

martym said:

regards throttle pot adjustment, read when most adjust it increases revs! on doing this, would then retarding ignition timing counter act increased revs ?

Hi Martin read your post with interest, there was a thread on here a month or so ago (which I can't relocate) which explained exactly how to set up your throttle pot and AFM's. You are correct in what you said above about the idle speed increasing when you set the throttle stop screw to get the pot voltage correct.
What I did was remove the pot and elongate the two holes thereby giving you a bit more scope for adjustment which means that the idle speed is now ok and I have to say it did improve the top end power/torque of the engine and improve the fuel economy at the same time.
I wouldn't use the timing to change the idle speed set the btdc figure properly and leave it alone, Good luck
Cheers.....Tony..

[martym]

tozerman said:

martym said:

regards throttle pot adjustment, read when most adjust it increases revs! on doing this, would then retarding ignition timing counter act increased revs ?

Hi Martin read your post with interest, there was a thread on here a month or so ago (which I can't relocate) which explained exactly how to set up your throttle pot and AFM's. You are correct in what you said above about the idle speed increasing when you set the throttle stop screw to get the pot voltage correct.
What I did was remove the pot and elongate the two holes thereby giving you a bit more scope for adjustment which means that the idle speed is now ok and I have to say it did improve the top end power/torque of the engine and improve the fuel economy at the same time.
I wouldn't use the timing to change the idle speed set the btdc figure properly and leave it alone, Good luck
Cheers.....Tony..

cheers Tony
when you say remove TP do you mean remove the 2 small bolts at opposite side of where stop adj screw is ? does the switch just come off when 2 bolts removed, then elongate bolt holes ?

[tozerman]

Yep, just undo the two small bolts and pull the thing off, I used a rotary file in a drill to "gently" elongate the holes, what I was finding was when the pot voltage was spot on the idle speed was too high (this was using the throttle sop screw) so having some adjustment on the pot itself means you can back off the pot so the idle speed is good and the pot voltage is spot on !!
cheers.....Tony..

[martym]

tozerman said:

Yep, just undo the two small bolts and pull the thing off, I used a rotary file in a drill to "gently" elongate the holes, what I was finding was when the pot voltage was spot on the idle speed was too high (this was using the throttle sop screw) so having some adjustment on the pot itself means you can back off the pot so the idle speed is good and the pot voltage is spot on !!
cheers.....Tony..

That makes sence, giving abit of ajustement without having to open throttle up using screw. In your opinion if TP is not set right can this cause hesitation? ?

[tozerman]

[/quote]
That makes sence, giving abit of ajustement without having to open throttle up using screw. In your opinion if TP is not set right can this cause hesitation? ?
[/quote]

Most definatley if the pot voltage (middle wire) is not between 0.6v and 4.5v that can cause hesitation in my opinion, for example full throttle enrichment does not happen until 4v is reached ! the pot tells the ecu what load you are putting on the engine and therefore what fueling is needed, also if at the other end of the scale if you are getting less that 0.6v, when you are on a light throttle you will get very little fuel at all which ( as in my case also ) can give you hesitation!
Also worth checking the basics as well like plug gaps etc.
Cheers.....Tony..

[martym]

tozerman said:

That makes sence, giving abit of ajustement without having to open throttle up using screw. In your opinion if TP is not set right can this cause hesitation? ?

Most definatley if the pot voltage (middle wire) is not between 0.6v and 4.5v that can cause hesitation in my opinion, for example full throttle enrichment does not happen until 4v is reached ! the pot tells the ecu what load you are putting on the engine and therefore what fueling is needed, also if at the other end of the scale if you are getting less that 0.6v, when you are on a light throttle you will get very little fuel at all which ( as in my case also ) can give you hesitation!
Also worth checking the basics as well like plug gaps etc.
Cheers.....Tony..

Cheers Tony...
My plugs are brand new & set as nearest damit to .75mm. I would say my hesitation prob is at low end of throttle, ie if ticking over & I press throttle, engine sort of dies of a second before it picks up. If I feed throttle very slowly, revs increase ok.

[GreenV8S]

martym said:

if ticking over & I press throttle, engine sort of dies of a second before it picks up. If I feed throttle very slowly, revs increase ok.

That is the symptoms of the throttle pot not working or out of adjustment. Does this only happen when you open the throttle from idle, or does it also happen if you abruptly open the throttle under cruise conditions?

[martym]

GreenV8S said:

martym said:

if ticking over & I press throttle, engine sort of dies of a second before it picks up. If I feed throttle very slowly, revs increase ok.

That is the symptoms of the throttle pot not working or out of adjustment. Does this only happen when you open the throttle from idle, or does it also happen if you abruptly open the throttle under cruise conditions?

I would say it car is cruising at say 3000rpm & I put foot down it picks up ok, if crawling along it tend to miss a little as revs pick up.

[tozerman]

Just found this link regarding how to set up the 2.9 V6, this should help you !
Cheers.....Tony..
http://www.haggishead.myby.co.uk/TVR/ford29diagnos...

[martym]

tozerman said:

Just found this link regarding how to set up the 2.9 V6, this should help you !
Cheers.....Tony..
http://www.haggishead.myby.co.uk/TVR/ford29diagnos...

Cheers!
I already have this printed off. I have drilled holes out on T.P & refitted it, turning it so as to increase voltage, (don`t have tester) warmed car up & I do think the hesitation when reving up on tick over has improved. I will need to drive car now to see how it feels.
cheers for your help.

[tozerman]

Be careful Martin, without a proper voltmeter you can never be certain what the actual voltage is, remember we are talking about tenths of a volt here and most digital voltmeters measure in hundreths of a volt, worth borrowing/buying a digital meter I think I paid about a tenner for mine ! good luck mate.
Cheers.....Tony..

Edited by tozerman on Saturday 13th December 21:06

[martym]

tozerman said:

Be careful Martin, without a proper voltmeter you can never be certain what the actual voltage is, remember we are talking about tenths of a volt here and most digital voltmeters measure in hundreths of a volt, worth borrowing/buying a digital meter I think I paid about a tenner for mine ! good luck mate.
Cheers.....Tony..

Edited by tozerman on Saturday 13th December 21:06

Take on board all your advice! looking at TP switch & the actual travel that it turns (approx 200 degrees)I don`t think you can actually do much harm elongating holes etc not wanting to sound clever which i am not but don`t think injection system on S2 is rocket science. Started out 20 odd yrs ago with simple carb-points cars & last yr owned a 240 bhp Astra VXR (which i would not-could not play with)