In an effort to sort out idling issues, I\'ve had the TPS off once or twice, I\'ve been adjusting the idle screw, the throttle cable tension and the screw that controls the two large butterfly valves in the TB in an effort to find a sweet spot in terms of idle speed while within the correct TPS voltages (VTA1 & VTA2 on teh PFC). The problem I have is when I get the idle speed down to the correct value, the TPS voltage readings are way down out of range. The only way I can get them within range is by adjusting the throttle cable tension, the problem here is the idle speed is over 2k rpm at this point.
In terms of refitting the TPS, can anyone tell me if you need to wind the unit around insitu before refitting the screws? The spring inside the TPS doesn\'t appear to have much tension when I put it back in place, I do seem to remember that it some spring tension was released when I removed the TPS first time around.
Any help appreciated.
CJ
From memory you do have to wind it round and fit it. Iirc you can fit the sensor so the prongs are in the correct position, then twist it so the screw holes line up and there is tension on the spring this way. Can barely remember as it was ages ago when I did mine! Have a search on the net as I remember there were comprehensive write ups on rx7club.com
Quote from: memskiI remember there were comprehensive write ups on rx7club.com
Thanks memski, found this thread which is along the same lines, looks like you have to tension up the TPS before fitting:
http://www.rx7club.com/showthread.php?t=637990
QuoteThe TPS is always under spring tension, even at closed throttle and has to be rotated on so that the tension is there.
CJ
On a related note, I reckon the reason the engine is stalling from cold is because the lower butterfly valve is too far closed - theres not enough air getting thru the TB for the engine to turn over. When i first took the TPS off some time ago, I noticed that the lower butterfly valve was very slightly open, now its completely closed regardless of wether the engine is warm or cold.
Does anyone know if the BF valve is adjustable or its it state determined by the TPS or some other mechanism? I have the TPS values within the stated thresholds, if I wind it up any more, the voltage values will be way out.
CJ
Hi CJay
You can adjust the BF with the stop screw that\'s just by the accelerator cable linkage. Sounds like you need to check your wax valve as well - it actuates the fast idle cam. I\'ve just covered this in this thread:
http://www.mazdarotaryclub.com/forums/showthread.php?t=40062&highlight=sorting+high+lumpy+idle
Once you\'ve got the BF in to a reasonable place you can re adjust the TPS.
HTH
Ian
Quote from: ianelvarYou can adjust the BF with the stop screw that\'s just by the accelerator cable linkage. Sounds like you need to check your wax valve as well - it actuates the fast idle cam. I\'ve just covered this in this thread:
Ian, I know you can adjust the 2 upper BF valves with the screw on the the side of the TB, is there a seperate one for lower valve? If so, could you point me in the right direction? I\'ve check thed therowax valve and it appears to be operating correctly when the water gets up to temperature, as far as I can see the fast idle cam is working correctly. If only I had a second FD TB knocking around for comparison purposes!
CJ
sounds like you have an air leak somewhere tbh.
Quote from: m4drxsounds like you have an air leak somewhere tbh.
Take your point madrx, I\'ve checked the rats nest etc and I can\'t find anything apparent in terms of air leaks. Whats confusing me right now is should the lower butterfly valve be very slightly open at idle? Mines completely closed, it seems that the engine is struggling to pull in enough air to keep ticking over when started from cold.
CJ
ok, if you had an air leak causing a problem it would be either the butterflys themselves or after the TB.
the lower butterfly should be open slightly as you have said i can confirm this. what i would suggest is taking the throttle body apart and putting it back together whilst comparing to another if you can get hold of one or pics of one.
i have 3 throttlebodys and one of them is powdercoated but i cannot put it on due to the butterflys leaking etc. when i first got it the butterflys etc where misaligned and had the springs the wrong way etc.
hth
Reckon I\'ll take the TB off again (5th time!) and have a good look over it, I should probably invest in another TB for comparison or replacement purposes :2Rolleyes
CJ
Quote from: CJayIan, I know you can adjust the 2 upper BF valves with the screw on the the side of the TB, is there a seperate one for lower valve? If so, could you point me in the right direction? I\'ve check thed therowax valve and it appears to be operating correctly when the water gets up to temperature, as far as I can see the fast idle cam is working correctly. If only I had a second FD TB knocking around for comparison purposes!
CJ
It\'s right by the stop screw for the upper two. Might have a rubber cap on it, so isn\'t always immediately obvious that it\'s adjustable. You\'ll have to slacked off the little nut that locks it off. Sorry I can\'t post a pic, I haven\'t got my camera handy - I think it\'s labeled in my other post though. I\'ve been chasing an idle problem with mine, and it turned out to be a rats nest hose crimped shut!