Well I was looking at my vafc last night and I noticed that the TPS voltage was at .3 closed and at ,will .2 volts make that much off a difference and cause it to bogg?

 

I am new to VAFCs so I wouldn't know but hopefully someone can help you out soon dawg!

 

What? voltage ref. is 5 volts, Ill have to go back and look at my books to see what it will be at idle.

If your only getting .2-.3 volts that is terrible, youve got a reference or return problem with the tps and the computer.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EL Vap133 &raquo;</TD></TR><TR><TD CLASS="quote">I am new to VAFCs so I wouldn't know but hopefully someone can help you out soon dawg! </TD></TR></TABLE> thanx Vap.

Well as I posted before the voltage at closed throttle should be .5 and at WOT it should be 4.5 as to where mine is at .3 and 4.3 at WOT, is this enough to cause my car to bogg out when I slam the gas or launch?

 

No, that voltage sounds fine, if you were over 5 volts or 0 then yeah the comp. see's a problem.

its just looking for a range/parimeters.

 

I think it would actually. Try adjusting it and see.

What injectors are u running and what tune on the VAFC?

 

TPS Voltage should be very close to .49v @ closed throttle and 4.49v @ WOT. with a 5v reference signal

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by krustindumm &raquo;</TD></TR><TR><TD CLASS="quote">I think it would actually. Try adjusting it and see.

What injectors are u running and what tune on the VAFC?</TD></TR></TABLE>

I'm running DSM 450's and the vafc was tuned at import power house.


Modified by UNDER PRESSURE at 6:18 PM 1/23/2004

 

Was this problem present before installing the VAFC?

If no, was it present ever since the install, or just recently?

It can cause bogging problems when setup incorrectly.

 

I know nothing about the vafc or tps votlages, but from a strict electrical point of view, the computer uses that voltage to figgure out the fuel map for the injectors, so a 0.2 V difference measn the computer thinks that the car is at a lower throttle position than it is, which will make the car run leaner until the ECU picks up the problem in the mixture from the 02 sensor and corrects it. (Assuming this is done)

So taht could explain the bogging intiially, yo go lean, the ecu noticies it and corrects it.

You probably have a bad connection somwhere on the tps...Check that the ref voltage is 5 V first, if it is then start looking at any connections made in the wire, solder them again if you arent sure....a bit of resistance can make that drop.

 

To be honest I might have to say that it needs another tune cause I always had the vafc in my rex, before it was boosted it picked up fine, after I boosted it and tuned it on the butt dyno it still picked up fine, but when I had it tuned professionally it picked up okay for awhile then the bogg problem became present. Put it this way when I step on the gas pedal gradually and put it to the floor it revs up and picks up real good but when I mash the pedal to the floor it boggs as if it wants to turn off and all of a sudden rips forward like no other, I think the fuel maps need to refined to correct it when step on it.

 

i have the same setup, and my bogs a bit too, but thats mainly because ive never been on a dyno.
try to first play with the throttle settings, try setting it at 50% 51% try 90% 91% try 98% 99%

if that doesnt help try to make sure your fuel map adjustments are not rich down low and try to make the map more smooth down low wait till after 3000rpm to make any big adjustments

 

write down all the tune stuff, then try some changes.

It sounds like you have too rich (or lean, check your A/F) of maps at low RPM for high throttle, so you could try tocorrect them a little. If that doesn't help, return them to normal.

If rich then: try setting the Throttle percentage higher. If that works cool, if not return the settings.

If lean then: try throttle % lower.

I got no more ideas, so you'll have to have a pro do it if those don't work

 

I'll tell you this you know how the air fuel ratio is suppost to cruise around in the stoich section well when I first had it tuned it used to do that now it stays rich and just gets in the stoich section every once in awhile. So I think it'll be best to just get it retuned.