TPS Voltage range

doug93sc

Registered User
Could low TPS voltage affect WOT Performance?

I ask because I have been trying to figure out why my car has been down on power for a long long time (can only chirp the tires from a stop). I measured the voltage last night and at idle it is at .956V and at WOT it is only at 4.13V.....now I was reading over on TCCOA that the range for WOT should be 4.3-4.8V but that was for a 5.0. Of course my service manual and EVTM do not give the specified range, thanks in advance for any help.

BTW I do have a BBK 75MM TB and I do have the holes elongated already, should I get another TPS?
 
Hi Doug,

Your TPS is right in the perfect range, as long as it varies voltage smootly from idle to wot then I would say thats not your problem.

Does you car run rich and gas mileage worse than before?

Tune up recently?

A little more info on to of it just chirps the tires off the line will help us help you :D

Did the power just go down since it has gotten hotter outside, being the m90 generates alot of heat power does go down quite a bit when hot outside.

Garett
 
Well I was just hoping that would be it.

Actually it does eat gas with higher than normal boost about 16 PSI.

It does it either on hot or cold days and has been for over the last 4 years/6,000 miles. I guess I am just used to being able to nail it at 20 mph and fry the tires. The whole story is as follows: I replaced the engine with a 94 longblock about 5 years/6500 miles ago with the 36lb injectors, As far as engine mods:
73mm C&L with 36lb sample tube and 9" cone filter
75mm BBK TB/with ported inlet plenum
AFPR
Ported "s" model
Raised top
Intercooler Fan
Ported exh. manifolds
190 LPH Fuel pump
2 1/2" high flow cats into single 3 1/2" back into 2 1/2" mufflers

Also I am running new plug wires and Autolite Double Plat's

I have agonized over this for as long as I have had the problem and I know a Tune by Dave D. would help but there is something else that is wrong that I will find eventually.



I have done to it, I have replaced almost all the sensors as they went bad
 
38 with the vacuum line on or off? OE setting of 39 with the line off should generate 55psi at WOT with 16psi boost. I would set base fuel pressure (vac line off) at 40-41 and try again. You should see a lb for lb rise with boost.

When idling with the vaccum line connected expect approx .3psi drop for every inch of idle vacuum. Most cars idle at about 32-34psi with the line on.

And then let me tune that beast. :D :p
 
Well last night I tried to adjust the AFPR and it just is not working right (pressure is all over the place, it must be no good). So I put the factory FPR back on and now at idle/line on is at 34psi and WOT/line on about 50 psi. Still no change in performance.

Yes I know you need to tune it Dave but I just can't afford it at this point,(if I could only sell my steel valve covers for $450.00 I would be set)when I do you are the only person that will do it. :)
 
Have you changed your fuel filter lately? You should be getting 55-60 psi at WOT. Also, how are you checking the WOT pressure - I used an extension hose on my fuel pressure gauge (off the fuel rail schraeder valve) and tied it to one of the wiper blades; so I could monitor it on the highway. My problems went away by changing the filter every 15,000m
 
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