check your throttle maximum!!

[acannell]

90 daytona 2.5 turbo

noticed that all of a sudden my AFR's were 15+ at WOT and I could only generate 7 psi boost.

checked all my vacuum lines, everything ok
checked fuel pressure, ok
hooked up fuel pressure gauge and checked while driving under boost, ok

HMM.....

looked for gas leaks, didnt see any at pump or injectors or anywhere, didnt smell gas either

decided to check throttle position sensor (TPS)

hooked up OTC 2000 and had it output TPS voltage

it was .64V foot-off, and if i floored it it was 2.2V!!

spec says it should be about 3.5V at WOT!

noticed if I pushed realllllyy hard I could make it go up...

suddenly realized my FLOOR MAT had slipped under the throttle pedal and was severely limiting its movement

threw floor mat in back seats and tried again

now I could get 3.14V at WOT

thats STILL too low

I went under the hood to move the throttle by hand and see what the TPS had to say..

if I opened the throttle by hand as far as it would go the TPS would go up to 3.82V!

So that tells me that the throttle pedal/linkage are not moving the throttle plate far enough, and that its not the TPS sensor

I looked in the FSM for some kind of throttle adjustment, but didnt see any, and looking at the linkage, their doesnt appear to be any.

So I put a big nut under the throttle cable spacer at the pedal, and now when I floor it the throttle blade maxes out and the TPS says 3.82V.

Not sure why the pedal/linkage isnt opening the throttle all the way..do these stretch over time?

Anyways, WHO KNOWS how long I have been running at 85% throttle!!! You can set the OTC 2000 to display relative throttle position instead of TPS volts, and when I was flooring it BEFORE i added the spacer but AFTER I got rid of the floor mat, thats what it said, 85%!!! For all I know I've been running at 85% throttle when I've been flooring it for MONTHS!! This could explain all kinds of problems, like high EGT's, scan tool indicating knock, strange changes in AFR's, not to mention lack of power!!

CHECK YOURS!

[glhs727]

great advice!!

[Screamin4banger]

Quote:

Originally Posted by acannell ..do these stretch over time?

Yeah... They do.

Thats the first thing I check if the cars a real dog. I used about 3/4" worth of washers to take up the slack on an 85 duster back in 93, that was 143K on an 8 y/o car. Other cars have varied amounts of stretch. I would imagine an 18 y/o car like yours would no doubt need some slack taken out. If you can pick up a nice new factory cable you may be able to lose the nut or whatever.

I'm curious What your mileage is.

[acannell]

when i bought the car the odometer was broken at 130000+