Thread: Part throttle hesitation

-WOT is fine
-foot off pedal slowing is fine.
-part throttle accel and decel there is a small amount of hesitation/missing causing faint pops in exhaust.

EDIT: Could this be caused from when I pulled the dizzy to replace oring and when i put it back together the timing is off?

-Done all this:
Wires
Plugs
new Fuel filter
reground maf
rotor button


EDIT

I figured out 2 things:

I need a better Multimeter
and
My MSD ignition box is too close to the ECU....
(thats whats been causing all the jerks/hesistation/pops.)

i just finished an avenir swap and its doing the exact same thing.

i got codes for:
- throttle position sensor malfunction
- rear O2, no activity (wasnt connected, i reconnected it and the code went away, the problem remained)
- crank angle sensor (cuz i have the wrong fidanza flywheel)
- EGR flow malfunction (no EGR on Avenir motors)
- trans position... something ( i did a B15 trans swap too, i think i hooked up the neutral sensor and reverse sensor backwars, so i disconnected one of them to keep the reverse lights from coming on in neutral)

the only one of these codes i could see affecting performance is the TPS. but i think it has more to do with the wonky idle then anything.

I'm almost 100% that a rich condition is causing the hesitation under part throttle. I wont know until i hook up my wideband though.

im thinking it is caused by one of these things:

- im running a stock fuel pressure regulator and a walbro pump. i've heard that this combo causes higher then stock fuel pressure.
- bad front O2
- the TPS problem
- possible maf problem, but i didnt get a maf code.
- the wrong tune on my ECU ( im using a nistune daughterboard, nistune overlayed the avenir fuel maps for me and compensated for the maf im running, but who knows?")

for your setup, it sounds like it is running rich too. could be also an injector stuck open as well as any of the potential problems i mentioned. cant say for sure.

will update once i learn more or fix my problem.

guess ill check the voltage on the TPS.

stuck injector should be stuck on WOT too, not just part.

Im also going to get a timing light to check it.

yeah.. i never did my timing. i just put it in the middle.

i really dont think its an ignition issue though.

is yours boosted?

im getting this problem at only like, 10-25% throttle, if i give it anymore gas it runs great. makes me think more and more that its a TPS issue...

so i fixed my part throttle hesitation problem. the little finger on my TPS was on the wrong side of the throttle body's dowel pin. therefore, it wasnt picking up any change in throttle position.

now the motor idles nice and low, however, when i give it more then 10% throttle, it dies a rich death. this is caused by the fuel maps since its not tuned. i loaded the NA maps and it would rev fine.

^ nice job

still working on mine.
I tested my TPS its reading fine at 2K Ohms.

Found a cap on the VC Tee that was lil dry rotted, so going to replace that and see if theres a difference.

you measured resistance? measure the voltage on the brown connector center (yellow) wire. it should read between 0.2 V at closed throttle and i believe just under 4 V at WOT.

the grey connector is the idle circuit. the yellow wire on the grey connector should read 12v when closed, and 0v at anything but idle.

Set to .45-.5V closed, and make sure it doesn't go over 4V at WOT.

the service manual didnt say check voltage , just resistance. unless i didnt find that yet

Coheed's diagnosis is correct - .45-.55 closed, 4 open.
Take a look on se-r.net. (Go to google and type 'tps se-r.net' and the writeup will be there on how to check).

adjust. If that doesn't work, look for a vaccum leak, and also clean your egr/bpt while doing it.

after further reading, I'd say do your tps adjustment, then do your idle/timing, and It's always a good idea to do the egr/bpt regardless of whether it's working like a champ or not!