Hey guys,

For those that have had to replace their Throttle (body) bodies, what were the symptoms?

So here;s what my car is doing..

Seems to run just fine after cold start up. I drive for a while on the hwy etc and its fine. Like 10 mins later when I get off the hwy, the car wants to die at every stop light, or even low speed rolling.

I can be slowing down to pull into my driveway and it will stall.

Along with the stalling is stuttering/ hesitation when I try to accelerate at low speeds. That maybe a separate issue though, but definitely seemed to get worse at the same time the car starts to chronically stall.

Idle is set at 1250 and it holds steady idle when I start it up. There is no CEL which is causing the biggest concern. Its running on MAF currently but also stalled using a MAP sensor/ Haltech tune.

I can avert the stalling by gassing it, but even then sometimes when the rpms drop to like 200 its not enough to bring it back to life.

I logged with Cipher the other day the 2 sensors in both TB and the APP. Both sensors in each overlayed and didnt show any breakup. Only caveat is that the car may not have been hot enough, as I logged right after a cold start.

Need to get this figured out soon, cuz it has to make a long road trip coming up.

Thanks!

 

Mine failed a few years ago. The only symptom I had was the engine cutting out severely when I would go WOT

 

You would be throwing a CEL and going limp if the TB were acting up. The ECU tracks the TB plate position vs pedal position (2 sensors on each) if it's anywhere it shouldn't be even by a slight amount, instant limp. it sounds more like a fueling, vacuum leak or maf issue to me.

 

str8dum1, can you log APP and TPS when it happens - do you see it jitter? I think it could still be an issue without CEL if it's a mechanical failure that's not registering via the sensor. You could disconnect your charge pipe and video it?

 

I can't fix mine as well.

We spent the whole day troubleshooting.
My car had no idle since last week, swap throttlebody and maf...nothing. Sound like the butterfly is staying shut with delayed throttle response.
Yesterday the igintion was on while we checked the gas pedal sensor, I heard a click under the dash...like a rely and all of a sudden I got rock solid idle.
Left the car overnight, no idle this moring....battery was dead, think we left a light on or something.
I had two other thottlebodies on hand. I pluged them in with out removing my own, one at the time I check what they did when my friend switched on. All did the same.
On, no movement stays closed and switch off it opens and shut.
Relearn doesn't work at all...manual and with a scanner
It's like the throttlebody isn't getting a signal

 

I havent looked at alot of logs before. Would you expect the intake cam solenoid to shut off during steady rpm? Might be coincidence but, the stumbles when the solenoids go to 0% (0*)

You can see at the end of the 1st log when i tried to give it gas to keep the car running

I didnt see any jitter of the TPS or APP.

 

No idea

What I picked up using the scanner on mine. When monitoring APP and TPS full throttle 4.6X volts only comes delay after a few seconds but using the testing function on the scanner not touching the pedal, 4.6 volts is almost instant.
Also while the scanner does the relearn idle is normal but as soon as you disconect it stumbles back down.

 

When 2 of mine failed what happened was no throttle responce and stalling.It wouldnt restart unless i took the neg cable off for a few minutes and i could drive about a mile before it would happen again.

 

not fuel, no leaks, and it did the same thing with either MAP or MAF tuning.

is there a way you could take a quick cipher log of your all your cam values along with rpm, tps, and APP?

steady cruise on the hwy like 2800ish rpms (60 in 5th or so) followed by some quick burst accelerations. Would love to see a normal baseline.

 

I should have some logs laying around somewhere. car is in the shop ATM so I can't make new ones. CSV or graph?

 

Rich,
Are you sure the idle is actually at 1250rpm...even with mine reset to 1000rpm it wouldn't stay at 1000rpm, it wouldn't "remember" that and would resort back to 650rpm. then with the cams it couldn't keep the idle up and it would stumble and bounce the idle all over, and sometimes die.

Tom

 

graph or csv is fine.

ya the idle is still 1250ish. it idles perfectly (which is nice considering the super tight double valve springs and the C8 cams). Its only i throw it into neutral for a rolling stop that it stalls out.

RcDash let me borrow a different TB. So i'll try resetting everything (APP/air idle/tps) this afternoon. IF still no dice, i'll try swapping the TB this weekend and see if that changes anything.

 

rich, i have an extra sitting here in my garage. email me and i can mail it to you to test out if you like.

 

So it seems that my TB is really sensitive to calibrations.

I was doing the TPS reset, but never when the car was hot. In the FSM is explicitly says, all these conditions need to be met, otherwise the calibration fails.

After I did the cal, the car went back to driving like normal.

20/20 hindsight cuz the car started acting up on the dyno after we pulled the stock ecu to reflash it. Then it acted up again, after I pulled the stock ecu to try my ProEFI128.

So everything seems to be back on schedule. Now i have to get used to driving this clutch again.

 

Good to hear...

 

so do the Throttle body relearn when the car is hot?

i'll make sure to remember this next time. I had some issues for a while that just resolved after quite a while.

which clutch do you have now rich? I haven't driven in about 8 months so this twin disk os giken will own me again also.

 

ya all these have to in check when trying to reset the TB

PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.

Battery voltage: More than 12.9V (At idle)

Engine coolant temperature: 70 - 100°C (158 - 212°F)

PNP switch: ON

Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine
is started, the headlamp will not be illuminated.

Steering wheel: Neutral (Straight-ahead position)

Vehicle speed: Stopped

Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/
T” system indicates less than 0.9V.
For A/T models without CONSULT-II and M/T models, drive vehicle for 10 minutes.

Im using the Spec ST twin disc. I've only driven this car less than a dozen times since I pulled the stock block in october 2009. LOL

 

dang, i feel ya on that. I'm sick that i haven't put more than 1000 miles on my car in the last year and it's not even a track car!!

what is the PNP switch?

 

Yea it's explained in the FSM, I wanted to do it one day until I saw the long list of prerequisites LOL. The big one is engine=warm and load=off.

 

Did you ever fix the issue if so how did you