GM Reduced Engine Power Mystery Solved - Throttle Position Sensor Faulty ( Possibly)

#1
I've just stumbled on this video on youtube.

Could be a useful bit of info for the forum.

Not sure this has been mentioned before on here.



Might give this a go myself, You know with age related wear, it might be worth renewing. For better throttle response
 
#2
you will find the z22se throttle body doesn't come apart that easy you basically have dig the side cover off with a screwdriver the part with the brushes is micro welded to the spindle so you have to remove throttle flap to pull that out might be easier just to get another throttle body
 
#3
Well due to the age of these vehicles they are becoming more rare to find at the scrapyards/breakers. So it is becoming harder to just replace the throttle body . and with another body that is potentially between 10 - 20 years old.

I drive the vectra b and the last few breakers yards i've been to, they say that they don't get them in anymore.

The vectra B and C have different mounting bolt areas so they are not quite the same. Got the same idea but not quite same shape.

I do not know the difference with Astra's Zafira's etc. The guy in the video is basically saying people are unnecessarily replacing the full throttle body.

When all you have to do is replace the black plastic side part. called a throttle position sensor kit. As the guy in the video points out it is the fingers that slide on the variable resistor, That are faulty, triggering reduced engine power.

After dismantling the whole body he finally identified this as the problem.

So rather than meddling with the accelerator position sensor, Which some people have done. Without any joy

https://z22se.co.uk/threads/pathetic-throttle-response-causes-solutions.28791/#post-1259134

This could be the answer. I see that Graham2704 has a 2.2 direct with a poor throttle response which has no "go" in it anymore.

I would say there could be a connection here that needs further investigation

It would be interesting at least to open it up and see how it looks :peeking:.
 
#4
sorry if it sounded like I was saying not to have a go I don't know the difference between the throttle body's I have changed all those parts. about 10 year's ago I bought a 2.4 inlet plus throttle body the inlet ended up in the shed but I tried to fit throttle body. the car would never start so I stuck multimeter on the two throttle body's and found they were different. so I bought a second hand 2.2 throttle body and changed circuit board plus that part with the fingers. that part was welded to spindle so I had file of welds to remove it and then get it lazer welded back on new spindle .it probably is the problem but the 2.2 and 2.4 throttle body I have didn't come apart that easy
 

evocarlos

Stupid Bollocks
Staff
#5
the z22se tb is a sealed unit and once you pop the cover theres not much to do inside unless you have the ability to apply the carbon resistive strip on the pcb that makes up the 2 tps sensors
there are always options you can still get new tb's altho the new one i bought was from an ls4 and has a 76mm blade
i bet you could convert to the 2007 z20net 6pin tb if there was a shortage in supply :)
 
#6
the problem I have with the 2.4 throttle body I converted is that when I start it cold the engine goes nuts even abs light comes on but if start it with 2.2 throttle body once the revs come down and swap them over It drives lovely can leave it off 2 to 3 hours will start normally but first thing in the morning it goes nuts again
 
#7
think i have 3 or 4 spare throttle bodies now?
as the 2.4 has a larger butterfly than the 2.2 the ecu struggles to set desired idle speed as its getting more air flow for same opening of throttle. this leads to the ecu over correcting the throttle. opening to far then shutting to much and repeating.
no idea if this can be mapped out or not?
 

evocarlos

Stupid Bollocks
Staff
#9
the same issue is present in the base map for the supercharger builds with the LSJ throttle body, it has a 67mm blade and on cold start the rpm bumps upto 2000rpm and not 1500 and as the the tb is linked to the abs pump thru canbus when there is a problem with the the tps signals the ecu request 0 torque shutting the tb down then relying on ignition timing to run in limp mode
once mapped the P code error and lamp never return
 
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