Severe power loss.....please help!! - Toyota Nation Forum : Toyota Car and Truck Forums

borboyous · 08-09-2005, 09:00 AM

Hi all,
had this prob for a little while now, even though the car has been fully serviced, the power drops off SEVERELY at the 4200 rpm mark, it makes a sound like its either backfiring or injectors are not working properly? Any ideas?

Thanks!

JekylandHyde · 08-09-2005, 09:44 AM

4200 rpms = TVIS opens
Maybe your TVIS is not opening.
Is this a turbo MR2?

http://www.mr2-tech.com/bgb/mechanic..._system/26.htm

borboyous · 08-09-2005, 09:52 AM

Yeah '90 turbo model. What does the tvis do?

JekylandHyde · 08-09-2005, 09:55 AM

Your engine has 16 valves. 8 of them are for the intake.
Below 4200 rpms, the TVIS is closed which means air is not getting to 4 of them.

With air being restricted, the engine pulls harder offer more low-end torque.
This give you good low-end spunk around town ... when you get on the gas and start revving the engine out, the TVIS opens at 4200 to allow the increased air flow that you would want.

That is when all 8 intake valves start singing and you can feel a jump in power.
If yours are not opening, your car will be pathetic above 4200 rpms.

borboyous · 08-09-2005, 10:01 AM

Well done that man! I will look into it tomorrow cos its 1am here lol

borboyous · 08-11-2005, 12:18 AM

Hi there!
How the F..... are you supposed to check that TVIS VSV sensor thing? I can't even get anywhere near it! Anyone got any hints etc? Also is there a part number anyone can give me for it so I can price it up?

Thanks