20V BT BOGGY UNDER 4K

slootmaker1
Posts: 3
Joined: Fri Feb 26, 2016 8:50 pm

20V BT BOGGY UNDER 4K

Postby slootmaker1 » Mon Jan 15, 2018 8:13 pm

I have an issue with my blacktop 20v boggy down under load on full throttle between 2500 and 3500 rpm, Once it hits 3500 the engine regains power slowly and at 4000rpm it pulls hard til redline. I'm running stacks and tomei poncams. I don't believe its a fuel issue since it pulls hard to redline. I've checked the timing. The engine idles smooth. It's been suggested that might be the powerband but it doesn't feel right at all. I have driven it with the vvti solenoid disconnected and top end of the powerband is noticeably slow but the low end is slightly better. Has anyone had an issue like this before? Any advice would be greatly appreciated! :?

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totta crolla
Club4AG Expert
Posts: 487
Joined: Tue Mar 26, 2013 5:21 am
Location: Oxford U.K

Re: 20V BT BOGGY UNDER 4K

Postby totta crolla » Tue Jan 16, 2018 2:39 am

What is the spec. of the cams and ecu ?

jdm86gtz
Club4AG Expert
Posts: 300
Joined: Fri Jan 11, 2013 10:13 pm
Location: Ireland

Re: 20V BT BOGGY UNDER 4K

Postby jdm86gtz » Tue Jan 16, 2018 5:22 am

The blacktop VVT operation is off at low rpm, on during mid rpm and off again at high rpm (your cam spec will determine what your engine prefers), unlike the silvertop that is off below 4400rpm(ish) and on above that rpm.
Check for fault codes, make sure the throttle position sensor is set within spec.
Also I found the 20Vs to be fussy about the O2/Lambda sensor.

slootmaker1
Posts: 3
Joined: Fri Feb 26, 2016 8:50 pm

Re: 20V BT BOGGY UNDER 4K

Postby slootmaker1 » Wed Jan 17, 2018 5:20 pm

totta crolla wrote:What is the spec. of the cams and ecu ?


Factory ECU. The Tomei Poncams are the max i could go with stock valvetrain. After speaking with the previous owner the car it did the same thing with the factory camshafts.

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slootmaker1
Posts: 3
Joined: Fri Feb 26, 2016 8:50 pm

Re: 20V BT BOGGY UNDER 4K

Postby slootmaker1 » Wed Jan 17, 2018 5:36 pm

jdm86gtz wrote:The blacktop VVT operation is off at low rpm, on during mid rpm and off again at high rpm (your cam spec will determine what your engine prefers), unlike the silvertop that is off below 4400rpm(ish) and on above that rpm.
Check for fault codes, make sure the throttle position sensor is set within spec.
Also I found the 20Vs to be fussy about the O2/Lambda sensor.



Thank you for the info. There are no fault codes and i haven't checked the tps sensor yet. I dont have any noticable exhaust leaks before the o2. The previous owner said it did the same thing on with factory camshafts. The wiring to the o2 wasn't done very well (but connectors) so i'll address that as well.

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