Do Not Sell My Personal Information Jump to content


  • Join The Club

    Join the Lexus Owners Club and be part of the Community. It's FREE!

     

Fuel Cut, Belt Slip Or Boost Leak?


Recommended Posts

Hi Guys,

Some times when I accelerate (mostly when I floor it) i get a pause when the engine is at about 2.5-3k rpm. It feels like the traction control has just kicked in, but obviously without the light coming on. If I lift off and then on again slowly the engine speed will increase and I get power back.

Problem is that I'm not sure what is causing this - could be fuel cut or belt slip. The FCD is on 9 and engine revs all the way up to the limiter. The tensioner is all the way to the right if looking toward the car from the front, so cannot tighten any more but the belts were 2nd hand and ive just taken delivery of 1 5pk800 and 1 5pk780 belt.

If it helps the power loss seems to come in more often the more people i have in the car. Sometimes the car judders as well. Anybody have any pointers/ideas?

Hope that made some sense. Cheers,

Ed

Link to comment
Share on other sites

Sounds to me like your leaning out the engine a tad, which is a problem with the FCD cause it gives a percentage right through the range, rather than just a ceiling like the black box,

I'd suggest trying setting 10 first, and if you dont hit the fuel cut at the top it should be better,

Link to comment
Share on other sites

Stav - i had the FCD on 10 and moved it to 9 to try and fix the problem.

Bazza - i was also thinking clutch but the revs don't rise when i feel like i've lost power. It just kind of sits at 2,750ish (when torque starts to come in) untill i lift off and then on again. If i lift off and then floor it, it does it again most times. I am planning a new clutch soon as the pedal is v high.

When the car judders it feels more like power surge - power loss - power surge - power loss: which was why I thought it could be belt slip I:e boost - no boost - boost - no boost etc.

Link to comment
Share on other sites


Hi Guys,

Some times when I accelerate (mostly when I floor it) i get a pause when the engine is at about 2.5-3k rpm. It feels like the traction control has just kicked in, but obviously without the light coming on. If I lift off and then on again slowly the engine speed will increase and I get power back.

Problem is that I'm not sure what is causing this - could be fuel cut or belt slip. The FCD is on 9 and engine revs all the way up to the limiter. The tensioner is all the way to the right if looking toward the car from the front, so cannot tighten any more but the belts were 2nd hand and ive just taken delivery of 1 5pk800 and 1 5pk780 belt.

If it helps the power loss seems to come in more often the more people i have in the car. Sometimes the car judders as well. Anybody have any pointers/ideas?

Hope that made some sense. Cheers,

Ed

I get the same sometimes and i have the silver ecu from TTE, the pause happens at exactly 3k and the shudder is more towards WOT.

it is not clutch slip

Link to comment
Share on other sites

Asi - Not fitted the 780 belt yet literally took delivery of it while writing orig post.

Rob - WOT = Wide open throttle??

Steve - Boost gauge not fitted - was thinking of fitting it on Saturday (or maybe that not the done thing at shows? :lol: )

Link to comment
Share on other sites

My car does the same thing sometimes and I’m pretty sure it’s caused by the slipping belt. I think it only happens when the rpm is low and the bypass valve is completely shut.

I tried closing the bypass valve by hand, in idle, and the belt is obviously slipping a bit before regaining grip.

Please wait a few seconds for Video to Load!

Yesterday I picked up a 790 belt but I wasn't able to fit it. I will get an 800 belt tomorrow and then I'll use some anti belt slip (no idea what it's called in English) on the pulley. My current belt is 803 and the tensioner pulley is all the way to the right.

Link to comment
Share on other sites

Asi - IIRc dump valve noise is boost pressure releasing due to the bypass not opening quick enough when you lift off. As the SC is running and the throttle is closed the boost pressure has nowhere to go so escapes out of the hoses i think - hence the dump valve noise. I only get it when at full throttle in too high a gear and then lift off.

I'd suggest giving the bypass vlave a good oiling.

I'm assuming the sort of grinding noise at high revs when you change is normal as a few Youtube clips have this too.

Link to comment
Share on other sites


Patrick i think you may be right i'm going to try and fit my new 800 belt (which then leaves the assumtion that these belts strectch if it works) before Japfest and see if it helps - otherwise another job for Saturday lol along with fitting new IK22s and boost gauge.

Link to comment
Share on other sites

right thanks. it always happen when i change gear when at high revs. i have 5pk788 belt and 5pk800 so will fit once i get my new engine in.

Mine did that as well. I thought it sounded great until I let my girlfriend rev my car with the bonnet open, then I realized it was actually a sqeek when the throttle was released. I tightened my belt as hard as I could and the sound disappeared :)

Link to comment
Share on other sites

when fitting the belt remove the tensioner put belt on the compressor and then refit the tensioner with the belt on it already then install the mounting bolt - it is so much easier and takes less time

Link to comment
Share on other sites

Latest Deals

Lexus Official Store for genuine Lexus parts & accessories

Disclaimer: As the club is an eBay Partner, The club may be compensated if you make a purchase via eBay links

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share






Lexus Owners Club Powered by Invision Community


eBay Disclosure: As the club is an eBay Partner, the club may earn commision if you make a purchase via the clubs eBay links.

DISCLAIMER: Lexusownersclub.co.uk is an independent Lexus forum for owners of Lexus vehicles. The club is not part of Lexus UK nor affiliated with or endorsed by Lexus UK in any way. The material contained in the forums is submitted by the general public and is NOT endorsed by Lexus Owners Club, ACI LTD, Lexus UK or Toyota Motor Corporation. The official Lexus website can be found at http://www.lexus.co.uk
×
  • Create New...