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Bad Throttle response, low vacuum 

 

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 Post subject: Bad Throttle response, low vacuum
Posted: Mon Aug 25, 2014 10:51 pm 
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Age: 31

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Joined: 21st Apr 2014

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Ride: EFII XR6

Location: Wamberal
NSW, Australia

Hey all,
Having some weird problems with my EF fairmont that have all happened at the same time, thinking that are all related to a single problem.

I have low vacuum when in gear only, 18 in/hg in P and N, but only 8 in/hg when in D
Because of the low vacuum engine thinks it's under load, so when going from D to R, car gives a massive jolt. And when going back into P revs rise to about 1800rpm then fall to normal.

There is also a massive delay in throttle response when full throttle is applied.
Usually is extremely responsive and will rev pretty much instantly, but now, whether stomping on it from a stand still or stomping on it while cruising, there is around a 2 second delay while the revs rise slowly to about 2500rpm and then it revs hard and fast just like normal after that.

I've tried searching everything I can think of but can't find any threads with the same symptoms I have.

Any advice or input is greatly appreciated!

 

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96 EFII XR6 - 4480 pacies, 100cpi 2.5" cat, lukey 2.5" exhaust, CT006845 Camtech Cam, ported t/body, Ported & polished & 50thou shaved head, pep pro stainless valves, h/duty valve springs, 10.75:1, custom CAI, 42lb injectors, Bosch 023, runs on E85, custom J3, shift kitted auto

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 Post subject: Re: Bad Throttle response, low vacuum
Posted: Tue Aug 26, 2014 10:25 pm 
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Age: 31

Posts: 11

Joined: 21st Apr 2014

Gallery: 14 images

Ride: EFII XR6

Location: Wamberal
NSW, Australia

Also when stalling up to launch off the line, will only stall to 1000rpm and won't go any higher, won't even break traction. It's really frustrating because once it reaches around 2500rpm, it really gets going, the problem seems to be in the lower revs.

 

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96 EFII XR6 - 4480 pacies, 100cpi 2.5" cat, lukey 2.5" exhaust, CT006845 Camtech Cam, ported t/body, Ported & polished & 50thou shaved head, pep pro stainless valves, h/duty valve springs, 10.75:1, custom CAI, 42lb injectors, Bosch 023, runs on E85, custom J3, shift kitted auto

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 Post subject: Re: Bad Throttle response, low vacuum
Posted: Wed Aug 27, 2014 5:38 pm 
Getting Side Ways
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Ride: el wagon

Location: melbourne
VIC, Australia

Check your timing.
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 Post subject: Re: Bad Throttle response, low vacuum
Posted: Thu Aug 28, 2014 8:43 am 
Getting Side Ways
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Ride: EF XR6 Wagon, AU2 XR6 VCT

Power: 148 rwkw

Location: Auckland
New Zealand

This may be a long shot. But it sounds like your torque convertor is trying to lock up any time the transmission is in gear, instead of just at cruise in 3 and 4 - so you would be getting basically full load from idle, and no torque multiplication. When you are up to speed, can you feel the torque converter lock up around 80-90 kmh in 4th? If not, it is probably already locked up. That could be a converter problem or an ECU problem.

But I can't think of anything else that would put that much load on the engine at idle in gear. It's not a problem with suddenly getting more air when you put it in gear, as it would inject more fuel and revs would rise to TC stall rpm. Besides, what could even do that?

Anyway, FWIW.

 

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95 EF XR6 wagon, 17" FTRs, DBA, QFM, KYB/Koni, AU block, ported EF head, SS Inductions, Territory intake, MLS gasket, milled, Franklin RH24B cam, Coby headers, no cat, Tickford 2.5", 2800rpm stall, J3 chip

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