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flat spot when under load after head swap 

 

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 Post subject: flat spot when under load after head swap
Posted: Thu Jan 08, 2015 1:04 pm 
Oompa Loompa
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Age: 32

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Ride: 5.0L eb fairmont ghia, xe ute

Location: gold coast
QLD, Australia

I recently cracked the head on my xh longreach so i replaced the head with a complete au tickford non vct head including cam and rocker gear it seems to run quite good until you put it under load like going up a hill or in a high gear it gets a flat spot like its starving for fuel do i need to change to a xr6 fuel regulator or adjust timing to suit the tickford cam.
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 Post subject: Re: flat spot when under load after head swap
Posted: Thu Jan 08, 2015 2:11 pm 
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Ride: falcon ba futura

Location: auckland
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Has the head been skimmed? i remmember it being an issue on the E series if more than .010 inch was taken off the anti knock sensor would kick in and retard the timing. you can get thicker gaskets for them now but it used to be a real issue in the eary days
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 Post subject: Re: flat spot when under load after head swap
Posted: Thu Jan 08, 2015 2:45 pm 
Oompa Loompa
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Ride: 5.0L eb fairmont ghia, xe ute

Location: gold coast
QLD, Australia

yes the head was skimmed but im not sure by how much and i used an au mls head gasket which i think are thinner than e series graphite gasket so do i need to advance the timing a bit to stop this happening
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 Post subject: Re: flat spot when under load after head swap
Posted: Thu Jan 08, 2015 3:30 pm 
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Possbly,tho the problem was due to the sensor detecting pre-ignition due to higher compression, advancing timing may just cause the sensor to try and offset it.maybe this is where you need an ecu mod. Be intresting to find out.
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 Post subject: Re: flat spot when under load after head swap
Posted: Thu Jan 08, 2015 3:55 pm 
Getting Side Ways
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Ride: 96 EL XR6

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Disconnect the knock sensor and go for a run, will run fine without it, will just put a code in the ecu saying its faulty, many people run without them, ~ Simplest way to find out.

I had my head skimmed .30 thou and put an AU MLS gasket in and had no problems, went like a cut snake compared to before, amazing how the small boost in compression made such a difference.

 

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EL XR6, T5 Speed - Full Factory Fitted Tickford Body Kit, AU Engine, Billet Camtech 845 Cam, J3 Chip, MLS Gasket, Intake, Extractors, High flow cat, 2 1/2in exhaust, K&N Air Filter, 3.45 LSD, - My Pride and Joy

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 Post subject: Re: flat spot when under load after head swap
Posted: Thu Jan 08, 2015 6:43 pm 
Fordmods Newbie
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Whats the j3 chip i see mentioned sometimes?
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 Post subject: Re: flat spot when under load after head swap
Posted: Fri Jan 09, 2015 12:59 pm 
Oompa Loompa
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Age: 32

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Joined: 27th Feb 2012

Ride: 5.0L eb fairmont ghia, xe ute

Location: gold coast
QLD, Australia

tried disconnecting the knock sensor and it made it worse looks like i might have to change the fuel reg to an xr6 one and also get a j3 chip to give it a xr6 tune.
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 Post subject: Re: flat spot when under load after head swap
Posted: Fri Jan 09, 2015 2:01 pm 
Getting Side Ways
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Ride: EF XR6 Wagon, AU2 XR6 VCT

Power: 148 rwkw

Location: Auckland
New Zealand

XR6Chris wrote:
Whats the j3 chip i see mentioned sometimes?


A little light reading for you :D
off-topic-f6/tuning-your-falcon-with-a-t-i-performance-j3-chip-t68577.html

By far the best money I spent on my EF XR6.

TI Performance provided excellent service (before and after sale). There are other suppliers as well.

 

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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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 Post subject: Re: flat spot when under load after head swap
Posted: Fri Jan 09, 2015 2:42 pm 
Getting Side Ways
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Ride: 96 EL XR6

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mad351 wrote:
tried disconnecting the knock sensor and it made it worse looks like i might have to change the fuel reg to an xr6 one and also get a j3 chip to give it a xr6 tune.


If it ran worse id say it's doing its job and is retarding the timing when it's connected to try and achieve a "safe point"

Check your timing, your possibly too far advance for the slight boost in compression, it should run fine on the standard computer and fuel reg, 300kpa reg over fuels them, my XR made more power going from 300kpa to 270kpa on the standard XR tune, (no I don't have Dyno sheets sorry)

Also check the balancer hasn't spun, will give you a false reading of the timing if it has.
Make sure you put the ecu into diagnostic mode when setting/checking the timing, otherwise it will be severely retarded if you set it to TDC without being in Diag. Mode.

You havnt accidentally let the chain slip a couple of teeth on the cam sprocket?? At TDC compression stroke the cam mark should be around 3mm above the right hand side of the head.

 

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EL XR6, T5 Speed - Full Factory Fitted Tickford Body Kit, AU Engine, Billet Camtech 845 Cam, J3 Chip, MLS Gasket, Intake, Extractors, High flow cat, 2 1/2in exhaust, K&N Air Filter, 3.45 LSD, - My Pride and Joy

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 Post subject: Re: flat spot when under load after head swap
Posted: Fri Jan 09, 2015 2:53 pm 
Getting Side Ways
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Age: 23

Posts: 461

Joined: 31st Mar 2013

Ride: 96 EL XR6

Location: Hervey Bay
QLD, Australia

If the above checks out fine, I'd be next throwing a fuel pressure guage on it to check fuel pressure, condition of the pump itself and check valve. Replace your fuel filter too if it has not been done recently.

 

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EL XR6, T5 Speed - Full Factory Fitted Tickford Body Kit, AU Engine, Billet Camtech 845 Cam, J3 Chip, MLS Gasket, Intake, Extractors, High flow cat, 2 1/2in exhaust, K&N Air Filter, 3.45 LSD, - My Pride and Joy

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 Post subject: Re: flat spot when under load after head swap
Posted: Sun Jan 11, 2015 2:10 pm 
Oompa Loompa
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Age: 32

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Ride: 5.0L eb fairmont ghia, xe ute

Location: gold coast
QLD, Australia

if the chain was out a couple of teeth or even 1 tooth wouldnt it be running pretty rough or not wanting to run at all
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