Strange one,
The car (rev2 turbo) is well maintained, will good fairly recent plugs, ht leads, cap n arm, walbro fuel pump etc. Running good afr's and runs well.
The coil was a couple years old and died on me a week friday. No running problems prior to this. I replaced the coil and ignitor and now it loses throttle. Tried another coil and ignitor and no difference. Even added earths to them and still the same.
What I mean by loss of throttle is, I can be on light throttle, wot or cruising and it just starts engine braking, which is vicious if you're boosting and can snap back on power making the car unstable. If you press the clutch the engine idles perfectly but no matter what throttle input with the pedal the engine remains at idle, If the engine is still engaged with the drivetrain and give it throttle the turbo still boosts and the bov still blows off (recirculated ssqv) but no power.
When it first started doing it, it would stay with no power until you let off the throttle and reapplied it, but it seems to be getting worse and this no longer works to bring it back to drivable. I can drive it and it never faults, other times its every time I apply throttle, lightly still in vac or boosting. It used to cut on partial throttle (spooling)every time at 4k revs for some reason, that was the only reoccuring thing I found to recreate it.
Turned ebc off so running 0.8bar but boost or vac it still faults.
Removed the ecu and looks perfect inside, with the tps disconnected it still revs up so I don't think it's related.
I'm just a bit baffled.
It just cuts in and out like a switch no missing or pops n bangs, cuts exactly like overboost, fuel cut.
Anyone experienced anything like this?
Any help appreciated
loss of throttle on rev2 turbo #updates#
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loss of throttle on rev2 turbo #updates#
Last edited by mrturbotom on Sat Apr 26, 2014 7:32 pm, edited 1 time in total.
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Re: loss of throttle on rev2 turbo #updates#
Usual first question:
Error codes?
Error codes?
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Re: loss of throttle on rev2 turbo #updates#
Peter Gidden - SBITS wrote:Usual first question:
Error codes?
I'll recheck it
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Re: loss of throttle on rev2 turbo #updates#
It hadn't logged codes. Been to work and back. It's faulted on my journey. Read codes and none stored
Re: loss of throttle on rev2 turbo #updates#
It'snot a mechanical issue with the cable itself is it tom?
Does it to it if you manually actuate the throttle, or is only under load when driving?
Does it to it if you manually actuate the throttle, or is only under load when driving?
Re: loss of throttle on rev2 turbo #updates#
It'snot a mechanical issue with the cable itself is it tom?
Does it to it if you manually actuate the throttle, or is only under load when driving?
Does it to it if you manually actuate the throttle, or is only under load when driving?
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Re: loss of throttle on rev2 turbo #updates#
madmr2man wrote:It'snot a mechanical issue with the cable itself is it tom?
Does it to it if you manually actuate the throttle, or is only under load when driving?
No the pedal cable is fine. You can make the bov blow off consistently as you pump the pedal until it springs back to life. And the boost gauge shows the vac difference of throttle open and closed.
But it'll idle smoothly uneffected by my throttle input.
The afr snaps from say 13:1 to the gauge max of 22:1 as quickly as the power snaps off. So no splutter lean out, if you get what I mean
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Re: loss of throttle on rev2 turbo #updates#
From what you've said AFM would be first suspect.
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Re: loss of throttle on rev2 turbo #updates#
And get rid of the aftermarket bov as your running a AFM.
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Re: loss of throttle on rev2 turbo #updates#
markstevieandmads wrote:And get rid of the aftermarket bov as your running a AFM.
Makes no difference, its recirculated anyway
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Re: loss of throttle on rev2 turbo #updates#
Peter Gidden - SBITS wrote:From what you've said AFM would be first suspect.
Picked another up yesterday. I'll try it tomorrow and post what I find
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Re: loss of throttle on rev2 turbo #updates#
Fitted the afm but my car is 2 deep on the drive so road test tomorrow hopefully
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Re: loss of throttle on rev2 turbo #updates#
A friend had a good running turbo but carried out a rev3 conversion so got a few parts off him.
Fitted the afm, fuel pump relay and resistor, coil and ignitor again.
Added extra earth cabling to the engine.
Its exactly the same,
I had a good drive for testing rather than driving to get somewhere, it does it at 3800rpm in every gear, every time it gets there, it'll start to engine brake (22:1 afr, no popping or overfuel smoke) and i can't get it to hold there as soon as the rev changes it comes back to life on this occasion.
Only other fault the car has which it just started to do before it broke down is the dash boost gauge is showing its maxed out.
It is unplumbed and my greddy fcd is disconnected.
The gauge goes to the first line (atmospheric pressure line) with ignition on which is were it used to stay (one day started going up and down on its own) but as soon as you start the engine it maxes out, just as if the map sensor is unplugged.
Good earth to its brown wire, 4.9v at the left wire, nothing on the middle wire ignition on, start engine and both the left and middle wire are 4.9v.
Not sure if this is related in any way.
Any further advice welcome
Fitted the afm, fuel pump relay and resistor, coil and ignitor again.
Added extra earth cabling to the engine.
Its exactly the same,
I had a good drive for testing rather than driving to get somewhere, it does it at 3800rpm in every gear, every time it gets there, it'll start to engine brake (22:1 afr, no popping or overfuel smoke) and i can't get it to hold there as soon as the rev changes it comes back to life on this occasion.
Only other fault the car has which it just started to do before it broke down is the dash boost gauge is showing its maxed out.
It is unplumbed and my greddy fcd is disconnected.
The gauge goes to the first line (atmospheric pressure line) with ignition on which is were it used to stay (one day started going up and down on its own) but as soon as you start the engine it maxes out, just as if the map sensor is unplugged.
Good earth to its brown wire, 4.9v at the left wire, nothing on the middle wire ignition on, start engine and both the left and middle wire are 4.9v.
Not sure if this is related in any way.
Any further advice welcome
Re: loss of throttle on rev2 turbo #updates#
Bloody hell, i don't know where to start with this!
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Re: loss of throttle on rev2 turbo #updates#
Going to try another distributor
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Re: loss of throttle on rev2 turbo #updates#
Have you tried swapping the map sensor/checking the vac lines to the sensor and the wiring for the sensor ? ( especially at the ecu side of things )
Sorry if you already have - I know what its like when your trying to fix something and then some one starts firing other suggestions at you.
Sorry if you already have - I know what its like when your trying to fix something and then some one starts firing other suggestions at you.
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Re: loss of throttle on rev2 turbo #updates#
Id also be looking at the ecu and see if the caps have blown. Common problem.
Doesn't cost anything to pop the lid off and have a look.
Doesn't cost anything to pop the lid off and have a look.
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Re: loss of throttle on rev2 turbo #updates#
I've tried another ecu, map sensor etc.
It boils down to 2 things now. A distributor which I've picked up today but yet to try and wiring.
It boils down to 2 things now. A distributor which I've picked up today but yet to try and wiring.