3200GT cuts out when throttle pushed hard... but re-sets fault with ignition off (for a few minutes)

D

delberts3200

New Member
Messages
28
OK had a recent issue with fuel....thats sorted and this isn’t related. Thanks again for your help on that one. You’ll just have to trust me that this isn’t related. This fault started before all that. I spend about half a tank sussing out what was happening yesterday. Great fun....you do forget!

So the car starts and drives normally. After 5 mins perhaps of running fine when you increase throttle you will instantly lose all power like the ignition has been cut. Ease off and it goes again but if you reapply same degree of throttle it will do exactly the same again, Infact you can jerk forwards and backwards in quite a harsh recurring manner which almost becomes self perpetuating. (The Traction light can flash) Ease off and gently accelerate you can get through it....very gentle throttle it’s drivable...without boost perhaps??

The revelation came yesterday that if i pull over, switch off....restart then it is fine for about 5 mins and then it comes back. If i was reading this I would say that due to my recent fuel problem it was likely **** or blocking the filter or pumps or something...but it isn’t its too instant and to violent to be fuel. It will reset and drive properly for a few mins on every ignition reset. No check engine or any other light.

Any suggestions greatly appreciated....
 
davy83

davy83

Member
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2,821
Its not boost, the turbos would not so this I suspect and you need to be above about 3500 rpm for the turbos to be doing anything? What sort of RPM are you at when this happens.

If its as sudden as you suggest, then it has to be perhaps an intermittent wire connection somewhere? But if it was the throttle body or the pedal sensor (both capable of creating this sort of problem) you would expect an ECU light, and the car is know for being oversensitive to these problems and throwing an error at the slightest sign of trouble, so the absence of an error makes me sceptical that its one of these. Same goes for most of the sensors like the RPM and CAM sensors which can cause bit problems but will throw an ECU light at the drop of a hat.

I am thinking kaiser valve? or a vacuum leak of some sort? The big cover under the plenum can cause this, and it can be quite disturbing. I would check all the vacuum hoses and try to see of the big cover under the plenum is loose (more or less impossible to inspect!). You may be able to hear a vacuum leak if you listen around the top of the engine and get someone else to rev the car.
 
Rex B

Rex B

Member
Messages
657
If the traction light flashes then your problem could be linked to the abs unit as it is designed to cut the fuel/ ignition supply if it detects loss of traction and this can be very harsh on early cars. Try putting it in sports mode to see if there is a difference.
Rex B
 
davy83

davy83

Member
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2,821
Rex B said:
If the traction light flashes then your problem could be linked to the abs unit as it is designed to cut the fuel/ ignition supply if it detects loss of traction and this can be very harsh on early cars. Try putting it in sports mode to see if there is a difference.
Rex B
Click to expand...
I wondered about that, the only thing I was thinking is that once that traction control doodad cuts in it takes a moment to go back to normal and would not give you the kangaroo sort of motion he was describing?
 
G

gemini

Member
Messages
144
The knock sensor will give an error code.
It was my first thought, but as you can give the car full throttle in the 5 first minutes of drive, it can't be a knock issue.
It can't be a plumbing problem too.

I suppose the ECU is set up to ignore the data coming from one of the sensor during the first minutes of drive, and you probably have a problem with this sensor, no idea which one unfortunately.

I think the O2 sensor are ignored for the first minutes, but it should be the case only if the car cold, isn'it?

Or maybe a bad temp sensor, it would make sense.
 
Oneball

Oneball

Member
Messages
11,106
O2 sensors are ignored for the first couple of minutes, not due to engine temp but due to sensor temp. If you disconnect them the ecu will revert to the same non feedback map as during initial start.

I know you said it isn’t but I’d want to rule out fuel system too. Have you got a gauge to measure pressure at the fuel rail? Increase in throttle opening without an increase in fuel is like hitting a brick wall.
 
D

delberts3200

New Member
Messages
28
Thanks for your replys...... I have the 3 pin diagnostics and i can read basic codes. What’s the best software to use on my laptop? Will it store codes with no check engine lights?

Mazzer kangaroo

still trying to gather as much info as possible.... ignition reset didn’t work on 1 occasion last week.... just making sure i can posit a video link then i can probably do better than this one....
 
Oneball

Oneball

Member
Messages
11,106
In my mind that’s fuel or air.

fuel pressure and regulation at the fuel rail
throttle body
throttle pedal
collapsed inlet hose low pressure side
blocked air filter.
 
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