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Discussion Starter #1
hi there,

I have a problem with the running of my 2.0 AAC T4 (1991 non cat) initially i would drive the van and when it reached temp and under load it would drop its revs then pick up again and so on but intermittently, at the time the manifold gaskets were blowing so i rectified that problem thinking that may have been the source of the problem ie, intake of more air causing the fuel to become weakened. I rebuilt the top end of the engine and everything ran fine until i took it onto the motorway and the problem arose again although this time it drops in power almost like a mini surge which i would liken to when you are about to run out of fuel, however there is ample fuel in the tank. I changed the 2 pin temp sensor but this did not alter the problem and in-turn causes the temp light on the dash to flash!.... i have read various threads with similar but not exacting problems with this type of engine, i would value anybodies similar experiences and advice on how they solved the problem. I will be inspecting the vacuum hoses to the digifant and see if that makes a difference, i have also considered the coil to be at fault, i have ruled out the fuel system simply because it does not stall and there appears to be no issue when driving at low speeds ie around town and incidentally i live at the top of a hill and at normal speeds it gets to the top with no problems it seems to be at speed under load...! annoying to say the least! :confused:



not the best looking van but a work in progress and only has 40k on the clock....probably because you cant go very far in it! :)
 

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descibing your simptoms i would firstly change the coil common probelm with the probelm your claiming also check dizzy cap rotor arm T:

cheers wayne
 

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Discussion Starter #3
cheers, i have checked the rotor arm for movement and there are no signs of wear to the dizzy and the rotor arm has been replaced, i will order a new coil and give that a go and see how i get on T:
 

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Discussion Starter #4
Changed the coil today van seemed more responsive but still showing same symptoms although on two occasions I lost power and could not rev engine and had to switch engine of and restart assume similar to limp mode. Running out of ideas does anyone know of any code reading software available cheers
 

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Aha!!! Then it is... try checking you MAF mine did this on the Bora.. was driving fine then died or loss of power like yours.. took it to the dealers who plugged it in and it came back with a list of faults:

Injector fault
Coil Pack fault
Lambda probe failure
Spark plugs etc...

In the end after a weeks diagnosis it turned out that the MAF had sent the ECU haywire and it was giving out false signals. It was replaced FOC and by god did it go once more..:tu
 

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Discussion Starter #10
Thanks for that this is an early digifant system so does not strictly have a maff sensor it has a co2 sensor which I assume works in a similar way I will disconnect this and try it, incidentally what year was your bora, cheers Paul
 

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Bora was a 99 (T) 2.0 Sport Auto.. got it with 18k after my dad had it then traded it with 30k and that was back in '08.. miss that car :(

P.S was down your way last weekend over at Clitheroe..
 

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If its an early digifant engine it will have an Idle Stabilisation Valve on the air intake side.. It has a fag packet sized relay under the dash, they were prone to failing. They have to be paired i.e the serial has to match the valve.. it may then be that both need to be replaced. The valve can be cleaned an lubed up using carb cleaner and 3 in One Oil and work the door of the valve back and forth. it will re calibrate itself one reconnected to the car. If no improvement then you know what's at fault..

Yup! Just Googled it - it lies right on top of 2&3 cylinder.
 

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Discussion Starter #13
Clitheroe nice place, bit posher than burnley :) i have had it out today went through all basic checks once again, checked timing and idle valve all appears in order. I noticed on closer inspection that there was a hairline split in the vac pipe to the ecu, so cut it and refit and went for a drive however when it reached temp it started to buck once again. I removed the connector to the throttle position sensor and carried on the test and it seemed to behave. I checked the timing once again and retarded it slightly as it appeared to be running slightly to fast when i did this i could hear sparks shorting from the new plug leads and dizzy, i removed all these and the leads had rusted causing poor connection due to condensation, when i removed the dizzy cap the rotor arm had seized to the shaft and that too had rusted with condensation (Incidentally i replaced all these items earlier in the year). The running seems more settled and i have been running about for a couple of hours and it seems ok!. I will let it cool down and go for another drive and see, that is still tps disconnected. cheers for the advice i will keep you posted.
You would be lucky to find a low mileage bora nowadays i jumped at the chance to buy this van with low mileage and its given me nothing but headaches so far! lot to be said for high milers :)
 

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Discussion Starter #14
had a couple of test drives in van and all seems to be well at the mo... hopefully i can now concentrate on the interior.
 
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