Engine Cut Out Around 4500 RPM

[steverrquattro]

between 1 and 3 and also between 2 and 3 you should get between 4.5 and 5.5 volts

Is pin 1 and 2 negative and 3 the positive?

[Mikes2]

Not that I can see - since 3 is common to both measurements it must be earth. 3 goes to pin 30 of the ecu which is earth. 2 goes to pin 12 which is +12v ref. 1 goes to ecu pin 9 which is the signal for barometric pressure

[newsh]

Steve I’m pretty sure the boost gauge on these old cars will show “absolute” pressure.
1 Bar is atmospheric pressure, when it reads 2 Bar it’s actually 1 Bar of boost.
I had an early LHD 82 car with analogue dash but don’t remember exactly how it worked, my 84 car reads absolute pressure though, with a max of 2 bar (1 Bar of boost) URS cars are all like this too.
To actually see how much boost you’re making on the 20 valve you’ll need a gauge that reads up to 2 Bar of boost.

[steverrquattro]

Not that I can see - since 3 is common to both measurements it must be earth. 3 goes to pin 30 of the ecu which is earth. 2 goes to pin 12 which is +12v ref. 1 goes to ecu pin 9 which is the signal for barometric pressure

OK, so pins 1-3 = 0v and pins 2-3 = 5v.

[Mikes2]

Pin 1-3 result is bad. have you checked continuity between F96 and the ecu based on the pin outs I posted. That's the next step.You have to hope for an open circuit between ecu and f96 because if there isn't you need to measure the voltage supply at the ecu end and if you're still getting 0v from the ecu, the ecu will need replaced.

[steverrquattro]

Pin 1-3 result is bad. have you checked continuity between F96 and the ecu based on the pin outs I posted. That's the next step.You have to hope for an open circuit between ecu and f96 because if there isn't you need to measure the voltage supply at the ecu end and if you're still getting 0v from the ecu, the ecu will need replaced.

That makes sense and yes I have to hope for a broken wire. The ECU is buried at the back of the centre console so will take me a little while.

Can’t imagine getting hold of another ECU nor the price if there was one, so it’s fingers and everything else crossed for now.

[steverrquattro]

Rain has stopped play for the moment but most of the centre console is out and I have access to the ECU. From barometric connector to ECU pins 3 to 30 and 2 to 12 have good continuity. There is no continuity between pins 1 and 9.

I have just lashed up a temporary wire between these two and with the ignition on I’m getting a healthy +4.99v. Now I’m presuming that the wire from the ECU at pin 9 goes straight to pin 1 of the biometric connector and as such I’ll cut it close to the ECU and run in a new wire.

[steverrquattro]

I've been for a test drive and although the car feels quicker, there is is still hesitation at some point on WOT. It almost feels like when the MAF is faulty but then it just goes right up to the red line.

I'm not getting any of the previous unidentified fault codes and the 00581 barometric altitude sensor fault (F96) has cleared as this is now getting the correct voltage from the ECU. What I do get is just the 00281 Speed sensor.

I'll get the pressure gauge out next and measure the boost.

[Mikes2]

Pretty sure it's a straight wire. If you peel back the rubber boot at the connector at the sender end - that's the most likely place for the break

[steverrquattro]

The next steps........

When this hesitation/flat spot, whatever you want to call it occurs, I am now beginning to think that it is fuel related. Below is the list of what I will look at next:

1. Injectors. Take them out and get them cleaned.

2. Pre fuel pump filter. I've had to take this off three times so far and clean the rust out. There have been some 5mm flakes in there at times. Perhaps there is some blockage in the tank which is restricting fuel, so maybe an inspection is needed.

The post pump fuel filter was changed 1,000 miles ago should be fine as should the fuel pump which is a BOSCH 044 and again has done around 1,000 miles.

Any other thoughts?

[newsh]

Check the small vac hose to the fuel pressure regulator, make sure it’s not leaking, even a small leak can cause problems as boost pressure actuates it to increase fuel pressure.

[steverrquattro]

Check the small vac hose to the fuel pressure regulator, make sure it’s not leaking, even a small leak can cause problems as boost pressure actuates it to increase fuel pressure.

All is good with the pipe and thanks for the suggestion.

Yesterday I met Paulius at the Thorseby Hall car show and he said to check the plug gaps. Having checked them, they were all at 0.6mm but I did notice that the electrodes on what was currently in the car (spark plug on the right) and have only done around 1500 miles have started to wear. What would cause this and should I be using another type?

I put a known good set in and unfortunately it’s still the same. I’m definitely thinking now that it’s some sort of blockage on the tank.

[newsh]

Might be a fake plug or maybe lean running caused by fuel pressure dropping.
Can you hook up a fuel pressure gauge? Not easy to see the pressure when driving but a friend got creative with a gauge on the line by the fuel rail, a torch and a GoPro

Have you got a good solid 12V feed to the fuel pump? The original wiring is really thin.
I run my fuel pump direct from the battery under the rear seat via a relay operated from the original wiring.

[JariP]

Or your chips are just too hot for the hardware. That looks like warning signs for a preignition damage, you are melting you engine. Are your running the hardware those chips were made for?

[steverrquattro]

Or your chips are just too hot for the hardware. That looks like warning signs for a preignition damage, you are melting you engine. Are your running the hardware those chips were made for?

I believe so. It is an original RS2 ADU engine with the original ancillaries including injectors and turbo. They were sold to me by a reliable forum member.