O2 Sensor placement + cheap oscilloscope

[luxmoggy]

Hello,
I am in the process of rebuilding my engine. Jaguar XJ6 Series III 4.2 EFI. Well it is out I am doing the prep work for converting to MegaSquirt.

It seems that some of the cars have O2 sensors in them. Here is a picutre of the one of exshuast header. At the bottom it has a plug which is were the sensors orignally went. IS this still ok to conect the sensors to or do I need to find another place for them.




On another point has anyone got or heard of these "JYE Tech oscilloscope DSO 094"? I seem like an OK scope to start with and should be fine for all the testing and checking on the MegaSquirt.

Thanks for your help
Iain

[Matt Cramer]

Can't help you with the 'scope, but the O2 sensor location looks fine.

[trakkies]

I've got a Rover SD1 with basically the same Lucas/Bosch injection, and it too has provision for lambda sensors in the exhaust manifolds for countries where cats were specified, but not the UK.

However, if you don't need to comply to those regs, a wideband sensor is more useful, as you can use ratios from about 12.5:1- 15.5:1 for better power output and economy at cruise. But wideband sensors are less tolerant of extreme heat, so need to be mounted rather further away from the engine.

http://wbo2.com/lsu/position.htm

On my car, it's mounted near the back of the gearbox (after the downpipes join), and after experimenting with the delay setting in TS works just fine.

[luxmoggy]

Thanks for the replies.

I was thinking of using 2 SLC OEM with Bosch 17014 Wideband sensors.
So as they are Wideband sensors they should be mounted farther down the exhaust system.

[trakkies]

Thanks for the replies.

I was thinking of using 2 SLC OEM with Bosch 17014 Wideband sensors.
So as they are Wideband sensors they should be mounted farther down the exhaust system.

That's what I was told. It could be there are newer ones that will survive being very close to the heat, though.

As regards the 'scope, I'd go for a secondhand Textronix, if space isn't a problem. My 465B is over 20 years old and still going strong. And get a small cheap battery one for use on the car - I paid about 25 gbp for a PCB one from Ebay, and fitted it to a case. It's good enough for looking at noise etc in sensor circuits.

[geewiz]

Bosch's recommended max is 900 degrees F. for their LSU4.2 wide band. I ran this sensor at 12 inches from the nearest valve in a cast iron manifold [with a washer type heat sink], with no problems for several years. I run fairly rich mixtures & this may prove to be too close for lean [hotter] mixtures. I recently tried to run at 7 inches in a stainless header [ with a heat sink] but that proved to be too hot. [ the temps were reaching 950 F.] The sensor gave false reading [it read richer than the actual] I re-calibrated it and moved another 6 inches downstream, just past the turbo] & it is fine now [a heat sink was used].

[440roadrunner]

Hello,
On another point has anyone got or heard of these "JYE Tech oscilloscope DSO 094"? I seem like an OK scope to start with and should be fine for all the testing and checking on the MegaSquirt.
Iain

This guy doesn't seem to think much of them. I won't be buying one

http://tronixstuff.wordpress.com/2010/0 ... illoscope/