cat and lamba sensor 1989 car

[arrisbmw]

Hi Guys. when did they put cats on e30 1.6i .and lamba sensor in exhaust. any idea of year please.

[Brianmoooore]

From whenever anyone asked for one, or from when it was compulsory in the market they were sold in is the short answer.'
In the UK, this was from 01/08/1992 although they were 'emissions equipment ready' from the introduction of the M40 and the facelifted M20.

[arrisbmw]

thanks Brian. if my e30 been sitting for a few days needs longer cranking before it starts. any idea what thay could be i was thinking fuel pressure dropping over time. i haven,t changed the plugs or fuel filter yet.
thanks in advance.

[Brianmoooore]

Dropping fuel pressure is a likely candidate, but that can be due to a leaking FPR, a weeping injector(s), a leaking non return valve in the pump, or a simple leak in the pipework.
Cheap ebay fuel pressure test gauge, and clamps on the fuel feed and return rubber hoses in turn will determine which.

[arrisbmw]

thankyou. that makes sense, previous owner said when started from very warm, take 30 seconds or so in idle to stop the uneven and hunting idle, i suppose that could be connected .

[Brianmoooore]

A hunting idle suggests a weak mixture, but an uneven idle could be either as a result of a weak or rich mixture. A leaking injector will pool petrol in the inlet manifold after the engine is stopped, and if the engine is restarted while this petrol is still present, it will cause rich running until it all passes through the engine, but as I wrote in my last post, test, not guess.

[arrisbmw]

ok thanks brian, getting back to testing fuel pressure how does that work. I,m guessing i need a gauge( what pressure should i see on a 89 1,6 m40.) a T piece. then put in line feed pipe than return pipe. but how do i test.? thanks
p.s i think i saw a video putting the gauge in the feed from tank run the engine check pressure if it does not hold overnight, could be the return valve in the pump, or leaking pipework. the guy just put non.return valve in fairly near the pump is that correct.

[Brianmoooore]

The pressure shown on the gauge, with the engine running, is what is written on the FPR (3.0 bar for a M40, IIRC), less the amount of partial vacuum in the inlet manifold, which with the engine idling should be approaching half a bar. If you pull off the small reference hose to the FPR, then the pressure should rise to the full 3.0 bar. The reference hose arrangement is to keep a consistent pressure across the injectors, which have one end inside the manifold, and the other end held at a consistent 3.0 bar above the pressure in the fuel tank, which is effectively atmospheric pressure.
The pressure will also rise to close to 3.0 bar under wide open throttle, because under those conditions, there is very little vacuum in the manifold.
Testing for leaks is done by switching off the engine and observing what the gauge does over the next few hours or days.
If there's still most of the pressure there after a week, then all is well.
If the pressure falls considerably in minutes or a few hours, then there's something wrong.
If you clamp the fuel supply hose immediately after stopping the engine, and this cures the dropping pressure, then there's either a leak between the pump and the fuel rail, or the pump non return valve is leaking.
If the pressure still drops, bring the pressure up again by starting and stopping the engine, and clamp the return hose from the FPR. If this stops the pressure drop, then the FPR is leaking internally.
If clamping both hoses doesn't stop the pressure falling, then it must be one or more injectors leaking.
It's a BMW approved repair to add an external non return valve near the pump, rather than replace an otherwise good pump, in the event of it's internal valve failing.

[arrisbmw]

thanks alot that is brilliant. is it o.k to use a gauge from an air compressor . ? adapted with fuel line hoses all clamped securely. in a T formation.. cheers

[Brianmoooore]

is it o.k to use a gauge from an air compressor . ?

Not ideal, if it's the usual 12 bar type - 3 bar will only be 1/4 scale, so changes will be more difficult to see compared to the ideal 4 bar max. gauge.