1995 SRi X20XEV won't start

[ilovedmymantas]

Look on the front down-pipe, just before the flexi-joint to the catalytic converter.

Sadly it means getting under the car to access the sensor.
The connector should be up near to the coolant header tank on the bulkhead.

You may know it as a lambda sensor?

[btcctroy]

1st of all check the plug on the lambda sensor as the fault indicates no continuity.
the lambda sensor doesn't do anything while the engine is cold or on full throttle
the coolant temperature can also cause awful running problems with no code thrown up
the camshaft sensor will cause all kinds of problems if its not right.
again check the earth connections on these as it will simply not run right

[Joner1983]

So I've just changed the cam sensor. I checked the plug for the lambda sensor and it seemed intact and clean so I've ordered a new one. Trouble I've got now is the old sensor won't budge. I've soaked it in WD40 specialist penetrant 3 times and still nothing. I've now cut the wire so I can get the ring end of the spanner on there but still no good. Any suggestions how I get this off without getting it on a ramp?

[Robsey]

I usually use plus-gas rather than WD40.

But if penetrant doesn't release the sensor, then see if you get a gas-torch on the sensor, then undo it whilst it is still hot.

[Joner1983]

That was a great shout Robsey, managed to get my heat gun on it and that done the trick. Just got to wait for the new one to arrive now

[Robsey]

Glad I could help.

[btcctroy]

I usually use plus-gas rather than WD40.

But if penetrant doesn't release the sensor, then see if you get a gas-torch on the sensor, then undo it whilst it is still hot.

Definately a blow lamp! mapp gas really

Be aware that removing it may strip the insert of its threads

[ilovedmymantas]

Be aware that removing it may strip the insert of its threads

On the plus side that would be a chance to change for a 4-2-1 downpipe, every little helps

[Joner1983]

So I've changed the lambda sensor and cam sensor and I've got no real improvement and now eml light is permanently on. Paper clipped again and I'm gettimg same codes as last time

[Robsey]

It is not unheard of for new parts to be faulty...

But I would have another look at all your connectors and ground wires.

Have you looked at the ECU connector and pins?
The ECU sits in the right hand footwell kick panel.

Being at the bottom of the A pillar, sometimes a corroded a pillar or scuttle panel can allow moisture to cause water damage to the ECU.

[Joner1983]

It is not unheard of for new parts to be faulty...

But I would have another look at all your connectors and ground wires.

Have you looked at the ECU connector and pins?
The ECU sits in the right hand footwell kick panel.

Being at the bottom of the A pillar, sometimes a corroded a pillar or scuttle panel can allow moisture to cause water damage to the ECU.

Ah yes, I've had this problem before with the ECU getting water damaged. Had to have it overhauled about 7 years ago, probably could have just replaced it with a used one for less money. I better take a look at it and see if it's got wet again

[Joner1983]

Also where can I find the earths? I can see where they all connect to the wing next to the battery but I can't see where they connect to the block and other stuff

[Robsey]

Not 100% certain on the XEV as I have an NE...

But my earths are located at the end of the injector rail (gear box end),

And I have a few earth wires behind the rear camshaft housing - behind cylinder No 2.

All earth wires "should" be brown.

Daft comment - but you do have a thick earth wire between the bell-housing and the inner wing,
Or
a wide earth braiding from the end of the gear-casing to the inner wing

[btcctroy]

hi Pal,

definately seems like faulty cables to me.

just another thought, are all the fuel injectors firing as i have known them to give up on cars that have been stood

Troy

[Joner1983]

I'm pretty sure it's not the injectors as at times it seemed to idle and rev ok, only really started playing up when I tried to drive it round the block.

All the earths going to the inner wing look like a thick brown wire, no braided connections that I see.

I've had the ECU out and despite it feeling a tad damp on the outside the inside appears alright to my untrained eye....

Might be a call to an auto electrician unless I can find any obvious damaged or loose cable

[Joner1983]

[url=https://postimg.cc/kBkD3chM][img]https

Here's the inside of the ECU. Unless I'm missing something it seems ok?

[Robsey]

That looks perfectly clean and dry.

So we are back to looking at the wiring and connector pins.
Especially if you have an intermittent fault.

It is highly likely that a wire is 'damaged' inside it's insulation.

A thorough check would be to take off the whole loom, and "bell out" every wire to every pin.

Now is a good time to make a pin-out listing of the ECU, and the loom itself.
About 60 wires in all.

But if you do not understand the schematic diagrams in Haynes, then an auto electrician may come in very handy.

The fact that two sensors are affected, still makes me think that an earth is loose, damaged or dirty.

[Robsey]

Hmm further thought.
It is widely known that the crank sensor can suffer badly from "electronic noise" caused by a damaged sheath.

Check the routing of the crank angle sensor cabling.
And also check that the sensor is not damaged or distorted.
There were several sensors made with plastic bodies, however the proper Bosch units have metal bodies that do not distort if clamped / bolted tight to the engine block.
BUT - A damaged sensor would not give intermittent problems.

According to the Vectra-B Haynes (the Simtec 56 ignition system wiring is not listed anywhere in my Cavalier manual, the earth for all the sheaths / shielding and for the crank angle sensor is on ECU pin 29.

The oxygen sensor is not earthed through the exhaust.
Instead it is wired directly to the ECU.
But it also has it's shielding sheath grounded via ECU pin 29.

Other ECU earths are...
Pin 2
Pin 7
Pin 11
Pin 15
and pin 19

Pin 4 for manual gears.
Pin 4 via park / neutral switch for auto-box.

All seven connections are brown wires.

[Joner1983]

So I've let this one sit for a while but since my last post I've changed the cam sensor, crank sensor and coolant temp. sensor. But now it won't start at all. I've tried cold start but it doesn't seem to be even burning off the spray which makes me think I'm not getting a spark anymore. I'm totally lost now....

[Robsey]

Okay simple stuff first.

Is the distributor cap clean and dry inside.?

Is fuse 11 still clean and dry?

Do you have an engine light on?
It should be on if you are not getting the car to start.
Do a paper-clip test for fault codes.
You will have to ignore crank-angle / no rpm signal (3-1) as that will not clear until the engine starts.

Is the fuel pump relay working? Clicking?

[ilovedmymantas]

There was a similar problem on Vxon that might help, you may have been right in your first post
https://www.vauxhallownersnetwork.co.uk ... it.157639/

On the fuel side of things, something I'm a bit more familiar with.

Have you fitted a new inline fuel filter, the one bolted underneath near the tank?
A dirty filter can cause fuel starvation and fits your earlier symptoms. Is the tank low or holding stale petrol, a possible cause of blockage.

I hope you get this working soon, my eco sri was fun to drive
Looking forward to the progress pics!

[Joner1983]

Thanks so much for everyone's help with this. In an unexpected twist I received an offer for my 95 SRi and it has now neen sold. Very sad to part with it as I've had it for 11 years but I've still got 3 more Cavs and my 90 SRi is costing £££s to get roadworthy so the cash will come in handy

[Robsey]

It is a shame, as we will never know if this ever gets sorted.
Unless of course, the new owner joins the forum.

At least you have a few more cars to keep you going.

[Joner1983]

Yeah would've been nice to know what the problem was but I'm sure it'll turn up somewhere in the future. I'll post some pics on my '90 SRi thread as soon as I get it back from the garage