non-start Sensor Issue - Solved

[Dave Cav]

Hi Folks, running an L reg 93 mk 3 Cavalier 2.0 GLSi hatch. It is a thing of beuty and only 61000 on the clock genuine and supported with paperwork etc. Last year towards the end of summer sometimes it would start with a little rough running and bad idle, once out on the road this would clear. Early nov 2021 one day in the petrol station it just refused to fire up. Tow truck home and looked it all over, no fault obvious. Days later the same thing happened in B&Q. Again two truck to local mechanic, again car started first thing next morning with no issues. Mechanic advised electrical issue and recomended auto sparkie.This guy had had the car since late november and has still not found the issue, original advice was to change the crankcase sensor which he did and when i went to pick car up next morning, again it would not fire up.last week he reported to me that while again trying to find the issue he reported to me that the cat was glowing cherry red, i did some research and then sugested he change the Oxegen sensor as the plugs were a great color and no sign of unburnt fuel or really bad idle or missing when it did run.now last week he has just asked me to take the car away, he has given up and told me he just could not be bothered to order and fit said oxegen sensor. So here i am looking for sugestions and advice as to what to do next, at this time i have it booked in to another auto sparkie with a better reputation than the last one.all help will be greatly appreciated.

[ilovedmymantas]

From your description there are so many things this could be. To narrow down the electrical problems use the paperclip test in the How2 - modern auto sparks don't have the software for cars of our age so if it's not an easy fix, drop it
viewtopic.php?f=31&t=630
It may be the fuel relay, I've had that happen with a similar problem on my first cav.

What condition are the plugs now? If the cat (assuming the car was actually running) was glowing then that could be sensor, cat or a blockage in the exhaust system.
If the test comes up with nothing I'd look at the exhaust system.
good luck and don't be a stranger

p.s. Looking at your first post from 2 years ago, I assume you mean 71 thousand on the clock

[Robsey]

Hmm - a lot of this exhaust milarkey seems like a red herring.
Glowing catalytic converter? - I surely doubt that.
Yes these boxes run in excess of 270°C for the monolith to be effective, but glowing hot sounds excessive.

If it is anything to do with the Catalytic converter, look to see if it is blocked.
A blocked exhaust would prevent the engine from running as soon as back pressure builds up.

I am assuming that this is not an intermittent non-start issue.

Changing the Oxygen / Lambda sensor would not prevent the car from starting, as they are "ignored" until the exhaust / catalytic converter gets up to temperature.

So - lets look closer at the issue.

Non-start, either hot or cold.?
Cold - often due to moisture.
Hot - often due to component failure due to heat.

Both infers possible component failure, wiring or connector issue.
That is a huge array to go at.

First things first.
Check all grounds and live feeds.
Grounds are brown wires.
Battery live are red
Ignition live are black.

I always stress that 95% of failures are due to damaged, dirty or corroded connector pins or damaged wiring.
So obvious checks are to look at the connectors for:-

The ECU - see if the ecu or connectors have got damp / corroded from water ingress in the driver's footwell.



Fuel Pump (and injection) Relay in driver's footwell.
Put a new (good) fuse in slot 11 under the dash.
(The image shows fuse 13, but you want No11 - far left, middle row).



Silly question, do you have an immobiliser or alarm fitted?
If you do, short pins 1 and 18 in the alarm socket behind / next to the glove box. (Assuming it does not already have the cover cap with the bridging strip / pins fitted).
We are linking the two blue/red or red/blue wires in the connector.





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Beyond that, it is a matter of checking for a spark and / or fuel delivery to the engine.

[Robsey]

I have to make a lot of assumptions, as there are five types of two-litre engines available.
20 SEH,
20NE and C20NE
20XE and C20XE
C20LET
X20XEV

I am going to guess at the C20NE, as that is the most common engine for that year (1993).

The technology is quite simple on this engine, so there is little to prevent it from running.

Only the crank angle sensor would prevent it from starting. All other sensors would allow the car to start, but it may run very lumpy. (Mass Air Flow sensor).

If it is electrical related, then I would check your coil, the wiring to it, and of course the HT leads.
It goes without saying to check the distributor cap, rotor arm etc.
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The engine light will stay on until the car starts, so you will probably get the engine position sensor (crank angle sensor) code anyway.
This can be a bit mis-leading.

----‐------------

That leaves fuel delivery.
Check to see if your plugs are getting wet,
Or disconnect one of your hoses to the fuel rail and try cranking - see if fuel runs out.

[vexorg]

Fuel pump relay would be my first thought on random non-starts

[Dave Cav]

thanks for all the replies guys so far, yea mistyped the milleage, 71k. i have only driven it around 3 0r 4 k per year last five years.to clarify what is going on, i went to the sparky on thursday and removed the flat battery, as i said he has had it since november. charged battery overnight and went back friday to fit and collect car. as usual it started right on first turn with my arm through the window, this car has never needed any press of accelarator to start it, in fact it just dont like it at all. so car running and as sweet as, perfect like normal, was only a two mile drive back home and in that time it developed a bad miss, running rough, had to keep revs up because of stall threaten. parked it at home and lifted bonnet, stinking hot smell and yes the cat was very hot, turned engine off, waited like 2/3 minutes and again it just turned over and over and would not fire up. three hours later it did like nothing had happened before but as it warmed up again it got very rough, bad idle, a little miss at low revs but over 1200 or so it is as sweet as, quick run round the block, turn off engine, try and restart, nothing again. every time this has happened i have run just routine basic checks, every plug is getting a healthy spark, plugs are as good as you would want them to be, burning golden brown and all gaps correct, fuel is being delivered to every injector and they all look sound. so again i am back to were i was when this fault first developed last october. its time now for my gardening work to almost begin, thats what i use the cavie for, back seat permanently folded down for 8/9 months of the year to allow me to carry all my gardening tools etc. i volunteer for a local charity and sort out all the pensioners gardens etc all thru summer, gives me a great sense of purpose and its all i can manage now workwise after developing a dicky ticker.come wednesday it will be back into another auto spark, really hope he has a magic wand.cheers guys, this is the strangest issue i have ever had with any vehicle and i have had many over 48 years or so.

[Robsey]

Hmm - heat related non-starter.

We are looking for something that is failing when it warms up.

Do you get an engine light for approx 4 seconds after starting?
If so, then a fault code has been stored.

You can "flash out" this code by shorting pins a and b in the diagnostic plug.
Turn on the ignition - engine not running.
It should give a sequence of pulses.

See here -
viewtopic.php?f=70&t=16896&p=171534#p171534

If you do NOT get an engine light -
And you have already checked the HT leads, rotor arm and distributor cap, then I am erring towards a duff ignition amplifier circuit within the engine ECU.
(In the right hand kick panel).
Thankfully, the ECUs for the C20NE engine are the most common on ebay - look for alpha-code GE.
The down side is that almost all will be used, and therefore have an unknown history.
(I am still assuming that youhave the C20NE engine)
Hard to tell without a reg or vin number to look up.

[Dave Cav]

hi Folks, finally the Cavalier is up and running again, four months later lol.
Two auto sparkies failed to diagnose any issues with a variety of sensors so i kind of gave up with them both.
went back to basics and got under the bonnet myself as health is a bit better than late last year,no more that about 15 minutes at a time bending over the engine though or im stuffed for days and my discs would pop out again.
so plugs fine, output from coil fine, leads a bit weathered and sort of soft. Distributer was a mess, how it even ran at all has me amazed. The carbon brush that sits on top of the rotor was non existant, completely worn flush with inside top of cap and two contact cams completly worn away. So treated the car to a new distributer, cap, rotor, leads and plugs and now running like a swiss watch again after 4/5 months, ok i was unable to take the job on myself health wise or i could have discovered the fault ages ago lol. relied on external help and only found two sparkies who just did not want to help, second guys told me just to scrap it lol.
so now its all going again i am now thinking it is time to let it go to a fellow cav fanatic, only kept it on as i used it for my odd job handyman work, folding rear seats down and putting lawnmowers and tools etc inside, health wise i dont think now i will get out much anyway. so if anyone knows a person who would like a nice Cavalier let me know. thanks for all your help and sugestions.

[Robsey]

It is a shame to hear that just as the Cav is sorted again, you are thinking of parting with it.
Poor health is a cruel thing, but I am sure you have thought long and hard about it.

Does that mean that your local lawns and gardens are going to become over-grown and full of weeds. Oh eck.

I hope whoever gets the car will realise what a unique beast it is.

[Dave Cav]

Hi Robsey, cheers for your nice comments. Yea my health has got much worst last couple of years and covid had me redundant most of the time.
I had a couple of guys working for me but with no work they went elsewhere. trying to be a one man band but thats restrictive as i dont have the muscle power for the tough jobs.
I think it may be best to let the Cavalier go now, it has been a great car, only that one breakdown in five years i had it, just over 70k, i have all the old paperwork including a pile of MOT's, it has sailed through five MOT's for me and just got done again october last year, taxed in Feb and insurance is due in June so gives me maybe a couple of months to find a buyer. Guess i should take some photos and show them of to prospective buyers, inside and outside body condidtion would be excellent, no body damage or rusty bits, lovely car and always commented on, even the police have stopped me just to chat about it lol. i fitted a modern radio so it would talk to my phone hands free etc, but still have the original Philips radio cassette lol, and it works. have a decent size folder with service history, old MOT's and reciepts for anything bought over the years. If you know of anyone please point them my way, cheers.

[Robsey]

Cavaliers are gaining popularity, so it should not be hard to find a buyer.

Indeed, ideally location, proposed selling price and photos.

Although you do not meet the minimum post quantity, I am happy for you to start a for sale thread on the forum.

Otherwise, if you are happy to use facebook, then there are several Cavalier groups. Cavalier Corner is by far the busiest.