Intermittent non starting.

[MarkW]

Hi all,

I was wondering if you guys can help, I have a Cavalier 1.6 C16NZ SPi (yay) it has developed an intermittent non start problem.

It turns over but won't fire, I had the AA out two days ago when it let me down, and lo and behold, the car fired up as soon as he arrived.

Now, he reckoned an ignition fault, so, I have changed the spark plugs, HT leads, distributor cap + rotor arm (for good measure )

Everything was great for two days. Now I just got marooned in Homebase carpark for 40 mins (not nice) while the poxy thing wouldnt fire. I checked for spark at the plugs, and I couldnt see a spark (but I'm no expert ).

Was just about to call the AA again when the bloody thing fired up.

Now, to add insult to injury, the tappets are now WELL noisy from No.1,2 area.

I have checked all the wiring that I can see, everything is connected OK.

I am by no means a mechanic, so I may have missed something.

Just wondered if anybody had any ideas on the cause or if anyone has had the same fault.

Thanks in advance guys!!

Mark

[Mr M3]

Does the em light appear whilr trying to start it? The fuel pump relay would stop the light coming on, and obviously starting lol

[MarkW]

Yeah EM light is on when it turns over, I tried my trusty Gunson diagnostic on it as well, no faults in the system.

[MarkW]

Are you saying that if the light is OFF the car should start, or are you saying if the light is ON the car should start?

Sorry, not that knowledgeable.

[Mr M3]

The relay being at fault stops the em light from coming up.

[MarkW]

And that means it won't start I take it?

Sorry, don't mean to go on, but I aint that clued up on Vaux mechanics!!

[Mr M3]

Yep a sure way to tell if this is at fault, the relay stops the em light from coming on. So yours comes on even when it won't start?
The relays can play up when they get hot.

[MarkW]

Yeah, it comes on when I switch on the ignition and stays on while I turn the car over.

That does seem to be about right what you are saying about hot relays, I have done a fair bit of driving today, about 70/80 miles and getting stuck in traffic. Car was fine until I got back home and went to go out again about 15-20 mins later.

Git wouldnt start for a couple of mins!!

Then of course I got stuck at home base.

Thanks C4llyT I'll check the relays in the morning. Any other ideas you've got are greatly appreciated!!

Cheers

Mark

[LongLiveTheNova]

Ignition coil overheating?
My 1400 spi had exactly the same prob.
Yeah the ECU light won't come on if the fuel relay is playing up as the ecu is powered through the relay.

[MarkW]

Thanks mate, I'll check that too.

[Mr M3]

Good point the coil getting hot. Was thinking coil, but thought they either worked or they didn't

[MarkW]

Thanks fella's, I'm off to the breakers in a bit to grab a couple of relays and a coil.

I'll let you know how it goes!!

Cheers!!
Mark

[MarkW]

OK, picked up the wrong coil being the prat that I am....................

Couldn't find the relay for the fuel pump? whereabouts is it??!!

Also, fault is now happening with the car cold as well.

Any ideas??!! I'm stumped and it's really getting me down.

[azza69]

the fuel relay will be sitting next to the ecu. (driverside kickplate in the footwell) itl be a 1.5 inch high black or blue relay.
if the engine light is coming on with ign it wont be this at fault tho

check for spark and fuel

[Aragorn]

gm multec doesnt need fuel relay to power ECU only motronic does

ive tried to start mine a few times with no relay and the light comes on like normal

does the fuel pump run when your cranking it?

[azza69]

gm multec doesnt need fuel relay to power ECU only motronic does

didnt know this.. could well still be the relay at fault then

[screamer69]

dont the 1.6 have a crank sensor ??? if so check that out if it has it wil be on front of the block near the engine mount but like i said im unsure on the 1.6

[MarkW]

Thanks guys!! I'll be checking that!!

[TurboAde]

Hi all,


Now, to add insult to injury, the tappets are now WELL noisy from No.1,2 area.

Do you still get this? Does it happen all the time or just after it has started?Or has it gone away altogether now? If you have hydraulic tappets they may be sticking and not actuating the valves, hence starting probs. It's a long shot (but it might just work!)

[MarkW]

Noise seems to have gone, but I must admit, it happens more so after the car finally decides to start. I shall dig into that!!

Thanks!!

[MarkW]

Sorry to bump an old post, but for the benefit of others, I have traced the fault to the ignition module behind the distributor.