Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

From memory - the 1.8 SPi / CFi can be slightly jittery at idle when working fine.

Just a slight flutter every now and then is quite normal.

If it is a definite regular mis-fire, then check your distributor and rotor (if you haven't already done so).

The weakness on my 1.8 and a previous mk2 1.3 was the leads... I used to get some green powdery (copper oxide) corrosion building up in the h.t. lead caps... especially the main / crown lead between the dizzy cap and the coil.
In extreme cases, the faulty lead caused my 1.3 rotor to burn out a few times.

Other than that - ensure that all connections are clean and dry.
Both on the HT leads and the sensors etc on the injector / ecu loom.

Ok, so it's acceptable to have some random bumps when at idle? Seems a bit odd, but I'll go with that for now... You've got more experience with these engines than I, so I'm happy to rock with that. Given the exhaust parts I'm looking at are 30 quid a section, and another 16-30 for the sensor, I'll look to replacing the downpipe and the mid-section, as I think something in there is giving me the noise, and I'd like to rule out the issue completely with newer hardware and fresh birds nests. Plus it's peace of mind for later, which is just as important.

To that end, has anyone used Klarius exhaust parts before? I'm not looking to get anything silly expensive for now, not unless I either win the lottery and can afford to overhaul the entire car in one hit. These seem to be available and not overly expensive, so I'll likely give them a shot. And the spring bolts I'm guessing I'll have to get from a Vauxhall garage, right?

Any thoughts, let me know. Cheers lads, been very helpful thus far!

Had similar issue with my one eight, turned out to be the inlet manifold gasket - spray WD around join between inlet manifold and block and see if you hear difference in engine note. I will say though the 1.8s can be a bit lumpyish at idle and play funny buggars some time. Mine occasional sits at near 2k RPM for no reason - wondering why it won't slow down when approaching a stop! Remember everything is at least if not more 20 years old.

Take a look at the little rubber pipe elbows on back of hood over the carb and also on side of carb, the rubber perishes and splits giving a vacuum leak, likely more than one is leaking or split.

Other things to check:

Brake servo pipe not leaking
Pipe that leads from back of carb up to under bulkhead apron plastic. This goes into little module hooked on bulkhead. Make sure it's not hanging off or split/blocked.
Check breather mesh in rocker cover not blocked (need to remove rocker cover) and associated pipes - dipstick area.
Check distributor pick up pins not caked up with fur and rotor arm & little brush in middle of cap is not perished/burnt.

Cheers guys! Been a while since I last checked this thread, but some more good stuff here to keep me occupied this weekend, I feel. Learning all the time here, and secretly wishing I had the diesel back on the road to give me less of a headache, but it's all good!

I did change the coil, as several points of enquiry did lead to the fact that could be on the wonk, but alas not. Still, 20 quid, new coil, and I have a spare (which DID have a lot of corrosion on the terminals... I think maybe a lead clean is due this weekend...).

Still got to do the exhaust, although I think I'll end up doing the whole lot in one go, lambda and all. Peace of mind, and it's not stupidly expensive all things considered.

Cheers!
Mike

Bloody hell, I've sorted it!

So, turns out to be the EGR valve and gasket... Never had to deal with either of those in any cars I've had in the past, so wasn't an immediate concern for me when troubleshooting. Had a friend of mine who is more knowledgeable than I suggest it as a point of failure, and whaddaya know? Bloody thing was full of crap and the gasket had corroded away something fierce.

Lacking parts to make a proper repair for now (I'll be using a blanking plate and proper gasket for a permanent fix later), I've had to make do with some firegum to form a temporary gasket and left the vac line off for the time being. The difference in running at idle and pulling away is immense in comparison... Now all I need to do is replace the corroded exhaust, and we're back to decent running again!

I'm wishing more than ever that I had the diesel back on the road now... none of this faffing with EGR valves and the like there, OH no...

Woohoo - excellent news on getting the old girl sorted.

To be honest, the 8 valve petrol engines are usually pretty much bomb proof.
I have to admit that I have never suffered an EGR issue on any of my petrol cars.
Usually oxy senders and damp in the ignition.

As a further point though -
Modern diesels are even more problematic than petrols due to having egr valves and diesel particulate filters that clog up for fun.

Thank the Lord for proper cars from the 80's and 90's.
Not modern electronic garbage we struggle with today.

Good job my old diesel is the 1.7TD Isuzu then, will likely outlast the rest of the car!