My old girl is too sensitive

[Leekins vs MK3 Cav]

I own a 93 Cav with a genuine 240,000 miles in the clock on the same 1.6 engine. Still in good nick but for a while now she has been playing up. It starts well, goes through all the gears and sits at crusing speeds comfortably. BUT - it has a habbit of cutting out sometimes when i pull up at say, traffic lights. It doesn't idle very well, revs vary from 500 rpm up to 1600 rpm, it goes up and down then it can cut out. I've tried all sorts of things but have now run outta ideas.

PLEASE HELP!!!!!!!!! I determined to get it up to quarter of a million miles, only 10k to go!!!!

[dave's.veccy]

welcome to cavmk3

Assuming its a SPI (Single Point Inj), Have you cleaned out or replaced your idle motor??

I had a 1.8 that used to play up on idle and every so often i used to pour redex down the small port above where the Idle valve is whilst it was running. This used to cause a lot of smoke for a small while but after about 5 minutes of a little spirited driving the smoked clears and it idled nicely.

[Leekins vs MK3 Cav]

Thanks for a quick response!

Yeah it's the spi model. Is the idle motor the same as the idle control valve, the little black thing that screws into the front side of the air/fuel intake? Really only noticeable after removing the air intake? If it is the little black thing that is held in place with 2 small screws - then yes. This was one of a few things i did by replacing old with new/second hand. To be honest - it hasn't really made a difference. I spoke to a vauxhall specialist who suggested i take it out and manually pull in/out the centre shaft bit - but nothing.

[v6sri]

sounds like a split vacume pipe?but id emagen u tryed that ,i duno i give up

what stuff have u dune so far lets try an narrow it down id like to c this hit 250

[Cavalier342]

Ye, my 1.8 engine plays up on idle at rare times, but mostly when its really cold. For example i start the engine, drive down the road, then as i slow down for the junction, the car jerks a bit, the rev gauge needle jumps a bit and i can hear it basically trying to make its mind up between gears then when i shift into N, the idle is a bit funny and can sound quite jumpy. But after a short while, it drives as normal. I would imagine its the idler valve myself, cant think of any other problem to be fair. My Cavalier's on 85k miles at the moment, but i guess those bleeding idler valves can play up at anytime lol. Anyways hope it helps buddy, I'd love to see her reach that milestone myself I'm sure she will anyways, these lovely cars are faithful

[Cavalier342]

by the way, i just noticed, my last post just before this one, made the total number of posts in the Engine and Transmission section 1111

[dave's.veccy]

Thanks for a quick response!

Yeah it's the spi model. Is the idle motor the same as the idle control valve, the little black thing that screws into the front side of the air/fuel intake? Really only noticeable after removing the air intake? If it is the little black thing that is held in place with 2 small screws - then yes. This was one of a few things i did by replacing old with new/second hand. To be honest - it hasn't really made a difference. I spoke to a vauxhall specialist who suggested i take it out and manually pull in/out the centre shaft bit - but nothing.

No probs, i was quick to spot the question

Its got many names in the motor trade but yes thats it. These are prone to seizing up but then you get the Eml illuminate then or they just get bunged up with carbon deposits and cause problems

There is also a 3 way diaphragam valve which is known to cause idling issues also which also has vacuum pipes going to it from the throttle body as surgested above. My Expression came with a free snap-on screwdriver bunging up the vacuum pipe to the formentioned valve. You cant miss the valve, its got 2 pipes in one side and one out the other located to the left of the throttle body unit

[oojimmyflip]

This happened on my old MK2 but it was traced to the chip mounted on the coil, with the later models having electronic ignition I'm not sure which part of the electronic system this relates to.

[Leekins vs MK3 Cav]

Thanks for the replies........... I am going out this weekend to have a fiddle, on the cav that is. I have a couple of ideas on what i need to do. I'll let you all know how i get on.

In the meantime, here's what I've done.....

1. Replaced the idle control valve coz i actually f**ked up the old one trying to free the shaft bit inside it,
2. Had the rocker cover off, cleaned the mesh inside it, the breather from this to the air intake housing, (including other pipes)
3. Even removed sections of exhaust to check on foreign deposits,
4. Driven HARD,
5. Poured redex through the system,
6. Replaced HT leads & distributor/arm
7. Think thats about it.

I did the paper clip test - the cheap way of finding the fault codes - it came up with suggestions that a couple of sensors were 'detecting' something not right. I did this ages ago and didn't get round to following this up - this was like, 60,000 miles ago.

Just out of interest, is it worth de cating these cav's?