Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

I have a 1993 cav which starts first time, every time but after it has warmed up and then I turn off the engine for a stop, it has trouble starting as if it is flooded. If I turn it over for a while and tickle the throttle, it will start but lumpy until revving seems to clear the lumpiness. After that she runs fine.
I found the corrugated pipe from the air filter and, i assume the airflow meter into the carburetor had split which has been replaced but this has not had any effect. It is as though the choke is coming on when warm starting, perhaps.
would anyone have ideas as to what to check, please?
Rupsey

If it's a C20NE then it won't have a carburetor. They are multi point fuel injection engines.

Is it overheating at all?

Try cleaning out the idle control valve.

I would look at the spark plugs...
Are they sooted up? - they should be if it is running rich.

The weakest link for rich running would be the lambda sensor, low down on the front exhaust pipe, just behind where it straps to the back of the engine.

Next weakest link is possibly the air flow meter or it's hot-wire sensor.

You have already checked through all the air ducting.
That just leaves the vacuum pipes, of which there are many.

It goes without saying about checking all wiring and connectors.

My car has been running smelly and lumpy recently, but that was due a totally tired out exhaust (cat & back box are both shot).

wow, thanks guys, that gives me a load of things to check. The card does not overheat, when it gets to temp, the fan comes on and down it goes. One thing I have noticed (may or may not be related) is when I leave it to idle for a while, it starts to get the lumpiness again and, I think, would stop after a while. If I press the accelerator it will be lumpy but revving will clear. It will idle at about 800 so seems normal without any dips in revs. It just seems to clag up when idled for 5 mins or so.
So to summarise I need to check (probably in order of priority or easy things first):

1) Check all the vacuum pipes for leaks - may be worth replacing some or all
2) Lamda sensor way down
3) Check wiring - what about the temperature sensor if it is not sending the right engine temp?
4) I will check the sparks but is regularly serviced
5) airflow thingy (how do you check if this is working correctly short of replacing it
6) clean idle control valve

Will do these and check back.
by the way I need a rear drive side lamp glass for the hatchback version!

Many thanks for all the suggestions

Indeed - the engine management coolant temperature sensor could indeed cause those symptoms.

I had got mentally side tracked by the difficulty with hot starting.
My prior similar experiences had been failures of the 1.8 SPi MAP and Lambda sensors.

James McGrath wrote:If it's a C20NE then it won't have a carburetor. They are multi point fuel injection engines.

Is it overheating at all?

Sorry for the delay. but no it does not overheat. It gets up to temperature and the electric fan comes on and down she goes.

Just to jump in with another question for the gurus, what are the diameters of vac pipes present on the C20NE? Looking to change all of mine at some point, was wondering if they're all the same or various sizes.

I have looked on Ecat.
For vacuum pipes on the C20NE,they quote two sizes.
3mm bore and 4mm bore.
There are other pipes, but these are not vac pipes.

Cheers Robsey, I always forget about Ecat. I'm pondering getting some silicone hose to replace all the rubber vac lines, just needed the ID of the pipes in question. Now I can get the right stuff, hopefully!

Well, not been as active as I used to be, but I've still been tinkering with the car and HOPEFULLY (and I always say that shortly before I'm disappointed) I've traced the issue to the fuel pressure reg. Given the damn ting is over fueling at idle but apparently fine when under power, it would appear that the differential at idle (of which there should be none) is on the wonk, and giving too much fuel for too little vacuum, thus resulting in too much being pulled out of the injectors during their firing phase. Also given that the C20NE is a fire-once-per-revolution injector system, that results in a LOT of fuel building up on non-ignition cycles, which would explain the inconsistent misfires I get.

Assuming this IS the culprit, then I can only assume the 1.8 is also suffering a wanky reg, because the symptoms are identical (to the point where you can see the fuel being injected in the SPI setup, and it looked excessive) and thus the resulting behaviour is too.

At this point, I have a replacement FPR on order (and those ain't cheap! 78 quids, but it IS bosch). I'll let you all know either from the excessive celebration or tears of woe that follow as to how it went.

Watch this space...

I am indeed watching with keen interest.

I know my MOT was initially failed due to high emissions - possibly suggesting a similar issue to yours.

There aren't many other items on the C20NE system that can go daft.

Like you, I have changed / renewed most of mine... so interesting to see if it is the fuel pressure regulator.

Fingers and toes crossed for a positive resolution to your running woes.

Well, the solution eludes me once again... after injuring myself contorting my fingers to get access to the FPR without disconnecting anything else, I had it finally removed, hoses replaced and ready to go back in... until I discovered my halfwit self had managed to put the back hose on the wrong way around. After more swearing and bruises, it was sorted, and ready to fire up.

Wait... why does that sound worse than before? Lumpy... like something isn't right at all... and why is the engine light on? Ok, so back to examining it, finding nothing wrong and then disconnecting the battery in case the ECU somehow confused itself. Only after doing so did I THEN realise I'd somehow managed to knock the connector bar enough to disconnect the closes injector. Duh. Duely reconnected, I fired it up, and that sounded MUCH better. Then slightly worse... then back to it's old tricks again.

Bum.

And... I'm not sure what on earth I'm hearing, but I get a kind of whirring, slightly scraping sound from the bell housing... not constant, but every now and then. Or is it the sump... yeah, I think it might be. I'm wondering if something has gone wonky down south, but I don't have the time today to sort it.

Still, I did a quick vac test on the old FPR, and it really wasn't moving much, so I'm glad I DID replace it in the end. Just... I wish it could have fixed it. Still, there's always the next discovery... right?


Edit: I DO have a replacement O2 sensor that I should try... just to see if it's that... didn't stop the 1.8 playing silly buggers, but if it's contaminated, no clue what it could be doing. That's the next one to try!