Problems with a Vectra C 1.8 2003

[awilson1234]

Hi everyone!

I'm completely new to this, so please forgive me if I'm doing anything wrong! I'm not a mechanic, but I am fairly clued up with cars.

I purchased a Vectra C 1.8 2003 in Feb this year. I've put nearly 10K on the clock since purchasing with next to no problems until now! Its now got 82K on clock.

When I first got the car I notice the temperature was constantly at the bottom end of the scale, changed theremostat and it fixed the problem.

Now and again since I got the car it started, ran rough for 5 - 10 seconds then stalled. Its got worse recently and does it more often. If it doesn't do this, it can sound like it is just running generally lumpy.

I know theres the auto choke on the car, if I start whilst its still running in the higher revs the car kangeroos, if I allow the choke to turn off it runs fine.

I sometimes get a flat spot when starting in 1st.

I think thats about it.




So far I have;

• changed plugs
• changes air filter
• cleaner throttle body
• sprayed through MAF with carb cleaner
• changed temperature sensor on thermostat

Any other ideas as to what it could be?

EGR valve is not fitted..

Thanks!

[ChrisBilly]

I used to have the same problem with the occasional non-starting, it went away when i replaced my leaky broken egr. Maybe make sure there is no leak around your blanking plate. It could possibly be a vacuum leak else where.
The flat spots are common and can (debatably) be soothed out with the air box mod.

[awilson1234]

I'm pretty sure it has already got the air box mod, but I will check tonight.

As far as the EGR valve goes, I'm pretty sure its not got any leaks around that area and I've not seen anything anywhere else. I had began to think coil pack?

I just don't want to be throwing money at it!

[calibra_se8]

Have you had it checked for fault codes? Could lead you to the problem or near it anyway.

[rich r]

Rather than blindly changing things, I would definitely get the fault codes read - they could point to a failing sensor for example. In this case, possibly a temperature one, or yes, maybe a weak spark causing a slight misfire.

You might be interested to know that the concept of a 'choke' has no meaning on modern common rail fuel injection cars. There is no additional butterfly valve. The ECU uses information from the intake air temperature, coolant temperature, engine vacuum to calculate how much fuel it should add. It also varies the ignition timing and idle rpm to keep the engine running smoothly. Once the engine is up to a certain temperature, it then starts looking at the signal from the exhaust oxygen sensor to see how much oxygen is left over after combustion, and then uses this to decide to increase or decrease the amount of fuel it has calculated in order to keep the engine running as cleanly as possible. You can hear this switch from open loop mode to closed loop mode if you start the engine from cold and let it idle. After about 30 seconds or so the revs will drop and it'll idle smoothly.

[awilson1234]

I have had the car plugged in, but there were no faults live or stored.

I've changed the plugs, and the temperature sensor in the thermostat.

Are there any other temp sensors to change?

The misfire only seems to happen during the first 30 seconds, indicating it must be during the open loop mode, I assume? What should I check/change/clean to solve the misfire I'm experiencing during this period?

It does idle quite low, at around 600rpm, but reading other threads and posts it appeared to me this was normal?

Thanks a lot for your replys!

[rich r]

OK, cool. The fact that it only does it in the open loop startup mode should help.

Airflow meter springs to mind - this also tells the ECU the temperature of the air entering (so it can work out the density of the air, and hence the amount of oxygen).

The MAF can fail to report the correct value, yet still not fall outside the limits that the ECU would flag it up as faulty. However, they're not cheap, so it'd be better if you could borrow a known working one to test.

[Das]

With the car running pull the multiplug on the Air flow meter and see if the idle changes, if it doesn't that would be my next port of call. Coil pack does seem to be the other weak area on them too. Do you know anyone with a 1.8 that you could swap over these parts and see if that helps.

[awilson1234]

I don't know of anyone else with a 1.8, my old man has a 2.0 turbo diesel but thats it... I guess they are completely different!

I took the air filter out last night and did the mod of removing the plastic section, whilst I was there I took MAF off and blasted through with electrical connection cleaner (I've already used carb cleaner which had a bit of an affect so thought it would be worth it..)

The car seemed to drive smoother, but I've not cold started yet. I noticed a few days ago when I was reversing into my garage the revs dropping really low when I let off the gas and dipped the clutch completely down, then revving itself to make sure it didn't stall. However, it didn't do it last night after what I did! ^^

I will get her out the garage tonight and have a go!!!

[rich r]

Carb cleaner might be a better bet than the switch cleaner, as they tend to contain oils to coat the contacts and keep them from corroding. Carb cleaner evaporates totally leaving no residues.

You might find that the MAF sensor itself is degraded rather than just dirty - but you might as well try cleaning it first before condemning it.

If it does seem to help with the stalling issue, then at least you've narrowed down the fault to one area.