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[aaronjb]

Me again

So after fixing the vac hose problems ( http://www.omegaowners.com/forum/YaBB.pl?num=1276462558/15 ) I've discovered a new fault..

The autobox is now very lazy when pulling away in 1st (though first is definitely engaging - selecting 1st and switching to 2nd produces the same results of slow pulling away with a definite change of gear when you switch to 2nd) and this morning couldn't reverse off my drive at all (up a gentle slope) despite plumes of black smoke and gunning the throttle, I just wasn't going anywhere..

Does that sound like clutch/brake bands to anyone else?  If so, I suppose I better keep an eye on that Carlton AR35 box on eBay!

[Elite Pete]

I would check the gearbox fluid levels first but the diesels are hard on the AR25 box

[tunnie]

how many miles has it done? Check the fluid level, it should be level with the fill plug 

[aaronjb]

It's got 93k on the clock so relatively low mileage for the year, assuming it's never been clocked 

I would check the gearbox fluid levels first but the diesels are hard on the AR25 box

Yeah - this car has a towbar with caravan electrics fitted, too, so it could have had a hard life if it's been lugging 1500Kg of caravan around for those 93,000 miles..

I'll get under there and check the level at the weekend when I do the oil/filter/etc on the engine. Which reminds me.. why do manufacturers never fit a drain plug to automatic transmissions? Nissan made the same design choice on their early boxes, too  :-/ I don't really want to have to pull the pan off to change the fluid!

[tunnie]

It's got 93k on the clock so relatively low mileage for the year, assuming it's never been clocked 

I would check the gearbox fluid levels first but the diesels are hard on the AR25 box

Yeah - this car has a towbar with caravan electrics fitted, too, so it could have had a hard life if it's been lugging 1500Kg of caravan around for those 93,000 miles..

I'll get under there and check the level at the weekend when I do the oil/filter/etc on the engine. Which reminds me.. why do manufacturers never fit a drain plug to automatic transmissions? Nissan made the same design choice on their early boxes, too  :-/ I don't really want to have to pull the pan off to change the fluid!

They did have them on Senators, but it was removed on the Omega to make room for more electrical components. To be fair, apart from the TD AR25 combination they rarely need attention until at least 150k

[aaronjb]

Ah.. I had an epiphany as I was driving home tonight..

The only thing I changed between the car driving alright when pulling away, and it feeling rather like an asthmatic slug, was the EGR solenoid & MAP sensor hoses (in my other post) - so how could the 'box have suddenly taken a turn for the worse?

So I thought to myself.. what if the EGR solenoid is stuck open? That would keep the EGR valve permanently open whereas before the valve was essentially connected to nothing (well, the MAP sensor!) and would have been permanently shut..

That would probably mean, I thought, that at idle/low speed/pulling away there would be much more pressure in the exhaust than the intake and the engine would be ingesting large chunks of exhaust gas instead of fresh air. Hm. That would explain why it overfuelled massively (clouds and CLOUDS of black smoke) as the ECU would still inject the right amount of fuel for fresh air..

On boost when the car took off at great speed, the pressure in the intake would probably be greater than in the exhaust, so some intake charge would disappear down the exhaust (essentially a huge boost leak) but it wouldn't overfuel - as shown by the lack of black smoke at speed.


So.. I parked up part way home and pulled the vac hose off the EGR valve (so I now have a small vac leak in the vac pump circuit, but I can live with that) and pulled out of the junction the way I would have had to before..

The car took off like the proverbial off the shovel!


So.. I think I found my fault - well, two faults.. one, the vac hoses misconnected and two, a £10 solenoid valve that's stuck open.

We'll see what it drives like when cold (as it was much worse then), but it looks promising... Huzzah!