STILL got crappy fuel consumption, and clouds of back smoke

Oscar · Post by **Oscar** » Fri Jun 17, 2011 5:06 pm

UPDATE:

Took the ZX (oh, and the family) to Devon for a week. Smoke and fuel consumption issues have come back with a vengeance.

A couple of points: smoke most evident when the engine is under a load. For example, going uphill at about 2000rpm, or moving off fast through 1st and 2nd eg when pulling out of a layby and needing to match speed of traffic quickly. Car would stop smoking if dropped back down a gear, but often this pushed the revs up to 3000rpm. We were filling those little Devon lanes with black smoke on occasion.

As I mentioned previously, the intercooler has been cleaned inside and out, but I've discovered it's not airtight, so I improved that by crimping the crimps between plastic and ally tighter, and ziptie-ing it up.

Before I get the injectors out for testing, is there anything I'm missing or should be trying?

Cheers

Oscar

Hi folks

OK, I know this is a ZX, but it's the same engine (just a bit bigger - 1.9 Turbo) and anyway, I feel safe here....

We're only getting 9 - 9.5 miles per litre/40-43 miles per gallon, even on a long easy run, there's a lack of power, and when the engine is under a load, I get clouds of smoke out the back.

I'm thinking injectors, wondering whether the pump needs adjusting, and I know that the intercooler needs a good clean.

Any other thoughts? Any help appreciated.

Oscar

mds141 · Post by **mds141** » Fri Jun 17, 2011 5:16 pm

Does the air filter need cleaning/replacing? Try a good dose of REDEX.

MULLEY · Post by **MULLEY** » Fri Jun 17, 2011 8:09 pm

Have you also checked the fuel filter? If its blocked that can restrict how much fuel is delivered & therefore affects performance & oddly can make mpg drop as well.

It might be a combination of factors such as the air filter being very dirty as mentioned, along with the fuel filter & perhaps a clogged/dirty intercooler.

Have you checked that your exhaust hasn't collapsed internally, if there appears to be a wool like stuff eminating from the tail pipe then thats your issue.

Oscar · Post by **Oscar** » Fri Jun 17, 2011 8:18 pm

Sorry, should have said that air and fuel filters were changed recently. A flippin' bird's nest fell out of the air filter housing when I opened it up and I really expected that to sort the issue, but no.

Exhaust...it's a bit noisy, all right. I might get it up on the lift and have a good poke about.

kiwi · Post by **kiwi** » Fri Jun 17, 2011 9:09 pm

Oscar if you lived here and that was a petrol ZX you had you could have always gone into a former shell station which is no longer owned by shell and rebranding by a company called Z (pronouced Zed).

Any way shellVpower is now called ZX Fuel

Perfect fix?

Post by **mat_fenwick** » Fri Jun 17, 2011 10:45 pm

Can you hear the turbo spool up at all? Black smoke indicates too much fuel/too little air. Unlikely the pump needs adjustment.

Oscar · Post by **Oscar** » Sat Jun 18, 2011 6:59 am

Not really. I floor it and the car has a little think, trundles along for a while, I go away and make a cup of tea and by the time I get back it's picking up a bit of pace. With the BX, you felt it instantly, used to surprise the boy racers up Bluebell hill. What are you thinking?

Perhaps the air supply is blocked further down.

Post by **mat_fenwick** » Sat Jun 18, 2011 9:57 am

I'm wondering whether you have a boost problem, either from a blockage, wastegate stuck open or turbo seizure? IIRC you have a similar top mounted intercooler as the BX?
If you undo the hose to the intercooler from the turbo on the LHS as looking from the front of the engine, hold something like a piece of paper over the hose and rev the engine fairly hard, you should get a lot of air coming out. If not, the problem is turbo related. If you do, it'd probably be worth checking the intercooler for any restrictions. NB if you do clean the intercooler out with a solvent, wait for it to evaporate before putting back on.

Oscar · Post by **Oscar** » Sat Jun 18, 2011 4:37 pm

OK, will give it a go, cheers. It's getting embarassing leaving smokescreens behind me up the hill.

Philip Chidlow · Post by **Philip Chidlow** » Sat Jun 18, 2011 4:42 pm

Oscar wrote:OK, will give it a go, cheers. It's getting embarassing leaving smokescreens behind me up the hill.

Never bothered Mat on the BXagon

lucky rich · Post by **lucky rich** » Sun Jun 19, 2011 12:57 am

If you do go down the cleaning out the intercooler route with a solvent ,just be a tad carefull ,,,,,,,,,i cleaned out one with brake cleaner ,filled it up overnight then drained all the clag out in the morn,,,,,left it over a day outside in the wind to dry out ,,,,,,when i started it after wards it reved its tits off with the trapped fumes ....... only lasts for 10 secs or so ,,,,,but dont af make you jump.

DavidRutherford · Post by **DavidRutherford** » Sun Jun 19, 2011 8:43 am

Grey/brown manky looking exhaust from an XUDT engine is usually crappy injection patterns / poor injection timing causing a naff burn. Not the same as black smoke, which is overfuelling, but just a low temperature poor quality burn.

When the engine is running, does it have that strong "cracking" clatter of a diesel engine, or is it soft and muted? If the latter, then the injection timing is retarded.

Also, when idling, does it miss a cylinder every now and then? listen to it run, and it should be completely even. If it just stutters for an instant, and then continues, that indicates an issue with fuel delivery.

Also, how well does it start in the morning? Count the compressions. 1-2, this is a good engine. 3-5, it's OK. over 5 and you may have injection and/or compression issues. If you have to churn the starter for a week, then there's no surprise!

Another thing to consider... is this an engine late enough to have EGR? if so, then strip the intake system off, blank off the EGR and spend a week cleaning out the inlet manifold. The restriction that puts on the engine is massive.

Oscar · Post by **Oscar** » Sun Jun 19, 2011 8:29 pm

Loads of top quality advice, as usual folks. I'll give it all a good go next weekend I reckon. Thanks.

Oscar

...erm, what's "EGR"?

Post by **mat_fenwick** » Sun Jun 19, 2011 11:13 pm

Exhaust gas recirculation. Do you have any pipework between the inlet and exhaust manifold? From memory it's a stainless steel corrugated tube if fitted.

Sorry for going on about black smoke- I had missed the bit about the colour and for some reason assumed it was black...

(I've learnt something as well!)

Oscar · Post by **Oscar** » Sat Jul 02, 2011 8:32 pm

Update:

We have a clatter, David, so it's not the timing. Takes 3 compressions to get going in the morning (I take more personally, fnar fnar), so that's acceptable. There's a good positive push of air out of the tube under revs, thanks Mat.

Got the intercooler off, cleaned the dead flies out of it in the shower (it's ok, SWMBO doesn't read this forum), gave it a good scrub, and drained the oil out of the little tube off the front that goes down to the fuel pump. I didn't clean the crud out of the intercooler as I didn't have enough solvent here. I'll do that later.

It's made a difference, a good one. Much faster, much less smoke, you can feel the turbo now. Took it for a 50 mile thrash at 70-90 and got 40mpg from it. Dropping from 5th to 4th at 70mph and then revving up to 90mph produced a bit of smoke the first couple of times and then was fine , and it pulled away up Bluebell hill well enough, although still not as good as the BX. SWMBO is away next week so I'll buy some solvent of some sort and clean the intercooler innards out and see whether that helps any more. Rich I'll make sure it's all gone before I put it back on, cheers.

Thanks all and thanks to Stewart for telephone consultations.

Oscar