Loss of power

Post queries regarding your Mk3 Cavalier's mechanical components (engine, transmission, turbochargers etc.) here
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Loss of power

Post by Freakmandu »

Hey :)

Was on a little tripette today when suddenly the cav lost power and started being very sluggish when under load. Its reminiscent of a plug or two going, but the engine isn't sounding like that's whats happened. Ive had a bit of a rattle from the cat recently, nothing major just a slight rattle when pulling away but that's now quite a bit worse and seems to rattle all the time. Im thinking perhaps its time for a new cat - could anyone tell me what happens when the cat gets blocked or something? Or any other suggestions as to what may be wrong would be appreciated. When I rev the engine its fine for about 2000 revs, but rev it any further and it just goes bleh. Starts and ticks over fine.

Oh, and the problem gradually gets worse the longer the car is running, until eventually I was trying to go up easy hills in first and it was still struggling even then, but if I stop and let it cool down a bit itll manage the same hill in second or third (only just, and quite slowly though)
User avatar
Cavalier342
Registered user
Posts: 9818
Joined: Tue Jul 22, 2008 10:46 pm
Location: Dorset

Re: Loss of power

Post by Cavalier342 »

If the baffles inside the cat converter rust away, they can break off and cause a blockage as it's a thin lattice type design inside the box. That would lose a bit of power but not a lot.

Sounds like it's something else... What engine do you have again? Could be a MAF sensor or something, hard to tell really. :scratch
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

c20ne - got a 1992 cd
User avatar
Cavalier342
Registered user
Posts: 9818
Joined: Tue Jul 22, 2008 10:46 pm
Location: Dorset

Re: Loss of power

Post by Cavalier342 »

Being an 8v there's less to go wrong than the bigger 16v blocks... Have you checked the basics under the bonnet? Could be worth checking the distributor cap, and the rotor arm.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

had a quick look while I was waiting for it to cool down, all seems fine except the rubber at the top of one of the plugs was blisteringly hot. Was going to have a proper look tomorrow.
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

If the exhaust blocks it can make it flat as a pancake! Depending on how much flow there is it can be anything from won't run at all, to a mild loss of power under load. What you have described would fit the bill perfectly. Usually find that if I have a suspicion of this then removing the o2 sensor allows it to breathe and will confirm it. When you switch off the pressure drops, sometimes allowing the blockage to fall back so it can easily come and go. The more it's blocked the throatier the engine sounds under load, a deep roary note.
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

Oh yes, and additional heat is a by product is of the exhaust gases having nowhere to go.
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

Could it be the lambda sensor itself causing the problems? It was quite black and manky when I saw it as my mechanic was changing that part of my exhaust. It'll probably be the cat though, knowing my luck - its always the most expensive bit :(
User avatar
Gaz
Registered user
Posts: 6985
Joined: Sat Sep 22, 2007 1:05 pm
Location: Manchester

Re: Loss of power

Post by Gaz »

lambdas are always manky,
Image
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

It's possible for the 02/lambda to have an effect, and easy to eliminate by unplugging it. It could be a lot of things but you have described classic blocked exhaust symptoms though and my money would be on that.
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

Thanks :) Ill go look out for a reasonably priced cat then. Any thoughts on the best place to try?
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

What year is yours? I thought you had an early car, if so then you could knock the middle out of it?
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
Cavalier342
Registered user
Posts: 9818
Joined: Tue Jul 22, 2008 10:46 pm
Location: Dorset

Re: Loss of power

Post by Cavalier342 »

I usually use this website:


http://www.cats-direct-shop.co.uk/parts ... onverters/


Decent prices and fast delivery.

She did mention it was a 92, so could be early or late, if it's early you can get away with it, if it's got one on there however, then chances are you need one on there.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
User avatar
ashs_cav
Registered user
Posts: 399
Joined: Thu May 02, 2013 9:11 pm

Re: Loss of power

Post by ashs_cav »

Could this work for the x20xev SRI 16V?
Enaing the blocked system and the 02 Sensor?
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

ashs_cav wrote:Could this work for the x20xev SRI 16V?
Enaing the blocked system and the 02 Sensor?
Decipher enaing?
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
ashs_cav
Registered user
Posts: 399
Joined: Thu May 02, 2013 9:11 pm

Re: Loss of power

Post by ashs_cav »

Meaning* haha
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

Mines a 1992, J reg. First registered 30/04 if it makes any difference :)
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

Cavalier342 wrote:I usually use this website:


http://www.cats-direct-shop.co.uk/parts ... onverters/


Decent prices and fast delivery.

She did mention it was a 92, so could be early or late, if it's early you can get away with it, if it's got one on there however, then chances are you need one on there.

Thanks :) Not too bad a price on there at all! Certainly less than I was expecting.
User avatar
Cavalier342
Registered user
Posts: 9818
Joined: Tue Jul 22, 2008 10:46 pm
Location: Dorset

Re: Loss of power

Post by Cavalier342 »

J-reg would suggest that it's the early model ( horizontal slotted grille) and badge on bonnet. In which case it doesn't need a cat.

The cat converters are only expensive if you get the ceramic type ones. Supposed to last longer but hits your wallet more than anything.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

Image

That's mine, but doesn't it have to have a cat if it already has one?
User avatar
Cavalier342
Registered user
Posts: 9818
Joined: Tue Jul 22, 2008 10:46 pm
Location: Dorset

Re: Loss of power

Post by Cavalier342 »

My auto passed it's MOT with no cat, as it's a 92 model. The tester said, technically the law wasn't introduced until 1993, so he was a bit more lenient and it passed the cat test anyway...

It's an early model so I'd take it off, and put a standard pipe on there, and just say that's how it was.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
User avatar
Envoy CDX
Club Admin
Posts: 9681
Joined: Sun Sep 23, 2007 3:51 pm
Location: Jarrow, Newcastle Upon Tyne

Re: Loss of power

Post by Envoy CDX »

Grey area regarding cats. If it had one, it should keep one..

However beforr shelling out hard earned. Drop the cat offand see if it cures thr problem :)
Check the Rules!

Raw 8v Power! - Bad Cav, Naughty Cav... Cav want's to do 90!

The How2 Index
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

I'm not up on the latest mot rules, but when I was a tester the cat test was applied to k registered vehicles onwards. Earlier cars only had to meet a maximum of 4.5% co and a hydrocarbons limit, which if I recall correctly was 1200ppm. Certainly as Gary suggested, before you spend too much money get the box off to see if it solves the problem. My exhaust blocked at the back box, and if the cat has collapsed it could potentially fill the rest of the system with bits and clog anywhere from there back.
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
planetc
Registered user
Posts: 6258
Joined: Wed Oct 20, 2010 9:59 pm
Location: Eating cake in Bexhill On Sea
Contact:

Re: Loss of power

Post by planetc »

Also worth noting that most cat failures are due to a misfire allowing unburnt fuel to pass through it. Be sure you don't have any misfire issues to avoid killing a new cat.
"No the temperature gauge doesn't work........
we've driven 150 miles today........
the heater went cold last Thursday........
they check the level when it's serviced don't they?"
User avatar
Freakmandu
Registered user
Posts: 221
Joined: Mon Oct 31, 2011 9:34 am
Location: Abbots Langley

Re: Loss of power

Post by Freakmandu »

Well, I have had a bit of a rattle from the cat area for a few weeks now - it was quite minor but I don't like rattles so I was going to get it looked at, but as I was out on my trip I missed a turn. I reversed into a driveway to turn around, and as soon as I went back into first again the rattle was quite noticeably a LOT worse, was now constant instead of intermittent, and a lot louder - this was the moment when I lost power. The rattling is still, however, coming from the cat area. Ill get my mechanic to check it all, but I think it probably is the cat that's the problem here.

Havent had any misfire problems at all.
Post Reply