Loud backfires, loss of power at low revs.

[oliver.james]

So, just when all was going so well... :dapprove:

I started the car this afternoon to find a possible misfire when low in the rev range; along with an awful 'blowing' / 'spluttering' type noise heard from the exhaust.

There's very little power low in the rev range, then a sudden surge of power comes back around 2.5K - 3K point. Also, just to make things more fun, when sitting at idle, I've been getting pretty loud backfires.

I had to use the car this afternoon; once the engine was warmed up (after approximately 20 mins of driving) the symptoms disappeared completely and the car was running perfectly. I was hoping it was just a glitch and that it had cured itself.

After leaving the car for a few hours, I started it up to drive home and it was doing exactly the same thing again. I started the drive home with exactly the same loud blowing/spluttering noises and loud backfires with very little power low down in the rev range. In addition this time, after a couple of minutes of driving the 'toxic fumes' warning light began flashing on the dash then went out...

Again though, after 15-20 minutes of driving it cleared again and the car was running fine. Help please!

 

[Cro]

Could be any of coilpack, ht leads, plugs, lambda dude.

Start checking with the easy stuff, Just check all the plugs are in tight, and the ht leads aren't arc'ing anywhere. You can swap the lambdas about and it'll work fine. See if that makes any difference

 

[magh]

as above would be the first things id check/replace

 

[oliver.james]

Would the spluttering sound from the exhaust and backfiring be a result of the same thing?

Mentioning lambda, I've just had a de-cat fitted (a week or so ago) ; could that have anything to do with it?

I'll start by checking those things listed, cheers guys! I'm assuming if the plugs got damp it could cause similar symptoms?

 

[magh]

it would indeed, if fitted correctly wouldnt make a difference, have you got any warning lights on the dash?

 

[Cro]

Chances are with a decat you'll get a warning light but should run as normal. The spluttering and power loss will be because its down a cylinder most likely.

 

[jenic]

Chances are with a decat you'll get a warning light but should run as normal. The spluttering and power loss will be because its down a cylinder most likely.

This.

Turned out to be an injector down on mine, got to admit, the noise was sort of epic for the few days it was like that though

 

[oliver.james]

it would indeed, if fitted correctly wouldnt make a difference, have you got any warning lights on the dash?

I had the 'toxic fume' light flashing for 30 seconds or so, then it went out.

Chances are with a decat you'll get a warning light but should run as normal. The spluttering and power loss will be because its down a cylinder most likely.

It's been running as normal until this afternoon.

I'm a n00b when it comes to this, as I've never experienced anything like it before; I've been lucky in the past I think!

I don't understand why, when the engines warm (say after 15 or 20 minutes of driving), the problems disappear completely and everything runs perfect again :S

 

[oliver.james]

This.

Turned out to be an injector down on mine, got to admit, the noise was sort of epic for the few days it was like that though

Mike, was that also an easy fix?

 

[jenic]

Yes it was.

Fuel rail guard off, fuel line off, pull the rail out gently, swap the injector then reverse. Really simple

Can you get it on a diagnostics, even a code reader or RSTuner will do.

 

[oliver.james]

Did you have backfiring with the injector issue?

Thinking about it, would a backfire be caused by fuel but no spark? So possibly eliminating the injectors as the fault?

 

[jenic]

No it wasn't, and yes that would make sense.

Ideally you need to put it on a code reader really.

 

[oliver.james]

Sadly, I can't really get to do anything with it until Thursday. :dapprove:

I'll just have to drive it carefully and with a bit of persuasion until then.

Thanks for the help guys

 

[Dave.]

Water in a spark plug well does a very similar thing mate, mines had exact same consequences. Make sure it's dry in the wells, plug leads and plugs. If it is water, it won't evaporate as it's sealed in by the leads.

 

[oliver.james]

Water in a spark plug well does a very similar thing mate, mines had exact same consequences. Make sure it's dry in the wells, plug leads and plugs. If it is water, it won't evaporate as it's sealed in by the leads.

What was the fix for that? If there's water in there, is it as simple as getting it out and drying everything off? Or, did you have to replace plugs, leads?

 

[Dave.]

I did the following...

Remove leads completely and check for water above the plugs with some blue roll, if it's damp BINGO.

Remove the leads and wave them around to get rid of the water. Worse case let the water evaporate overnight.

If there is water in the wells mop it up, by dabbing paper in the wells. Then remove plugs and dry them off.

Fit back together, free, lovely!

Hope it is that mate!

 

[oliver.james]

I'll be sure to check that too.

Cheers for all the replies, I've got a good idea of what to have a look at now!