arghhhh!

driving home from my girlfriends and happily set off on my merry little way when i notice that the car is making a funny noise, kind of a tapping/pulsing. I stop, pop the bonnet and the sound appears to be coming from the area of whatever cylinder is under the intercooler at the battery side of the engine bay.

I initially put it down to the engine being cold and continue on my way. After about 30 seconds BANG! car now sounds like a tractor (similar noise to loosing your exhaust pipe) car still ticks over, but there isn't a great deal of power, boost needle is also flicking instead of holding a constant reading. Manage to drive the car home, approximately 1 mile. The car still manages to idle and there is no CEL error light showing.

Any ideas from peoples experience to aid/worsen my sleepless night as i contemplate a hefty repair bill.

A very unhappy

James

 

Blown exhaust gaskets?

 

I'm hoping something along them lines and not a cylinder!

 

Dont worry mate. My sport wont go over 3k RPM going up hill, just creates 1 hell of a racket. I think its the manifold I fitted blowing. I'm hopefully going to get it into the garage tomorrow to have it removed, cleaned and sealed and refitted.

 

You haven't popped the hose to your dumpvalve have you? Or has it come loose?

Dave

 

id check that

although the tractor noise is a bit worrying

 

I'll check the dump valve hose in the morning, but i wouldn't have thought is would have sounded like it does.

Thanks for the tip though

James

 

Is the engine rocking in situ; if it is then a piston could have gone; compression test it.

If the engine isn't rocking search for pipes not now connected.....

 

The engine is rocking in situ, I've had it compression tested. 1+3 are coming out at 150ish, 2+4 are coming out at 130 ish. (Idon't have the exact figures to hand). I should add that this is a sport, not a turbo.

 

You have an intercooler and boost gauge on a sport???

 

There seems to be 2 problems running at once on the thread.

The original one that started the thread was my UK Turbo.

I will check to see if the engine is rocking while idling. I'm hoping, especially judging by the sound, that something has just come off (thinking exhaust manifold on one of the cylinders)

James

 

Sorry James, I didn't mean to hijack your thread. I put my problem up to see if you were experiancing the same phenominan.

My cars currently in the garage so I will soon see.

Simon

 

No problem simon, wasn't having a go mate, just clearing up the confussion. I hope yours gets sorted quickly (and cheaply)

I just need to find someone decent and local to take a look as i don't fancy the local main dealer as i've had experience of the quality of their work with another car franchise

James

 

Best of luck mate. For the last 3 months mines caused me nothing but problems, and a big hole in the bank account. The only garage that could look at it this morning is a little backstreet job. Run by a nice guy, who's currently restoring a DB6 and an official Brembro centre!!. Crossed fingers for you.

 

by how you describe the sound i wouldn't be suprised if you have a spark plug that has popped out.

 

Mark,

Is that a possibility? worth checking though. the spark plugs are a ****ter to get to mind

 

Spark plugs aren'tas bad to get to as you think, drivers side just take out the airbox and you're there, passenger side just take out the battery and undo the washer reservoir so you can move and you're there.
Use a 3/8 drive ratchet and this is easy.
Did you check your hoses?

Good luck mate.

Dave

 

all the boost and dump valve hoses seem to be fine, I'm going to try get a local mechanic who i know of from a friend to come have a look as he's a proper mechanic and not a spanner monkey with some lego instructions!

my main thing is that i want my pride and joy to be cared for, i have lots of bad experiences with YT monkeys that seem to work for a lot of main dealers

James

 

Problem solved!!!!!!!!

it was indeed a spark plug that had spent a month or so working it's way out!
The car now lives again and feels great.

Only thing at the moment is that the idle speed hunts a little, but i think it's the ECU re-learning how to idle on 4 cylinders as apose to 3!

James

 

Nice one James,

For a moment I thought that could be a little expensive for you.

Keep a eye on the idle though.

Cheers

Martin

 

Only read this today James.

Glad you got it sorted.

Its not what I thought it was going to be. Was sure it would be the manifold / gasket to the underside of the head.

Easy job though and should'nt have cost you much in the end.

May be new pants or steam cleaning of the old ones

Ste.

 

definately new pants, Ste!!!! I pretty much shat-me-self when it went bang!

Thanks for the support though guys, I'm definately keeping an eye on the idle problem at the moment, it's quite curious.

How long does it take the ECU to reset after the battery is disconected as the battery was removed to put the spark plug back in (cylinder 2) so wondering if I have a failing MAF that the ecu has been correcting for and now it is struggling after a reset. could be a thought.

James

 

Any one able to answer my question about the ECU in the above post?

any help is much appreciated

James

 

Try unplugging the Lambda if it cures it then that is your problem, or you could replace the MAF if you have the type 2 one, its cheap enough.

 

cheers simon,

I'm spending tomorrow evening with my mate who's a mechanic fitting some new discs so i'll have a go then. It is the stage 2 engine, hence my worrying about the damn MAF sensor!

is it the Lamba that controls idle then and not the MAF? is the Lambda as dangerous a sensor to die as the MAF is?

James

 

No mate the MAF is the critical 1, if the lambda's shot the petrol just won't stay in the tank for very long, not that it does anyway in a scooby.

Another way of testing the lambda is a volt meter on the signal wire (black usually), you should see it rise and fall once a second between 0.1 and about 0.8v.

 

I don't supose you (or anyone) knows the part number for the MAF sensor on a 99 UK spec impreza and how much it is?

when fitting, will the ECU need a reset or will it be quite happy just to take it?

 

Sorry mate, I run the phase 1 MAF

 

no probs, thanks for your help this far though Simon, Much appreciated

 

22794AA010 I think is the number your after, but you can just get the sensor for about £77,(think that might be for the sensor unit not the complete sensor and housing).