Loud rattling noise

[jamie_eaton]

Right then on my way home from having my car tuned the other day i noticed a strange rattling when boost started to kick in, or should i ay when i put my foot down a little.
i found this link
http://www.mazdarotaryclub.com/forums/showthread.php?t=18408&highlight=rattling
and not sure but maybe sounds like this, you see i also had an aftermaket rad fitted, so think my air con , condenser was moved a little , im not sure.
The sound was like a little macjine gun going off under there!!, i also noticed an awfull smell!! like leaking gas, then the next day my coolant alarm was on buzzing when i turned it over, but then turned off?? i just have not got a clue!.
Hope it nothing serious

[g11ary]

Check that nothing has rattled loss, then have a look at the blanking plates on the plenum, if they come loose then would would get that rattle and possibly gas smell. It would also sound like a small exhuast leak if you lift the bonnet.

[clive]

Hi Jamie,

Bit difficult to answer this one, have you still got an air pump and a cat ? as it could be either of these that have died.

Also have you got a boost gauge so you know its not overboosting as the "rattle" could be detonation !

The water problem means the water level was down and as soon as you started the engine the water circulated and water went over the buzzer and stopped it.

Is the engine still running O/K, More info please

[jamie_eaton]

Right thanks for the info, no i dont have the air pump that was removed when the single turbo went on, and the cat has gone too.
The engine seems to run fine and ok its just when the foot go's down and boost comes on.
Also i have when i speed up it gest to a certain ammount then feels like it cuts out , and sends me forward, like the fuel is cut or something?.
I have a bosch o44 pump and the tank was about quarter full??, arrrrgh!!

[Carl]

It will almost certainly be detonation.Be very careful!
Regards
Carl

[jamie_eaton]

Oh what!! no, what exactly does this mean? is this bad?

[Ricco_04]

Detonation is bad as it can kill your engine (if indeed this is the problem?). Assume it was tuned for 97ron then are you using Optimax?

As you have just had it tuned the best bet is to contact whoever tuned your car and describe the same to them and see what they perscribe as the best course of action.

HTH

[gmogle]

Have you got a Power FC and Commander, the commander should show the detonation bar. I thought it beemped when it went too high ?

Gareth

[Carl]

Detonation is uncontrolled ingnition of the fuel/air mixture.
Basically it means that when you hear a noise like that and some hesitation too that the fuel is not being burned in a slow long controlled fashion,but instead you get a very quick and major pressure rise that can damage your seals. Effectively instead of a controlled burn,you get an uncontrolled explosion at the wrong time and place in your engine.
This is most important to sort out.
It is usually noticed only on boost in turbo charged engines,but can happen in a naturally aspirated engine too.
Regards
Carl

[jamie_eaton]

Right thanks guys!! i have not driven it since as i have been a little worried
i spoke to pip and this is what was said...Hi Jamie
Sorry, again, for the slow reply. I wasn't in on Mon and I didn't get round to my emails yesterday.
From your description, it does sound as if it may be det, but this is one of the things that we are most careful to avoid when mapping, so hopefully there is a less worrying explanation. I have just had another look at the dyno plot and the ignition map, When we had the car on the dyno, it was only showing 0.2 bar of boost at 4000rpm, and the chances of det at that pressure is remote, similarly, the ignition map was left conservative as we were running out of time. I'm not saying thta it couldn't be det, but I feel that its unlikely. Please have another look around under the bonnet to check that nothing has come loose and is rattling.
I should have the commanders in by the weekend, in which case I will send one up to you, then we can see if the ECU is picking anything up. Failing that, I'll need to see the car.............
So it may not be after all!! i hope not!!!,,, any more ideas any one? cheers J

[rx7veilside]

couple of times i had low fuel tank and under boost knock was quite high i try too keep tank topped up..i have just popped 2 seals that was prob down to split in fuel press regulator vac line..be very carefull my advice is slowly take it back to pips so it can be checked..it almost certainly sounds like u are getting either fuel cut or fuel starvation.dont risk it

[strange_days_uk]

Jamie. did you ever figure out what thhis problem was, I think I have the same thing ?

[Martiny]

Yes Jamie, can we please hear what the problem was?

[jamie_eaton]

I havnt been back to pips yet, ill have to get christmas through then take it to have it checked out, i havnt driven it since