MR2 Turbo Gen 3 whistle and over fueling

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Thu, 25 Apr 2013 19:52:23 GMT

Just an update, found the hole in the exhaust, it was on the exhaust just after the flange to the dump pipe. Hopefully it can be welded rather then having a new mid section of exhaust pipe made up......

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Sun, 21 Apr 2013 09:09:40 GMT

All sorted. Looks like from pressure testing the intercooler there was some water sitting in there. After driving around enough its blown it out. Everything is working fine again but there is a tiny exhaust leak somewhere, it looks like the gasket on the dump pipe. Really hard to tell because I can't manage to see it, too much stuff in the way, but I was getting water droppets dropping out from somewhere there. It's definately water and not coolant so must be a slight leak somewhere in the exhaust. When i get the exhaust brackets welded I'll get them to take a look as it will be easier on a hoist.

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Fri, 19 Apr 2013 09:38:22 GMT

I'm fairly confident in the exhaust leak so i'll sort it out thanks anway. Smoke testers make for the easiest diagnostic for vacume and exhaust leaks. Just don't want to have to take it to a shop with a smoke machine if I don't have to.
On a modified turbo you have a lot of noises going on. Also exhausts will drawn in air on the pulse, hence why a hole will cause problems especially near the the sensor. When tuning EFI systems on previous race cars even we wouldn't use the O2 sesors you can hook into the back of the exhaust as we found them inacurate. Instead would use a drilled bung much like a factory O2 sensor bung to take the readings and that wasn't just for idle, thats for full dyno tuning runs. Thanks anyway, I'm 90% sure I'll be able to find a leak and get the car ready for its next track event.

Re: MR2 Turbo Gen 3 whistle and over fueling (artymr2)

Fri, 19 Apr 2013 09:21:24 GMT

As suggested prior, have you tried disconnecting the O2 sensor?

If there is a small leak, the sensor will not detect extra oxygen, you will have positive pressure in your manifold so no outside air will be sucked in.

Yes O2 sensor only starts generating a signal once its warm, on my previous gen2, it started to work after about a km of gentle diving following a cold start. The gen3 has a built in heater so should start to work sooner.

Another way of finding leaks (including vacuum) is to use a stethoscope with the tube open at the end. You can easily hear any wind, its very sensitive.

Cheers

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Fri, 19 Apr 2013 08:40:21 GMT

Yeah I'll be looking for the carbon stains if its leaving any. Otherwise I'll try a few other tricks to locate it. Worste case it will go on a smoke machine. O2 sensors are very sensitive so if the leak is anywhere near it will detect extra oxegon. It will keep adding more fuel till it doesn't detect any excess but this will never happen, thus runs very rich. Anyway finding this leak will not be fun. Both exhuast brackets have snapped after the last race so need it rewelded. If those broke i'm not suprised there could be a crack somewhere else.

Re: MR2 Turbo Gen 3 whistle and over fueling (artymr2)

Thu, 18 Apr 2013 14:28:58 GMT

Look for black soot to locate leak.

I wouldn't have thought a leak small enough to create a whistle would effect the mixtures to such an extent?

Cheers

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Thu, 18 Apr 2013 09:43:26 GMT

Not sure what exhaust it is. Looks like a custom job. I'll take a look around this wekeend and report back but I'm fairly confident its a hole soemwhere in the exhaust near the O2 sensor. I've never had a hole int he exuast so I didn't know if it makes a whistle sound as it sounds a lot liek an intake leak. I read on Suby forums though that when they get holes in the up pipe to the turbo it makes a whistle sound liek the turbo spooling.

Re: MR2 Turbo Gen 3 whistle and over fueling (purple5ive)

Thu, 18 Apr 2013 09:29:20 GMT

is it an ebay dum pipe, must have cracked they are known for doing sousually around the area near the o2 sensor (genral area so look around there where the collector meets the pipe)

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Thu, 18 Apr 2013 09:18:06 GMT

Just as an update I reckon I know what the issue is. I reckon I have an exhaust leak from the dump pipe somewhere. This would explain the whistle under boost and also at idle it will get extra oxegon into the exhaust system causing the idle to run rich from the o2 sensor.......only problem is I haven't been able to spot where the leak is yet.

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Tue, 16 Apr 2013 16:13:04 GMT

Well the idle air controller does make a lot of noise. Is that how they all are? You basically hear it hissing away at idle but if you squeeze (block) thre vacuum line going to it from the manifold it goes quiet, mkaes the car stumble a bit?
I have fitted a new rubber hose to this, so definately no cracks on that one. I'll go over all the lines again but I can't find any vacuum leaks. It definately runs rich though, you can smeel the fuel through the exhaust plus when driving you can hear it pop as the unburnt fuel blows in the exhaust.

Re: MR2 Turbo Gen 3 whistle and over fueling (MR2QIK)

Tue, 16 Apr 2013 15:50:38 GMT

Sounds vac related to me. Check for small splits on the ends. It's been a common problem for me over the years.

Re: MR2 Turbo Gen 3 whistle and over fueling (Mrskylighter)

Tue, 16 Apr 2013 15:36:01 GMT

Hmmm, your timing set correctly at 10 degrees? Mine was out on my gen3 which caused a weird warm idle running rich once.
Have you tried a stock standard gen 3 ecu to confirm the Mines hasn't developed an internal hardware fault of some kind?

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Tue, 16 Apr 2013 13:42:49 GMT

I've checked the vacuum lines and they all seem good. If there is a vacuum leak ater the MAP sensor however it should technically run lean not rich as it will drawn in air after the sensor. That's why I'm leaning towards the O2 sensor as it looks most liekly to occur during closed loop but Toyota say if there is a problem with the O2 sensor it ALWAYS will be picked up by the ecu and register a fault code. It's very odd becuase it does start idling properly but if I let it boost up immediately after it wont idle. Apparently the O2 sesor doesn't kick in till it is warm which doesn't explain the over fueling during start up either.

Re: MR2 Turbo Gen 3 whistle and over fueling (Mrskylighter)

Tue, 16 Apr 2013 13:16:46 GMT

How about the vacuum line to the map sensor? I'd be checking all the small vac lines running through the engine bay and replacing with new if they are old and cracking.

Tried unplugging the O2 sensor? without it connected it will give a fault code but the ecu will use default values. This might indicate whether yours is stuffed?

Re: MR2 Turbo Gen 3 whistle and over fueling (track_mr2)

Tue, 16 Apr 2013 12:12:14 GMT

It has a mines chipped ECU so basically standard at start etc....
I have reset the ECU just recently as the battery died and I had to fit a new one. As the car isn't street registered I haven't driven it more then maybe 1km as it has that idle issue.