Friday, June 26, 2009

Finally... Another update... after a few KMs...

Well... been driving the MR2 a few time, and have noticed a few things...

1) Engine is running rich - under medium and high RPMs, you can feel the engine a bit sluggish, and at TOP RPMs, it feels like it is being sufficated. This has also been confirmed by Sean.

2) A fair amount of backfire when running at various High RPMs levels - When starting to hammer the mr2 around corners/track, and when you are sitting at coninuous high RPMs, the engine starts to backfire a bit.

3) Between 1100 - 2000RPMs vibration - The engine vibrates rather vigurously between 1100-2000RPMs, under load or not, which can be readily seen when lifting the bonnect. I think this was why we hated the Urethane bushing, probably.

4) Fuel consumption is high - I've had the opportunity to drive the MR2 through several cycles / Fuel tanks. Typically, I get about 300-340Kms per tank. Taking everything into account, I'm getting about 10-11Ltr/100Km. To provide you an example, my wife's Forester gets about 10.5-11Ltr/100Km, which is a Flat 4, 2.5Ltr AWD, 1.4Ton car!!!!!! That means that either the Mr2 is extremely thirsty, or I have a very economical Forester!!!! I think the initial is true... and the forester is tuned on the rich side, due to it's bad head design.

So... what do all these points outline... the 20v BT Engine is not running at it's Optimum, and is running extremely rich!!!!! :-(


Anyway... it was recommended by Warren, my mechanic, to check the synchronizing the Throttle body, and possibly clean them out. Was Warren right... Definitly. Warren lent me his throttle body sync tool. So... what did I do...

Well, first off, you have to remove all the induction boxes and Velocity stacks (V-Stacks)...

Then before I started the cleaning, I measured how much air each throttle body was sucking in... it wasn't even registering!!!!!!!! Eeeeek... So I decided to clean them out, and sure enough, I was getting a reading... 2Kg/cm^2... Of course, each throttle body had a different reading, so I used a adjustment screw to adjust the idle induction, and then start measuring at each RPM point... sure enough, once the idle was adjust, the rest was in sync too... thank goodness. By the way, the blacktop Manuals, which are readily available on the internet, outlines the procedure to perform this, so I won't be repeating it here again...

Anyway... took the MR2 for a test drive, and was there a difference... You bet... the difference was enormous... but it still did not cure some of the problems... it still had the virbration, not as sever, but it was still there, and fuel consumption has improved a little, but not much.

So... I've checked the timing, it was spot on 10Deg BDC

I've checked Ignition Leads, and it was OK.

I've checked TPS, and although a bit suspect, it still had measurements within check, although some of the pins didn't read anything!!!! I need to come back to this again.

Spark Plugs... Now, let me tell you something... Use Plantinum or Iridium plugs... DO NOT USE COPPER Plugs... This has also made a huge difference, from a lot of backfire, etc, to a nice clean burn without backfire, and less noise. The engine feels a lot smoother with Iridium plugs, but those nigly problems are still there.

So the search continues. Alas, I have no pics and other updates, as I'm starting to fix up some stuff on the inside... But hopefully, I will put some more updates soon.

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