[PERTH] 20v BT in AW11 ... Running Extremely Rich... Advise required.

[kassma]

Hey All...

Have completed my 20v Blacktop conversion on my AW11, but have noticed that the engine is running extremely rich...

I have a quick question... noticed that between 1100RPMs to 2000RPMs, the engine is actually vibrating a lot? At idle and above 2000RPMs, the engine is fine... Idles smoothly, and once you hit the 2000RPMs, and accelerate, she is pretty smooth all the way to redline of 8500RPMs.

I've done a normal service to it, and my mechanic replaced the spark plugs with Copper plugs (No reason for Platinum other than longetivity). timing adjustement and tune up. I've replaced the oils and oil filters. New fuel line, cleaned injectors, etc... all the normal stuff to keep an engine running smoothly. Factory Velocity stacks (Including Black top airbox cover) but after market filter (New) and Brand spanking new factory engine mounts...

The other thing I noticed is that if you step on the accelerator hard... there is a put-put-and-then-vroooooom... If I do it above the 2000RPMs, I only get a Vroooom and clean rev.

I've spoken to my Mechanic about it, and he put the O2 sniffer into the tail pipe, and he indicated that the engine engine is running extremely rich in this rev range, and hence, the cause of the vibration... meaning, it requires tunning....

So, my question... Has anybody got any experience with tunning a BT 20v engine? Where do I start, and how do I go about this... where do I look and where do I start? I've already downloaded the BGB for the BT 20v on the internet, but just hoping somebody had similar situation or could give me pointers into the right direction...

Many thanks in advance...

Mike

[c2888]

Bridge your diag port and pull the codes if it's got any.

New thermostat doesn't go astray, helps it warm up quicker and get you out of cold enrichment.

New o2 sensor if not already, I'd consider them to be a consumable as well. Blacktop ecu is quite finicky about it's sensor inputs

Good fuel, 98 is good, I notice a improvement with half a bottle of nulon? pro strength, seems to pick up a bit in the low end.

Clean up your throttle bodies, some carb/tb cleaner down the throats, it makes a bit of a smoke show if you do it running They tend to get a bit of buildup around the edges of the butterflies and cause some uneven air distribution.

I've also noticed that my AE111 ecu takes a while to "get comrfortable" Takes about a week of daily driving before the idle comes down.

[kassma]

Hi C2888...

Already tried pulling codes, but nada... According to the ECU, it's clean and happy.

Warm up is pretty fast, within 2-5mins of driving and engine is warm and happy.
Idle at a constant 850RPMs. and is rock solid. When cold, idles at about 1200RPMs.

Only fuel up on 98Octane fuel.

O2 sensor is possible... I will try to unplug the O2 and see results...

Did notice a lot of gunk around Throttle bodies when I had the Velocity stacks removed, so I might just clean that out first...

The ECU takes that long to get comfortable!!!!! Hmmmm... Maybe that could be the problem, as I've only clocked about 200Km and about 3/4 tank of fuel. That's a possiblity...

Thanks for the suggestions... Any other advise/ideas...

Thanks
MIKE.

[X kyle X]

Id deff give the 4 trottles a clean!

You would be surprised how much that helps!!

Did u replace fuel filter?? Are your spark plugs fouling up quickly??

[Scoobzd]

1100RPMs to 2000RPMs, the engine is actually vibrating a lot?

We have a BT in an AE-95R Wagon with a Razorback ECU.

From programming the ECU my guess is the VVTI is coming in too soon..

Needs to be set @ around 3500rpm.

But it's just a "guess" !

[kassma]

XKyleX... You have a point there... Didn't think of checking the spark plugs... This will be the first thing on the agenda...

Definitly on the agenda first up, is a good nice clean of the throttle bodies... the 20v BT throttles are extremely sensitive.

Scoobzd... I don't have a programmable ECU... I'm using the factory ECU, and can't imagine that the VVTi is adjustable on this ECU. Besides, I thought the VVTi engagement on the BT is triggered by a combination of MAP and TPS? And can be engaged as low as 2500+RPMS.

Thanks again...

MIKE.

[adamaw11]

Needs to be set @ around 3500rpm.

at that rpm you're missing out on some low-end. Set it to 1500rpm (as long as its above 70% throttle or so)

I don't think vvt is the problem in this case, but you can unplug the vvt solenoid and see what happens.

all reasonable advice so far,

You replaced spark plugs, but what about the rest of the ignition system? dizzy, cap, leads, coil etc?

I had a vaguely similar problem caused by a crack in the distributer cap allowing spark shorting out onto nearby by metal. (a missfire at low revs that goes away at higher rpm)

Missfiring would explain unburnt fuel....

[kassma]

Hey All...

Finally gotten around to toy around with the MR2 again... It certainly has been a while... and hence, posting an update as well as some possible queries... Anyway, here it goes...

1) Checked the spark plugs, and I've currently got NGK ifr6f-7d spark plugs. These are not the recommended ones, and couldn't find any reference to them? Does anybody know anything about these? Are they Irridium sparkies?
Anyway... They looked in good shape, and no real signs of overfueling.

2) Removed the Velocity stacks, to inspect the throttle bodies... They aren't really clean and a bit dirty, so I definitly would need to get some EFI Cleaning liquid to spray in there... any recommendation on which one and how to clean it out?

3) At idle, the Idle up control valve take most of the air for keeping the engine running. This allowed me to put my open hand onto each throttle body to inspect synchronisation (PS: What ever you do, if you do this, do NOT REV the engine). Sure enough they were out of sync, as Cylinder 1, I could hold my hand on for about 2sec, whereas Cylnder 2, I could only hold it for 1sec, whereas the 3 & 4, I could hold it for 3-4 sec... This is at idle, so I'm assuming they would be out of wack a bit once getting to the medium revs. This means that C1 would run accuretly, whereas C2 would run a bit lean, and 3 & 4 would run rich... This needs to be confirmed with one of those Throttle body measuring device... I need to borrow it from somewhere...
Yes, of course you can adjust the TPS... but that defeats the purpose of having quads!!!!!! Also... I can definitly hear the C2 sounding a lot more agressive than 1, 3 or 4.

Anyway, that is about it for now... More to follow...

MIKE

[kassma]

Hey All...

Just in case anybody is following this, finally had some time to work on the MR2 again...

Anyway....

I borrowed a Throttle body measuring tool from my Friends Mechanic shop, so before starting any work, I removed the velocity stacks, and put this device into the throttle bodies... It didn't even register any reading!!!!!!!!!

Got some EFI cleaner, and cleaned out the throttle bodies... Took about a good couple of hours cleaning them out, with a cloth and the EFI cleaner... Now, at least the Throttle body measuring tool is measuring something... Throttle #1 has a whole Point higher than the other 3 throttles. Hence, I think this is where the problem is, as throttle #1 also has the TPS connected to it.

The difference in performance... Well... quiet a bit of a difference... Similar from going from the 16v to the 20v BT... it really pull hard all the way to 8500RPMs... Before, it was kinda sufficating once you reached the 7000RPMs.

Anyway... Also read up the manual, and there is an adjustment screw on all 4x throttle bodies, which I will be looking at next week-end...

So stay tuned on results...

MIKE.

[Rallystanza]

Ihave a BT20 Valve into my AE86 and running stock ECU and I am finding that mine is also running rich.

The motor is fully rebuilt to relatively standard specs. Standard ECU but I have mounted the air temp sensor right out the front of the radiator just behind the grill. New everything.

It runs quite rich, as in not tested but does chuff a fair bit when i load it up according to friends driving behind.

I run an Davies Craig EWP with thier controller and a big radiator and the thing runs cold most of the time, however when it does hit temps where the ICV shuts off the idle drops to about 700 RPM....

My base timing is around 8 BTDC at the moment.

So yeah, how to make it run a bit less rich at the correct operating temp, is there someway to do a 'tune up"?

Good topic MIKE

[mattysshop]

8 BTDC!!!???

don't be scared.. get some timing into her!!

i'd be checking TPS position also..

[kassma]

Be carefull with adjusting the TPS in a hurry... I wouldn't recommend it, although checking the TPS might be worth doing according to the 20VBT manuals.

I will be publishing everything on my blog... but in short, your accelerator cable is connected to Throttle #2, your TPS is connected to Throttle #1, and Throttle #3 & #4 don't have anything really connected... Now, what can happen is that your throttle bodies are out of sync. If this occurs, especially with Throttle #1 and the others, then you have a problem... IE: My Throttle #1 reads a whole value more than the other 3x throttle, and hence, throttle #1 will run appropriate air/fuel mixture, but the other 3 will be running richer, as it's injecting for the same amount of air, but the air isn't coming in, hence, you have a rich running BT20v.

My engine had 68KKms on the clock, so I would hate to see how bad out of wack a 102+
KKms engine would be. Adjusting the TPS will is only a band aid solution. adjusting TPS to from the current setting of "Too rich" and "just right", will only give you "Not-so-rich" and "a-little-leaner", but you are not setting the Throttle bodies for optimum performance for each cylinder. Defeats the purpose of quad-throttle body. Hope this makes sense.

Anyway... Will be soon updating more on this as I'm working with it.

PS: 8BTDC is the standard timeing the manual indicates, although I would probably say, that 10BTDC would be better for the Ozi fuel if you are running 98Octane. Do not run anything less than 98Octane.

Also worth googling around for the "20v Blacktop Manuals" which are floating about on the internet... there is a whole section on how to tune the quad throttle bodies.

Regards
Mike

[mattysshop]

all my 16v's and both S/T 20v's (ffitted with 3SGTE AFM's - bigger)

i have run between 20-28 deg BTDC base timing.. (that means with the T/TE & E1 bridged)

they all seem to love it.. had an extra knock sensor and on ran it on the dyno on the S/T 20v also!! found that that one liked 22 deg BTDC..

[kassma]

Actually, on a different note... I had the oportunity to work on the MR2 last week-end, and I've checked my TPS as per the BT manuals...

Most values are within range, with exception of IDL-E2, which gives me no reading what so ever???? Nada, silch... but one thing I've noticed is that there is no cable/wire going into the IDL connection???? Which leads me to think that this is not important... it has a little rubber block out plug in there.

My MAP sensor is OK too, etc.

Ideas? Can anybody check their TPS for if there is a cable going into the IDL location, as I don't have any, and there is a blank rubber thing-a-magic in there?

Thanks
MIKE.

[c2888]

bingo, blacktop ecus don't use IDL. You can open up your ecu and have a look in there, nope, no terminal marked IDL in their either

If everything is in spec, no codes, just drive it for a week, it'll start to sort things out for itself.

Mines not a blacktop, just a late silvertop running blacktop electrics. What is everyones fuel usage like? I get 7.6l/100km quite easily with the occasional trip to redline.