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89 Tsi, running rich, black smoke and sputtering


surpra550
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OK I just bought my first Tsi, right here on this website. It was the 89 Fiji blue with 55k on it. It has some minor bolt on mods. Under full throttle or normal driving, it seems to be ok. Once you level out or are feathering the throttle, the car loads up, smokes black smoke, and runs crappy. At first I thought is was lack of fuel. But today I rode behind the car and you could see the black smoke billow out. It also sounds terrible while it is loading up. I have no clue where to start. The seller told me about this but said he fixed it due to a bad vacuum line. That didn't seem to be the problem. Any help would be greatly appreciated!! Thanks in advance.
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please list mods that have been performed.

Maintenance:

New NGK Plugs & Wires

Distributor cap

Vacuum advance

Vacuum lines replacement and removal

2nd air cleaner removal

Replaced Strut isolators

Repacked front bearings

Rebuilt TB

New Injector clips

Jet Valve Elimination Kit

New Brakes front and rear

New o2 sensor

Brake pads fron and rear

 

Mods:

Cross Drilled & Slotted Rotors

Stainless Brake Lines

Rising Rate FPR in stock location

Stainless fuel line with pressure gauge on TB

2.5” Turbo back *DM exhaust with Magnaflow

Ported & Stressed Relived exhaust manifold

MBC set to 13psi

AHP with K&N filter

1st gen MAS

1st gen BOV

TB center removed from top part for better air flow

Kenwood CD player

Manual Boost gauge in stock location

Powder Coated Valve cover with new gasket

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Could be running on the secondary injector. Start the car and unplug the green injector, if it keeps running look else where.

Could be a vacuum leak or dirty injector, leaky bov , hacked 1g MAS. I would check that bov after the injector.

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Could be running on the secondary injector. Start the car and unplug the green injector, if it keeps running look else where.

Could be a vacuum leak or dirty injector, leaky bov , hacked 1g MAS. I would check that bov after the injector.

I will give it a try. Thanks!

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If that DSM BOV isn't modded it will leak nearly all the time. Google 1G DSM BOV mod to see the fix for it. The few psi extra past stock boost will put in too much fuel at low/mid rpms making it too rich. The spit and sputter is your misfiring fouled plugs when this is happening. What plugs you using?
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If that DSM BOV isn't modded it will leak nearly all the time. Google 1G DSM BOV mod to see the fix for it. The few psi extra past stock boost will put in too much fuel at low/mid rpms making it too rich. The spit and sputter is your misfiring fouled plugs when this is happening. What plugs you using?

Not sure about the plugs other than they are NGK. We have checked most of what you suggested but can't seem to nail the problem down. I will check into the BOV. Any more help would be appreciated. Thanks Bill!

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The plugs are NGK BPR7ES. They are not fouled i drove the car two hours to meet you in DC and my girlfriend followed me all the way. The car did not have any smoke. Most any car at WOT will smoke. You do have to remember this is a 22 year old car and if you beat on it you will break it.
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The problem is in the BOV. The way i drove the car i never saw this issue except with steady throtle at 70 mph. I replaced the vac line to the BOV and it improved. Find a hard pipe and a BOV and it will be a non issue.

What kind of BOV would you recommend??? Can I do anything to the BOV that is on it now to straighten it out???

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The plugs are NGK BPR7ES. They are not fouled i drove the car two hours to meet you in DC and my girlfriend followed me all the way. The car did not have any smoke. Most any car at WOT will smoke. You do have to remember this is a 22 year old car and if you beat on it you will break it.

Well if wanted a car NOT be beat on I would have bought a K-Car! Lol...The smoking isn't at wide open throttle. It is under partial boost or feathering of the throttle. I just need some input on how to fix it. Can I just buy a different BOV and install it?? Or what if I just remove the BOV that is on it now?? Also the A/C was a broken fitting behind the Compressor, I didn't even need to add freon. Feedback appreciated!

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  • 2 weeks later...
I removed the oil seperator. There is just an Air Filter venting the valve cover. When i had the car you could see the manual boost guage creep up to zero while at 70mph. When to manual boost guage hit zero that is when it would start to sputer. I just got used to it and watched the boost guage so I would accelerate or back off just a bit and the boost guage would drop back down the the vac side while at speed and the sputer would go away. I hope this info helps Supra 550 and you guys figure out what is going on. I crushed the 1st G BOV and checked it with a handheld vac guage.
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What that meant was before there was boost but the rpms were high that makes enough volume of the low pressure to the BOV to cause it to open and then it starts to puke because its way too rich with all that air blowing out.

 

If you have the separator you might give it to him so he can put it back on.

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Problem solved!! I removed the BOV and it accelerates perfectly!! Now the next big question....with running 14-15lbs of boost, do I need to bother reinstalling another BOV. Will there be any performance advantage?? Thanks for the input!
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The seperator was included with the other removed stock items if you need it. i am glade to hear that the issue is corrected. The main purpose of the BOV is to take back pressure off the turbo between gears. it is a little more complex than that but for general purposes this is why most people use BOV's. It will extend the life of your turbo. You do not get any HP gain in reality it can hurt the over all performance if you dont route the air from the BOV back into the system. The mass air flow sensor has already accounted for that air and now it is out of the system. A lot of newer turbo car vent the bov back into the system and several guys have done the same thing on thier quest's.
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