# rich or misfiring? (Mike K?)



## Niceguy (May 30, 2003)

This post is directed towards morepower2 a.k.a Mike K.

I have noticed in a few different threads that you relate a black tailpipe, and rich symptoms on an SR20 to insufficient spark and misfiring. I have been having these issues, and have always thought the Bluebird ECU I was using was just rich. I was looking into purchasing a wideband o2 monitor and Greddy EManage to tune out some of the rich spots, but upon reading your posts, have thought otherwise.

My setup is as follows:

B15 shell
U12 BB ECU
U13 BB DET (rebuilt, N1 oil pump, new bearings)
Gti-R T28 and manifold (8 psi)
Spearco front mount
Forge Recirc Valve
3" downpipe, 3" test pipe, 3" mandrel exhaust
Walbro pump
370cc @ 3 BAR, stock 53J MAF
stock ignition
Oil press, EGT, boost gauges


Before I proceed, I just want to say that the car is quick. I really don't have a big problem, except for running rich, maybe misfiring? Although, my oil does smell like gas. My main concern is knowing that the car could be a lot faster, upon clearing up the rich or misfiring problem.

I don't actually feel a misfire, the engine revs through the whole RPM range, although seems to strain itself upon reaching 6700 RPM's or so, I just attributed that to the stock cams. Nevertheless, it pulls right to 7100 RPM, where I shift.

My original idea was to purchase the Zeitronix wideband o2 monitor, and Greddy EManage like mentioned before. I just want the car to run well (all the bugs worked out) before I start messing with JWT programming, larger injectors and MAF.

My other concern, is why I would be misfiring @ 8 psi on stock ignition? It should be fine, especially with my .025 gap. (I've tried .020). Unless it's just a rich condition, and not misfire.

Do you have any recommendations, opinions? Maybe I should try the Crane Hi-6 ignition before I go messing with A/F maps and tuning via wideband?


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## Niceguy (May 30, 2003)

Engine idles fine, decels fine, doesn't stall, gets about 270 miles to 13 gallons of 93 octane, has great partial throttle power, it just feels like it pigs out at WOT...although it's still fast.

TPS is within specs, MAF is regrounded, no boost leaks, no vacuum leaks, recirc valve is fine.


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## Niceguy (May 30, 2003)

Oh, here's another idea.

The intake filter to the T28 is down by the engine crossmember. The intake pipe itself is about 1 foot long and puts the filter close to the ground. I'm not the one who created it this way!

Could turbulence be causing erratic MAF evaluations, and incorrect readings at high speeds, especially with the JWT POP CHARGER? That's where I feel the most sag in power, is at higher speeds, like when doing a downshift into 4th gear. Also, if I make a high speed run to 120 mph or so, and clutch, put into neutral, and coast, the car will almost stall. I believe this is b/c of invalid MAF readings caused by the turbulent air, creating an overly rich condition.

1st and 2nd gear have insane power, and spin the tires right off the heavy 17" wheels.

Maybe I should re-do my intake pipe, putting the filter up in the engine bay, somewhere...or maybe even create an airbox of some sort around the filter?


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## Niceguy (May 30, 2003)

Here is a post from SR20forum regarding MAF turbulence:



charlie2020 from SR20forum said:


> OK one more thing when i first did my swap my filter used to sit under the battery tray exposed to alot of outside air when it was like this i had trouble getting my o2 voltage above .88volts no matter what i did to the SAFC and it would hit a stall point at high speed where it didn;t want to go any faster..........then I installed the splash guards that go under the radiator just so happened my air filter just about rested on top of it........after putting the splash guards on I noticed a huge difference in the top end performance and my o2 voltage hit .94 volts.......and the car steady climbed to 130mph+ with no problem


The problems he outlines here, are the EXACT same ones I'm having. Hopefully I just answered my questions. I will try relocating my MAF, or building a box around it, and see what happens.


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