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Wo ist die Rennstrecke?
Join Date: Mar 2004
Location: St Johns, FL
Posts: 1,210
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Failed Emissions
My 88 951 failed emissions this morning with too high NOX readings. According to the tech, it could mean the catalytic converter is not working properly. He also said the O2 sensor might be bad.
The car runs fine and no check engine lights. What do you think it could be? Rgds Don |
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08-11-2004, 09:31 AM
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Super Moderator
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i'll bet it's the cat.
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'89 turbo-s (2.7, wolf3d ems, garrett dbb turbo, tial 46mm, etc. fast!) |
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08-11-2004, 10:07 AM
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Registered
Join Date: Feb 2003
Location: Houston, TX
Posts: 295
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It might be the cat, but it's very likely you have a vacuum leak. I went through an ordeal with mine last year, and a big part of it was vacuum leaks (4!), a new cat, and proper TPS adjustment.
A vacuum leak will allow air in that creates a lean condition that'll throw the NOx high. Things to check: BOV (mine was shot) J-boot - they're frequently cracked vacuum hoses - you have a bunch to check fuel breather valve - mine had a tear in the diaphram TPS - make sure it's adjusted properly, that's what kept tripping me last year Given the complexity of the vacuum system, and my own bitter experience with this problem last year, I'd believe you have a vacuum leak. One of the best tools I ever bought was a vacuum tester at Sears. It really helped track the source of vacuum leaks. Good luck.
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89 951 |
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08-11-2004, 08:18 PM
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Wo ist die Rennstrecke?
Join Date: Mar 2004
Location: St Johns, FL
Posts: 1,210
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Found out today that the car is missing the O2 sensor which is making it run rich.
I own a 79 930 (CIS car) with +400rwhp and the difference in cars is pretty amazing. The 951 is nearly bone stock and drives/rides incredibly. However, I want to get a little more performance out of the 951 without sacrificing drivability or reliability. Is a cat-back system worth it on this car? Or is a MAF kit a better way to go? What about removing the CAT? Thanks |
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08-12-2004, 05:40 PM
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Super Moderator
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don't bother with the cat-back system. if you want performance (and not just a sweet exhaust note) you should go with the 3-inch lindsey exhaust that also removes the cat.
as far as MAF goes, i haven't seen one yet that is designed for cold air intake. they all sit right in the engine compartment and draw the super-hot air from the engine area, which makes the car run crappy at lower speeds or when you're stuck in traffic or driving around the city. at highway speeds they seem to work better than the stock air intake, though i'm not convinced it's worth the price/tradeoff. the best bang-for-buck upgrade is of course the DME chip. i've heard that guru makes the best chip for the 951 so far. i know a local guy who's done the lindsey exhaust, chip, and MAF conversion on an '86 car and the dyno shows 298hp at the wheel. not bad for minor upgrades.
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'89 turbo-s (2.7, wolf3d ems, garrett dbb turbo, tial 46mm, etc. fast!) |
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08-12-2004, 09:48 PM
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Wo ist die Rennstrecke?
Join Date: Mar 2004
Location: St Johns, FL
Posts: 1,210
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$1800 for a complete MAF system is pretty steep. With my 930 and powerstroke, the best thing I could have done was removing the back-pressure from behind the turbo. Once I took away all the restriction, it spooled up faster which added a little more power - in the case of the 930, I added 20+hp to the rear wheels.
Is the same concept true with the 951? Thanks |
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08-13-2004, 07:35 AM
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