I need some serious help and don't know where to start diagnosing on this. I'm just gonna start replacing parts, but would really appreciate some help.

Emissions @ 2500 rpm:
HC 1753
CO 5.54%
C02 8.8%
O2 5.3%

I understand that the CO2 is the measure of air fuel and should be near 14.7 or so. At idle my HC's went to 3000 and CO2's were at 5%.

I pulled plugs 6 and 8 before firing up the engine and they were wet.

Engine info: 355, CC502, BBK 58, Accel 30#, 1.5 RR's,

New electrical stuff : Taylor wires, AC delco plugs

Next up is two new O2 senors, new coil. Then a new opti.

I have a tune from PCMforless.

The engine runs quite smooth, so I don't think there is a miss.

Thanks.

Nate.

 

Is it possible to screw up rebuilding the fuel rails? Like could I have the return line and feed line mixed? I ask because my engine builder took them apart for cleaning. but when he tried to reassemble them, something didn't fit quite right. It was the brass looking keeper that holds the two lines into the rail I believe. So I ended up cutting the part and making it work. Bad sign?

Anyway I'm stumped. Maybe someone could point me in the direction of diagnosing, meaning what tools can I pick up at Autozone to check things like fuel pressure, A/F mix, and a host of others things I should know - but do not.

And maybe this extremly rich condition explains my abnormally low temperatures - cylinder heads stay cooler and do not heat the coolant as much.

Edit> checked fuel lines against Chilton and it is plumbed correct. So could O2's make THAT much of a difference?

 

Anyway you can get me a datalog?

The cam that you used is a real easy one to tune in but often the elevation throws a big curve ball in.. Especially in the speeddensity cars.


Let me know how I can help.

 

I don't have the tools, but will gladly purchase them to fix thie problem. I need a cable and something like TTS Datamaster, right? What and where to buy?

I'm dropping the car off at Tunex to have them look it over, hoping they can find something.

 

I took car to Computune. They said my Vacuum was too low. Vacuum at idle was 11", when it should be 15", according to them.

I have seen threads about low vacuum issues, so I guess I should start searching them for info. I have no idea how and why vacuum would affect A/F ratio. Any help is greatly appreciated.

Also the mechanic said that the compuer dumped fuel like it was at 1/4 throttle while it was idling. I don't know if really knows what he is talking about, cuz he was only somewhat familiar with LT-1s.

But point is I am WAY too rich. He recommended NOT putting my cat on as he has seen carpets catch on fire from burning cats. I dunno...

 

a vaccuum leak is unmetered air. air that is entering the intake manifold after the TB. this would cause a leak condition and your emissions would be way off. You can take carb cleaner and spray it around the manifold, hose and the TB. You will know when you have found the leak, when the engine idle changes as you are spraying the carb cleaner.