Running lean??

[14of2000]

So now I have a new issue, I have a 14b rebuilt with a 20g wheel and a stock 14b housing. I am running 450cc 2g black top injectors and a stock 1g maf with the lower honeycombs removed. So with that in mind I am running off of the wastegate. But my car is running extremely lean from the looks of the plugs, and the fact my exhaust manifold was red hot the other day. But the plugs are pure white, so I looked at them a little closer with a magnifying glass and i didn't see any signs of detonation on the plug itself. I only have a narrowband af gauge (useless I know) but this restoration has kinda zapped my funds at the moment, But the gauge is constantly in the "rich" zone. Do these narrowband gauges just take a guess at where my afr is?

I did a boost leak test at 15 psi and the only thing I could hear leaking is something under the intake manifold, so what I'm thinking is my intake manifold gasket might need to be replaced because its sucking in air pretty much directly into the combustion chamber. Am I wrong in thinking this would cause the car to run lean?

The first one in the pic looked just like the others, I touched it and it came off.

 

[jepherz]

A narrowband is essentially a stoich switch that tells the ECU if you're below or above 14.7. It's mostly useless for determining your actual AFRs across a wide load range. Also, it is only used by the ECU in closed loop, to tune the fuel map to run stoich for efficiency. As soon as you are above the threshold RPM, load, or TPS, your ECU is going to shoot for a more rich mixture.

The fact that you have a hacked maf is pretty suspect. Getting around fuel delivery issues by doing so is a pretty archaic work around, since adequate, OEM substitutions are a dime a dozen and chips have been burned to compensate 100%.

 

[theevozero]

Fix your boost leak and get a wideband. Quit guessing. If you don't have money to fix it right, I suggest you quit driving it, unless you want it to end up costing a lot more. Your boost leak would cause your narrowband (o2 voltage) to stay at 1v, or in other words, rich. There appears to be a lot of fuel on those plugs.

 

[14of2000]

Sweet thanks for the replies, ok I am going to pick up a new intake manifold gasket tonight. I am not going to drive it until it's fixed. This is a freshly rebuilt motor and I don't wanna grenade this thing lol So your saying those plugs look like my car is running rich? I always thought white was lean and black was rich? /ubbthreads/images/graemlins/dunno.gif

 

[5OF2k]

Youre right as far as the plugs go, OP. I have no idea what he's talking about above...?

Ideally, your plugs should be tan in color on the electrodes. White is a sign of a lean burn, which isnt good. By wastegate pressure, what do you mean? What is your actual boost pressure? Those 20g wheels WAY outflow the factory 14b wheels, so your lean condition isnt at all surprising to me...

As said above, get a wideband, and to be safe a bigger set of injectors. Cooking a new motor because you couldnt afford the essentials for your setup only leads to you needing another motor.

Hooe that helps!

-Jake

 

[14of2000]

Ya I absolutely agree there, by wastegate pressure I mean 8 psi is where the boost holds. I was thinking possibly the timing but I made sure I was dead on and it idles and runs great all speeds I just know it's not right for the plugs to look that way.

 

[nemovr4]

Wondering if getting then new intake gasket worked things out?

 

[tektic]

Your intake gasket will make your low fuel trim high and mid and high low with a lot of fluctuation based on boost. In boost it will be rich because of loss of in metered air in vacuum it will be lean because more unmetered air. And then the ecus compensation, wich will put it all over the place.

 

[theevozero]

I don't know, I'm drunk.

 

[14of2000]

Sorry guys I got a little sidetracked with moving. So update my car has now quit idling steady and the vacuum is at -12 MmHg and it use to be at a steady -20 to 21MmHg. So I have done a boost leak test and when I pressurize the intake manifold at the elbow. It sounds like something is leaking between where my motor and transmission meet?! Can anyone tell me what that could be?

 

[James]

You need to do a little more work and figure out where it is. We can't play point the finger games from this side of the screen.

Get sole soapy water and spray down the areas you think air may be getting through. When you see the bubbles you know you found the spot. Then take a picture and show us or describe it with some detail

 

[gvr4ever]

Make sure you tighten down your plugs enough. Happened to me after I did a compression test. If they leak, it will throw everything off.