Running Rich......

[87TurboGirl]

Ok here is the deal. I have had alot of problems with my car every since we bought it. We just recently rebuilt the engine, now my hubby says it is running rich.

At WOT I get alot of black smoke and the car is stalling as if it is cutting out. Falling completly on its face. Feels kinda like you floor it and then take your foot of the gas suddenly. I am trying to run 10lbs of boost on 93 octane.

I have a scan master and something we noticed is the first screen with O2's and retard. Before the rebuild my number seemed pretty normal (or so I was told) now they are as follows

O2's are anywhere from 100-890

retard says .06 - 11.5

the retard is what is bothering me. I have never seen numbers there before.

Any ideas on what could help? Or even what the problem could be? Anything will be helpful.

 

[Eric Stage I]

The chip is probably set up for around 15-16psi boost (if its a street chip), which means it will supply fuel for that amount. If you run 10psi, it will be very rich because the chip is expecting 15. Running too rich can cause knock (in addition to running too lean). Also the richness may be causing it to cough and stall at WOT.

You "should" be able to run more boost than 10psi on 93octane (you get 93 down there?). You might try increasing boost a little at a time to lean it out (keep an eye on knock). The O2 readings are only useful at WOT and typically should be around 800-820 area on pump gas.

If you only want to run 10psi, then you may need a chip tweak or start turning the fuel pressure down, but I don't think you'll get the pressure down far enough to take that much fuel out.
Let me know if need anything, I can help in the chip area, and I'm not that far from you.

Regards,
Eric

 

[87TurboGirl]

Yes we can get 93 here at one gas station near the airport. Usually I only get 92 at amaco.

We've tried turning up the boost with no luck we still get the same results. We will try it again.

What about the retard on the scanmaster is that anything I should keep an eye on or a number I should keep it under?

 

[Eric Stage I]

Try and keep the knock retard down to below 3.0 or 4.0.

Another possibility is your ignition is fizzling out. You might try and reduce you plug gaps to see if that stops the cutting out problem. If you're at .035" now, try .030" to see if it stops, if it stops, maybe a new coilpack is needed.

Running that rich can be hard on plugs anyway.

Eric

 

[OneLethal87GN]

Are ya sure the MAF isn't going out? BTW, what was the rattling noise? Still haven't found mine yet.

 

[87TurboGirl]

We still aren't 100% sure what the tapping is, we think it is a sticky lifter. Is there are way to check the MAF?

 

[OneLethal87GN]

The usual way they tell you to check the MAF is to tap on it with a screwdriver handle while the car is idling. If it stumbles then it is bad. However, I don't think this always works, so I suggest just watching the readings on your Scanmaster and see if they are rapidly changing over a large range. I had one go bad once and the readings went from 20s or so to over 100 in a matter of seconds, and this was just while idling.

 

[87TurboGirl]

Ok let me see if I understand this.


If your O2's are bouncing all over the place like say 8-12 readings per minute the maf is bad?

The reason I am asking is because when I start my car and watch the O2 readings they are all over the place at idle (i.e anywhere from the 028-770 range) so its changing constantly.

Follow up:

It is now impossible to keep my knock retard below 4.0. On the highway it is at 14.6-19.2. So we stopped driving it today.

We also regapped the plugs and we are in the process of getting a new coil pack.

 

[TT/Ameasap]

Did you remove a maf screen? If you did, then that might have something to do with it...... Thats all I can think of rite now, so HTH

 

[Eric Stage I]

In your first post, did you mean you were showing knock retard at wide open throttle or all the time? I think we were assuming just at full throttle.

If you are showing knock while cruising or all the time then that can be a sign of a major problem (a mechanical problem). If there is something rattling in the engine, it will also set off the knock sensor. Be very careful at this point. It could be something minor, like an exhaust pipe hitting or something. But it could also be major, like bearings (hope not).

By the way, the O2 readings will always go up and down at idle and cruise. They will only stabilze at full throttle.

 

[87TurboGirl]

I am getting the knock retard when driving period. WOT, Crusing, Highway, 1,2,3 gear. etc. etc. Not at Idle though.

We are positive it isn't the bearings we already took those off and looked at them. That was our problem the first time. We know as well that it isn't the exhaust it sounds like it is coming dead center of the drivers side valve cover. We have checked all of the rockers & the arm. and they are fine so that is why we are thinking it is the lifters.

The lifters are new they were bought less than 1.5k ago when we rebuilt the engine. We got the Lunati lifters. We have the stock GM replacement lifters in the garage and we are thinking about trying to change them out to see if that solves the noise. Sound right?

 

[OneLethal87GN]

Like Eric said, the O2s constantly go up and down. Only under WOT do they seem to stablizie until you let out. Your MAF counts should be around 05 or so at idle. They max out at 255. When I said they bounce around when the sensor is bad I mean they go all over the place and the car will run poorly when you try to accelerate. These cars are great when they are running fine....but..... when they mess up, they are a PITA!!!!!