Ok I just got my car back togather (383 LT1, 13:1 commpression with direct port nitrous) and took it to the strip where I found that I have a hesitation when I jump on the throttle?

Last year my last run of the year I sprayed a 200hp shot (not unusual) in the 1/4 where my fuel solenoid piston failed and I was putting fuel in the engine through the injectors and nitrous fuel jets making it run very rich after the finish line. Long story short I had NX rebuild my solenoid with a new piston with the stronger material.

This year I put in a new set of NGK BR7EF (same that I ran last year that look good until my solenoid falure, 2 steps colder then the stock NGK TR6) and it has a hesitation when I hit the trottle fast, but if I slowly get into the throttle it runs fine? I thought that maybe the engine was all loaded up so I put in on the highway for a mile at 70-80 MPH to try to see if an injector would clear or somthing else. But the car was stalling a stop signs and around bends?

I pulled all plugs and the straps are white/gray and everthing else is pretty much black with some worse then others. So am I still running rich?

The car was tuned on a dyno last year and everything was running great until my nitrous issue. besides that the only thing related tht I changed over winter would be the alternator wire that runs from my alt. to my battery. I went to a 6 gage battery cable from a 8 gage audio wire.

Thanks for your help!

Just an added note I run a Mallory Hyfire 6 CD ignition with a promaster coil. And my pluggs are gapped at .035".

 

You've got way to much information in there that isn't relevant.

Hitting the throttle fast and getting a hesitation usually means it's gone too lean. Opening the throttle quickly dumps a huge amount of air quickly into the engine. Under normal circumstances, the accelerator pumps compensate by giving the engine an extra shot of fuel to mix with this huge gulp of air.

Since you're not running a carb, you need to find out why the computer isn't giving the extra fuel with the sudden lean condition. There's also the possibility that the computer is dumping extra fuel into the engine but it's too much. Maybe the extra fuel that the NOS was putting into the engine was what the engine wanted and now you're running too lean.

As for plug color, you need to shut off the engine at speed then stop and check the plugs. There's more to reading plugs than just color. Reading plugs takes skill. Most people tune with an O2 sensor now as it's more accurate over the entire powerband. Of course the only way to really know what it's doing is to have the O2 on a scanner to record a run.

Try disconnecting and plugging the fuel for the NOS and see if it still does it. Maybe it's still leaking or maybe it's sucking air.

 

I am sorry for all the info I just want to get everything out that might help. I have tried what you suggested and bypassed the nitrous system and it still runs the same.

According to my wide band the AFR is right where is was tuned to be at idle, about 14.7, and the scanner also shows nothing out of the ordinary. The driverside rear plug is the worst looking or blackest plug out of them all.

I also pulled the vacuum line off my fuel regulator and hit the throttle to see if the pressure was dropping off or the car ran any better but it seems to stall out more with added fuel pressure right after I jump on the throttle.

 

What's the wideband saying when you go to WOT under load?

 

Good question, but if it is anything like last year it will be right arount 14. How would the WOT AFR affect the hesitation off idel, it does not have to be slammed to WOT but if I just snap the throttle real quick it acts up, but like I said if I get on it easy and smooth it acts better.

Thanks

 

Could be a slew of problems, tps may be going bad, watch the voltage when slowly working throttle to make sure its linear. Also may have a vacuum leak, even an exhaust leak can cause, if near the 02 sensor, it will sense raw oxygen thinking car is lean and dump extra fuel in to reach what it thinks is 14.7:1.. Do you race at PRP?? I see you live in Pittsburg as I do, I dont remember seieng that car run "10's" as you stated in other post..
I do Prom work, if interested stop by.

 

I do race at PRP, maybe I will see you there some time.

I did a quick vacuum leak check on the engine using map gas but found no leaks and do not think that here is any exhaust leaks.

One thing that I did notice this year that I do not remember is that after letting the car run the tank builds pressure and when I remove the gas cap the pressure releases. At the end of last year I still had about 4 gallons of VP fuel in the car so I jumped the fuel pump with my 12 volt battery charger at the lowest amp setting and pumped most of the fuel out before the fuel filter. I did it in multiple sessions to not harm the pump. 3 years ago I did remove the Evap canister and plugged the line coming out of the tank with a bolt, but never had an issue in the past years stilll having the vent tube and vented gas cap.

Not sure if all of this is relivent but I thought I would mension it.