[daytonaracer]

We have a modified circle track 2.5 that occassionally, but usually not always at least once per race gets this hitch or bog where the engine kinda cuts out somewhere between 4,500 and 5,000 at WOT, for a short duration. Been there most of the season and we just put in a new motor and it is still there so it doesn't appear to in the engine. Common parts between the two is 02 sensor, HEP/Rotor (we have swapped cap?, wires and coil trying to solve it), MAP, fuel pump, computer, and entire throttle body. Kinda looking for suggestions (any more component swaps will start to get expensive), it does not happen consistantly, and when it happens, duration changes and it will go away on its own, burping the throttle seems to help it go away...maybe. Seems to not happen when we first start but will at some point, but does not seem wholly neccessarilly temperature related as it can just happen once at like lap 12 in 15 lap race and not again. Its not getting worse but it is also not going away.

I think thats all the detailed info I can give, the frustrating part is racing is what brings the problem to light so only 2 races left and would like to solve this...preferably not by a whole swap of every possible component.

Lost the lead in the heat when it did it once, and it certainly didn't help in the feature, did it once there too, where we finished 4th.

 

[NAJ]

Is this a turbo car?

 

[daytonaracer]

No, its a TBI car, and not to be a smart @$% that why it is in the NA/TBI section

 

[NAJ]

No, its a TBI car, and not to be a smart @$% that why it is in the NA/TBI section

I look at so many threads daily I sometimes do not pay attention to where they are located.

 

[Katlaw]

And lets not forget that lots of posts are started in the wrong place.

Law

P.S. I'm curious about what could be causing this as well.

 

[94GTC]

If you had a wide band you could narrow it down either a/f or ignition.

 

[daytonaracer]

I do have a version of A/F (homemade led bar) and unfortunately because it is so short in duration and no telling when it happens we haven't caught it, but under normal race conditions all seems well.

 

[NAJ]

I do have a version of A/F (homemade led bar) and unfortunately because it is so short in duration and no telling when it happens we haven't caught it, but under normal race conditions all seems well.

If you are reading off the stock O2 Sensor that is equivilant to a Narrow Band A/F gauge and is not going to help you or give you true A/F Ratio.

 

[The Pope]

all AF issues aside and assuming there are no codes I think you have an electrical problem. All of these cars turbo or not normally run great at WOT and have problems with part throttle when in closed loop. Something is killing the engine under a heavy load. Too much voltage from the alt. Spark plug wires miss firing (try riches wires that don't use the push through tips). The coil is getting hot and caving. The computer is hot and failing.

I would check your spark, coil and computer. The wires cost a bit but a computer from a pick n pull and a coil is cheap.

A wideband and an adjustible FPR from Holley would be nice to adjust AF at WOT for the most power. Running circle track I would also change the full pump plug to something else, maybe solder the connection. The plug can be bouncing around and losing the connection too.

Just sounds like either a computer problem or a spark problem, not a sensor FI problem. These computers freak out when they miss fire, not violent with NA like a turbo but it will slow you down

 

[daytonaracer]

I only get it maybe 2 times in an entire night of racing so whatever it is it is very intermittent......

As in post we have tried new plugs, coil, and wires and it persists with no change ......... Computer could be it I can try swapping that .... or possibly the HEP in the distributor

have an adjustable FPR .... I guess a wide band can be on the list but unless there is a constant indicator that it is going to happen the driver can't watch the gage 100% of the time, so may have to buy and put in a video camera.

Fuel pump is after market with ring terminals and nuts on it