hey guys my car has started to stumble on itself after a period of idling. My wideband shows a lean situation...the car literally tries to die like it is stalling. Any ideas??

 

Perhaps its going lean by fuel starvation? Fuel filter.... Fuel pump.... those would be the first things I'd check.

 

Changed filter new walbro less than 5000 miles on it...

 

Thats good info to know up front by the way. Hmm.... Maybe your walbro sucks? Maybe your tuning sucks?

 

chris at rotary perf did my tune so...........also a good friend. Maybe a voltage problem?

 

I found out a few weeks ago that my walbro doesn't like to be choked down with the stock resistor pack. It pulls enough current through the stock pump circuit to overheat the resistor pack if your car has one. I started having hesitation problems with my walbro and I checked voltage at the pump connector and I had 4.5 volts at idle. I checked fuel pressure and measured 19 PSI, barely enough to run the engine. I checked the resistor against specs and measured 4.0 ohms. I replaced the resistor with a known good one and put the stock pump back in and I now have 29 PSI and no more hesitation. My opinion is to only use a walbro on a TII, not NA and only do a rewire mod on TIIs as well. Check your pump volts at idle at the connector (backprobe it).

 

I agree on doing the rewire if you have a Walbro or Supra pump. The resistor pack was only allowing 10.7v at full throttle for me. These pumps need the higher voltage. Check out their flow charts.

 

Can you post your map? I assume some kind of standalone, so it's going to be a tune issue. My guess is that as the engine heat soaks, you are moving into an untuned area of the map...

 

prim and sec injector clips switched around...?

 

yea let me look for the map!!

 

B,
your car is pissed cause all my broke **** is hanging around

sorry