The car: 2001 base lude with JRSC@6ish PSI, Hondata s200 w/boost w/datalogging, CAI, DC 4-2-1 w/2.5" pipe - resonator - world sport 2,

The car is garaged 90% of the time, only driven on weekends. One weekend it was all good, a few weekends later it was fubar. It will run perfectly normal for about 5 mins, then when it's warm and switches to closed loop(I'm assuming) it starts to spit and sputter above 20% throttle. I have datalogged while it was warm and running poorly, yet I see nothing unusuall. MAP is acting fine, idle at .7V and WOT at 4.5V, and showing about 7PSI. TPS showing .5V to 4.5V, coolant at 192, intake at 150(no Icooler), and finally the O2 bounces around from 0 to .9V. Vtec is also normal.

In the beginning I suspected a fuel problem, so I put in a new Walbro 255, no glory. I'm not sure what try at this point, with sensors showing normal reading in the datalog.

To the best of my knowledge, the only thing different between open and closed loop is the ecu starts trimming maps based on O2 readings while in closed loop. I've also read that the ecu will revert to open loop during WOT, yet it still acts funky at WOT once its warm.

I don't want to just throw parts at it till something works. The fuel pump, in hind sight, wasn't the best idea....but it's in there now and one less thing to look at i guess.

Please throw out any suggestions/ideas you might have. Driving the company minivan on the weekends is killing me

 

closed loop makes the engine run based on the feedback from the 02 sensor. When it crosses into open loop it is running purely on the values entered into the fuel table. check your injectors, timing marks, distributor, plugs and if all is good check the tune.

 

Is there a way I can force the ecu to stay in open loop? Then if the car runs normal past the current 4-5 minute mark it would confirm that it is indeed open/closed loop related? And if that were the case, could i simply leave it in open loop?

 

I could be wrong, but I believe if you jump the 2P service connector it will keep the ECU in open loop.

 

You should be able to switch to open loop within the Romeditor program. The problem sounds like a tuning issue.

 

I've never used the rom editor, only the data logger. I have never tuned maps before, the car was tuned by Payne Technologies.

Where is this 2p service connector located? Can anyone confirm this will force open loop?

 

just in case check out the fuel filter, might be clogged from sitting a week or two.

 

Well, I jumped the service connector and went for my usuall trip around a few blocks. Ran great for the first 5 mins or so, like usuall, then the same old spit n sputter. I have to think that either jumping the service connector doesn't force open loop since it's a Hondata ECU, or that the problem isn't loop related after all. Guess I'll move on to ignition parts and swap cap/rotor, wires, and coil last. Plugs are new as of a month ago, right after this **** started.