I'm having trouble finding information on this problem, any insight is greatly appreciated! I have a 98 si with a 2000 gsr swap. I've got a t3 garret set up. I'll try to sum up what's going on. I put the gsr in and ran it like that for about 6 months (ran fine no issues) before I got my boost set up (running 6 psi). Replace the head gasket (not OEM), arp head studs, timing belt, water pump etc. running p27 with new hondata. Got everything back together to start tuning. And 3rd pull into boost and overheat. Turns out I was getting cylinder pressure into water jacket causing air lock (was not getting coolant into cylinders, no milky oil or white smoke). My a/f ratio was bouncing around quite a bit but leveled out once it got a cel for engine overheat. I've now had the head checked for straight and installed new OEM Honda head gasket. Wanted to warm up the motor and then re torque the head. Anyways now in the process of bleeding the coolant I had another air lock which caused the overheat cel again. It was running like it had a misfire and again the a/f guage was bouncing around considerably. As soon as I got the cel light for overheat it completely loss the miss sound and ran like a new motor. Also my a/f ratio straightened right out again. Any ideas why a cel would straighten everything out like that??

 

I apologize if maybe I posted this in the wrong section. Any thoughts on what the overheat code triggers the ecu to do? Once again it is obd1 s300 v3

 

When the CEL kicks on it usually runs on a basemap, which is a set of values that are inefficient fuel/power-wise but will get you around. I had a problem in an old CRX where the TPS failed and idled poorly but if I unplugged it the CEL kicked on and the idle raised up. This is normal.

Fix the problems, reset the ECU by unplugging battery for a minute, and go.

 

I could be mistaken, but I do not recall a specific CEL code for overheat.

When you threw a CEL code, did you actually pull the code?

 

Code 11 is not a factory Honda/Acura code... it was created specifically within the Hondata system framework. You can set the parameters up for this protection, and thus, WHEN the MIL illuminates if you so choose, and how the engine is protected once the coolant temperature reaches this threshold. I believe the default value is 212' F.

 

Good to know, thanks for clarifying.

 

Ive been told the s300 has a "limp mode" built it that runs a richer mixture, or reverts back to a base map? Still trying to wrap my head around why it turns the bouncing a/f ratio to a steady 13.0-13.2 on the AEM wideband.

 

Fairly impressed that this has seem to stump the communitee, but what I have found out so far that may be of use to someone else trying to work through a similar problem is it seems to be maybe a communication issue of some sort between the hondata and ecu. I plugged my obd2 gsr ecu in and it runs perfect with Steady a/f readout. I'm going to get the other ecu checked out by a shop and post the results.