I am working on a 98 teg GSR.
problem 1.
The car has been a bit of a complication in the past. It has burnt 2 exhaust valves in the past 2 years with no warning. He was just cruising at highway speed both times and torched the valves. Both occasions there was a ton of hard build up on the valves, plugs and head. The last time it was apart was this spring.(about 2k miles) I pulled the plugs the other day and they have the build up on them again... im sure the valves do to. Basically its most likely going to toast another valve soon. The residue looks like a white powder. It burns oil, but only when you rev it out and only burns a little..


problem 2. =no CEL
The car is running terrible. It will run good for about 10 minutes then begins to fall on its face breaking up and backfiring. Within the first 10 minutes the front 02 is in range meanwhile the back 02 sensor is out of range 3.8v(even in CL)... after it warms and you are driving they switch, the front goes out of range to 3.8 and the rear comes into range. that's when the car gets almost unbearable to drive. It will keep kicking out of closed loop and enter a status called "open drive loop" (not open loop) you can be driving down the road and all the sudden it starts breaking up and all the sudden it will enter Open drive loop and take off like it has good power.. within 20 sec or so it will try to re-enter closed loop status and start breaking up and falling on its face again. The cycle will keep repeating.
temp sensors reading ok, map looks to be in range, tps looks OK. basically they all look OK except the 02 sensor behavior, the heaters on both are staying lit all the time. I doubt they both would all the sudden die and not throw a code. If you let the car cool for about 5 minutes the cycle will repeat.. front 02 will work the it stops and the rear starts to work... it has a soft code pending of p0136.. there's no info anywhere on this code.

Without knowing the logic behind the computers actions its hard to diagnose the issue. I dont want to start throwing parts at it and hope it works. I want to find the problem. Any help is appreciated.

 

I hope I'm not stating the obvious but have tried switching the ECU in the car with a KNOWN GOOD ecu out of another 1998 Integra Gs-R? It really just sounds like an ECU problem if you read it over a couple times. If you are able to borrow an ecu to test this theory and it turns out to be the problem I have a spare ecu out of my 1998 Integra Gs-R. I'll gladly sell it to you on the off chance that that is the problem. Give it a shot if you are able to. It may be that it needs an ECU. Good Luck with this one.

 

I dont have any access to a gsr ecu (p72??) Its hard to find stuff like that to borrow and swap in. Its definitely crossed my mind though.

Does anyone know why the computer might kick back into a open loop status during driving? its almost like its a limp mode.. problem is the cel should come on if it was a limp mode.

 

Well depending on the cel it can put the engine in to a safe mode where it pulls timing and in general takes away all power to prevent damage from being done. or at least thats what it likes to think it does. And on the off chance the cel bulb is burnt out or removed...you might want to check that. its extremely easy to take out the gauge cluster to check. there are two screws on the top of the bezel that surrounds the gauge cluster. Take those out. lower the steering wheel via the tilt function and pull the bezel out. it is held in by two clips on the bottom though so you have to pull. then there are only 3 screws holding the actual cluster in place. one on either side and then on directly in the middle on top. should be easy to spot them after you take the bezel off. the only explanation I really have for the reason it kicks on and off during driving is that there may be something wrong internally in the computer causing it. depending on the code scanner you have it should give you some kind of explanation of what the code means. I have a can 2 obd2 scanner and it gives a reasonably good description. there is alo a website that you can enter the code in and it will tell you what it is for. the website is honda based and I wish i could remember it. but besides the point you really need to locate an ecu to test. they are reasonable easy to find and it is just a direct plug in. just make sure you get one for a 1998 as i believe they varied slightly by year. not the plugs but the information on them. ask around im sure someone would be willing to let you try theirs. if i was closer id let you try my spare to see if it fixed the problem.