Ok here is what I got.
I have a 1997 civic cx with a 1997 gsr swap has I/H/E, test pipe,throttle body, intake manifold, fuel rail and FPR. OBD2 to OBD1 conversion with a chipped P28.

So about a month ago my car started to act funny on the freeway at about 3000rpms the car would studders for a split second. First the coil went out so I replaced it and the igntion control module, the cap and rotor. After that It threw a code 43 CEL saying low fuel system pressure. I swapped in a walbro 255 fuel pump and a new fuel filter. THE CEL STILL COMES ON.

Now everything I read says O2 sensor, only I have no O2 sensors on my car we took them out of the programing and are running the car open loop. So there is no way the O2 sensor can be causing this. I tried unplugging the o2 sensors, plugging them in and even switching them and still the same problem.

Anyone got any ideas as to what could be causing this?

 

what's the fuel pressure at the rail ? stock regulator/rail/injectors (you did't say stock or aftermarket). try a stock ECU first, where was this chipped p28 from ? I hope it's not one with a "Spoon or skunk2" chip from ebay.

 

No way on the eBay crap. It was chipped by a local shop. AEM FPR, golden eagle fuel rail pressure set to 45 stock injectors. The ECU ran fine until last month then all this started.

 

so you just have the o2 code now ? HAVE YOU confirmed it's at 45 psi via a fuel pressure gauge ?

 

No not an O2 code it's a code 43 low fuel system pressure. Everything I've read said the O2 sensor is bad but that can't be because my O2s have been removed. And yes I have a pressure gauge on the fuel rail.



Thanks for your help.

 

45 with vacuum line off or on? if it is chipped what pressure does the tuner recommend?

 

About 47 with vacuum line on 60 with the line off.

 

Have you checked for vacuum leaks? Reset the code then see if it comes back

 

Yes, rest the code and I comes right back. I even just swapped out the injectors, cleared the code started it up backed out of my parking spot and bam CEL back on.

 

any way to use a friends dizzy to see if that solves ur problem? if that's the last thing u messed with and now get the code has to be with the dizzy... a connection would be shorting out or not getting enough current... your dizzy does control injector firing

 

Problem was before the dizzy then the coil went out.

 

I unpluged the primary O2 sensor and the car runs better no chugg but the CEL stays on. We went back into the Chip and made sure the O2s are disabled (there were). I'm lost.....Main relay, MAP, or TPS sensor is what I was told it could be.

 

Anyone?

 

basically all i'm thinking is the dizzy because if a replaced coil had to go in there. your best bet is to try and borrow a stock ecu and a replacement dizzy to see if the code goes away. sometimes chipped ecu can have issues because honda intended for their Engine Control Units not to be messed with. try that and tell us how it goes.

 

Ok I will try another dizzy and see if that works.

 

Try a stock FPR or another aftermarket, AEM FPR are known for fail maybe in idle you see good pressure but it can be falling out of pressure when the engine is in load.