The swap is a 96 gsr obd1 in a 93 ex coupe. The entire swap is stock including ECU. It some times wants to die out when it has been sitting for a long time and you try a cold start. Once it's warmed up a little it holds idle fine. Also once you get up to about 3k rpm it hesitates badly and bogs. It also does this when you jam the gas all the way to the floor. When VTEC kicks in its just a lot of noise and the same slow hesitation and bogging. It is not throwing any CEL's. The spark plugs, plug wires, ICM, dizzy cap, rotor and o2 sensor have been changed out. It has a new K&N filter, fuel filter and fresh tank of 93 gas. Any ideas is welcome. Thanks

 

check timing, map sensor, and tps.

 

Took it to a mechanic to have timing and cam position checked, I used a known good TPS and MAP off another car with the same results.

 

Also forgot to mention I cleaned up and retightened the 3 ground points on the engine and on top of the tranny.

 

I would consider checking next for bad/clogged injectors as well as fuel filter and fuel pump.

 

along with what ils said check the timing belt. being a tooth off is famous for causing erratic idle issues. spin the engine by hand counterclockwise and make sure the gears and crank are all up.

 

Took the car to a shop and had them look it over. They said that timing is good both dizzy timing and mechanical timing. They said it is getting proper amount of spark. The fuel filter is brand new and is flowing properly. They did a fuel pressure test form the filter and found that is putting out 225 KPA's or 32-33 PSI. The proper range is between 31-38 so it seems to fall into that range. But if I unplug the fuel pressure regulator, the PSI obviously jumps up,and the car runs better like that. I noticed a lot of people online people giving different ranges from 35 all the way up to 50 PSI for their GSR's. Should I be upgrading even though the pump is working right? Should I just install a new civic pump or can I install a gsr?

 

I think probably the next thing to do is swap for another obd1 stock gsr ecu. Never hurt to try. Trial and error. Also check for loose wires or crossed wires/plugs since the motor is obd2 and especially the IAB, from the engine bay to ecu. Oh and what about idle air control valve? No one has mentioned that. Good luck.

 

The wiring I think is solid, I have an extra harness and after first having this problem I completely reinstalled that second harness with the same results. Testing the ECU with a spare is probably the only thing I have not done because I can not find any one local who has one for me to try out. I have triple checked all wires, plugs etc. I have also tested sensors, TPS, MAP etc. and they all tested good.

 

Can you get a socket obd1 ecu with a gsr basemap? Like p28? It's hard to find obd1 p72 ecu. It'll be around $150 or lower depending on who you go with.

 

up your fuel pressure, my stock gsr fpr is set at 42 and goes up to 44 when given a little bit of throttle, and btw how are you measurig fuel pressure, hope not a b&m pressue gauge, those suck ***

 

fuel pump could be on its way out. stock gsr fuel psi is around 42psi, 31-38 is for an LS and even those often are closer to the 38

 

I'm getting the psi data from a local shop who hooked up a MAC fuel pressure gauge via the fuel filter check screw, so I'm confident about the numbers. Is there a way to up the pressure or adjust the pressure on a stock pump? Also if I have to buy a new pump will a stock GSR pump bolt right up?

 

did you calibrate the tps to the correct specs?

 

There was no calibration, I have a regular stock throttle body with the stock TPS riveted in from the factory.

 

the easiest way to test this is to use a gauge with a hose and go drive the car. if the psi drops when you punch it you have just confirmed the issue.

fuel pumps are easy to change, just in the back seat area. few bolts and it's good and done. ive done a friends in a parking lot before.

 

Threw in a used but known good fuel pump and still have the same problem. I also replaced the FPR with a used known good and it still had the same problem. But I noticed that when I unhook the FPR the car runs better, so I'm trying to hunt down a cheap adjustable and see if that solves the problem.

 

Just in case anybody was following this post, I finally found the problem. I was able to find someone who had a rack I use. I popped off the plastic that holds the fuel lines underneath the car and found out there was gravel stuck in in there that dented the lines. Replaced the lines and car runs 100% now. I'm guessing the dents slowed the gas flow and was starving the motor.