Error Code 22 & 87

[Blizz]

I have a 90 coupe that i recently purchased. The guy had done 4cyc to a 5.0 swap with A9L and 90 harness. I have preformed all the trouble shooting steps that were in earlier post. I have correct voltage and ohm readings and even swap Bap sensor with good one from another car and can not clear code 22. Also dump codes and it is always there. Car idles fine and when it gets to around 3000 rpms it stumbles, stalls and backfires and no power.

He has also rewired the fuel pump relay and it constantly runs with key in the on position and I'm getting error code 87. Didn't know if I should rewire it correctly and replace the wiring? I also installed a 225 lph fuel pump and Kirban FPR and can not get fuel pressure set under 45 psi, it doesn't change with or without vacuum?

 

[jrichker]

How to clear codes.

You need to clear the codes any time that you replace a sensor.

Clear the computer codes by disconnecting the battery negative terminal and turn the headlights on.

Turn the headlights off and reconnect the all sensors including the MAF and anything else you may have disconnected. Then reconnect the battery negative cable.. This clears all spurious codes generated when you disconnected any sensor and ran the engine. This does not fix the code problems, it just gives you a clean slate to start recording what the computer sees happening.

Run the car for at least 30 minutes of driving and dump the codes.


The fuel pump return line may have a kink or obstruction. That would prevent the fuel pressure regulator from working properly and not be able to lower the pressure to a constant 39 PSI..

How the fuel pressure regulator works
The fuel pressure regulator in 5.0 pushrod Mustangs is a shunt regulator that works in parallel with the fuel injection system. The regulator bypasses fuel back to the tank to maintain a constant 39 PSI to the injector tips. A constant pressure insures that the computer will always have the same flow rate to base its calculations on.

 

[Blizz]

Thank you Sir! I will give it a try and let you know.

 

[mikestang63]

welcome to the world of hack job 4 cyl to 8 cyl conversions.

 

[Blizz]

Thanks, LOL. If I can get a few issues resolved it should be good. He has already done five lug conversion, tub k-member, control arms and coil overs. It has CC plates, having issue with getting camber adjusted on passenger side. Need to find a good paint and body guy here in the Dallas area.