Im working on the swap of my eg, I converted it from obd0 dpfi to obd1 mpfi, I done myself the wiring.

At the moment I dont have check engine light on so looks fine, the problem I found is that the car is not running fine at low gas

I inversed the wires of the throttle possition sensor and checked with the multimeter that the signal is correct from 0.4 to 4.5 at full trothle

At this point the car runs well when is stoped, the engine turn well and hiting the 8000rpm, the problem is when I drive the car, is misfiring and dont run fine from 1500 to 4000 rpm.

I notice that inverting the TPS wires so 4.5 volts with closed gas and 0.4 with full open the car runs perfect until reach the end of the gas pedal, it cut at full gas as the TPS send the closed signal at this point but the car runs perfect from 700 to 8000RPM

any clue of what could happen? timming is good, new plugs, checked the resistance of the coil and correct, checked the ground in the distributor and resistance on the ignition unit and crank sensor, checked the coolan temp sensor.

Really is strange that with the TPS in the correct possition car run fine without a gear, problem start when car is runnig

 

I continue working on this, I discovered that disconnecting the MAP sensor, the car runs well.

I changed the MAP for a new one and tested voltage, ground and signal and all looks fine, but when I reconnect the cable again the same problem

Someone have an idea of what could be happening?

 

Car only runs well when the ECU send a higher fuel signal, I checked the presure on the output of the fuel rail and I get about 80PSI, after that removed the rail and injectors and the tip of 3 injectors is broken, I will go to the junkjard today to look for a set of injectors and rail with fuel pressure regulator.

I think this could be the main issue of the bad performance

 

I think 80psi at the fuel rail may have something to do with it as well. Unless you have reduced your injector flow rate by 50% somehow?

Stock fuel pressure should be 36/43psi.

 

Yes it is very high, all is stock from the y8, I tested with another fuel pressure regulator, but the same issue, its possible that the intake is taking air from someware? I dont know how I can test this

 

A vacuum leak around the intake manifold usually displays itself as bouncing RPMs @ idle.

These fuel systems are a return style system. Do you have a fuel return line from your fuel pressure regulator back to the fuel tank?

 

Finally I Found the problem, the timing was not correct by one tooth, I fixed the problem, but checking the timing with the strobo also the mark was not in the correct place, the main issue is that im running a p28 with the y8 engine the timing is different by 4 degres, I put a regulable cam gear and adjusted the difference to get the timing correct, now is running perfectly