I recently rebuilt an M20B25 and swapped out my M20B20. I have a 173 ecu. I had everything in as stock and it was running strong once i found all the vacuum leaks and minor issues (engine temp sensor, TPS out of adjustment). I purchased a 2.7" miller maf conversion (Gen III) from Ireland Engineering(installed chip in correct orientation and soldered the correct wires). I also upgraded to 17.5lb green top bosch injectors added an adjustable FPR to bump fuel pressure up to compensate for the larger injectors (tried a range of pressures from 35psi up to 60 psi and the stock 43psi). Settled at 50psi as it at least gets me to work and back. Once said items were installed the car started running like garbage. Idle is at about 1300rpm at all times and will ocasionally drop to 750ish and then right back up, soon as i touch the accelerator to move, to 1100-1300rpm. It hesitates and bucks through the rpm range up until it hits about 4k. The engine barely can pull the car up a hill at 4k in second gear. Also the engine really loses power and bogs at WOT. It will pulls harder at 3/4 throttle than it does at WOT. I'm at a lose of idea. I've followed the maintenance manual and tested every possible cause of erratic/high/low idle and everything checks out within limits. every relay and fuse has been tested and is the correct one for perscribed position. I've pulled the ECU and checked perscribed pins at the ECU connector in accordance with the manual. Now my question is what the hell is going on. I'm about ready to push this car faster off a cliff. Does the ECU lose its adaptability when the MAF/chip is installed? Is the MAF/chip combo not accepting the larger injectors? the only thing i havent done was revert the injectors back to the stock 14lb. I'll be doing that tonight. If anyone has experience or has had a similar problem please chime in and let me know what you have checked or what your fix was.
Sorry about the novel just wanted to be detailed as possible on the issue.
Sorry about the novel just wanted to be detailed as possible on the issue.
Comment