Timing issue or something else...CODE-51

[Old94Max]

94 Maxima GXE with a S.O.H.C. engine with 221,000 miles. This thing started going through fuel injectors like candy. First the ecm showed a code 51 - fuel injector signal circuit fault. Found the # 5 injector was bad so I replaced it. Drove the car for about 2 weeks and the # 1 injector went out-replaced it. Drove the car again for 2 days & the # 6 injector went out so I replaced all of them. After that the car still ran rough as if it were missing or still had a bad injector but did not throw a code for a day or so. Then the # 3 injector went out again !!! I have checked several different things & replaced the TPS, Coolant TEMP. Switch, Ignition Module & Coil. The car has new plugs, wires, cap, rotor, button, & .PCV. The timing belt has not been replaced but I did inspect it about 20,000 miles / 1 year ago & it looked fine. Is it possible this thing jumped time even though it has cog style pulleys on the cam gears ?? I have started searching to see what makes the injectors pulse to dispense fuel but have found nothing. Could it be the timing belt or my ecm is fried sending incorrect voltage/signals to the injectors. There are no codes at this time and car still runs very rough !!!

[jltibbs]

Hey bro, this is Jeremiah from Advance in Smyrna. Have I talked to you before? I think the issue you might be experiencing is the newly added Ethanol in our area. You might ought to go ahead and change that belt out. You also might check with Dr Automotive and see what Randy says.

[Old94Max]

O.K. guys I am an old school mechanic but this one has got me so I need some help from someone that may be more knowledgable on this car than I am. I removed the timing covers to see if this thing had jumped time. The belt, tensioner, water pump, & cam seals, valves, springs, etc.. all looked perfect. I rotated the engine to TDC on the # 1 cylinder & the dimples on the sprockets aligned perfect with the dimples on the covers. I reassembled everything and then changed the cam position sensor & distributor. Started the engine & set the timing to 15 degrees advance. The car still runs rough. I started pulling the plug wires while the engine was running. When I got to the # 4 & # 6 cylinder & pulled these wires the cars running condition did not change. I left the plug in the head & installed another plug in the # 4 & # 6 wire. Both plugs are firing. All the injectors are new so I placed a screwdriver to each injector & the injectors are pulsing. I have even installed another ECM but this did not help. Before you post please read all the items on the previous post that have been changed & yes the MAF sensor tested good so I do not think that is the culprit.