I'm the original owner of a 1990 Maxima SE bought in Guam. It has 160K miles on it.2 days ago the car started to run rough. I have since done a complete tune-up (plugs, cap, rotor, wires, gas and air filter) I have a Oxygen sensor on order. It is bearly driveable, it feels like it is running on 5 cylinders. I would like to check the ECU module for troubleshooting clues, but can no find it. My Haynes manual for 85-91 Maximas doesn't cover the later years to well.The car has the original injectors and the all of the sensors are original. What would you suggest?
Thanks
1990 Maxima SE running rough
90 Maxima injector connector
Thanks for the quick reply. Is the Injector connector repairable, or do I need to by a new harness?
at our dealer we have sub harnesses you splice into the existing injector wires. one for each injector. You cut the injector wires about an inch away from the injector(battery disconnected of course) strip your wires ,cut your sub harness wires to desired length strip them. crimp an uninsulated butt connector on the injector wires on the car. soldier it once cool slide the appropriate size heat shrink over the harness. crimp your connector wires in the other end of the butt connector then soldier them. Once cool again slide the heat shrink up to cover the exposed metal and over lap onto the wire insulations. shrink it down. wrap with electrical tape for additional protection and cosmetic purposes. reconnect to the injectors and you good to go. try to stick with the proper polarities of the wires in the connector.
Thanks for the info on the injector wires. I bought the sub harness from the dealer. The unit I bought has 3 injector connectors ganged together to a common pair of wires. I am in the process of cutting back the wire loom wrap. It doesn't appear that the wires have a common source, at least on the side closest to the fire wall. Should I just spice each injector seperately?
yes the subharness you recieved is for the injector campaign on the 84 to 88 maxima and 84 to 89 Z. they will work on your car you cut the sub harness up so you end up with 3 seperate injector connectors with pig tails to splice in to the individual main harness leads. you cut the old injector harness about an inch from the connector. make sure you have more then that on the new ones. it wil give you room to solider.
I believe the computer on a 90 max is located behind the right kick panel. the procedure for pulling codes is in the nissan articals section. it may be listed for 240 but its the same procedure. are you not doing 2-6 because of location? if you do one its not a bad idea to do all since they useually al suffer from the corrosion. try wiggling the others best you can and see if you have any more improvement.
I'm holding off on 2-4-6 until the weather clears here in SoCal. I have a 65 Mustang that I'm prepping for paint in my garage. It looks like I will have to remove the upper intake manifold to get to #2. Can I get to it without removing? I have wiggled the connectors on 2-4-6 and didn't have the change in rpm like 1-3-5.I also have to repir a CV boot on passenger side, the fun won't stop.
I couldn't find the procedure for codes in th Nissan articles. My Haynes manual has a good description of the codes. I just need to get the ECU in hand. What are the acceptable ohm ranges for injectors? 1 & 5 were 12ohms, 3 was 16.5. Again I haven't checked 2-4-6 yet. I assume if I have to pull the upper intake, I might as well replace all the injectors? This car is starting to show its age and in about a year a newer Maxima will probably replace it.
ohms specs are really not that important when checking injectors on a car that will run. The important thing when ohming them out is that they are all the same. your readings already indicate a possible problem with 3 you are correct if you are going to do one it is recommneded to do the whole set. 3 is not real bad but is slightly high recheck it and make sure you are in good contact with the pins.[no corrosion between your tester lead and the injector pins]
ok do your self a favor and take your hanes manual. head out to the side of your house. open the trash can and insert said manual. It is completely wrong for the type of injectors your car has. It is correct for 84 to 88 maximas but nothing more. The 89 thru 94 vg engines have completly different intake systems and your injectors are inside a fuel supply rail[rather then having the hoses between them and the rail]. The orings wont come with the injectors you will need to get them seperatly. you want the one around the nozzle and the one around the body of the injectors x6 for both. you will not be needing any hoses.
completed the replacement of the injectors on Saturday. Thanks for all of your advice! I ended up replacing all of the injectors, all of the connectors, the fuels lines connecting the fuel rails, the intake manifold gaskets, and the upper radiator hose. I cleaned quite a bit of carbon and dirt from under the intake manifold. The O rings between the injectors and the inside of the fuel rail were included with the injectors. The ones between the manifold and fuel rail were not. The car runs very well. I'm looking forward to some improved fuel economy. The cost of the project was around $450 for injectors, wiring harness, gaskets, upper radiator hose, plus buying metric allen wrench sockets for torqueing the manifold. Thanks again!