ignition or injectors?
ignition or injectors?
i just picked up a 91 zx tt, got it running but only 3 of the 6 are firing. the car has been sitting for 2 1/2 yrs. i added new gas started it up and started pulling coils to see which ones were firing the first 2 and the seccond on the right are dead holes., i have fuel pressure and have spark(put a plug in the coil, held it to the block and watched it spark). replaced the plugs and still nothing on those holes. any help on diagnosing the problem would be a life saver, i dont wanna just put injectors in (pretty expensive) but if neone has ideas i would appreciate it.Thanks, Ryan
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z32partsmo
- Posts: 35
- Joined: Wed Jan 27, 2010 7:03 am
- Car: 1990 z32 NA 2 seater
Re: ignition or injectors? (MIXY)
First thing check for codes ecu located passenger side under carpet in the kick. then ohm load check all injectors remove harnesss from injector and prob it should read 10-14 ohms if it reads ol or higher than 14 then they are bad and need to be replaced. If it sat that long you may also need to replay the fuel dampeners , actually I would do that anyway and replace the fuel filter. If the problem is spark it could alkso be the PTU located passenger side front of motor or the CAS located driver side front of motor. also check ignition relay located under hood behind driver headlight and check fuel relay located driver kick panel its green relay.
Re: ignition or injectors? (z32partsmo)
excuse my ignorance but replay the fuel dampeners? i took the fuel line off from the outlet of the fuel filter and there is fuel flow. and if the injectors are bad do you recomend replacing them all. if so do you know if injectors from a maxima cross ove to a z?Thanks,Ryan
Re: ignition or injectors? (MIXY)
If you have spark at the coil and fuel at the filter, it's most likely fuel injectors.
First thing to always to is run ECU diagnostics to rule out the obvious
http://www.ttzd.com/tech/diagnostictech.html
2nd item on the list is pull all the connectors that have the spring clip as they are very prone to corrosion, especially after being parked for so long. Scrape away all the corrosion you can, and then treat with a high quality contact cleaner such as MG Chemicals. The ones to be most concerned with are: CAS, PTU, MAF, Injectors, AAC, FICD, Air Regulator, and TPS. While the connectors are off the injectors, check them with a multimeter. They should read between 10 and 14 ohms to be in spec. The Gen 1 injectors do fail quite often, but the proper Nissan ones are the ones to use on a stock vehicle.
The Fuel Pressure Reg and Fuel Damper are important items, but they won't keep the engine from starting. If they are black in color, they are original and likely not up to spec and may already be leaking past the diaphragm, but for now I'd concentrate on the above until it fires up.
As you may or may not know, it requires pulling the plenum to change injectors (or grind the screw areas) as there are areas where the casting interferes with removing the injector cap screws. Take a flashlight and have a look.
If you do pull the plenum, be aware there are a bunch of coolant hoses under there (and PCV hoses) that will possibly need to be replaced as they age and are notorious for leaking. The best is to bypass that trouble prone circuit as it was an ill-guided feature that was designed into it.
Read all you can on the tech items on this site so you know what you will encounter. It's actually not difficult, but knowledge is the best tool there is.
http://www.ttxtz.com/tech.html
First thing to always to is run ECU diagnostics to rule out the obvious
http://www.ttzd.com/tech/diagnostictech.html
2nd item on the list is pull all the connectors that have the spring clip as they are very prone to corrosion, especially after being parked for so long. Scrape away all the corrosion you can, and then treat with a high quality contact cleaner such as MG Chemicals. The ones to be most concerned with are: CAS, PTU, MAF, Injectors, AAC, FICD, Air Regulator, and TPS. While the connectors are off the injectors, check them with a multimeter. They should read between 10 and 14 ohms to be in spec. The Gen 1 injectors do fail quite often, but the proper Nissan ones are the ones to use on a stock vehicle.
The Fuel Pressure Reg and Fuel Damper are important items, but they won't keep the engine from starting. If they are black in color, they are original and likely not up to spec and may already be leaking past the diaphragm, but for now I'd concentrate on the above until it fires up.
As you may or may not know, it requires pulling the plenum to change injectors (or grind the screw areas) as there are areas where the casting interferes with removing the injector cap screws. Take a flashlight and have a look.
If you do pull the plenum, be aware there are a bunch of coolant hoses under there (and PCV hoses) that will possibly need to be replaced as they age and are notorious for leaking. The best is to bypass that trouble prone circuit as it was an ill-guided feature that was designed into it.
Read all you can on the tech items on this site so you know what you will encounter. It's actually not difficult, but knowledge is the best tool there is.
http://www.ttxtz.com/tech.html