Qic12c

Gday guys i have a 89 fairlady and im having a few issues first off the check engine light flashes on and off occasionaly and i stuff around with the wiring looms then when i start the car its fine no light also occasionally the car miss fires but returns to normal any answers would be awesome thanks josh

ZLover4Life

Pull ECU codes.

And test the resistance of your injectors... more often than not, they are the source of misfiring. Should be 10-14 ohms.

Qic12c

So i did the test on the ecu 55 fine and i am getting about 10-12 ohms on all six injectors so is this all good or is there a loose connection somewhere?
Thanks for the help

ZLover4Life

It has to be a connection. When you say the CEL flashes, is it fast or does it come on for a little while and then turn off? If it stays on for a few minutes, you should try to do the diagnostics while the light is on, so that you can figure out which sensor connection it likely is. If you can't do that, the following will activate the CEL and thus should be inspected:

12*: air flow meter circuit
13*: engine coolant temp. sensor circuit
14*: vehicle speed sensor circuit
26*: boost pressure sensor
31*: ECU
32*: EGR function
33*: exhaust gas sensor circuit (left)
35*: exhaust gas temp. sensor circuit
43*: throttle position sensor circuit
45*: injector leak
51*: injector circuit
53*: exhaust gas sensor circuit (right)


Regarding the misfiring, clean and re-gap your spark plugs (replace with NGK plugs if they are another brand).

You could also try this if you have some money. (Don't bother replacing the EGR valve if you do - just eliminate it, as it's not needed on the Z32 and can cause significantly more harm than good if malfunctioning or if the vacuum lines are misrouted.)

Qic12c

thanks for the help zlover4life i re-gapped the spark plugs and it seems to have gone and as for the CEL as it was on i checked the ECU and still came up with 55 so should i check all the wiring? and with eliminating the EGR valve can you still do it with the engine in the car
Thanks josh

ZLover4Life

If you pull the plenum, it's possible... not easy, though.

xpwarrior

That's a fact. I took the whole system out in pieces. The tubing can be cut in various places to ease removal. The bolts that hold the valve on are too long to be removed so I backed them out as far as possible then cut them off and unscrewed them the rest of the way with pliers.