omniserv

Does any one know where I can find the procedures for reading the EUC codes. The manual I have is not very good and is hard to follow. It covers all the differant modles so figuring out which is which is hard to do.

I have a 1987 300zx NA 2+2 with the sensor light on. I have pulled the ECU and watched the red and green lights flash, but don't know what they mean. The manual says something about differant modes, only to add later that the modes only apply to CA cars, and this is not a CA car.

Any help at all would be great.

Thanks

Chris

WolfMan

hmm, same issue here, CA cars "from California" have really hard emmisions, if you are seein that code, it means something with your smog is out. I was thinking about posting the same question, I bought the hanes, but never figured out how to read the codes, and noone in the area has a computer scanner, so if anyone knows how to read a 1986 2+2 plz let me know also.

AZ-ZBum

Good grief. There is no need for a code reader.

THe instructions for reading codes is in the Haynes manual. Or factory service manual.

Basically, you turn the screw all the way one way (I don't remember if it's clockwise or counter) and count the red and green lights. Then you compare those with the codes in the book.

FranksZ31's

I have the service manual for 85 300zx and I can fax you the codes and how to reset the ecu before you begin reading the lights. However, once you know the codes you will need to diagnose each one. Just let me know which codes show up and I will fax you the proceedure.

omniserv

I have a 1987 and accroding to my Haynes manual the codes are differant from the 1985?

AZ-ZBum

The 87 has more of them. But the rest of the codes are the same.

omniserv

I was finally able to read the codes. There's nothing wrong with the car, I read in another post that after so many miles the sensor light just comes on. So I pulled the bulb.

Also I have seen a few post where ppl have had the engine miss out at 2500 to 3000RPM's, or right in the middle of the power band. I have put new plug wires on and will be taking it in for new injectors next week, thanks to the recall.

Would the O2 sensor cause this to happen, or should I look to the fuel system? The first check of MPG were not that good either, 15MPG, however I did drive it hard many times for test drives.

I plan to replace

fuel filter
air filter
Spark Plugs
Fuel injectors (recall)
Dist. cap
Rotor cap
already have new plug wires.

Any other ideas?

Other than the lack of power in the 2500-3000 rpm range the car runs great and idels fine.

Thanks

Chris

FranksZ31's

Read RPM thread under Franksz31's

omniserv

Thanks for the advice. I did read the RPM post and doesn't sound like the problem I have.

The car drives just fine and the RPM's can go up to the rev. limiter (thanks to the floor mat I know) , it even seems to run smooth at highway speeds.

Only notice a problem when taking off, as you move up through the gears between 3-4 gear at about 2500-3000 RPM it just acts like a dog. You can put your foot to the floor and feel it miss out. It does keep getting faster until you are past the 3000 rpm mark, just not as fast as it should.

I have 2 idea's as to what might be going on. First consider that the RPM range we are talking about might just be where the engine is making the most HP. If the ingnition system is week that's when it would show. Also it might be a fuel supply problem (filter,injectors,Regulator or pump) because at those rpms the engines is burning the most fuel it ever will.

I have not completed the tune-up yet. Was going to wait until the dealer changed all the injectors. Once that is done I bet it will run fine. I'll post whatever the I find so that others that follow can see.

Thanks

Chris

WolfMan

lol, kinda going thru the same issue, on your throttlebody, I think thats what it is called, there is a black box on the side, have that checked out, that will kill the power off real good. That little gadget is responsible for regulating your air via reading your knock sensor. Just a suggestion.

omniserv

Thanks for the help reading the codes, turns out there are no codes showing up. But still have the problem of lack of power esp, at about 2000-3000 rpm's. The car does seem to run better when it's cold. Does anyone have any idea's? Chris

FreeLanceBum

Have you replaced the O2 sensor?
When the sensor light comes on, thats when your supposed to change the O2 sensor.
Also, after a certain amount of miles the sensor light will just stay on, then you remove the big plastic cover under the stearing wheel. Look on the left for a yellow wire that has a tag on it, This tag instructs you to disconnect it after however many miles.

A few other basic maintinance things you can do cheap; is replace the PCV valve (Posative Crankcase Ventalation) it screws into the passanger side of the upper intake manifold, and the hose from there goes into the top of the valve cover.
Also, while the car is running, pull the vacum line off of the fuel pressure regulator, if gas comes out, it's bad.

omniserv

I have a o2 sensor ordered and hope to replace it this week. Also checked the fuel reg. and it seems to be doing it's job. I ran a fuel pressure test and it's 30-40 psi depending on the RPM's. Another funny thing is the car runs much better when it's cold. Don't like to drive it hard before it warms up, but noticed it has much more power before it's warmed up. This makes me think it's more of a emisions problem.

omniserv

Replaced the O2 sensor and still no change. Even tried another set of plug wires just iincase the new ones I had were bad. I have noticed that when cold the car runs much better. Now I just have to figure out why that might be?

FreeLanceBum

It could be your EGR valve. That could definetly cause it to miss out.
And it only happens after it warms up. Had that happen to a Buick I used to own.

omniserv

I ran the test in the manual on the EGR valve. The car does run better with the new O2 sensor but still not the way it should. It runs very well before the engine warms up. So something in the ECU changes. That makes me think that the ingnition and fuel system is fine, I did test the fuel reg. and it seems to be ok.