[MarcOfMaccTown]

Hello guys, another long read for you. Maybe you can help me out.

I have an 86.5 Hardbody with the 3.0 V6 with TBI. My truck has been running very rich since I bought it about a year and a half ago. It has no power whatsoever after 2nd gear, and takes forever to reach highway speeds. It will do the speed limit on the interstate and then some but I'm lucky if I can get to 45mph before the merge lane ends. Once I get up to speed it will do 80+ all day long.

It used to burn a small amount of oil, I pulled the heads about 7-8 months ago and replaced just about everything but the valves. The new valve stem seals solved the burning oil issue but I still have no top end power. I checked the compression on each cylinder a few weeks ago. It was the first time I had ever done a compression check so I followed the instructions in the tester package.

I pulled all the plugs and tested each cylinder buy cranking the engine 5 rotations per cylinder. The lowest reading was 130PSI and the Highest was 140PSI. The Haynes manual reads that the specs for cylinder pressure at 300rpm is 173PSI, 128psi minimum, with maximum difference between cylinders 14psi.

I also tinkered with the MAF about a week ago buy cleaning it with alcohol and q-tips. Since I cleaned the MAF the truck has died on me several times and drinks fuel like no tomorrow. It drank fuel before I cleaned it but it never died on me before, not once.

Sooo.. Long story short, I tried to see what the ECU would tell me and it told me jack shit. I got 3 red flashes 1 green flash, Code 31 which reads in the Haynes as "The ECU input signal is beyond "normal" range This repair must be performed by a dealership service department."

I also got 2 red flashes and 4 green flashes, which would be Code 24. My only issue with that one is that it isn't listed in the Haynes. So I have no clue what it means.

I checked the ECU as instructed in the Haynes, that doesn't mean a whole lot so If you think I might have missed something please let me know.

Ok I feel like a real dope now. I just now realized that the ECU sticky applies to my 86.5 too. I didn't wait for the 3 flashes to enter Diagnostic mode... Will try again tomorrow and get you guys the real codes.. Sorry

 

[MarcOfMaccTown]

I just checked the ECU codes again and it still doesn't act like the Sticky says it should.

The sticky says both lights (green and red) should flash simultaneously, once then twice then three times and so on. Mine never blink simultaneously, when I flip the switch to on i get 1 green flash....2 red flashes...4 green flashes....3 red flashes. Each separated by a pause. If I flip the switch back to off after any set of flashes, I get two solidly lit lights.. One green one red.

What am I doing wrong?

 

[rdixiemiller]

Not sure, but there are people on here who know these things well. Be patient and one of them will chime in.

 

[Nissanpickup]

well your lack of power problem could mean that you tps is bad or your maf sensor could be bad i mean ive never cleaned them with alcohol ive always used maf cleaner so maybe that did it as far as the ecu codes go it might not be the ecu for that year vehicle cuz i have a 91 and that is how the ecu works on it the lights blink green first then red i do have a list of how you can pull the codes and what each code means but i cant find it right now when i find it ill let you know the web address hope this helps you out any

 

[Nissanpickup]

Ecu Self-diagnostics For 87-95 Pathfinder - Nissan Pathfinder Off-Road Association here is the web address for that web site i told you bout earlier hope it helps you as much as it helped me

 

[veesix]

Reading the codes can take a little practice. I use a flashlight and a ball point pen.

I pull the ball and ink parts out the end of the plastic barrel, and use the barrel to toggle that tiny switch.

Hanging upside down, with my head under the passenger's chair: Keep that manual open to the right page, and re-read the instructions until you are sure its right.

Those compression numbers are low, and it might be the rings (considering the heads are new.)

 

[MarcOfMaccTown]

I actually pulled my passenger seat out so I could get at the ECU easily. I can read the codes with no problem, and I have read the instructions on how to read the codes on two different forums and the haynes manual.

They all say that both lights should flash simultaneously when I first turn the switch to the ON position. Instead I get 1 green flash....2 red flashes...4 green flashes....3 red flashes. I've tried it several different times and get the same readings each time. I guess I can take it to the dealership so they can tell me I need $2000 worth of sensors.

 

[zanegrey]

turn the key to the on position but not running.

the lights will flash, turn the switch on ..as soon as it flashes three times turn it off and the record the flashes...


the 3 flashes put it in diagnose mode...

 

[88pathoffroad]

You could also try disconnecting the battery to reset the ECU. It may take a little driving after that for the ECU to record new codes, but see if it gets the ECU to start working right, at least.