I am trying to see if my 89 Nissan (February) ECU box (if that's the correct name for the box in my truck) under passenger seat can give codes to me like newer models can. But when I remove the seat to get to the box, I find a plastic cover and bunches of wires running to it, but no screw or switch is visible. Does the cover need to come off somehow, or is this model too old to give me codes? I had a dealer once tell me my truck doesn't have any diagnostic computers in it, so they can't hook it up to get any kind of error codes, did he mean the ECU can't either?
I am trying to see if my 89 Nissan (February) ECU box (if that's the correct name for the box in my truck) under passenger seat can give codes to me like newer models can. But when I remove the seat to get to the box, I find a plastic cover and bunches of wires running to it, but no screw or switch is visible. Does the cover need to come off somehow, or is this model too old to give me codes? I had a dealer once tell me my truck doesn't have any diagnostic computers in it, so they can't hook it up to get any kind of error codes, did he mean the ECU can't either?
OK, I took the screws out of the floorboard and lifted the unit as much as it would allow me (a few inches on one end), and I see the green and red lights. I also see the screw for adjusting (I think), BUT HOW DO I GET THE PLASTIC COVER OFF WITHOUT BREAKING IT (TO GET TO THE SCREW)??? I PULL AND PULL, BUT I AM AFRAID IT MIGHT SNAP IN HALF OR WORSE, ANY CLUES???
OK, I took the screws out of the floorboard and lifted the unit as much as it would allow me (a few inches on one end), and I see the green and red lights. I also see the screw for adjusting (I think), BUT HOW DO I GET THE PLASTIC COVER OFF WITHOUT BREAKING IT (TO GET TO THE SCREW)??? I PULL AND PULL, BUT I AM AFRAID IT MIGHT SNAP IN HALF OR WORSE, ANY CLUES???
AAAAAGGGGGGGGGGHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!! !!!!! DOUBLE-SIDED STICKY TAPE!!!!!!!! THAT'S WHAT HOLDS TEH PLASTIC COVER TO THE BOX!!!
Now I have slightly warped the top of the metal box trying to pull the plastic cover off, boy that was an engineering break thru , I'm sure it took the engineers a long time to figure out that dilemma (to be as cheap as possible)... Any way, it doesn't have a diagnostic screw. It has a hidden switch. I saw a white sticker that said something about not applying too much pressure, be gentle on the switch (but no switch). So I pried off the little white rectanguler tab below the label, and what do you know? (A little tiny switch hiding just inside the metal box)...(I'm documenting all this for future referene for others who might want to know)....
OKAY, all that work and all I get is CODE 55 - NORMAL OPERATION (NO ERRORS)..... that doesn't explain why my truck has such a rough idling problem when I first start it up in the morning...I guess I was hoping for too much. Any other ideas? I've already changed the fuel filter, O2 sensor, dist cap, spark plugs, plug wires.....hmmmm
sounds kinda odd... how cold is it outside? Are you using a block heater? How is it running when it gets warmer?
Oh it HATES cold weather! (Though we don't have deep freezing temperatures here, I'm in Houston, Tx.) And it hates just having a cold engine almost as much(before reaching normal running temperature).The engine starts, goes to rough idling, then stalls if I don't keep my foot on the acclerator. The warmer it gets, the better it runs, (not perfect, but MUCH better), and does not stall. Excuse my lack of knowledge, but what is a block heater?
Last edited by DanaCat : Jan 15th, 2005 at 02:10 AM.
I think all of the vehicles I've owned that had an ECU, would let you read the codes off of the "Check/Service Engine" light by either manipulating the ignition switch, or installing a diagnostic fuse, or something like that. You're a brave soul digging into the ECU itself.
It sounds like you're done a lot of the standard "tune-up" things. How about the air filter, pcv valve, and egr valve (although I think egr would show a computer error if there was a problem, but there may be a filter on the egr)?
Is this an auto or manual? I have very little experience with Nissans, but I know an automatic Geo I had, had a heater plate between the throttle body and the intake manifold that would heat the fuel when the engine was cold.
BTW, being from Houston, I'm not surprised you don't know what a "block heater" is. Go to North Dakota and you'll see many a car with a power cord sticking out the grille. That way they can plug in their block heater at night and hope it keeps their oil from turning into paste.
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Jerry
2004 Frontier, King Cab, XE, 4x1, 4-cyl, 5-spd
I think all of the vehicles I've owned that had an ECU, would let you read the codes off of the "Check/Service Engine" light by either manipulating the ignition switch, or installing a diagnostic fuse, or something like that. You're a brave soul digging into the ECU itself.
It sounds like you're done a lot of the standard "tune-up" things. How about the air filter, pcv valve, and egr valve (although I think egr would show a computer error if there was a problem, but there may be a filter on the egr)?
Is this an auto or manual? I have very little experience with Nissans, but I know an automatic Geo I had, had a heater plate between the throttle body and the intake manifold that would heat the fuel when the engine was cold.
BTW, being from Houston, I'm not surprised you don't know what a "block heater" is. Go to North Dakota and you'll see many a car with a power cord sticking out the grille. That way they can plug in their block heater at night and hope it keeps their oil from turning into paste.
Thanks Jerry! Now I know why a block heater is a foreign concept, . By the way, I am driving a manual 5-speed. It does have a heater plate, if I remember right. Could that be the problem, a heater plate not working? I did change the air filter, pcv valve, and checked that the egr valve was not sticking (sorry, I have tried so many things I forget all of them until someone mentions them). How do you check to see if a heater plate is working?
Thanks Jerry! Now I know why a block heater is a foreign concept, . By the way, I am driving a manual 5-speed. It does have a heater plate, if I remember right. Could that be the problem, a heater plate not working? I did change the air filter, pcv valve, and checked that the egr valve was not sticking (sorry, I have tried so many things I forget all of them until someone mentions them). How do you check to see if a heater plate is working?
I know my auto had one, but I never disconnected it to see how it might affect cold starts and as far as I know it always worked, but like I said, I don't know how much of an impact a non-working heater plate would have.
I'm horrible with electricity/electronics, but I would expect that if you took a multimeter to the contacts (mine had two, I assume one hot and one ground) that you should read some resistance, maybe fairly large. But, if the heater plate is broken, would you read no resistance or infinite resistance?
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Jerry
2004 Frontier, King Cab, XE, 4x1, 4-cyl, 5-spd
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Can ECU on 89 z24i truck give codes to me?
. By the way, I am driving a manual 5-speed. It does have a heater plate, if I remember right. Could that be the problem, a heater plate not working? I did change the air filter, pcv valve, and checked that the egr valve was not sticking (sorry, I have tried so many things I forget all of them until someone mentions them). How do you check to see if a heater plate is working?
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