# ECU madness



## waveman56 (Aug 20, 2004)

We recently completed a valve job and allthough everything seemed to go well, our 88 NA would not start. It had been sitting for about a year before we had the time, knowledge & money to fix it.
I'v checked and we are getting gas, but I'm not sure at what pressure (disconected the line at the fuel filter). It seems rather low to my untrained eye, but does gush out when we crank the car. 
Worse yet there is no gas in the cylinder. I'v threaded a paper towel through the spark plug and couldn't smell even the slightest whiff of gas. The plugs themselves are dry. At first I thought it was the fuel pump or injectors. But when I put the ecu in diagnostic mode the red & green diode both blink simultaneously, for all codes;
1 long blink, 
pause,
2 long blinks, 
pause,
3 fast blinks,
pause,
4 fast blinks,
pause,
5 fast blinks

I was under the impression from the hanes manual that the red & green would blink seperately. Red for the tens and green for the ones. Is the ECU toast?


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## Zen31ZR (Mar 24, 2004)

Try using another ECU , if you can find one.


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## 0341TODD (Nov 15, 2003)

yeah, my factory service manual doesnt even say anything about that man. I cant find it anywhere........which isnt good.


Sounds like Gremlins again- call John Lithgow!


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## asleepz (Feb 24, 2004)

they should be different colors on the blinks

(depending on what code it's throwing)


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## waveman56 (Aug 20, 2004)

Yeah sounds like it's toast


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## 0341TODD (Nov 15, 2003)

yeah, that is not good whatsoever-they should always be different colors


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## asleepz (Feb 24, 2004)

1 long blink, ==I
pause,
2 long blinks, ==D
pause,
3 fast blinks, ==E
pause,
4 fast blinks, ==A
pause,
5 fast blinks == D


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## KungFuGrandpa (Aug 23, 2004)

the red is tens and green ones, ext. 2 red bliks and 3 green is code 23. A code 31 means that the ecu is malfunctioning. check for a code 31 thats one i had when i let mine sit for a year and i tried to start it and it wouldnt. My ecu was bad so check it out and try it with a new ecu in it


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## waveman56 (Aug 20, 2004)

Messed around with it for a while and I got it to give me one code. 42 fuel tempature sensor. So I'm working on getting that particular piece. Autozone, checker & nissanparts.com can't tell me if a new sensor comes with a the pressure regulator or if your expected to use your own. In the meantime I was curious if the fuel sensor does indeed stop the ecu from sending out juice to the injectors?

P.S. replaced the plug with a female spade connector but the circuit is still open


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## Zen31ZR (Mar 24, 2004)

waveman56 said:


> Messed around with it for a while and I got it to give me one code. 42 fuel tempature sensor. So I'm working on getting that particular piece. Autozone, checker & nissanparts.com can't tell me if a new sensor comes with a the pressure regulator or if your expected to use your own. In the meantime I was curious if the fuel sensor does indeed stop the ecu from sending out juice to the injectors?
> 
> P.S. replaced the plug with a female spade connector but the circuit is still open


 According to all I've been told about the fuel temp sensor , it only affects startup when the car is hot. When the fuel is warm , it sees that and makes the ECU spray more , probably to get rid of a possible vapor-lock situation. It should not affect your running the car at all.


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## waveman56 (Aug 20, 2004)

[email protected] said:


> According to all I've been told about the fuel temp sensor , it only affects startup when the car is hot. When the fuel is warm , it sees that and makes the ECU spray more , probably to get rid of a possible vapor-lock situation. It should not affect your running the car at all.


That explains a couple of things. I had forgotten to erase the code from the ecu. After I did and tried starting the car I got code 55, all good. So I guess it was the plug. Now to try and figure out why it's not starting.....and no error codes to go on 

I guess the ecu could be bad, not sending any juice to the injectors. Maybe it's time for the dealer to have a look at it.....


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## Zen31ZR (Mar 24, 2004)

waveman56 said:


> That explains a couple of things. I had forgotten to erase the code from the ecu. After I did and tried starting the car I got code 55, all good. So I guess it was the plug. Now to try and figure out why it's not starting.....and no error codes to go on
> 
> I guess the ecu could be bad, not sending any juice to the injectors. Maybe it's time for the dealer to have a look at it.....


 I'd avoid 99% of dealers at all costs. They pretty much , with few exceptions , exist only to drain your wallet. Dealerships profits aren't made on the sales floor , it's made in the service bay. I'd take it to an independent shop if at all possible , preferably someone who specializes in Nissans. And there is still nothing stopping you from finding an ECU somewhere and installing it yourself. I would check the classifieds here and at Z31.com , someone always has an ECU or is parting out a car. Before you do that , go through all the ECU connections , make sure they are all secure. Check all fuses and relays , also. It's rare for an ECU to go bad , and Z31 ECUs don't seem to have a history of it being common. Most times ECU failure is caused by an external source , such as a bad alternator voltage spike or bad grounding.


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## hondakillerZX (Aug 16, 2004)

jim wolf technology makes good ecu's for the 300zx you should go to their website i want to get one too


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## asleepz (Feb 24, 2004)

yeah for like 500 bucks. SCREW THAT


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## Zen31ZR (Mar 24, 2004)

SKD_Tech said:


> yeah for like 500 bucks. SCREW THAT


 With no other mods , I would consider it pointless also. Unless you were stuck at the limits of the stock ECUs power curves , it doesn't make sense to spend that much money just yet. Besides , a stock ECU can be had for $50 or less , and all he wants to do is make the car run again at this point.


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