My 94 max is running rough & lacks power! The engine light has come on and I don't have an OBD 1 scanner to trouble-shoot the codes.

I've replaced the spark plugs, wires and fuel filter. Also checked for a vaccum leak. No leak car still runs the same.

The hayes manual shows a picure of the computer box with the slot you turn clockwise. My car has two boxes with wires and connectors (no slot)
I love manuals!!! Can you guys give me some support or suggestions.
I'd like to solve this one myself. Nissan Dealers make my credit cards shiver with fear'''' Thanks, Rich

 

Have you checked your fuel injectors?

 

Welcome

If im not mistaking {have today once...thanks danNY} the top box is for the auto tranny,the bottom one is your engine computer. The screw is on the passeger side{mine had clear tape over it when i first check it.}

 

Thanks, I should have known not to trust the books picture!

I'll check the passenger side and go from there.

Thanks again Greenmax

 

No need for scanner. ECU might tell the problem via its leds.


Two things among many possibilities:

TPS Throttle pos sensor. Its en evil intermittent box... 90$.

Basic tests from its pins, seek with ohmmeter which ones:
- idle pos switch, does it close? Opens when gas pedal moves.
- 'kick down' activates somewhere at 2/3 gas pedal down
- resistor is linear 1kOhm-9kOhm. (VG30E)
...but these do not give intermittent failures

Mass Airflow Sensor
Copy from somewhere: If the MAF voltage is below the specified value, the ECM senses a mass airflow sensor malfunction. In this case, the throttle position sensor substitutes for the mass airflow sensor. Although the MAF is malfunctioning, it is possible to start the engine and drive. However, engine speed will not rise more than 2400rpm.

Haynes Manual:
Put a DVM probes into MAF pin b (second from left) & gnd
- Ign on, engine stopped 1V
- Idling, temp up 1-1,7V
- 2500 rpm 1.5-2.1V
- Important: linear voltage rise up to 4000rpm.

Test those first.

- Fuel pressure ok?
- In any case I would go through all wiring connectors, groundings, thin ctrl tubings.

 

I'll bet it's an injector. Been a few going latley including 2 of mine.

 

I had one go as well

 

yea me too........

 

Count me in for an injector, at least that's what I'm thinking.

A question about tripping the computer codes, when I set the screw to diagnostic (because the check engine light was coming on and the car was running bad) all it did was repeat the same sequence of lights. It would blink once, then two blinks, then three blinks, then four blinks, and finally five blinks then repeat all over again. I can't remember for sure but I think it was just the green light that was blinking.

I was expecting it to transmit any one of the various codes but from what I could see this sequence isn't mentioned anywhere. Is there a reason that the check engine light would be on but the computer wouldn't be able to report the code, or am I just being dumb and not reckognizing something obvious.

 

What is it with VEs and their appetite for injectors? Is there any way to make this problem completely go away? I've replaced all 6 of mine (very expensively, about 1.5 years ago), and one other has been replaced since then.

I've taken to only getting 91 octane from Chevron and no place else.

 

I've replaced 7 on mine so far.

 

I've replaced two but I've only owned the car for five days.

 

I was expecting it to transmit any one of the various codes but from what I could see this sequence isn't mentioned anywhere. Is there a reason that the check engine light would be on but the computer wouldn't be able to report the code, or am I just being dumb and not reckognizing something obvious.[/QUOTE]


- I have not had any error codes - still did not pass the exam. That evil thing was TPS, exam went through without any repairs.

From my experience I do state that computers can do anything; with this stupid ECU interface even moore... [first, these code-leds could be visible at will, installed on the dash...]

The error codes just might help, but most probably their indications are just for the russians.

I would work in this order: Do all PM =ALL, check all sensors that can be checked with dmultimeter [TPS, MAF], clean all connectors, ctrl tubing check (cut brittled ends), change TPS in any case, Ign Coils, O2, MAF, injectors...

LAck of power & led means ECU keeps now your engine in safe mode: retarded ign & under 2500rpm.

 

- I have not had any error codes - still did not pass the exam. That evil thing was TPS, exam went through without any repairs.

From my experience I do state that computers can do anything; with this stupid ECU interface even moore... [first, these code-leds could be visible at will, installed on the dash...]

The error codes just might help, but most probably their indications are just for the russians.

I would work in this order: Do all PM =ALL, check all sensors that can be checked with dmultimeter [TPS, MAF], clean all connectors, ctrl tubing check (cut brittled ends), change TPS in any case, Ign Coils, O2, MAF, injectors...

LAck of power & led means ECU keeps now your engine in safe mode: retarded ign & under 2500rpm.[/QUOTE]

Was this post done using an online translator? I'm so confused my brain wont stop Farting now.

 

from the error code sticky on the top of the forum page

http://pages.cthome.net/bbachinsky/nissan_ecm_codes.htm