Mechanics

CHECK ENGINE LIGHT

Nissan Other

1988 nissan pulsar nx when checkengine light is on the car surges at 250 rpm or 45 mph and wont go past that no matter what but somnetimes the light is off and it runs fine also when its acting up theres lots of black smoke from exhaust and temp or gas gages arent functioning idle is rough and will die sometimes whats up?
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Lissanne
April 5, 2007.



There are codes in the computer than need to be retrieved. Something is causing a rich condition that needs to be corrected or you will create more problems by waiting.

This is a 1988 Nissan Pulsa NX SE 1.6 I bought the car over a year ago the ck engine light was on then but it ran like a dream with one exception, the idle seemed to be set a little high even after being adjusted several times it would seem to go back to being a little high. I have driven it ifrom az. To san fransisco then a month later from az. To virginia and back with no problems until a few months after being back home in az. It started doing this and the starter went out (replaced it) at first it woulod only start the hesitating surges at250 rpm while sometimes accelerating uphill and could be corrected by disconnecting battery that stopped working until last night the car had ben diconn. From battery for 2 days when I connected and started it I noticed the ideling sounded good then I noticed gages where functioning and ck eng lht was off took it for a spin and it ran great. That was the first time I ever seen the light off, I thought you could only run the code readers on 1996 and newer?

Tiny
Lissanne
Apr 5, 2007.
Pre-96 vehicles had what is known as OBD I aka on board diagnostics I. Post 96 Vehicles have OBD II.

They became easier to diagnose after 96 as all the connectors are now uniform as well as technical allocations. Before, like yours, each manufacture had their own way of doing things and made it very cumbersome.

Anyways, when you disconnect the battery, the computer loses it's memory and needs to be driven to re-learn it's data stream values so it can make necessary adjustments. When it finds the problem you have it will throw the light again. Sometimes the computer can use a " default" value for an input that is out of whack. An input would be a sensor for example the tell the computer what it sees, the computer makes an adjustment to fuel/air mix and the change is the result of the output. So there may or may not be codes stored in the computer. Best bet is to have it checked.

For what it matters, have heard of a fuel pressure regulator cuasing your condition as well as a computer that is grounding the EGR valve Too long, in which case the computer would need replacement.