# 1990 Sentra Acceleration Problem



## WiltedBeauty (Dec 31, 2005)

A few days ago my 1990 Sentra started having acceleration problems. When you put it in gear, either reverse or drive, it is extremely slow at accelerating. It takes a minute or two to start speeding up, and then it accelerates with no problem up to about 70 - 80 km. I took it to a mechanic and after spending an hour, and $80, and checking the exhaust system, timing, fuel pressure and compression, he had no idea what was the problem. I don't know as much as I should about cars but it feels like there is a clog or something somewhere. Also the engine gets really hot, but the temperature gauge inside stays normal. The spark plugs have also been changed thinking that might be part of the problem but no luck. Someone suggested the catalytic converter may be plugged. If anyone might have any other suggestions for when I take it to another mechanic after the long weekend it would be greatly appreciated.


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## bob89sentra (Sep 15, 2005)

Welcome to the nissan forums
First off if you have a vacuume gauge hook it to the intake, and see what the gauge is doing. If it is holding 15-16inches of vacuume at idle, and not bouncing of fluctuating, that is goood.
Next start the car, and with it in park press the pedal to the floor, and the engine should rev up all the way in less than two seconds. If there is any bogging and the throttle is not responsive there is a problem.
If you haven't done a full tune up recently it would be a good idea.
IE spark plugs, wires, cap, rotor, air filter, fuel filter, PCV.
A good way to test for bad plug wires is to take an old windex bottle, and fill it with dishwashing soap and water, and when the engine is running spray the soapy water on the spark plug wires from end to end. If there is a hole burned through the wire there wile be visable sparks, that will also be audable.
It could be that your TPS (throttle posistion sensor) is bad.
Personally it sounds to me that it is a timing or IGN problem.
Let us know what you find
Bob


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## modenaf1 (Nov 12, 2005)

WiltedBeauty said:


> A few days ago my 1990 Sentra started having acceleration problems. When you put it in gear, either reverse or drive, it is extremely slow at accelerating. It takes a minute or two to start speeding up, and then it accelerates with no problem up to about 70 - 80 km. I took it to a mechanic and after spending an hour, and $80, and checking the exhaust system, timing, fuel pressure and compression, he had no idea what was the problem. I don't know as much as I should about cars but it feels like there is a clog or something somewhere. Also the engine gets really hot, but the temperature gauge inside stays normal. The spark plugs have also been changed thinking that might be part of the problem but no luck. Someone suggested the catalytic converter may be plugged. If anyone might have any other suggestions for when I take it to another mechanic after the long weekend it would be greatly appreciated.


I am by no means an experienced mechanic, or that experienced with Sentra's to be honest (I'm still in the process of putting a new thermostat housing on mine), but if you say it accelerates relatively well once you have it moving, but not starting off, since this does have an automatic transmission, perhaps some sort of a problem with the torque converter? Maybe low on transmission fluid perhaps?


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## dreamteam (Jul 29, 2005)

I will agree with your feeling that something is plugged.

It is likely that it is either fuel line or exhaust.

Check the fuel line for crimps or clogs.

Check the exhaust pipe for compression damage from an impact.
An exhaust obstruction can be detected with your foot , or a vacuum guage.
Put your foot over the end of the tailpipe(nice big tennis shoe please) and push hard to seal the exhaust. If your car does not slow down or quit in a couple of minutes, you have an obstruction.

The hot engine would seem to indicate an exhaust problem, or a poorly bled cooling system.


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## WiltedBeauty (Dec 31, 2005)

Thank you for the suggestions hopefully this will help them. I'm hoping to get my car to the mechanic tomorrow and I will let you know what they find.


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## Calimoxo2 (Jan 25, 2005)

WiltedBeauty said:


> Thank you for the suggestions hopefully this will help them. I'm hoping to get my car to the mechanic tomorrow and I will let you know what they find.


I don't know if this will help you but on my 1992 Sentra it had a horrible bucking problem at low speeds and I was convinced it was an engine mount or fuel delivery issue......

I traced it to a broken wire inside on the Mass Air Meter harness so when I decelerated the wire which was broken (the wire sheath was intact) would make contact and the Mass Air would read and bump the fuel and when that happended the engine bucked and disconnected the wire and the Mass Air would cut off....

I cant believe I ever found it....... Well at least I have new engine mounts...


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