Ask Someone: 1987 Nissan NX

nissan

#1

After driving maybe 10 miles I have no acceleration or more than an idle. Car will restart if turned off but no more than an idle. It’s as if something under the hood doesn’t work after heating up. The coolant is not hot just normal. After cooling off under the hood works just fine until driven enough to warm up under the hood. Two different shops have diagnosed the situation, every thing checks out.


#2

Could be many issues on a 31-year-old car. Have they checked the fuel pressure when this happens? Have you tried loosening the gas cap to see if the tank is under vacuum? Has the fuel filter been replaced?

Please list all the things the two shops checked/did so we don’t repeat them.


#3

Everybody has checked the fuel pressure and ignition. Not sure they’ve checked it when the problem occurs. One shop couldn’t duplicate the problem because of the need to warm things up under the hood. In fact they said everything is perfect. The second shop rode with me with the problem going and I told him it needed to be checked over at that time. I don’t know if they actually checked the pressure at that time. They did tell me they checked the pressure and it was just right. The fuel filter has been replaced. I haven’t tried the gas cap for a vacuum but I definitely will. I’ve considered vapor lock but the fuel pump is in the tank and the engine has throttle body injection, I think the first year for Nissan.


#4

It could be the ignition coil or some other ignition part failing when it heats up.

Have all ignition parts been replaced - cap, rotor, wires, plugs?


#5

Loosen and leave loose the gas cap before you even start the car to see if the problem even happens. It may turn on the check engine light, but it’s a place to start.


#6

Good ideas above. If the fuel pressure holds steady even as you try to raise the rpm by operating the throttle, my guess is that either the throttle is sticking, or there’s an exhaust obstruction. The shop can probably verify the throttle valve is moving ok without much effort, so that’s a good place to start. If that turns out to be ok, you may have to temporarily disconnect the exhaust system. If that fixes it then you probably need a new cat or muffler. I’m guessing new cat.

Edit: Might make sense to do an intake manifold vacuum test.


#7

Inside the distributor there may be a device that tells the ignition system just when to fire a spark. Some names for this part are pickup coil, signal generator, and electronic control module. It does what mechanical “points” did in the olden days. These have a tendency to fail when hot intermittently, and eventually fail altogether.


#8

That’s a good idea. And easily tested just aiming a timing light at the balancer. That test definitely makes sense.


#9

Wouldn’t that kill the engine. The engine continues to idle perfectly and starts right up if you shut it off.


#10

Thanks, it’s worth a try.


#11

A friend of mine has suggested the cat as the problem. Don’t know how hard it is to disconnect but definitely something to try. Thanks.


#12

Worth looking into but wouldn’t the engine miss with something like that. I keep thinking of the old days when you stepped on the gas the vacuum on the distributor would turn it to advance the points. Thanks.


#13

I replied to shanonia about this, but if it were failing wouldn’t it be intermittent and the engine would miss. Idles perfectly just no acceleration. Thanks, I’ll look at it.


#14

You’re right, ignition issues would probably cause different problems. Does this have a carb? Has it been rebuilt?


#15

If the timing advance vs engine rpm wasn’t working something like this might be a symptom. Probably not the first thing to check, but something to consider.


#16

You may need a helper to see if the throttle is moving when the engine is warm. It may be stuck at that time and your throttle cable may be sloppy or not held in place somewhere. A small clamp may be broken and the cable might just shift around and not pull hard enough. This is a strange problem for an 87. I don’t remember electronic throttle control in 87.

You can also check for a red hot cat. That could mean a broken wire to the electric choke. I have no more guesses for now.


#17

I guess it’s a carb but the fuel input is something called throttle-body injection. Not rebuilt.


#18

Actually was a first consideration but it doesn’t have points or the usual vacuum I’m familiar with. Not sure how it works. But I should be able to check that when the problem occurs and see what happens when I try to increase the rpm. You’ve given me something to check. Thanks.


#19

This is not a Nissan NX. There was not an entry tor a Pulsar NX. The engine is a little 4 that’s also in the Sentra, single cam.


#20

Hello, it is a small E-16i fuel injected engine, mine had a TBI fuel injector, next question, do you have access to tools and a manual on your car ? The Pulsar has a single ox sensor at front and your ecm is located under the passenger seat. I had a pulsar NX back in the 90’s and it was a nice car, economical, good looking and reliable, only problem was the head gasket that went bad twice and changing the pvc valve, hard as hell. I don’t think it passed 100k miles with us, but it was solid. It got rear ended by a Explorer with no extensive damage and the Explorer lost the front bumper and other parts, my wife and cat where fine.Thou should never driver under the influence of cellular phones. Back to your Pulsar, the Ox sensor has a service reminder for 30k miles and I wonder if you had it running rich for a while cat may be bad or if its bad (it will make you car stumble after warm up), now read this carefully: if you think your cat is damaged you can remove the hose that goes to the brake booster and do a vacuum test (if cat is clogged, pressure will rise after time and you will loose vacuum after time - this is the easy route) or you can try removing the ox sensor and driving it to see if problem goes away. It is noisy and you should not do it for too long because of the heated gas under the hood, just pull way anything that could melt in front of the sensor hole or put a piece of metal to bring the escape down. Remember that you also have a pressure regulator that if it stuck or the vacuum pipe broke it will reduce the amount of fuel in the rail, so bad acceleration but that would be constant ; If you had a leaking seal in the optical distributor it would cause a misfire and you would feel it all time. If this is a head gasket problem, you would have tons of white smoke at your rear and it would bulk like a horse under acceleration. Although it is pretty rustic, the ecm can be put under test and display error codes for you. Let us know what happen.