Loss of power, smoke, oil use help!

I have a Nissan pulsar n16 (almera) auto
About 8 months ago I was driving on freeway, had loss of power at high speed and felt like it was going to stall. When I accelerated it jerked a bit and kept losing more power each time I pushed the accelerator. Actually felt like I was braking slightly. There was also a large cloud of smoke that came out.
Since then I have kept taking back to mechanic and each time something replaced to fix problem but still occuring as well as oil consumption, previously NEVER used oil
So far I’ve had replaced:
Fuel pump
Starter motor
Finally motor rebuild a month ago due to to broken piston ring, which was meant to be the cause of all the problems.
I am still having the same problems and just noticed again oil was nearly empty.
Can anyone help with what else it could be?
Catalytic converter? Ignition leads?
If my motor was rebuilt could it be something else using the oil? Or are these symptoms of a other underlying problem that is causing all these?
When my motor was pulled apart I was told was in very good condition apart from broken ring
Any help is appreciated

P.s just thought id mention I’ve had no warning lights come up (ecm or oil)

You need to talk with your mechanic about this . . . he/she is (apparently) well aware of this and can advise you accordingly. Your post almost looks like a goof or a troll . . I mean someone had the engine apart to replace the piston ring and he/she can’t tell you why you are still using oil, down on power, and so forth. Also, it would help folks here if you could list miles and condition of your vehicle, maintenance and so forth. Good luck! Rocketman

First questions I have are these.

How much money were you charged for an engine rebuild?

Did the engine block go out to an auto machine shop and was the engine completely and physically removed from the car?
A lot of details need to be known about rebuild.

If it’s not leaking oil then it’s burning oil. If it’s burning oil then there’s a rebuild problem.
New engine or not, running that new engine out of or very low on oil makes it a junk engine.
Filling it up with oil after the fact helps nothing.

yes, you may now need a second rebuild as the engine may be ruined, as ok4450 says.

Any part on an older car can break, but a broken piston ring on this car is really unexpected. That shakes my confidence in that mechanic a bit.

A car that suddenly starts burning large quantities of oil may have a blockage in the crankcase ventilation system. Can be is simple as sludge buildup in the oil mist separator in the valve cover (common problem on Pathfinders) or oil/water sludge in the hose (common problem on 6 cyl BMWs).

The catalytic converter(restricted exhaust) could be at the bottom of your troubles. A good mechanic should be able to test the converter somewhat quickly.

No, im not a troll… Asking here before taking back to mechanic again as he cant fit me in. Also as I am still having the original problem and multiple things fixed so also questioning if I should find a new mechanic, even though trustworthy ones are hard to find. Also thought I would ask around for someone with the same problem
My oil was fine last week, I have been checking it every fill up on petrol, however I had a gut feeling to check it earlier.
My engine was not fully taken out, he said the bores looked fine and apart from the ring all was good.

Oh and the price I paid was $1500

For 1500 dollars I don’t see that this rebuild would be anywhere near a proper one. A proper rebuild is time consuming, heavy on parts pricing, and can involve 3-500 dollars just in auto machine shop sublet work alone.

Offhand, I would say the head was removed and serviced (possibly), the oil pan dropped, a hone run through the cylinders, and finished off with a set of rings and bearings while the block remained in the car. Even with a method like this there’s a lot of things to check.

What would I suggest? At this point I would run a dry and wet compression test as that can give a reasonable determination of a piston ring problem; or more than one ring.
If an issue shows up then you’re faced with how well the guy who did the work is going to accept a redo or giving you your money back.

I would also be tempted to run an oil pressure test with a manual gauge as that could show problems down in the lower end of the engine. Problems here revert back to the last sentence in the above paragraph.

“For 1500 dollars I don’t see that this rebuild would be anywhere near a proper one”

From afar, none of could possibly know exactly what the OP’s mechanic did with his engine, but one that this is clear is that he didn’t “rebuild” the engine in the classic sense.

For $1500 i’d bet that he pulled the head and pan. Pulled the offending piston out, replaced the one broken ring, and threw the thing back together. If the cylinder was scarred enough and all he did was a quick honing…that’s why it using oil now.

This guy did a pxxx poor job at this and you should be looking for a new mechanic. Before he costs you more.


I remember the Nissan Pulsar from the 1980s . . .

I don’t know what this “Almero” is that he put in parentheses

I’m with @Yosemite . . . I doubt the engine was overhauled. Probably only that one single ring was replaced. And all the other rings are original from the 1980s, with who knows how many miles by now

Valve stem seals and guides could be goners, on a car this old

I saw the motor apart, I could look under bonnet down to the ground and physically saw the pieces taken out and saw the new parts ready to go in.
I took it back today, was told the oil was “running in” oil so very thin, he changed oil, checked exhaust and found the problem code for throttle sensor so he has ordered that and fingers crossed.
I kept asking about oil use and he said he had a quick look inside engine and all looked fine so will wait and see after throttle fixed as it could explain symptoms

Here is copy of invoice from motor repair. As he is family friend, he didn’t charge alot for labour. Which is why I am hoping he is doing the right thing and should trust him, but if the throttle doesn’t fix it then I will have to look at new mechanic

Almera is the name of pulsar in other countries. The option to select model didn’t have pulsar so thought I would include that name as well for those other countries that don’t know the pulsar.
Its a 2001 model, had it since new and “touch wood” no other parts replaced ever, apart from consumable items. Female owner and I drive conservatively and look after it, which is probably why it has taken so long to need any major repairs i.e only just replaced radiator for the first time last year

It looks like what I figured it to be; an in-car overhaul. Sometimes this can be made to work but there are a lot of ifs.

One cannot buy that list of parts and simply install them on the blind assumption that things will be fine. There are a lot of inspections that should be done as the process goes along and some of that requires specialized tools such as inside and outside micrometers and so on.

Unfortunately, this sounds like a half-overhaul that went sour. An oil pressure test and both dry/wet compression test should verify any internal problems.

Well, a family friend discount on the labor could explain the low price he charged, but like @ok4450 states, there are a lot of specialty tools that are needed if the engine is not going out to a machine shop for inspection.


I don’t see valve guides on that repair order . . .

The way I read that RO I’m not sure that the valves were even ground. That regrind set (at least by some of the way the terminology has been used around my area by some) is taken to mean a top end gasket set and has nothing to do with the finishing of valves and valve seats.

It sure seems a better and safer option would have been to snatch up a low miles used engine but I guess I’m Monday morning quarterbacking here. :frowning: