Hello everyone, here i am, immigrant from the X-Type section. just sold it and aquired a beautiful X300, a 97 from canada, near mint body and interior. but the engine has a serious issue. i'm pretty much near the end of my diagnostic but i'd love people to talk about it with and confirm what i'm about to do (no, not put it on fire!)

So, the car is pretty much not driveable. if its realy cold i might be able to do like two or three corners before it get into this state that the youtube video show. with light gas it will rev up and down, throw random missfire, and missfire on 3, 4 and now recently 5 too (no 5 wasnt doing codes for a while during the diagnostic and you'll soon see why its surprising) once the engine gets realy hot it can even do this at idle and be very unstable. some other time it will just die if i give it some gas. it can also do backfire if i go wide open throttle (and it still wont go over 2k rpm, 1.4k if i'm lucky)

On Torque i see some weird info on fuel pressure and oil pressure. but any other sensor seems fine (some o2 sensor seems not to work, but i realy doupt they're the issue here) i see my maf working, my throttle position too, and my coolant temperature, and quite many other that we could consider faulty.

My fuel pressure is good, i just bough a 200$ fuel gauge kit to test it. i was disapointed it dint lead to the issue, even more considering the previous owner told me it was the fuel pump fault. what a liar! i had a nice 35-40 no matter what i did.

My exhaust output quite alot of smoke, so it doesnt seem clogged at all.

My spark?... well, i dont know! i though they were faulty because the 5th cylinder missfire only started after i placed the 4th cylinder coil on 5th cylinder. but when i placed them back, 5 keep missfiring and 4 did no matter what coil i put on. but for a momment i was sure and i purchased a set of 6 coils, i should get them sometime soon, and i'll change all 6 plugs at same time (they're realy not pretty. but then again, considering some other find, its not my first bet)

I removed valve cover and checked the timing, crank pulley mark on sensor, cam position sensor mark in the circle. and both camshaft mark right on top. i got pictures of cams if you guys want to be sure.

Now whats left? we ruled out fuel, spark, sensors, exhaust, timing... well there could be the computer, but if that'd be, i'd be expecting a much more consistent trouble. Well there's one thing left!

I did a compression test, and the results are not pretty!! from 1 to 6. 180, 185, 175, 165, 100, 190. Yes... 100 on 5! and the 165 right beside it might spoil that its the head gasket that is the issue. but its not quite obivious enough. sure thing, i'm about to remove the head and see whats going on here...


I guess i have no actual proof the injectors are in good condition. but i'm sceptical they could cause that.


So here i am, about to remove the head, if you guys got anything to say about all this. go ahead.... here's the youtube video

Thanks in advance to anyone who take of their time to help!

 

Are the air inlet bellows split just before the throttle body....could be an optical illusion?

Any codes?

 

when you did the compression check did you do it twice over...I always do just in case....try it wet as well to see if its a ring problem. Also always on hot engine with wide open throttle....no telling you how to suck eggs just a thought.

I wouldn't pull the head yet...even with one pot down on puff it will run better than that.

Try connecting a vacuum gauge and chiming back, they are only a few quid (or dollars) and are useful tools

 

As I said there are codes about missfire. So p0300 p0303 p0304 p0305. Beside those I sometime get some codes about catalyser malfunction but they only pop up if I get enough of missfire and issue. So I figured it's related and not directly leading to a trouble. If I clear code nothing instantly pop up. And when it runs on idle fine enough. It can run code free for a bit.

Don't worry about telling me how to do things... I did go to mechanic school but everyone can forget things. Actually I did took compression cold. It's a big difference? I dint remember anything about it. I though about doing a wet test soon. I'm not totally sure how much should I pour into to be honest.

About the air inlet. Not sure I understand you well but I did try to block the intake with my hand a bit to try and see if there was a big enough leak so it wouldn't care and it did stall. I know. Not a great test. I should check for a vacuum gauge I guess.

Thanks everyone I realy appreciate. I kinda feel overwhelmed with this. Good thing I did study all that! Haha

 

Have you ruled out contaminated fuel? If it has been standing any length of time, between fuel deterioration and water ingress, it can all become very contaminated, and the car runs like a dog, if at all...

 

Well now that you say it. When I did the fuel pressure. I though the fuel had a weird color. Green flashy. Like a damn highliner crayon. My tank is now running low from all the tests. I'll empty it and put a 20 in it and see. I ruled out the color cause a friend told me it wasn't worrying. But he's not a great reference anyway

 

One thing I just remembered. My air fuel ratio appear to be "a bit" off recommended chart.... I think it's worth mentioning.

 

The last person to fix their engine problem on here fitted a new crank position sensor. Think about it, this device tells the ECU where the engine is so it can send the sparks and the fuel. It could be squirting fuel but not sparking at the right time. The un-burnt fuel would indicate as a rich mixture. The fact that you say it changed which cylinders were misfiring tends to say it's not coils or squirters which are broken but the signal they are getting which is wrong. I doubt the ECU is broken since it's safely inside the car but the crank position sensor is right on a hot dirty exposed part of the engine. 20 minute job to change it.

 

if the crankshaft position sensor would be problematic, wouldnt my RPM gauge not show up, or be completely messed up? cause right now the needle work very well, and in OBD2 also.

Someone one another forum pointed out that my compression test was at cold. like very cold... so i redone it at running temperature and the results are ridiculously different!! from 1 to 6 210, 200, 204, 207, 205, 208

big difference!! maybe my head gasket is fine afterall.

 

Usually. The typical test is to watch the tachometer while cranking. If the tach needle doesn't move up to around 300?(correct me if RPM wrong) or so while cranking, then the crankshaft position sensor is not working. But if the tach does move correctly while cranking, that doesn't necessarily rule out an intermittently faulty sensor. The only guaranteed result is that if no RPM registered, then it is definitely bad.

 

uhm realy??? well my RPM gauge does NOT move while cranking. but i though maybe its just that car doesnt work that way. so maybe crank sensor afterall?? the rpm is actually fine once the car run!

 

Oh no... i just realised i dint unplug the injectors before my new compression test.... i aint proud of myself... thats what you get for beign hurry and try to do quick

 

I just watched the video. It seems OK at tickover and goes wrong with revs. It revs then dies then recovers and dies again. Could be the fuel pressure.

 

I checked fuel pressure. But it does not go below 35~

 

So i redid my compression test with the injector relay unplugged. and its aproximately the same, maybe + or - 5. thats it.

Although each time i started on a new cylinder. at about the seccond turn, maybe third, i'd hear a "pop" or "clock" noise. something like that, and wouldnt hear it again until i did a new cylinder. i realy have no clue what it can be...

 

I would guess that the cat fails when it gets unburnt fuel due to the misfire.
The thing I would be trying to check would be to see the spark signal to each cylinder and to see the injector signal to each cylinder. A fancy garage diagnostic machine would show that. Really it would be worth getting hold of a crank position sensor just to try. Even though it's obviously doing something.

 

Yeah I did use such machine in school. Gosh I wish I'd have this. I should of bough an oscilloscope before. There are usb ones on ebay for about 100$ but I can't wait the shipping right now.

With all the test I've done. The only two possibilities left in theory would be the spark or the crank. I'll do plugs tonight. Coils should be here soon. So if it doesn't do better I'll go for a crank.

I've heard plugs are a tricky pick on this engine. Got suggestions on what to buy? I'll probably go for the cheapest brand at canadian tire to be honest. But I'll consider any suggestions.

 

The way I look at it is you could spend money on expensive testing or expensive test equipment which will tell you which part has failed. Or you could just keep replacing parts until you replace the broken one.

I had another though about your crank sensor. The theory that the rev counter would indicate or not when cranking for a car that won't start is not relevant for a car which is running. Obviously if the car runs there must be enough signal for that and also for the rev counter. That does not mean the signal is as good as it should be. A crappy signal would mean the car would run badly.

 

Watch this video;

Jag revs badly. Owner says it needed a crankshaft position sensor again.

 

my issue isint realy like this guy though. it runs bad at higher rpm but he can still maintain it.


I'm realy wondering about what i see on my scanner though.

0.03 gram /s in the MAF and 3.5:1 of airfuel ratio commanded AND measured.

I did check the maf output with a multimeter while engine running though. and i had about 1.6 volt. which means 0.009 KILO gram /s

So two things. first, torque is not reliable on some data. Seccond, my air/fuel ratio is terrible and there's a reason for it. possibly linked to maf data in the scanner, but the maf itself is fine...