KA24DE wont rev above 2500 rpms, and now with white smoke!

[Firewind]

Well the problems just don't stop for my poor 240sx and it's KA24DE. So here is what I have done to it recently; removed the EGR, charcole, and most of the emissions on the intake manifold, other then that it's stock, and it ran GREAT after that. Until one day...

It all started when my car wouldn't rev above 2500 RPMs. Sounds like a maf issue. However, I traced it to being a leak in my intake manifold. (I have removed the EGR and the gasket leaked.) However, I fixed that leak, and the car seemed fine, for about 5 minutes. Then it started to idle rough and blows white smoke.

So I have white smoke coming out of my exhaust, of course my first thought is a head gasket.

But this smoke doesn't smell sweet, my radiator fluid levels are fine, and no bubbles in my oil. It's also clearly not blue-ish white, my oil levels are also fine.

So I did a comp test and here are my results

Cylinder 1: 142Cylinder 2: 150Cylinder 3: 145Cylinder 4: 142

That doesn't sound that out of scope for a KA24DE with 133K on it.

So I inspected my injectors, 2 of them looked slightly damaged, so I got some other used injectors and replaced them. The car ran a little bit better, but the same problems are pretty much there. Some times will not rev above 2500RPMs, and white smoke, and idle is rough.

So my thoughts are either it's a maf, or a fuel related problem, maybe FPR? I don't know how I can test these, any recommendations, or any thoughts maybe there is something else I can check. My local junk yard has some 240sx, so I can pull some parts off of them, but I never know if any of the parts will work or not.

Thanks

[spindrift187]

Although those compression numbers ARE pretty low, it shouldn't be causing your issue.

How long after you messed with the intake mani did it started doin this?

[Firewind]

Are they really that low? I mean I have heard of KA24DE's with 140 across the board and they seem fine with doing a turbo.

About 2 weeks after is when I noticed that I had the leak.

one other thing that I have noticed I have an exhaust leak from the headers leading down to the exhaust pipe. I am noticing fluid leaking from it when the car is running, feels and smells like gas. Hence I am wondering more about the FPR.

[spindrift187]

Are they really that low? I mean I have heard of KA24DE's with 140 across the board and they seem fine with doing a turbo.

About 2 weeks after is when I noticed that I had the leak.

one other thing that I have noticed I have an exhaust leak from the headers leading down to the exhaust pipe. I am noticing fluid leaking from it when the car is running, feels and smells like gas. Hence I am wondering more about the FPR.

When I look at buying a 240/motor, I dont mess with it if it has less than 170+/- across the board on a compression test. I believe nissan specs say 180psi is optimal, 150psi is minimal(someone correct me I know those numbers aren't exact).

But....After reading the rest of your post I think were getting somewhere. So there is gas coming from a leak at the exhaust manifold/head?

[Firewind]

Hmm, I wasn't aware that the compression for the KA's was that high. Well I knew I was looking at a rebuild next year before I go turbo, I was just hoping for one more year of it stock while I collect the rest of the money and parts I need.

The exhaust leak isn't at the head and the exhaust manifold, but at the exhaust manifolds, and the (for lack of a better word) down pipe to the cat. Where it goes from 4 pipes into 2, that is where I am seeing the gas at.

This exhaust leak was created when I took off the exhaust manifold and never replaced the gasket, and didn't realize it was leaking at first. This was also done at the same time I removed the EGR. I had to weld up the hole that was left in the exhaust manifold.

[spindrift187]

You DEFINITELY should not have gas leaking from there. The only thing that boggles me is that would not cause the smoke you are seeing. White smoke is coolant, so unless you somehow routed a coolant line into the intake mani(I know i know just sayin) I dont see where that's coming from. as far as the 2500rpm limit, Ive only ever known a MAF to cause that.

[liquid_cool]

You DEFINITELY should not have gas leaking from there. The only thing that boggles me is that would not cause the smoke you are seeing. White smoke is coolant, so unless you somehow routed a coolant line into the intake mani(I know i know just sayin) I dont see where that's coming from. as far as the 2500rpm limit, Ive only ever known a MAF to cause that.

hay spin..there is that pocket for coolent on the intake of the ka24de twards the front of the block..that might be his coolant leek!..the rpm's have me baffled thou...that would allso explain the gas oder allso.

[spindrift187]

its been awhile since Ive messed with the coolant lines on the DOHC mani so im a little fuzzy on that.

OP: Can you get a pic of your intake mani so I can see everything you've taken off? I don't think it's that but since you said that's when the issues started it's gotta be something you did.

[Firewind]

I don't have that great of pictures. I did re-route a few coolant lines, instead of them going through the throttle body, and intake manifold, they go strait into the firewall. I can see if I can get some better pictures. I do have a few pictures here. http://s216.photobucket.com/al...anted/

The KA24DE coolant just flow through the front part of the intake manifold into the engine block, and the intake manifold gasket is part of that. I did replace the intake manifold gasket twice, the first time I replaced it was because of all the work I did, the second time was because I thought it was leaking, and had to take it off to fix the leak on where my EGR block off is.

I used a felpro gasket the second time around because it was cheaper, but I am not sure I liked what it was made out of. Didn't seem like it'd resist water, almost seemed like it was made from thick paper. The first one I used was a Beck Arnley intake manifold gasket, which is very close to the OEM gasket. So i am tempted to spend another 25 bucks on it, to see if that will help.

However I am also debating the coolant leak theory. I have worked on cars that have had coolant leaks into the combustion camber, and the exhaust smells sweet. For me the exhaust smells more like heavy gas.

I will get some pictures tomorrow of everything that was removed, and how I have the pluming done for the coolant.

I am still wondering about the maf though, is there a way to test it?

[liquid_cool]

if your thinking mass amounts of gas is your culprit..then you only have one place to look...the injectors...its easy to see if that is the issue..pull the fuel rail of and have a buddy crank it over a bit..if gas is pourin out/not comin out..then its possibly an injector issue.

[spindrift187]

if your thinking mass amounts of gas is your culprit..then you only have one place to look...the injectors...its easy to see if that is the issue..pull the fuel rail of and have a buddy crank it over a bit..if gas is pourin out/not comin out..then its possibly an injector issue.

Good call I didn't even think of that. Ive seen people put injectors in and the O-ring on the fuel rail gets messed up and even with just the key turned to the on position(fuel pump priming) it dumps fuel. That's the only time ive ever seen fuel actually leaking out of the exhaust.

Im actually gonna go look at a 240 today hopefully to purchase, while im there im gonna check out the intake mani to see how the coolant lines are run(the pics are hard to get a good look at ya know).

The MAF can be tested, here's a link when someone else had an issue:zerothread/335660

[liquid_cool]

spin...ill take a close up of my intake manny and allso point out where the coolant runs throu it..ill post it on my myspace.

http://www.myspace.com/liquid_cool_ka24de

hope it helps pics are up.
Modified by liquid_cool at 3:49 PM 8/2/2008

[spindrift187]

OK now I remember what you're talking about liquid.

Is there ANY coolant leaking around the manifold area? The other lines im thinking of are generally just capped off so it's not like they'd get routed into it. The only thing I can think of is possibly some coolant seeping over to the intake ports due to a defective gasket(deformed/torn?) or not being tightened down enough. Other than that im pretty much stumped.

[liquid_cool]

OK now I remember what you're talking about liquid.

Is there ANY coolant leaking around the manifold area? The other lines im thinking of are generally just capped off so it's not like they'd get routed into it. The only thing I can think of is possibly some coolant seeping over to the intake ports due to a defective gasket(deformed/torn?) or not being tightened down enough. Other than that im pretty much stumped.

thats exactly what i was thinking of...rite in that area...remember..when hot..the coolant system is under pressure..the intake is not..so if there is a week point in the ghasket there..the coolant will push throu when under pressure....hope this helps....im getting ready to do a mod on my intake..its a hybrid of some i have seen..im going to separate that coolant area from the intake by using a modifyed plate i will make patterns today and get it going..ill post on it in the same place...my myspace...hope this helps.

[Firewind]

I forgot to take pictures this weekend, I ended up getting busy with other projects instead of my car. I will take some tonight.

I will check the injectors again, maybe I didn't put enough petro-jelly on the o-rings and one ripped.

Thanks for post on testing the maf, I will read up on it and test it out.

Well if I can't see a leak from the injectors I will have to assume it's the gasket, and I will get the Beck Arnley gasket instead of Felpro.

I will see what I can find tonight and tomorrow.

Thanks guys, I'll keep ya posted.

[nwcflip]

to test that MAF: let the car idle tap the maf with the back of a screw driver if the idle falls a little or even dies on you its broke and if nothing happens it should be in good working condition. You yourself can not fix it. if you can let me know. and don't bother trying to clean it it will only work for about 4 miles. they brake because of to much vibration and jerking from the air box not being tied down or to many cheap filters. go to pepboys to see if they can order you a remaufactured one for $350.00 its worth it then protect your investment with a K&N filter and tie down your air box. Don't chance a junkyard one because you cant return it in 30 days if that one breaks. you can return a reman if **** up in 30 days. Do it, Do it bacardi and cola!

[gera's240sx]

hi, when i get my 240 it had this problem, it doesn´t rev above 4000 and white smoke in the muffler, and it sound like a maf sensor fail but it was the timing shine out of place, it´s my experience i hope it help u... c u later

[Firewind]

Looks like it was another injector leak. It's just constantly spraying out of there once it has pressure.

I am going to check my timing too.

By the time I get a chance to work on it more it'll be almost mid September and almost time to pack up the car for winter anyway. So now I am debating if I should just pull the entire thing and rebuild it.

Thanks for everyones help on this.

[240sxbuffy]

YOU DO REALIZE THAT CAR COMPANYS SPEND MILLIONS OF DOLLARS DESIGNING ENGINES AND EMISSION CONTROLS TO MAKE THE ENGINE RUN ITS BEST AND JUST RANDOMLY REMOVEING THING RARELY IF EVER DOES ANYTHING BUT RUIN IT PERFORMANCE. DO YOU EVEN KNOW WHAT AN EGR VALVE DOES OR WHY ITS THERE?

[Vegascorbin]

Ok, you don't know what you are talking about.

#1 Automakers RARELY make an engine perform at the top level. Their lawers won't let them. That is why they have race teams.

#2 An EGR (Exaust Gas Recurculating) valve is designed to DEGRADE engien performance, by inserting exaust gas into the intake, but IMPROVE exaust emissions. It is strictly for polution control.

#3 Why would thousands of people that are trying for top PERFORMANCE remove the emissions systems from their cars if IT WAS GOING TO MAKE THE CAR RUN WORSE????????

Do not assume that the manufactures way is the best way. There is a multi-BILLON dollar aftermarket parts industry that proves you wrong.

[240sxbuffy]

Ok, you don't know what you are talking about.

#1 Automakers RARELY make an engine perform at the top level. Their lawers won't let them. That is why they have race teams.

#2 An EGR (Exaust Gas Recurculating) valve is designed to DEGRADE engien performance, by inserting exaust gas into the intake, but IMPROVE exaust emissions. It is strictly for polution control.

#3 Why would thousands of people that are trying for top PERFORMANCE remove the emissions systems from their cars if IT WAS GOING TO MAKE THE CAR RUN WORSE????????

Do not assume that the manufactures way is the best way. There is a multi-BILLON dollar aftermarket parts industry that proves you wrong.

AH spoken like a true backyard mechanic. don't understand it remove it to bad the ecm and every other componet is designed to work with everything intack. But I guess you know more It may be a billion dollar parts industry praying on unsuspecting people that don't know any better. When emission control was first intotuced 30 years ago I my have agreed with you A factory made RACE car is far from trying to out do the engineers that designed your street car good luck stay under the tree when you are working on your car sun stroke sucks

[ZOMG.SR20]

just wondering is it 2500 or 2400 because if its 2400 that's fail-safe mode and something serious has happened to the engine BTW there's a coolant line that runs through the TB

[Vegascorbin]

I am so glad that you know all and are the expert in everything.

And you were so nice to let us know this in less than 30 posts.



I bow before your obious superior inteligence. If I want to know anything about everything I know to ask you o great one.

[240sxbuffy]

I am so glad that you know all and are the expert in everything.

And you were so nice to let us know this in less than 30 posts.



I bow before your obious superior inteligence. If I want to know anything about everything I know to ask you o great one.

ma

LOL Maybe only less then 30 posts. but comes with 29 years of experience working on cars and being ASE recertified master with an L1, alternate fuels, Recertified parts and Toyota Expert Tech. I have take countless emission and fuel managment course both aftermarket and factory sponsered.I am certifed with DEP for emmisions repair for the state. Also by the way it is Ilegal to tamer with emmisions on Stree vehicales and in most states the car will not pass inspection after they are tampered with. I have put back together and straighted out cars that people like you have "improved " more times then you have "improved them" I am not looking for anyone to bow down I am just curious why risk damageing perfectly good cars for a race modifacation is one thing but to start ripping stuff of a car that you want to be daily driver thats a completly different story. I have done it all only when I started it was the small block with Holley double pumpers headers hi Pro cams high compression pistons roller rockers you name I have done it for myself and others