I've got a 97 240SX with a KA-T. I purchased the car with with the turbo already installed. The original plan was to throw an RB25 in the engine bay but plans change and it looks like I'm keeping the KA-T. I want to try and clean things up a bit and get it running right but first things first, my emissions is due and my engine light is on. The tube coming from the EGR valve that is normally connected to manifold is not connected to anything and I think that is what is causing the problem, or at least part of it. Anyone knows a solution to this problem or if someone can point me to a thread where this is discussed (I couldn't find any). Is there anything I can do to make it work and pass emissions?

Pull the codes from the ECU and make sure it's the EGR throwing the code.

The code that came up on he emissions test is: P0400:Exhaust Gas Recirculation Flow.

search in google with that exact phrase will lead you along the right path.

search for your year and model and the code....

"97 240 P0400" - keep tweaking the search with other keywords until its starts to dump links to discussions that are relevant. try adding the word egr to the end, or adding the engine code too, which is KA24DE.

The search engine here is a bit finicky, but should be pointing you towards the same results. try searching for P0400 - and specify either the 240sx/silvia forum, or the NA KA forum. It wont return results on words less that 3 letters long, and you are relying on past users to have titled their thread correctly.

This does not always happen...look at the title for your thread, I would have titled it "throwing Code P0400 - repair options?"

hope this helps point you in the right direction.

I tried the google route but couldn't find any turbo specific applications. Do you guys eliminate the the EGR system all together when you guys turbo charge the the KA or is there some way to keep it intact? The problem is that the EGR valve is no longer connected to the exhaust manifold so it is sucking up fresh air instead and triggering the engine light. If there is some way to tie it back into the exhaust system then I'm guessing it would function properly? Is it as simple as plumbing it in after the turbo into the down pipe?

superDorifto, I'm in CT also. How do you get yours to pass emissions?

pass is a "strong" word.

there is no way to fool the system in CT anymore. I'm planning on swapping in a stock KA every 2 years for the test until my car is exempt.

You will def need to hook the tube back to the exhaust, but that may not be the problem, thats why I suggested the search. AFIK most people eliminate the effimissions system when they turbo the motor to eliminate boost leak sources....thats not to say it won't work, but youre not gonna find much turbo specific help out there.

A lot of the decent builds on the forums are from states that dont have as strict regulations, are on OBDI builds where it is not an issue, or are built by people that just dont care.

The fact is that the engine will run fine, and not produce more emissions without the egr system if everything else is running right. Unfortunatley for us OBDII guys the test is not to see what is coming out of our tailpipes, but if the system is functioning correctly.

As an alternative you can always try to get a waiver. If you fail in CT, and you pay more than $660 in "qualified emissions repairs," from a state certified, " emissions repair shop," they will give you a waiver for the registration period.

So....your choices are

1 - run stock and forget about boosting ever again
2 - swap in an N/A KA - re-install your emissions crap and de turbo every 2 years
3 - pay 660 bucks until your car is exept (20yrs or older from date of manufacture)

Also if youre in CT you need to get on ONE. its our local forum, pretty good trading section and a good bunch of guys all around. 240sxONEdotcom (O wners of N ew E ngland)

I was afraid of that. They must have changed the cost of "qualified emissions repairs", the paperwork I got now says $787 before you can be exempt. I wonder how they came up with that number. I have the stock manifold and actually thought about taking the turbo off but I'd really rather not. I wonder how many times you can fail before they cancel your registration. I'll take it to a shop I know and have them scan it to see there are any other codes that come up. If it's just that one I might try to hook up that tube to the down pipe and see if that alleviates the problem. I'll definitely check out ONE, thanks.

They wont cancel your reg, you just cant renew it until you pass emissions.

They also have finally linked their databases, so they can tell the last time that the previous owner had the car pass.

basically were F'd in the A. I didn't know that it went up to $787...that suxors..

So you just need to pass emissions? The light coming from the EGR can be eliminated via capaciter placed inline anywhere, I suggest by the ecu, between the egr valve signal framus and the ecu. So the ecu never see's any problem. I have no idea what the voltage is for the cap though, so I just hooked my EGR line to my downpipe. You just need a bung welded to the DP and you can use rubber hose to connect the two. They sell special high temp hose at most parts stores. I used a piece from my K5 Blazer emissions system

You can also clear all the codes just prior to inspection, I used to have a toggle in place of the ecu fuse in my Celica so I could reset the ecu while waiting inline at the inspection station.

Once you eliminate the code issue, the car should pass emissions testing if the tune is worth a crap.

Early morning ramble...

Clearing the codes is the QUICKEST way to fail with an OBDII car....


With an OBDI car yes, youre right WD. Inline resistor for the temp sensor would fool the system into thinking the egr never has to open...with a good tune, it'll never through another code and you just need to pass the sniffer with no "trouble" codes sotred in the ECU memory - clear the data and your ready to go.


THIS IS NOT THE CASE FOR OBDII CARS - they made it harder for us to fool the system...
In CT for OBDII cars they dont even use the sniffer, the they actually plug into the OBDII scan port and to verify that the system is operating correctly.

To verify they check for "Monitor Readiness" - fancy name for tables of values that the ECU saves based on the output of specific sensors.

They check for 5 or 6 "monitors" I cant remember exactly what they are, but the ECU records and stores tables of values during normal operation. As you complete the factory designated driving cycles the values accumulate. Once enough data is collected the system turns the Monitor Rediness Indicators Green.

In this state, as long as the values do not exceede any of the factory values, the OBDII scan will "pass" the car.


Per your remarks WD....
You can manually reset the data with a scan tool...or disconect the battery, this clears your trouble codes, but also resets the monitors. They will not report out until enough data has been gathered...which is a huge headache. There really is no way around the test.

A "Monitor Not Ready to Report" Status is an instant fail for certain monitors...EGR being one of them. This effectively eliminates the option of just clearing the data before the test.

If you put an inline resistor the EGR Temp will always return a value of X temp...it will never change, the egr valve will never actuate, and unless your tables are already populated your monitors will never switch to the "ready phase to pass the test.

I have searched almost every single KA EGR/Emissions thread and as far as I can tell the system has no feedback functionallity built in. In my Lexus, the system could manually be cycled with the scan tool, and low/no egr flow could be determined. I do not know that the KA system has that functionality.

I have a hunch that if the monitor data is already populated, and you use the resistor trick you should be good......BUT

If you ever disconnect your battery, or clear the monitor data....it will never populate again, no data no pass. The only option is to swap a stock KA/ECU back in and drive it around until the monitor data populates and is ready to report.

Last time I pulled out my scan tool I think the following monitors were shown, Its in my car, I'll plug it in at lunch and post/revise the actual sensors that are checked.

EGR Temp
EGR Actuation/Flow
O2 1 Volt
O2 2 Volt
Heated O2


I'll be screwed becasue the AEM EMS disables all that functionality - the scanner wont output the data becasue there isn't any....

That's a bummer, I cleared the codes in my Celica, which was a 03 using the manner I described. Must be that AZ just required no codes to be loaded or some such BS.

Yeah, the codes and Monitor status are stored in different memory locations, but clearing the ECU resets both. I can't wait till my s14 is considered a classic....no emissions test required after 20yrs

Only 5 years to go...hopefully thats only 2 more registration cycles....

Wouldn't it be easiest to just weld a bung on the downpipe so you can just hook up the EGR tube? As long as the tune is good than it should pass any way and I'm sure a threaded bung like on a a stock mani or a barbed one as WD said wouldn't cost 600 like paying your way through the test.

You just need a bung welded onto the dp and then connect it to the EGR via special high temp rubber hose. Real easy and it works. GREDDY had their kit plumbed in a similar fashion iirc.

Hey I was jus wondering if anyone with a kat has tried to at a air pump to the intake system? I believe this would reduce emissions, as a lot of newer cars have them today. just a thought

its not so much that the cars can't "pass".

With a decent tune, or close to stock in good running order the KA will pass all day. Its the removal of certain emissions componenets that make the cars fail.

These parts...
egr
charcoal can

are known boost leak sources. On older 240s (pre96) you can just remove them, plug the holes and go about your wonderful KA-T life. On the OBD II cars its a bit more difficult as the emissions test actually checks to see if these systems are operating correctly.