Hi guys

Just wanted to say hello and ask if any one has ever had the same problem as I'm having.

I have a ca18det that runs off the scale lean when under any load, and it doesn't idle well

The ecu is throwing a code 11 and 34. I have tried 3 cas units and still get the same code, I have tried everything to make the knock and cas code to go away. to no avail

I have literally been messing with this for 3 months and have been looking for answers on google and forums the whole time. nothing has worked as of yet.

Could the knock sensor/circuit being faulty make the ecu throw the 11 too?

any ideas or suggestions would be would be awesome

thanks

Got the FSM handy? The table of contents for the troubleshooting guides for running down the source of those codes is on EF & EC - 32. I've found it EXTREMELY useful in sorting out my own gremlins.

Is it a stock ECU? Did you check the splines on the Exhaust cam? Honestly, it's rare for the ECU to actually throw a code for the CAS unless the wiring is bad, or the ECU is bad.

hi:

thanks for the response guys.

float-6969t that's what I keep reading in older posts

I have tried two ECUs and they both throw the same two codes, iv tried 3 cas and manually spun the cas and got 4 primes from the fuel pump, with no changes. the cams are new and the spines look good on both.the wiring harness is a new stand alone from wiring specialists, and I was personally on the phone with them while I back traced every wire to the cas, maf, resistors, and coolant temp sensor.

that's why its been so frustrating me. I tried to do this swap as clean as possible and just my luck its been the worst one yet. I did a ca18et full swap that was just ripped out or the donor car with a cherry picker that was less of a hassle.

could the knock circuit be causing the cas to do something like that?

is there something I'm overlooking or doing wrong?

A bad knock sensor or faulty wiring on the knock sensor will make the car run like s***. I bet that's the culprit.

does the car start?

If the knock sensor wiring is not connected or wired incorrectly (perhaps via your new harness) then you are going to get those codes which is known as Nissan's "FAIL-SAFE" mode. You should unplug the harness connector, unplug the knock sensor, locate the connector on the harness that connects to the knock circuitry on the ecu and do a continuity test between that connector and the knock sensor plug. Lastly, make sure your timing cover is aligned correctly via the two dowel guide pins or you will be killing crank angle sensors like crazy.

boost_boy wrote:If the knock sensor wiring is not connected or wired incorrectly (perhaps via your new harness) then you are going to get those codes which is known as Nissan's "FAIL-SAFE" mode.

Has this been your experience on all cars with knock sensor code? My knock sensor isn't connected, the ECU always has the error code for knock sensor, and I drive around with it like that all the time. And it is definitely not in fail-safe. (full rpm range, operates on the normal fuel/timing tables)

this is where I'm at now, I have the knock code gone. I had put Teflon on the treads and that was keeping it from grounding. so that's fixed. but it didn't really change anything

@ float_6969: it does run and is easy to set timing on the engine with both the CASs I still have, that's why I am having a hard time thinking its the cas unit its self.

but I did notice that it does run differently between the two when I change them, it still runs badly
and throws the 11 code but it sounds different.

so I might need to find a cas that is confirmed working. or just buy a new one

@ boost_boy I checked the timing cover and it is lined up on the pins correctly I think, also the cas sits flat against the cover with out the bolts in. so I think it fitting properly.


also can anyone confirm that the maf wiring for a s13 ka24de is the same as the s13 ca18det?
all the fsms I look at say their the same minus the green/yellow wire. but it never really says if the diagram is for a ka24e or ka24de.
so all I need to do is cut the green/yellow wire ka24de maf?

thank you for your help everyone

lol, and yes one of the ecus is tuned for the ka24de maf

The knock and CAS are separate codes, one won't cause the other to show up. Also, the failed knock sensor doesn't start the failsafe either. It just reducing timing (and so power) I know this for a fact because when I first installed my CA, I didn't hook up the sensor. The car ran OK, but it was down on power. Once I got the knock sensor hooked up, it ran much better.

What's going on with the CAS code is really uncommon. This HAS to be a wiring issue. I know you've traced everything back to the ECU, but what about grounds? Look on page EF & EC 82 in the FSM. It has all of the wiring associated with the CAS. In that diagram is a ground for the ECU, the CAS wiring, and THE SHIELDING FOR THE CAS SIGNAL WIRES! If this ground is only connected to the ECU, and isn't connected to the shielding or the CAS ground, the ECU is going to see a very noisy signal, and may throw a code for the bad CAS and would probably run poorly.

float_6969 wrote:The knock and CAS are separate codes, one won't cause the other to show up. Also, the failed knock sensor doesn't start the failsafe either. It is just reducing timing (and so power) I know this for a fact because when I first installed my CA, I didn't hook up the sensor. The car ran OK, but it was down on power. Once I got the knock sensor hooked up, it ran much better.

What does this mean exactly? Does it switch to the Knock Timing Map for timing, but stays on the Normal Fuel Map for fuelling? Or a constant timing retard?
It would be nice to gain some power only by connecting a wire and a piece of shielding. But if I'm running with retarded timing now, that would mean my lag will be even worse after I fix this, and it's barely tolerable now as it is...

The FSM doesn't say exactly what happens with a knock sensor failure. It's been a while since I've seen the ROM for the CA18, but IIRC there are two fuel and timing tables in there. I think it alters both the fuel and timing with a knock sensor failure, but I could be wrong.

positive leak to the ground maybe?

is your battery dies faster than normal?

CAS fault doesn't came so often . and if your car is working normal , i didn't think it is a actual CAS problem . ALso you said you changed several times.

Knock sensor failure doesn't cause any problem under any circumstances.

ok guys, I added a ground to the ground shield on the cas and the maf. and tried a brand new cas. it still is throwing the cas code.

but I have come to the concussion from what you guys are saying that is should be running better then it is regardless of the codes.

I'm kind of wondering, could the cams be put in opposite with out really noticing? I didn't personally build the head and don't really know 100%. it running lean the way it is could be explained if the cam derations and timing is wrong.

the engine timing is set right on the marks.

are the intake and exhaust cams the same?

You can't swap intake and exhaust and have the engine run. The intake cam doesn't have the splines in it needed to run the CAS.

This is starting to look like a bad ECU. Anybody local that you could put your ECU into their good, known running car and see how it acts?

I bought a extra stock ecu to try because I don't know anyone locally that is running a ca. I had thought it was the ecu also when I first started trying to diagnose the problem, but swapping to the stock ecu and stock maf. it still runs the same and throws the same codes. lol, I swear I'm ready to light this thing on fire and watch it burn.

I bought this engine because I have had a ca18et for a very long time, and always wanted to step up to the det
and get past that 10psi mark that the et is pleaded with

I have worked on and/or swapped a lot of engines in my day mostly Nissans to, but this is by far the most frustrated if ever been with and engine.

is there anything mechanical on the engine that could be giving me this grief? its an 8 port head but iv checked that the flys are closed when they should be and the vac-acu is working

thanks again everyone, I wouldn't have got this far with out you

Did you ever confirm that you wired the MAF correctly? Do you know your KA MAF is working properly? You're having trouble fueling your engine, but the malfunctioning knock circuit should be sending you way rich instead of lean everywhere. Which makes me think your ECU isn't reading load properly, causing it to underfuel because the MAF signal is wrong. My advice is doublecheck your wiring at the MAF and maybe swap one from a working car.

On second thought, I know you checked to make sure your fuel pump is working, but what about your fuel pressure at the rail? Maybe you got a clogged fuel filter or something.

as far as I can confirm the wiring for the ka maf is the same except the green/yellow wire is cut.

I have a psi gauge inline to the rail, its set at 36psi with the pump jumped and engine off

but I had a thought about the speed sensor. mine isn't hooked up. does it need to be?

I know some ecus use the speed sensor to switch off the idle tables. but iv never seen it be important on a Nissan ecu

thanks again

I would pay attention to the exhaust camshaft's key. Something doesn't sound right.

I'm pretty sure the cam key is good.

The ecu will throw the code 11 with out turning
The engine over. It's gotta be some where else

Is there major differences between the 78 and
98 Ecu?

Could I have the wrong ecu?

Both ecus I have are 78s

Woah, 78 is a FWD CA18DET ECU. I THINK that means the wiring connections are different. Did you use a FWD ECU with a RWD harness? I don't KNOW if that's an issue or not, but I'll bet boost_boy WILL know.

And if you're getting a code 11 before you even fire the the car up, that is a MAFS/WIRING/ECU problem. It HAS to be. But if you've got the wrong ECU with the wrong harness, that could also explain it.

I thought the 78 was for a 180sx.

The harness I have is for a rwd

That's the ecu the engine came with, but like I said before I can't trust any of the
Parts that came with it, cause half of them were the wrong parts

If it is the ecu that would be upsetting and releaving, all at the same time

I can't find the info now, but I found a site that listed the ECU numbers and what engine/configuration/chassis they correlated with.

UPDATE :

I changed the ecu to a 98 from a 200sx, it fixed the idle problems.it idles fine now.
it still goes lean under load but now it will only go lean when I let out the clutch and then the afr goes to 12.5 ish through the rpm range

I am still getting the code 11, but iv given up on trying to fix that since everyone says it should run
ok with it on anyway.

iv been reading that the AAC or the iacv can cause the lean off idle. so ill be trying to change those soon.

can you guys think of anything else that could still be cause this?

thx