ECU question

Discuss topics related to the CA18DE and CA18DET series engines.
cadet18
Posts: 226
Joined: Sun Feb 05, 2012 9:46 pm
Car: 89 s13 coupe ca18det

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I have a 35F11 ECU (S13 CA18DE) with a nistune daughterboard installed running my CA18DET in my S13. i came across some discussion on the nistune forums and an awaiting answers there too but figured id ask here. Does anyone know if running this setup will negatively affect anything drive ability wise. Ive never gotten my car to run 100% the way i want it to. Today while trying to fix my rich idle i discovered that i cannot get my idle to lean out anymore no matter how low i take my K constant i put it at 10 and no change?! Maybe theres some internal mess ups with it. the car was running rich and i can see the narrowband working and running -25% short term fuel trim but thats not enough for my idle. Maybe someone has some insight on this. I might send off one of my extra ECUs to get the nistune board installed in instead if i cant figure it out just because.


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float_6969
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Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
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It sounds like the car is running off of the failsafe map and not the programmed map. -25% fuel trim is HUGE. Something is certainly not right.

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sjbsuperman1425
Posts: 2889
Joined: Tue Nov 06, 2007 2:24 pm
Car: 1989 Nissan 240sx
CA18DET
Location: Bay City, MI
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If you want, I saved the stock bin file from my car a couple months ago so if something when wrong when I started tuning I had something to fall back on. I could e-mail it to you if you want so you could upload it and see if that makes a difference..

cadet18
Posts: 226
Joined: Sun Feb 05, 2012 9:46 pm
Car: 89 s13 coupe ca18det

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Thats what has me concerned about my ecu. i have checked almost everything except fuel delivery. i am going to try and find my fuel pressure gauge this weekend and check the pump output as well as change the fuel filter to eliminate that as a potential issue. The pulling 25% even with my K constant at almost 0 i feel is an issue. I got in touch with matt at nistune and it seems i have a ca18de base image with a ca18det map on it? maybe i have that backwards but either way there is a mixup with my ecu's base image. I am going to send out my ecu to autovaughn performance where they can but the correct basemap on it as well as change my nistune board over to one of my spare ca18det ecu's i have laying around. SBJ Thanks for the offer but i have tried a few peoples tunes with similar setups and this is how i came about this issue. i noticed that their K constant was about 100 lower than mine every time, which got me thinking why is my car so different from everyone elses. i understand it will be somewhat different every time but not 100 off on K constant. Thats a huge difference. I appreciate the offer though. I have left a message with autovaughn performance so hopefully hell get back with me soon and we can figure something out. If you guys have any other idea why this might be happening other than an ECU mixup im all ears.

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float_6969
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Joined: Mon Aug 26, 2002 1:55 pm
Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
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Location: Topeka, Kansas
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I think it's likely the ECU mixup. The DE only runs 270cc injectors iirc. The base image is going to be TOTALLY different. Also, the DE might run high impedance injectors (don't quote me on that part), which could change things as well.

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sjbsuperman1425
Posts: 2889
Joined: Tue Nov 06, 2007 2:24 pm
Car: 1989 Nissan 240sx
CA18DET
Location: Bay City, MI
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I have a 100% stock and untouched bin file. I haven't tuned my car or changed any of the values yet as the engine is 100% factory (besides the T28 but i still DID NOT tune for it). Just in case you may have misheard me haha.

Question though, why would you have it installed in a "DE" ECU if you already have spare "DET" ecu's...

cadet18
Posts: 226
Joined: Sun Feb 05, 2012 9:46 pm
Car: 89 s13 coupe ca18det

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SBJ. I gotcha i have 800cc injectors LS2 coilpacks Z32 Maf and a 2860rs that i have been running. the nistune rom packs have the factory bin file for the CA there as well which i already have on my laptop. Thanks though! I used the DE ECU bc thats what originally came with the engine when i bought it. at the time i didnt know it was a DE ECU... never thought to look. I later found out i was running the DE ECU and bought spares for this occasion (when something goes wrong). I also found out when pulling the ECU to ship to AVP today that i had changed the ECU to a 36F05 earlier when troubleshooting some things. I had forgotten i had done this so now i definately have a 35F11 base image on a 36F05 ECU. Def a problem there. i dont know exactly how this affects things but im sure it does somehow.

cadet18
Posts: 226
Joined: Sun Feb 05, 2012 9:46 pm
Car: 89 s13 coupe ca18det

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update on this. the ecu should be in the mail from autobvaughn performance. My ECU didnt want to connect for him so he swapped the nistune board over to a spare 36f05 ECU i sent in as well as matched the base image on the chip to the ecu. hopefully ill see it in the mail by sat or monday. i will update when it comes in and i have a chance to mess with it.

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float_6969
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OK cool, thanks for the update. Keep us posted as you make progress on this.

cadet18
Posts: 226
Joined: Sun Feb 05, 2012 9:46 pm
Car: 89 s13 coupe ca18det

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so the ecu didnt fix it. its one less thing i have to think about though. now i know the base image is right. right now when i start the car it runs rich like low 12's high 11's (AFR) until after its warmed up. then it will idle where i want it too. but when i go to drive it as soon as boost comes in its still running in the 14's. like its not going into boost... im thinking maybe my fuel pump is dying after 7 years? I dont really feel like messing with it today but hopefully this weekend or next week i can look into it some more. i dont have an in car fuel pressure gauge so no real way to see what my fuel pump is doing... anyone know of a way to see if its good or not?

cadet18
Posts: 226
Joined: Sun Feb 05, 2012 9:46 pm
Car: 89 s13 coupe ca18det

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checked the fuel filter... no blockage there. getting 36 psi at idle and it rises a bit when i open the throttle plate a bit. I took the fuel line off where it attaches to the fuel rail inlet and powered the fuel pump to see how far the spray would go for a very rough volume test. the fuel line started right about where the passenger fender bolts on under the hood and the spray distance didnt even clear the fender it sprayed maybe 10 inches.... i have a feeling thats not enough for a walbro 255? anyone every done this test or willing to give it a shot and see how far they can get? im guessing either the sock could be dirty or the pump could be going bad? ill try and pull the pump tomm and have a look i have to head into work now.

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float_6969
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Posts: 19853
Joined: Mon Aug 26, 2002 1:55 pm
Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
2015 SV Leaf w/QC & Bose (daily)
Location: Topeka, Kansas
Contact:

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Yea, that seems a bit low for fuel volume, but that's not a great test either, LOL. It does sound like a fuel delivery issue, and not an engine control issue. It sounds like you're down to a plugged fuel sock, failing fuel pump, or bad fuel pressure regulator. I would start with the pump.


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