S14 ecu 69F01 in limp

Discussions concerning the M7790 cpu

Moderator: Matt

Post Reply
jabran
 

Posts: 8
Joined: Tue Oct 16, 2012 12:49 am

S14 ecu 69F01 in limp

Post by jabran »

I just installed the nistune board 40 pin header, moved jumper from j11-j10 and programmed the daughterboard with the 69f01 firmware and slotted it in to find there wasn't communication.

Just some background

-car is a ps13 with an sr20det swap from an s14 as far as I can tell.
-Was previously running F-con silver so never really tried the stock ecu it was piggybacked to or even checked if it was a
always in limp mode.
-I had to install the consult connector directly to the ecu harness as it didn't have one, I have quadruppled checked the wiring.
- I have checked that the cable works and reads a stock r32 gts rb20 I here just fine, so it can't be that.

After realising that there weren't any comms I decided to inspect the board and do a thorough clean just in case but I did not find any broken tracks or any stray solder etc ( I also did continuity tests from the 40 pin to where I could see).

I removed the nistune and moved the jumper back to j11 and plugged it back in and still cannot get comms on the port, I also noticed that the fuel pump primes for "1 missisipi" whereas the other nissans I have here prime for cleaer over 4 seconds so it must be in limp I guess.

At this point I don't think nistune is at fault and it is indeed in processor limp mode.

I wired in an led from pin 32-+12v but it never lights up even with the car on ignition on only, surely that should light up and go off when the car is running or stay on if there is an error?

going from memory I believe this car only ever primed for 1 second and since the fcon doesn't really need the factory ecu to function it may be it was always faulty but this is just a theory/

Any other suggestions? Unfortunately I don't have any s14 ecus to check with but have plenty of r32/s15 ecus lol just my luck.

Jabran
PL
 

Posts: 957
Joined: Fri Feb 03, 2006 3:29 pm
Location: Adelaide, South Oz
Contact:

Re: S14 ecu 69F01 in limp

Post by PL »

Yep, definitely sounds like it's in limp mode. The other test is to listen to the ECCS relay. When running correctly there will be a distinct delay from when you turn IGN off to when the ECCS relay drops out. When in limp the ECCS relay has no delay - it drops out as soon as IGN goes off.

I'd carefully check the area around the 20+20 header for solder bridges first (shorting any of the data/address lines will definitely put them into limp), but after that it may be time to find another ECU. Fortunately they're pretty common.

PL
jabran
 

Posts: 8
Joined: Tue Oct 16, 2012 12:49 am

Re: S14 ecu 69F01 in limp

Post by jabran »

I had a look at the 20+20 header and found that pins 2 and 4 show continuity and I checked they also show conituity at j010-j011 pads.

I can't see any visual shorts at the header itself or at the j011,j010.
Matt
Site Admin
 

Posts: 8961
Joined: Sun Jan 29, 2006 1:45 am
Location: Adelaide, Australia
Contact:

Re: S14 ecu 69F01 in limp

Post by Matt »

Pins 2,4 are ground pins which connect together. This is normal

Plug the R32 RB20 ECU into the S14 loom. Ignition on and test you can connect to consult. Its the same plug and power/ground/consult wires so it should connect. If it doesn't then you have a consult plug wiring issue

If it connects then back to the S14 ECU

Focus on getting the car running without the board again. Leave jumper back at J11 and reflow all 40 pins again. Then try connectivity

If this doesnt work post macro photo pictures of the ECU header install from rear and the jumper onto the forum
jabran
 

Posts: 8
Joined: Tue Oct 16, 2012 12:49 am

Re: S14 ecu 69F01 in limp

Post by jabran »

I didn't even see this post untill today, I tottally forgot I could try the rb20 ecu.

Anyway as I had wired in the consult plug myself and due to whatever reason I mixed up the clk wire for the chk wire (I checked the wires a million times as well lol, sometimes these things happen haha) turns out the original ecu is fine as well as the new spare I have now.

The pump on this primes for 1-2 seconds it is a short time compared to the other cars. Going to try the board back in again and it should be good.

cheers.
Post Reply