KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

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JNM240
Posts: 8
Joined: Tue Jul 14, 2009 11:24 am

KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

Post by JNM240 » Mon Apr 01, 2019 2:18 pm

Hey guys, ive been running Nistune for a while now on my CA18DET, never even so much as a hiccup. Love it!

So ive now got a 1993 KA24DE that ive turbo'ed and put into my 1990 coupe and i am having a problem getting it started. The body wiring harness has never changed from the car through the 4 different motorsets that have gone through it, and the engine wiring harness is 100% original pulled from a unmolested 93 fastback along with the motor. Ive got Nistune type 3 board installed and working via a Consult plug i got from WiringSpecialties. I know the plugs by the battery should be plug and play, but due to an accident many many years ago, the E10 brown male connector has been removed and ive had to hardwire everything there. That hasnt been a problem until now.

Im fairly certain ive got it right, please check me:

SOHC Chassis E10 ----> DOHC Engine F9

R/B --> R/B ECCS relay
B/P --> B/P fuel pump relay
B/Y --> B/Y IACV Air Regulator
G/Or --> G/Or Neutral safety switch
Y/L --> Y/L 5th gear position switch
Pink --> Pink PAIRC solenoid valve
Br (unswitched 12v) --> Y/R P/S oil switch
Br (switched 12V) --> Br IACV-AAC valve

The E9-F8 plug should be good, as i have not clipped wires at that plug, but they are as follows:

SOHC Chassis ---> DOHC engine
G/Y --> G/Y A/C relay
R --> R ECCS relay
B/R --> B/R Ignition switch
G/L --> G/L ambient switch (exhaust gas temp sensor?)
B/W --> B/W ECCS relay
Or/L --> B condenser fan relay
L/G --> L/G IACV-FDIC solenoid valve

So my problem is this: It cranks with the key and turns over, and it has spark, but it has no fuel pump nor injector signal. I can jump either the fuel pump relay or the ECCS relay and get fuel pressure, but still do not have injector pulse. I have a constant 12V at the red wire of each injector, so the ECU isnt sending it a ground to fire. I know the ECU is getting power at pins 46 (red - ECU backup power), 47 (B/W - Power for ECU 12v switched) and 38 (B/W power supply for ECM).

Odd thing is, the black/pink fuel pump relay, i believe, *should* be ground, since that would complete the relay circuit, but it is power at pin 104 of the ECU. Is something at the E10-F9 connection that i have wrong, or did i fry my ECU installing the board? I have desoldered EPROMs before, so it wasnt a new experience for me, but anything is possible.

Any help or thoughts would be greatly appreciated!

Matt
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Re: KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

Post by Matt » Tue Apr 02, 2019 7:42 am

Try noid light on injector output from ECU to check flickering when CAS spun

Check when getting someone to spin CAS that RPM signal shows in the software. It should since you say you get spark when cranking

JNM240
Posts: 8
Joined: Tue Jul 14, 2009 11:24 am

Re: KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

Post by JNM240 » Tue Apr 02, 2019 10:46 am

Thanks for the reply, Matt.

I just double checked and i AM getting RPM signal in Consult while cranking. I used a noid light on the injector to see it wasnt receiving signal, but i guess i should try at the output from the ECU, like between pins 101 and 107?

I guess the question i have at this point is: is there any input signal to tell the ECU it should be on? I mean other than it receiving power, that is. I mean, like what tells the ECU to send ground to pin 104 to energize the relay? The orange wire in the dash plug is supposed to be 12v start signal, but i know on my CA18DET fastback car, i can unplug that dash connector entirely and it will still start and run fine, just not have any gauges working.

As a small side note, this engine had a blown head gasket when i purchased the car, then i pulled engine, harness, ecu and tranny and swapped in my CA18 motorset. The KA24DE sat on a stand for the last 4 years waiting for me to get around to building it, so the ECU was never tested or even known to be good. It just really seems everything is pointing to a bad ECU.

Thanks again!

JNM240
Posts: 8
Joined: Tue Jul 14, 2009 11:24 am

Re: KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

Post by JNM240 » Fri Apr 05, 2019 8:46 am

New ECU arrived today. Plugged it in and turned the key on, I get fuel pressure! Thats a step up! I will have to borrow the noid light again and pull the fuel pump fuse and check to see if I am getting injector pulse tomorrow before I install the Nistune board into the ECU. But its definitely a step in the right direction!

Matt
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Re: KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

Post by Matt » Fri Apr 05, 2019 7:15 pm

Should have power to ignition on signal, and then relay powers on rest. If that isn't working properly, then ECU won't do anything else. Fact is you can connect so that is fine.

I only can assist with tuning issues, not diagnosing wiring or other related problems. Noid light is power one side, and GND side to injector outputs

JNM240
Posts: 8
Joined: Tue Jul 14, 2009 11:24 am

Re: KA24DE(T) into a 90 SOHC coupe chassis with Nistune - wont start!

Post by JNM240 » Sat Apr 06, 2019 2:20 pm

So plugged the new ECU in, pulled the fuel pump fuse (so as not to have pressure, didnt want to start it at this point), installed the noid light, and cranked it over. I have injector pulse! Plugged the fuse back in, I have fuel pressure! So i unplugged the ECU, opened it up, installed the type 3 board, buttoned it up, plugged it back into the car, resized the injectors, then cranked it up.

It runs!!

Now, i have to constantly hold the throttle to keep it idling right now, but i still need to set base timing and sort other issues. But it runs!

I guess it turns out i had a bad ECU. Very odd that i could communicate with it and it would give spark signal, but no fuel pressure or injector pulse.

Thanks for all the input Matt, much appreciated!

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