SR20DET swap help ( injector pulse )

[wantsum?]

I need help from the SR20 swap veterans. This is going to be long as I'm going to be very specific.i will also be cross posting this to the forum.

Car will fire right off and idle smooth IF I squirt some fuel down the injector holes. As soon as the fuel runs out,car dies. Every time I check spark, i have it. ( 20 + checks now...)
Injector pulse is random. Sometimes its strong, then i immediately loose it.other times the injectors barely spit. Other times nothing at all. I have never been able to start the engine with out manually putting fuel down the holes. It did semi stumble one time while cranking. It wanted to start but couldnt.

However everytime i pull the CAS and spin it by hand i have pops and hum from each injector / coil.

IM AT A LOSS HERE. Any help would be great. It's been a 3 year complete restomod.. I want to drive the car to Shasta this year. I'm admittedly defeated. I have emails out to wiring specialties and RS Empathy.



Blacktop SR20DET. Completely fresh engine
New wiring specialties SR harness set to my build.
E5 ecu with a RS empathy tune set to my build.
Base time and CAS stab are right on ( 2 sets of eyes verified )
Walboro 255 pump with automotive FPR
Base pressure to 43psi.
New deatschwerks 740cc injectors.
New ISR z32 maf.
Fuel lines are hooked up correctly, strong fuel flow.
TPS came with engine, tests good, set properly.
CAS came with engine. Test good, set properly.more on that later.
Harness grounds hooked up. Plus 6 additional engine to chassis grounds.
Good battery mounted in the trunk. 0ga feed to starter. 4ga ground to chassis in trunk.

[sfdaugherty]

Does the fuel pump run when you turn on the ignition? It should be powered through the WS harness.

Shannon

[wantsum?]

Yes pump runs. We actually hard wired it for trouble shooting purposes. Constant 43psi at all times.

One thing thats important we discussed while less delusional this morning. I tried firing the car a few months ago. Stock harness. Stock ecu. Stock parts. I had the same issue. ( what I though was no injector pulse, could have been just super weak )

Now I have the new harness, new injectors, etc. Same ECU ( with a flash for mods ) and same CAS. Since the CAS is just a window switch,it works fine. It has to be a ECU issue.

Martin at RS got back to me quickly. He said to send the ecu down and he would pop it in his shop car and see what it did.

So I'm pausing everything until he gets it and conforms good or bad..

I'm still open to ideas however. ECU wont ship until tomorrow.

[spriso]

We have had customers run into a starting condition like this when they did not hook up the orange wire (pin 34 on a S13 SR20DET) to the "Starter" wire-- basically, this is telling the ECU to "Start" when you are cranking the engine over. I suspect that this is your issue. All you have to do is connect the orange wire to your Black/Yellow wire going to the starter solenoid.

The other issue that you may be running into is that some Datsun wiring will actually lose power during the cranking (as it bypassing the ballast resistor), when you test with key on, it has power, but if you leave the test light connected, you will see that you momentairly lose power during the "start" phase. Check your key on power to make sure that you are not losing power when you are "starting".

Hope that helps,

Michael

[wantsum?]

I'm running a painless ( far from it ) chassis harness with a wiring specialities engine harness. I do NOT have the trigger wire for the ecu or the starter hooked up through the ecu. I'm running it through the painless system. I will try hooking up the ecu trigger set up ( key switch to ecu ) through the ecu.

Not sure how this would affect it running though as the start signal isnt used anymore after you release the key to the run position. Correct?

[wantsum?]

Well hell. Hooked up the ecu side trigger wire. It fired! Good effing lord is it pig rich. I mean huge raw fuel pig rich. Billows fuel smoke. So I've got something to figure out there...

We have had customers run into a starting condition like this when they did not hook up the orange wire (pin 34 on a S13 SR20DET) to the "Starter" wire-- basically, this is telling the ECU to "Start" when you are cranking the engine over. I suspect that this is your issue. All you have to do is connect the orange wire to your Black/Yellow wire going to the starter solenoid.

The other issue that you may be running into is that some Datsun wiring will actually lose power during the cranking (as it bypassing the ballast resistor), when you test with key on, it has power, but if you leave the test light connected, you will see that you momentairly lose power during the "start" phase. Check your key on power to make sure that you are not losing power when you are "starting".

Hope that helps,

Michael

[spriso]

Like I said, we have run into this many times before with customers doing their own wiring. Glad that worked out-- and yes, as soon as the starter has done its thing, the signal is turned off to the ECU and it now knows that you are running.

As for your rich injectors, that could be many things... where is the vacuum signal for the fuel pressure regulator coming from?

[dynaguy]

Spriso to the rescue again. Michael saved my bacon a few times during my swap progress!!

[wantsum?]

I'm going to wire everything through the ECU that it's supposed to run vs using the painless chassis harness. After the start signal wire I dont want to take any chances on chasing an issue that shouldn't exist. I'll report back later on. Might take a few days after work to tear it apart and button back up