06 gto ls2 swap in a 93 nissan 240sx motor cranks but wont fire up

[awd2ks4]

Hey guys I'm new to the forums looking for ur guys advice on my swap not starting up. First off I bought a 06 gto 6 speed ls2 which is dbw and has a e40 pcm I believe And put it in a 93 nissan 240sx. I started the gto up, ran fine pulled it in the shop and tore her down for the swap. Had the two factory harnesses mated together by a reputable guy, who also had me ground one side of the factory fuel pump relay which got the pump working. I'm using the factory starter harness and it turns over but has NO spark or injector pulse. Cam plug has power, maf has power, and the Coils and injectors have power when cranking over but noid light shows no injector pulse. Fuel pump turns on and stays on while cranking for awhile. Fuel pressure is at the proper 55 or 60psi at the fuel rail. My obd2 scanner is showing 170rpms while cranking over. I sent my pcm to Texas speed for a bench tune and to get rid of the vats but at this point I'm really hoping they forgot to do that. Does vats cut spark? Is there anything I'm not seeing here? I'm about to send my pcm back to make sure its legit. I called them and of course they say (yep its off). But they did fail to remove the codes P0452and P0463 I'm getting. If it ends up being as simple as click of the mouse :wallbash:. Any help is much appreciated. Thanks in advance guys :)

[GMPX]

What is the full list of DTC's showing?

[awd2ks4]

Just the ones I posted my ecu number is 12596679

[GMPX]

P0452 "Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage"
P0463 "Fuel Level Sensor 1 Circuit High Voltage"
Neither of those will cause a no start.

Even with VATS enabled, an engine will often fire, then almost instantly shut off.
As you can imagine with conversions there is many things that can go wrong, you can't always assume it's something in the ECM.

[awd2ks4]

Me and my harness guy pretty much eliminated the harness from being the problem since it all checks out and has power everywhere. Vats wont cut spark? What else can I check for clogged injectors?

[awd2ks4]

I know those codes don't matter but they should still be removed. My obd2 dash hawk says one of those codes is evaporate but one I look them up they both are fuel related

[GMPX]

Vats wont cut spark?
I can't remember on the E40, but on the later E38's Spark and Fuel can be cut with VAT's.

[Taz]

... My obd2 scanner is showing 170rpms while cranking over. I sent my pcm to Texas speed for a bench tune and to get rid of the vats but at this point I'm really hoping they forgot to do that. Does vats cut spark? Is there anything I'm not seeing here? I'm about to send my pcm back to make sure its legit. I called them and of course they say (yep its off). But they did fail to remove the codes P0452and P0463 I'm getting. If it ends up being as simple as click of the mouse ...

You have discovered that these types of conversions can be difficult - if you don't own tuning software of some type. I generally recommend working with a reputable local tuner - especially one that will come to you (versus shipping off the ECM / TCM for programming), or purchasing tuning software and learning how to do this yourself.

Once you factor in the initial cost of the ECM / TCM tune (VATS disabled, gear & tire adjustments, etc.), plus the cost of a dynamic tune (VE / VVE / MAF), the cost of purchasing tuning software becomes at minimum expenditure neutral.

Even with a completely stock engine, something as simple as a non-OEM air intake tract, could cause a lean condition (Trailblazer SS often go lean with a cold air intake upgrade) - making tuning software an indispensable tool.


Regards,
Taz

[doubledip]

I can't remember on the E40, but on the later E38's Spark and Fuel can be cut with VAT's.

Really??? When you say later do you mean e38's in general or a particular os?

[awd2ks4]

I'm pretty close to buying efi live. So no one knows for sure about the vats and spark? Anyway to find out

[ScarabEpic22]

Unfortunately if Ross doesnt know and no one else on the forum has replied, then you might be SOL on it. I have only read an E40 before and never got around to tuning it, plus it was a stock truck and not a swap. Swaps are tricky in this regard, just because the harness and ECM are setup correctly doesnt mean one other tiny thing isnt off. So you get fuel pressure, just no spark when cranking? To me that sounds like a VATS problem...but then again I might be wrong.

In addition to disabling VATS, you also need to apply the Disable VATS Patch in the OS then full flash the ECM. I dont know if your tuner did that or not, E40/38/67/etc need this done as well as changing the VATS type plus turning the VATS off, its not like the LS1 where you just turn it off and flash it.

[awd2ks4]

That sounds right can u do that with Hp tuners or only efi live?

[GMPX]

Really??? When you say later do you mean e38's in general or a particular os?
When the ECM wants to kill the engine if VATS fails, the ECM internally flags injector cut, spark disable and starter disable.


That sounds right can u do that with Hp tuners or only efi live?
No sure about HP, but EFILive can certainly kill off the theft.

[doubledip]

hmmm ok .. only thought they killed injectors... well the last time i was checking it i was sure i still had spark butno injector pulse... anyway lets move on..

the most common cause i see for conversions not starting (assuming vats has been turned off correctly) is the wiring of the ignition circuit.. alot of the time people wire the ignition into the ignition circuit that loses power on crank.. best way to make sure this is not the case is any battery power for your loom and ignition power is wired directly to a Battery source (for testing purposes only) this will ensure that not only on ignition on but on cranking there is 12v where its meant to be...

dont know how many times i have had people assure me over the phone that it has igniton power and i suggest this method and they end up ringing back saying it started after doing this...

[awd2ks4]

Well the guy I had do the harness does a lot of the formula d cars so he can do ls wiring in his sleep. Ill keep the thread updated when I figure it out.

[doubledip]

Well the guy I had do the harness does a lot of the formula d cars so he can do ls wiring in his sleep. Ill keep the thread updated when I figure it out.

yes but its not the LS wiring that is the issue.. it will be the mating of it to the car that i was suggesting...

only trying to help...

if you take that route of thinking that cause he does formula d cars he can do the wiring in his sleep and i am sure there would be plenty that would vouch for texas speed doing hundreds of LS PCM's that they could do vats in their sleep that it isnt leaving much that could go wrong now


once again was only trying to help good luck

[awd2ks4]

Yeah I gotcha and appreciate it alot. That's really the only wiring that was modified on the harness its all plug and play in addition to the Dakota digital for the speedo. If that were the case wouldn't I lose power to the coils or injectors?

[doubledip]

Yeah I gotcha and appreciate it alot. That's really the only wiring that was modified on the harness its all plug and play in addition to the Dakota digital for the speedo. If that were the case wouldn't I lose power to the coils or injectors?

all depends onhow it has been wired.. thats why with the harnesses we do i tell the customer to power the ignition up with battery (only 1 ign trigger wire in our harnesses)

i dont know how many wires are in your harness that has been made it may cut the coils, injectors , ecu etc...

[awd2ks4]

Well I guess we will see what happens the pcm will get to tsp on weds

[doubledip]

cool... for your sake/sanity i hope it is something simple like vats not turned off... at least will be an easy fix :)

[awd2ks4]

Curious about ur sig. Why do u hate e40s

[doubledip]

because if you look at them the wrong way you brick them LOL

well that was my experience with 2 brand new $400 ones about 3 years ago... they have been connected up once each and been flashed with tech2 once each and that was the end of them ....so hence i hate them

E38's seem to be more tolerable but then that is also because over the last 3 years i have learnt more :)

[awd2ks4]

Well the ecu made it to Texas speed and they said vats was still on... so they had to rewrite the tune and remove it and checked again that its off. Hopefully when It comes back it will fire right up