Just tried starting my lq4/t56 swapped 240sx and it cranked good then stopped cranking all together. I did not try to turn the key again to see if it would crank again cause it's obvious there's an issue. Maybe there's something off in the tune to where it's flooding the motor and hydrolocking for example. Just put the HPtuners on it and I am not real familiar with the software (had a V1 AEM stand alone before). Car has a cam, ls6 intake, 80Lb injectors, and turbo. If you could take a look at the tune any suggestions would be appreciated.

 

Won't crank as in starter does not turn motor, or won't crank as in motor turns but won't fire? Sounds dumb to ask, but you'd be amazed how often those are used interchangeably. I notice you have your maf set to fail, but the codes disabled, so the maf can't fail. You need to set the maf to set a code on first error even on SD OS. Change VATS from "Serial" to "not Fitted". Lowest cell in maf curve, set to 20 g/s to get fuel until the maf fails.

 

It was a crank no start. Then it stopped cranking at all. Like I said, I did not attempt to turn the key again. I set the maflike that based on what I read elsewhere since I have no maf on the car. Do I still change the settings as you recommended with no maf at all?

 

Yes. The ECU needs to set the maf code. You can leave the SES box unchecked, but set it to MIL on first error in the menu option. Set your lowest (usually 1500 Hz) cell to 20 g/s so it gets air until the maf fails. Good news is, it likely didn't flood

 

that file needs an awful lot of work.

also need to know the combo in detail, fuel system type, map sensor, IAT sensor set up etc etc.

luke@dieseltech.com.au

 

So I figured out I have to do some diagnosing with the starter circuit first. I noticed the negative cable at the battery was pretty hot after only about 5 seconds of cranking. Not sure what's going on. I have battery positive ran straight to the starter. I have battery negative ran straight to a starter bolt. Then I have a negative off the battery going to the chassis. And I have a negative from the other starter bolt to the chassis. And I have a negative off one head to the chassis. Not sure what's going on unless the starter itself can cause the hot negative cable.

 

Yeah, I know it is far from being done. I was just trying to get the car started. I had it completely tuned on AEM before the computer went bad. I'm still learning the hptuners software though. LQ4, LS6 intake, 80LB injectors, cam/dual springs/hardened push rods (can get specs of cam if needed), 93 octane fuel right now, 400lph walbro pump, 5 bar map sensor in factory location, AEM IAT sensor, truck manifolds flipped forward for the turbo, hood exit exhaust, t56. I think that's it but if you have other questions let me know.

 

 

I have battery negative ran to the starter mounting bolt. The starter still has the engine ground also since I have a ground wire from the engine to chassis. And the starter has a negative from the other mounting bolt to the chassis. I've seen lots of people run battery negative to a starter mounting bolt and I figured that's best so it has as little path as possible for the starting circuit.

 

 

Put a new starter on it and that problem is fixed. Starter solenoid must have had high resistance.

 

Did as you said and the car fired up immediately. It died almost instantly but there's a few things I need to do under the hood before I go any further. I appreciate your help. Will add to this thread if needed once I get the other things taken care of. Thanks again!

 

Any idea what this means? I realized that I had not actually saved the tune (explains why it died since it has a stock 5.3 tune loaded) to the cars computer, just modified it for the future. Tried loading the tune into it and it came up with this message.


Well it won't attach my picture for some reason. It pops up with a message that reads "File OS ID does not match VCM OS ID. File OS1261005 VCM OS 9381344. Please load a file that is compatible with this VCM."

Edit again: Figured out why it was popping up with that message^. I had to click write entire. Now the car won't start again though. Different no start now though. Like it tries to start for a second but wwon't. Currently loaded tune is attached.