🔧 BUILD Twincharged 3800 Malibu

[Turbocharged400sbc]

6,1,2,3,4,5 iirc

 

[v6buicks]

 

[Turbocharged400sbc]

Yeah I r dumbs. My brains been second guessing myself that it was a countdown not count up lol

 

[Turbocharged400sbc]

It's holley so I'd refer to bs009

 

[ASlowV6]

That firing order is just what I found from someone who apparently went back and forth with Holley tech support and hammered it out.

 

[bs009]

Yeah the firing order you put into holley is different just due to where the crank and cam triggers end up landing unfortunately. I'm on the facebook group where I've posted on the thread there so I'm helping out where I can.

 

[Turbocharged400sbc]

Fuck bookface

 

[bs009]

I kinda agree, but it's just so convenient haha, plus the nested threading really helps organize thoughts nicely

 

[ASlowV6]

Yeah Facebook is pretty much awful. Like fundamentally it’s not bad, but for every good feature they introduce they add ten that are horrible.

 

[Turbocharged400sbc]

Mook Makes Forums in America Great Again

 

[Mook]

Ive been trying.

 

[Turbocharged400sbc]

Ive been trying.

MMFAGA!

 

[ASlowV6]

Okay, so I’m finally going to have some time to screw with this again today. I settled down a bit and came up with a plan.

First, test cam and crank sensors. I assume these test the same as the inducer proving Hall effect sensors I’m used to testing. Rotate engine over manually and look for 6ish VDC 3x per revolution on crank and 1x per revolution on cam.

Check spark. Check coil harness.

If that passes, shield wiring. I have the wiring to the cam and crank exposed right now because I had to modify the harness. I didn’t think this would be a big enough issue to keep it from starting, but maybe it is.

 

[Turbocharged400sbc]

Magnetic interuptor not hall effect.

You may want to check input config more on the holley

 

[ASlowV6]

The sensors are not Hall effect? I compared my tune to bs009 and everything looked identical. I verified that the sensors are being fed 12v rather than 5v.

 

[bs009]

FSMs say they're hall effect, I'm 99% confident I gave mine 12v too on my GP. No idea what the output voltage is but this video is pretty cool for visualizing the crank sensor:



I agree with everything mentioned, my guess is it's a wiring issue somewhere like a loose wire or something but I wouldn't rule out an issue with the ECU itself too. I've heard there were a few instances of this on the Holley groups recently.
I also read somewhere about a 5v sensor like a map sensor causing a no-start too, but that seems like a stretch to me.

 

[Turbocharged400sbc]

Crank is hall, cam is magnetic interuptor

 

[ASlowV6]

How is that tested?

 

[ASlowV6]

I took a data log while cranking, and this is what I’m dealing with. Crank sensor picks up RPM incrementally and then fucks right off. And then repeats process every 3/4 of a second or so. Not quite sure what this means yet.

 

[Turbocharged400sbc]

Regroundvthe pcm/block

Sounds like cranking voltage drop Dippin below 10v somewhere.

Pull plugs with throttle wide open to halve required cranking current draw and check that pattern again. Or backpin ckp or pcm and check v while cranking (in high starter draw rtr condition)

 

[ASlowV6]

My most promising lead right now is a failed cam sensor causing the issue. Terminator X feeds the sensor 12v on the signal wire. 12v is present at the plug while not plugged in. With sensor plugged in, there is 0v through the full 360 rotation of the engine by hand.

 

[Turbocharged400sbc]

Wait what is you t chain, cover, number and type of gaskets?

I've had the oem magnet fall outta the rm dbl sprocket, you kinda have to reform the tabs for it to be snug and not be able to walk side to side and stick to the back of the sprocket.

Look through cmp hole and roll it over 720* while you have it out to test with a dropped socket wand magnet

 

[Turbocharged400sbc]

I've replaced far more crank sensors than cam. And most of those from debris/tossed belt/idler

 

[Turbocharged400sbc]

I'd suspect wiring and terminals first.

I'm sure MookBOT 5000 could agree that while unplugged you should grab an assortment of sewing needles, small clips or pins of a junk sensor....and finger blast all the terminals looking for the proverbial hallway with a frankfurter sailing through it.

 

[ASlowV6]

It’s a double roller, and it’s been a while since I put it together but I think I just used double oem timing cover gaskets.

That’s great info. I’ll check that before I buy a new sensor. I’d think I can probably visually see it if I take the water pump pulley off right?