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First Start ISSUES... (Patreon)

Published:
2021-01-12 00:40:31
Imported:
2026-06
Tags:

Content

I wish I was posting a new video on starting the LS Volvo right now but unfortuantly... I'm not. 

Last Friday I was able to get everything on the "first start" checklist finished besides the cooling system. We went to attempt to start it and it cranked, made oil pressure, but wouldn't fire. It turned out the ECU wasn't detecting engine RPM and thus not firing the ignition/injectors. I started with the simplest thing and replaced the cam &  crank sensors with OEM units. Nothing. I tested the wiring harness and, from what I can tell, its all good. The crank sensor is getting 12v, a ground, and a signal to the ECU. After that I tried various tunes, updated the firmware of the tablet and ECU in the car (twice), tried turning off the cam sensor in the ECU. Still nothing. Went ahead and got ANOTHER crank sensor. Nothing. Spent 4 hours on the phone with Holley techs. Nothing worked. 

I was able to trick the ECU into thinking the engine was turning over momentarily by jumping the 12v and signal wire in the crank position sensor plug. I essentially just stuck a wire in and out as quickly as I could and the fuel pump turned on & the ECU light turned green. That more or less rules out a bad ECU.

So at this point the ECU is good, the harness is good, but still no signal coming from the engine. That means either all three of the crank sensors I got were bad, or there is something up mechanically with the engine. I'll try some more tomorrow but man, this is NOT fun :(

You guys got any ideas?

Comments

Pietro Ghedini

I know you said you ruled out a bad ecu, but are you sure there isn't something wrong in the plug? Maybe a bad connection, otherwise I have no idea. Spark plugs I assume should be good, coil pack? Maybe you did something wrong there? Inverted some cable by accident while wiring something. I dunno man. This kinda of problem is always something stupid. So annoying

Gingium

Getting the ECU to think it was turning over by by-passing the sensor ruled out the ECU and harness being bad. The engine is turning over just fine, but that doesn't mean something isn't wrong with the reluctor wheel on the inside. I'm going to try moving all the grounds and powers tomorrow. Maybe that will fix something! I'll also stick my phone in the crank position sensor hole to see how the reluctor wheel looks when the motor is turning over.

Carlo Vicenzetto

I agree, only other thing I could think is a fault in the fuel system, but he said the problem was the ecu not telling the injectors/spark plugs to activate

Carlo Vicenzetto

Maybe it's not the sensor itself but the connection to it from the engine or to the ecu or to the sensor itself

ProMods

Few things to check. 1) Have you looked at the diagnostics LED's on the front of the terminator while cranking? I think it's LED 5 or 6 should turn states when/if it acquires crank position. The values of colors for each state is online. 2) Assuming you have the dash setup, are you getting any RPM display at all while cranking? If it reads anything at all, it in fact can see at least some variation of crank signal.

Gingium

nooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

Gingium

Both LEDs are stuck blue and the RPM on the display is stuck on stall (besides when I jumped the wires). It's picking up ZERO crank signal

ProMods

10-4. You mentioned you tried OEM sensors, so thats good. One thing that would be nice to verify is that the sensor is reacting to the trigger wheel at all. I'm not sure if you have a buddy who has access to one, but it'd be nice to put an oscilloscope on the signal output of the sensor while cranking, to see if it shows a pulsed output as the reluctor wheel passes by. Should look like an oscillating square wave. Without having run the engine before, verifying the reluctor wheel/sensor relationship is good first may not be a bad idea. Otherwise, I'd suspect some sort of a short sensor wise. Do you have anything else hooked up to the 12V output from the Holley? The crank sensor is one of the few driven by the 12v side of the system

ProMods

Another, just "sanity" check type of question. That engine should be a 24x reluctor/ 1x cam configuration. Is that the configuration you have for the Holley?

Jeff Meyer

Well I know literally nothing about V8's or custom setups but I just wanted to say the work you're putting in is appreciated, really look forward to this being complete(and im not even a big volvo guy haha). shit gets hard but just imagine that thing sending it down the drag strip! Keep it up!

Gingium

Yeah an oscilloscope is definitely necessary if I can't figure this out in the next day or so. That is indeed the configuration I have in the Holley. Although at the moment I have it set to not use the cam sensor to make things simpler.

Gingium

Thank you! I'll hopefully get it figured out soon and get a video out to ya'll asap!

Jeff Meyer

Take your time man. Shit even upload a vid on how to buff a panel with cheap wax or something in the meantime idk. Dont stress, we got you.

Luuk Listing

Well, assuming spark plugs and coils are good. And there is no compression problem. Have you checked the fuel filter? Maybe a blown fuse? I don't know much about these engines but could there be an anti theft system preventing it from starting?

McWillies

I don't know much about LS's but are you sure there's a reluctor wheel in there?

Red Squirrel

Hopefully it turns out to be something simple/cheap. But sometimes it's the simple stuff that's hard to narrow down.