Doc99SS

iTrader: (2)

Over the Winter, I installed an LS2 402 stroker in my '99 Camaro SS. I had blown-up the LS1 engine at a drivers school. The short block came with the cam/Knock sensor extension harness for installing an LS2 engine into an LS1 car. I also have uploaded a new program taking care of the different displacement and the 39#/hr injectors, using LS1Edit.

The engine will crank over but will not fire. Have I missed something simple, like a reset, or what about the crank relearn?

Another problem is that I cant seem to get AutoTap to connect to the PCM, so I do not know if I have any error codes. AutoTap keeps asking for a serial port. I cant figure out how to get past this problem.

monsterchevylizzard

I am having ALMOST the exact same problem. . installing an ls2 where an ls1 was. Last night the damn thing just turned over and over . Plugs are dry and from what I can tell, I am getting no spark to my plugs ( kinda hard to gound out 6 in wires and turn a key at the same time ) . . . but my fuel pressure guage reads 45 psi on the fuel rail.

My BS3 interface shows my crank sensor is working because I can see the starter reaching 1150 rpm cranking the engine.

I just spoke with someone who told me to switch two of the three cam harness wires B & C to reverse the polarity for ls2 cam sensor. Im going to try it tonight, cant hurt anything.

Doc99SS

iTrader: (2)

I thought that switching the two wires on the cam sensor is done to get the tach to operate correctly. Anyway, its something to try. Finally, the two wires are actually identified, as B & C. I was under the car last nite and noticed that the three wires are labelled A, B, and C.

I am going to pull a plug and see if I am getting fuel. But you are dry, that does not make sense, does it?

monsterchevylizzard

Didnt freakin work !

I figured I am dry because the cam sensor controls the computer firing . . then I wouldnt get any fuel injector turn on or fire from the coils.

It looks like I have no fire and no fuel past the injector . . and all it does is turn over with the starter . . . even after I switched B & C.

Does anyone know if B & C are the right wires to swap ? and why ?

monsterchevylizzard

I was wrong. . its A and C wires. . .swap those two !

HSV-GTS-300

Bad cam sensor or cam wiring won't prevent it starting.....it would just crank over longer and maybe pop and backfire a bit for awhile. The tach won't work if you get the wiring wrong. The reason you swap the polarities over is because the LS1 cam sensor work on 12V and the LS2 sensor works on 5V.



Do you have a 24x reluctor wheel on the crankshaft and using an LS1 black crank sensor ?

monsterchevylizzard

How on earth does swaping cam wires reduce voltage ?

I just swaped A and C and now my fuel pump works when cranking . . . and not just when priming . . . but I still dont have any fuel past the injectors or any fire at the plugs.

Mine is a 408 ls2 from www.ls1performanceparts.com and they built it with an eagle crank . . so I am guessing it has the ls2 reluctor wheel and the sensor is black. The cam sensor is white.

dirtyratt

iTrader: (1)

I had the same problem with my swap it was the single ground wire at the lower block that hooks up with main ground wire. Just something to look at
Hope that will work for you....

monsterchevylizzard

No offense. . . but you just told me absolutely nothing ! ! !

My engine has a large gound wire from the block to the frame . . and my coil gound wire is also grounded to the frame if that is what you are talking about.

HSV-GTS-300

Don't know and don't care. But it works.


LS2 reluctor wheels were 24x (same as LS1) in 2005 only.
GM changed to 58x in 2006.
You would not be the first person to receive a block with the wrong crank reluctor to suit their cars' PCM if it is wrong.

monsterchevylizzard

SO . . . . does that mean that I need a different crank sensor ?


My interface does show that I am spinning 1150 rpm with the starter turning it . . so wouldnt that mean that my crank sensor is working ?

HSV-GTS-300

Nooooo........changing the sensor does nothing if the reluctor wheel is wrong.
You must have a 24x crank reluctor wheel + black LS1 crank sensor if you are using an LS1 PCM.



I don't know how your interface works.....I do know the GM car tachs work off cam signal...not crank signal.

HSV-GTS-300

Here's another interesting thing about 24x reluctor (exciter) rings. Someone could have the correct reluctor ring to suit their cars' PCM....but if the ring was installed on the crank backwards it still won't start.


"Exciter Rings
Be sure to replace the exciter ring anytime the crank is removed from the engine. GM sells it for about $15 under p/n 12559353. We install it with the tool that Larry Eriksson of Crankshaft Rebuilders designed, that is marketed by Goodson (p/n RRJ-350), because the engine will start, but it won't run, if the total runout exceeds .020", including crankshaft end play. Be sure to follow the installation instructions shown in the article and install the ring with the holes facing the rod journal because the engine won't start if you install the exciter ring backwards."

http://www.enginebuildermag.com/Arti...all_Block.aspx

monsterchevylizzard

I really appreciate your help . . . but I just went out and un pluged my cam sensor completely . . . hooked up my computer . . . and turned the motor over with the starter.

My computer reads the rpms just fine with no cam sensor plugged in. Starts at zero and goes up to 1150 - 1100 rpm with the starter cranking it. So the cam does not read rpms and my crank sensor is working.

As far as I know, the cam sensor just tells you which stroke you are on, the exhaust vs compression . . and the crank sensor tells you how fast and when to fire . . and thats the way it is working.

HSV-GTS-300

OK fair enough.

All I know is that the tach fitted in the car does not work if the cam sensor is not wired up correctly. Perhaps your computer does not use the same sensor input as the GM tach to display RPM.

So have you got it started up yet ?

LS1curious

typical cranking speeds are around 200-250rpm. Sure you have the correct reluctor ring on teh cranksahft ?

HSV-GTS-300

Here check this out.

Engine Controls 6.0 L
Helms Manual for a 2005 GTO...(with 24x LS2.)

Scan Tool Data List

Scan Tool Parameter...Data List...Parameter Range/Units..Typical Data Values

CKP Sensor................Eng,IG,............RPM...... ..................Varies
CMP Sensor...............Eng,IG,MF.........RPM........ ................Varies

Looks to me as if with a scan tool you could read RPM from either the CKP (crank sensor) or the CMP (cam sensor).

MF = Misfire Data List
IG = Ignition system Data List

http://www.ls2.com/boggs/LS2/Enginec...controls22.JPG

ChevyThunder17

iTrader: (48)

If Autotap isn't connecting to your PCM, I would start by checking the ground wires on the driver side cylinder head in the back, I believe it's G215. Without that, the computer doesn't have a ground. If it isn't grounded, it has no power, it won't fire the injectors...

Schwanke Engines

iTrader: (1)

What he said. Your cranking speed should only be around that range as said.

The other thing you need to be sure of is the cam gear. Is it the 2x LS2, or was a stock LS1 with holes in it installed?

ChevyThunder17

iTrader: (48)

Because you've got a 12V feed for the sensor, ground, and a 5V reference. The sensor pinout is different on the LS2.

Are you running the stock ECU? Judging from your earlier posts, I'm guessing you've got a Big Stuff 3.