BlueZee28

iTrader: (30)

Now, there are two issues I need help with. The first, is the engine will crank but it won't turn over. My tuner has HP Tuners and it is not showing ANY reading for crank hi/low and low/hi, as well as the crank positions current cylinder. Neither of those are showing a reading. He says the injectors aren't firing because the car doesn't know that it is cranking. It will crank all day but no fire. Everything else on HP Tuners seems normal, the idle air temp, o2's, TPS, etc.

I checked to make sure both the crank and cam sensors had their plugs secured, and they were.

We are sort of at whit's end here with this. He couldn't think of anything else to check.

For reference, the tuner made a thread on LS1tech, found here:

http://www.ls1tech.com/forums/conver...ap-91-z28.html



The second issue may be related to the other problem I just stated. When the car would crank, I didn't touch ANYTHING VATS related on the car. All we did was tune it out of the LS1 computer with HP Tuners. It cranked without disabling the VATS on the car itself. I was under the impression I would have to disable VATS on the car before it would even crank, but this wasn't the case? Then, when we started having the issue of it not firing, I decided to just try disabling VATS by soldering the Purple/White wire and the White/Black wires together under the dash, and then it wouldn't crank at all. Now when you turn the key, nothing happens. I was thinking those were the two wires that had to be connected together to disable VATS? And would VATS have anything to do with why the computer isn't getting a Tac reading?

one92rs

iTrader: (5)

i wouldnt think that the vats would cause it not to fire unless you wired it in thru the pcm. i thought it only used it not to start. did you change any pins on the ecm or just hook it up per harness build. what is the tooth count on the crank gear. are you sure the crank sensor is giving you a signal.

BlueZee28

iTrader: (30)

Pocket re-pinned the harness for me. I'm waiting for him to chime in and give me some ideas too.

The reluctor wheel is the 24x like what it should be. It is an LS2 crankshaft but the shop took off the wheel and installed the one from the original crank onto it, which is a 24x.

I'm not sure how to detect if the crankshaft sensor is getting a reading. How do you do that?

one92rs

iTrader: (5)

i would think it was like a hall effect sensor. maybe ohms when turning slowly.

one92rs

iTrader: (5)

http://www.hotrodlane.cc/New%20LS%20...0Not%20Run.htm

BlueZee28

iTrader: (30)

I'll have to make sure to show my tuner that link, because most of it makes no sense to me.

87CIZ

iTrader: (8)

i heard something on tech about crank relearn? maybe that could be it? no idea.

BlueZee28

iTrader: (30)

I did a quick search on Tech and it looks like that is just a code that can be deleted to pass emissions, or something like that.

With the VATS question I had...is it wierd that I could turn the key and it would crank without physically altering the VATS system in the car? All we did was tune it out of the LS1 computer and it would crank. I was told I was going to have to put a resistor in the wiring to get it to start, or solder the two heavy wires together, which I did just for grins and it made it worse (now it doesn't even crank).

SheldonZ28

iTrader: (1)

Nick,

Your VATS is not the problem, even if you didnt delete VATS, it would fire 3 sparks and then quit.

I had a similar issue with my swap into my trans am, i spent a week chasing my tail, i changed all my sensors, i checked wiring, checked all my refrence circuits, checked my sensor and power circuits i checked EVERYTHING, so i thought.

I would see hptuners show that it was seeing signals, but not give any cranking info.

It turned out that my CPU Ign + feed was going dead on crank, so the PCM Still got battery voltage, but the coils fired off the PCM. I had fuel, but no spark, and that turned uot to be my issue. The PCM i believe sends a 5v refrence to the coils to fire them, where the injectors just get grounded to fire them.

Try checking for +v @ your main coil feed, then have someone crank it and hold the volt meter there to make sure all your wires are showing the signals they should.

BlueZee28

iTrader: (30)

So what did you end up doing to fix it?

ghettocruiser

iTrader: (4)

First...I agree with shel. VATS isnt your issue here. And besides...VATS in the PCM is what you have to worry about. Not the cars original VATS. It would still fire for a few seconds. If it starts, runs for a few, then shuts off, then maybe look at VATS. I had issues with mine still being on even after programming it out.

Second...I also agree with shel on your sensor issue. The reason everyone says to use the big pink wire coming from the bulkhead connector is that particular wire has 12 during IGN AND during CRANK. That is VERY important. If you do not have power going to the PCM and circuits from a hot when CRANK wire, the car isnt going to run. You'll get dead sensors...like you have.

The only other thing I can think of, if you have the power wires hooked up correctly, is a dead power circuit in the engine harness. Somewhere one of the pink wire branches isnt getting power. I made this mistake when trimming my harness down. Thought all my pink wires were getting 12v, when in fact I severed a connection and my MAF and O2s werent getting power.

Check that the harness is being powered by a source with 12v while cranking. Easy to check...hook up a test light or voltmeter and crank. If it drops, you got the wrong wire.

J.

SheldonZ28

iTrader: (1)

I jumped a +v on crank and run to my PCM circuit to see if it did anything, and it fired up. I then had to re route the wire to a different feed that was +v on crank and run.

Pocket

iTrader: (24)

From his tuner, he is not getting signal from the crank sensor at all during cranking

Seems like a bad sensor

The engine has to run to do the relearn. An improperly installed reluctor ring would throw every bit of timing off, but it will still sent atleast SOME reading, so thats out too

Coils are based off of the crank signal, so those are out

Pocket

iTrader: (24)

His power circuit is very simple, the IGN's are divided among the INJ 1, INJ2, PCM fuses in the C207, and the single IGN hookup in the engine bay from the heavy pink from the C100

His particular loadout only has the HO2s on the IGN in the engine bay and wont affect cranking even if its disconnected

The fact that he even gets a reading from the PCM means its respective IGN and 12v constant connections are in place

It kicks back to the crank sensor circuit and sensor. Test continuity across the three sensor wires. If they check out, then replace the sensor

ghettocruiser

iTrader: (4)

So all other sensors are showing as active while cranking? Its just the crank sensor? If thats the case, then its possible the sensor is toast I guess.

Getting a reading from the PCM while not cranking is one thing, but is the reading still the same while cranking...IE the TPS and IAC and all are still showing function while cranking?

From what you said, Pocket, it sounds like the wiring should be ok...

And on the crank re-learn thing...I swapped PCMs from my 99 auto PCM to a 02 T56 PCM when the car was being tuned. The 99 computer was locked . I now get a code for the crank relearn, but it hasnt really affected anything as far as I know. Still not sure why a GM tuner is needed to fix that issue...

J.

Pocket

iTrader: (24)

From his PM

Im almost positive its to do with the crank sensor or wiring. He has to pull the starter to get to the sensor, Id test the wires just for peace of mind. Most likely they're fine because I ohm them out twice before I send a harness

BlueZee28

iTrader: (30)

I'm starting to think the culprit is the sensor itself. I recall the block having the sensor in it when it came back from the machine shop. They had hot tanked the block and sandblasted it, and it's possible that the sensor was accidentally left in the block during all of that. Besides, I doubt that the machinist would take it out and put it back in considering the block had over 100,000 miles on it. I'm going to get a new sensor and try that first, and if that doesn't solve it I guess I will focus on the wires and check for continuity. Wish me luck

Shift06

Is it a crank sensor from an LS1 or a 6.0? Does the sensor have to match the reluctor wheel?

Pocket

iTrader: (24)

Same sensor for both, and yes it must match the reluctor ring. 24x black and 58x gray

BlueZee28

iTrader: (30)

I picked up one from a friend tonight that came from a 2000 Vette. He said the motor was running when pulled and I believe him, so I'm going to try it and if THAT doesn't work then I'll pay $50 for a new one and try that. But I have a feeling this is going to work.

87CIZ

iTrader: (8)

i just had a revelation... we have something in common. the ls1 swap in my old 87 iroc is doing the same thing. it's carbed though. but the sensor was left in the block also when it was hot tanked... that has to be it. we've been thinking it was wiring or something dumb. we hooked the msd box straight to the battery to be sure it was getting 12v it cranks for days but wont fire also. It didnt help we got one of the first edition edelbrock msd boxs that had to be cranked super fast in the first place to fire. But we have an upgraded box now and still nothing. It has to be that sensor. It worked when the engine was pulled from the 99 SS but like i said it was left in im pretty sure when it was hot tanked.

BlueZee28

iTrader: (30)

Well I hope that helps you then. I called the shop tonight and they said they removed the sensor before they worked on it and put it back in when they were done, but they said they had to pry pretty hard to get it out because it was corroded with all the rust on the block. They said the plastic was pretty nasty when they pulled it out, so hopefully that means it is a bad sensor lol

cam-

Probably broke it. They arent made of unobtatnium they are wimpy plastic pieces and need to be treated as such. Hope this is your problem and you can move forward

87CIZ

iTrader: (8)

you swap sensors yet? I'm anxious to know if it fixed it! lol I didnt make it out to my car to steal the Crank position sensor to take it to my buddy to see if thats his problem also He had to work 12's today and didnt feel like messing with it.

smokin2002

are you running a painless harness or did you install something that came out of a donor car?? whats your pcm out of??

may not hurt to run over what you have wired up as far as the Chassis side of the harness, engine side is obviously pretty stand alone. i recently did a lsx swap into a 85 monte ss, most the wiring is still fresh in my head,

you will need to delete vats or purchase a lil bypass module, if neither the car will fire for split sec and shut off,

with key on check power at the coils and injectors, i think pink wires for both, they will be hot at all times, your sensor controls the ground to work the components when need be, if your hot it would lean on sensor issue. not much to the setup just a matter of figuring it all out :P

if you have no power there we need to re look your wiring

Pocket

iTrader: (24)

I reworked the harness

99+ PCM

Engine bay hookups were for PCM battery, aux electronic IGN, relays and gauges. His PCM powers up and shows reading on every sensor except crank, thus the intense scrutiny on the circuit

VATS was programed out, plus hes not starting at all because the coils nor INJ are being told to fire because the PCM doesnt know the engine is turning

INJ/coils are bank fused IGN power, not hot at all times

smokin2002

What exactly is "reworked"??

pins 1 and 40 on each of red and blue connectors should be grounded
pin 19 on blue should be 12v ign
pins 20 and 57 on blue should be to Batt+
then i never wrote in my notes but but there are 4 wires that feed both left and right banks coils/injectors, i want to say all pink wires? they all need a 12v ign source, they should had been originaly fed by one or 2 of the 3 big quick disconects black plugs

if we can run these wires over are confirm all good and injectors and coils have power when key is on id lean on a sensor,

BlueZee28

iTrader: (30)

Not yet. School has been kicking my butt. I'm going to try to get time to do it tomorrow, just swap out sensors and see if that works. It seems like the easiest test that I can do right now, and potentially the most probable thing to do to fix it.

Pocket

iTrader: (24)

Hope it works, it wants to fire

Read:
https://www.thirdgen.org/forums/ltx-...rt-finish.html

It is completely disassembled and rebuilt to best fit a 3rd gen with his option loadout and lengthened to fit under the dash along the stock routing

Actually there are two, INJ 1 wire which is ran through the C207 to the stock INJ 1 fuse give IGN power to the entire left bank of injectors and the left coil. Exactly how 4th gens do it. Same for INJ 2 on the right bank

PCM IGN wire along with the MAF IGN wire go to the C207 again and then to the stock ECM fuse

PCM Battery wires move back into the engine bay to connect to the stock fuel pump orange wire which has its own inline fuse located near the battery

I do not use the 4th gen body connectors that house the Batt, IGN, relay and gauge wires

BlueZee28

iTrader: (30)

A new crank sensor fixed the problem. It fires right up now

one92rs

iTrader: (5)

now get out there and leave us some black marks.

ghettocruiser

iTrader: (4)

Nice! Didnt realize the crank sensors could get buggered up so easy. Good to know for any future issues!

START UP VIDS!?!?!?

BlueZee28

iTrader: (30)

I got two short videos in my actual swap thread!


https://www.thirdgen.org/forums/ltx-...ns-6-0l-7.html