Thumper33

oh, another thing that might help me is that there is an upgrade package for the software that I'm using to interface with the PCM. It would tell me a lot more specific sensor data. Maybe this would help. It's $100 for the upgrade which I don't really want to purchase if it wouldn't help for sure, but I'm more than happy to throw $100 at it if it's going to help us find the problem.

Here is a link to everything that the program will tell me if I get the upgrade...

http://www.autotap.com/enhanced_parameters_gm.asp

Would that help?

Speartech

iTrader: (14)

I tell ya, those symtoms sound a lot like vats. The only thing I can think of is maybe something screwy going on with the computer. It's been tested TWICE here, once when we initially made the harness and once when you sent the computer back because the engine wouldn't start. Both times it tested perfectly here. I can send you a different computer with your file in it if you want to try that.

Thumper33

Well we all know we're not sure if that'll help or not, but I'm not sure where else to go from here. My other thought is that it could be the ETC module shorting out or something. I'd be happy to put a deposit down or pay for them temporarily if you can send them to me. If you don't have my info handy, just drop me an email at mnevitt@offroadtoystore.com, or call me at 720-979-7337.

John, is it at all possible that I could have a bad sensor, or a shorted sensor or something that for some reason doesn't trip a code even though it's bad? I'm tempted to get a list of each sensor that could possibly make the engine not run, and start replacing them. I'm at my whit's end here, and I don't know what else to do. I don't even feel like I can take it into a local shop because I'm afriad that they're just going to charge me hundreds of dollars, not find the problem and I'll still be nowhere. Oh, and don't at all feel like I'm mad any anyone here, especially you John. I'm sure we'll figure this thing out, and I know this sucks for you since you're a busy guy anyway. I'm mainly just frustrated because I don't know what else to do.

My other thought is that I could pull the harness back out, and hook up only the wires that the engine NEEDS to run. Like power straight from the battery, ground from the battery. Fuel Injectors, the sensor or two that It needs, and then try it that way so I KNOW I don't have a stupid cut in the wires or something wired wrong. I suppose with that in mind, I could just start unhooking everything that it doesn't need and that might be easier. I would think that it would blow a fuse if I cut a wire and it's shorting out. Let me know if anyone has any other ideas. I suppose we should try the computer swap before I start getting too angry with the thing .

Thanks again!

Mike

62ls1

iTrader: (1)

WOW. Good luck man. Reading all this has solidified me going carbeurated if I keep my LS1 for my lark project. YIKES!!

ghettocruiser

iTrader: (17)

haha...I was trying so hard not to say the words VATS again... but it really does still sound like it.

Ide say try another PCM...especially if John is agreeing to swap it out for ya or something. Sounds like your best option before you go trying to replace sensors. Get the "new" PCM, double and triple check all of your connections and make sure all the sensors are correctly installed.

The fact that the injectors are working, then seconds later they are shutting down...sounds like a clue that something may be screwy in the PCM, and VATs is still taking over. Just weird... Keep us posted.

Justin

mullenh

iTrader: (1)

ok I asked a guy at the shop he said 'cam sensor' or you wired it wrong or it is in your harness, not a lot of help i know but i did ask

kossuth

iTrader: (12)

Thumper, I'd try a different PCM. Perhaps there is an intermediate short in it that John just wasn't able to recreate in his shop. I'd loan you my PCM out of my S10, but I'm in Maryland so I wouldn't be much help. If maybe you had somebody local that could loan you a PCM that might help. When I was a radio repair guy in the military and we had a radio act up for no particular reason even after we tested all the components on whatever suspected card or module and they checked out ok, we would replace them with known good units just for ***** and grins. 99.99% of the time that magically solved the problem even though our test sets said the suspected unit was AOK. Another thought, check your PCM connectors and ensure no wires have been pushed out of the C1 and C2 connectors on the PCM. This isn't likely, but I'd look because it might be causing an intermediate connection or something of the like.

kossuth

iTrader: (12)

Also wanted to add. If you have spark then your cam and crank position sensors are good. No sense in even thinking about replacing them. The PCM uses those signals to trigger both the coil packs and the injectors.

Thumper33

Well, I have new information. I got the temporary loaner computer from speartech today... thanks John.

At first when I started the engie after changing the computer it ran like a champ. I let it idle for about 30 seconds just waiting for it to die. It never did, so I turned it off and figured I'd just double check the fluids before I let it go much longer than that.

I checked everything and tried it again and the 2nd time I started it up it immediately goes back to it's old habbits. about 1 second of run time and it cuts the injectors.

So I haven't had a chance to hook the new computer up to the scanner yet, but I'll do that later tonight and see if I can get a code from it. We'll see.

ghettocruiser

iTrader: (17)

Ok I have an idea... Here's what you do.

Put some water in the sink... Hold a cross over it and say a few prayers. Then...go light some candles in the garage, and while chanting praise to the LS1 gods, sprinkle the water all over the car and engine. The idea is to try to purge the "fix or repair daily" demons from the entire vehicle.

Haha.. ok. Sorry...

Thats really weird man. Almost sounds like an intermittent circuit failure in the main harness. And when you swapped the PCM it connected just right to work. Then after shutting it down and trying again the connection was broken again. This is definetly a goofy issue...

Justin

mullenh

iTrader: (1)

thumper the computer has a start cycle, it fires all of the injectors twice during the start cycle. Then relies on the cam sensor to tell them when to fire the injectors. It will not fire again unless the sensor tell them too. so you either have a cam sensor problem or your wirining is screwed,those are the most likely suspects for your problem. what did you do for a harness?
again i asked the guy who helped me install mine, a shop mechanic

Thumper33

it's a speartech harness, so I doubt that's the issue. Shouldn't the cam shaft position sensor throw a code if it's bad?

Okay, I'm out of other ideas. Can somone tell me how hard it is to replace the camshaft position sensor? I think my next step is to just replace that darn thing.

Thumper33

Hey Guys,

I just got back from a week's vacation and I'm ready to pound on it some more...

The one thing I've thought of is that maybe the accelerator pedal isn't functioning correctly. I heard somewhere that there are several resistor banks in there and if any of them read off then it will shut the engine down to make sure that it doesn't get into a WOT condition. Can anyone tell me what happens to your engine when you simply unplug the throttle pedal and try to start it? Also, perhaps a way to test the pedal.

I thought I saw somewhere online that I could download the factory LS1 repair manual. Anyone remember where that was? I thought I'd start checking some sensors and anything I can with an ohm meter.

Thanks!

Indyjc

iTrader: (1)

Can't help, but man I hope you get this thing going. Good Luck

RV6Flyer

Question: My throttle works fine when ign is first on. Engine runs for a few minutes....rough idle sometimes (Ls1, 226/226/114 cam, ported heads).

After a few minutes the throttle (pedal) stops working.....no blade movement.

Codes are 101 (MAF sensor performance).

I've used two MAF's, so I don't think its broken...wires are OK, too (speartech harness)

What are your thoughts....what is going on?

Jon the Newbie

Thumper33

I did eventually get mine working, but I actually have no idea how I fixed it. I left it alone for a week and now it works great.

I have no idea what to tell you. Could be a computer problem, or could be a bad resistor in the pedal or something too.

s10-den

thumper,you got to have a better answer than that?c'mon....lol,at least it is running,but I would sure like to know what was going on just for future issues(if it was my car).In case you get out somewhere and the thing starts acting up.

rohrt

I don't don't even own a LS1 and I want to know what it was too

Thumper33

Ya, I don't know... I wish I knew what it was too, but if I don't know how the problem got fixed, then I don't know what else to do.

Here is what I did.

I got the new computer from speartech, and plugged it in, it ran for 2 mins... I thought the problem was fixed. I checked fluids and started it back up. Same old problem. Ran for 3 cycles and turned off. Tried again and again, nothing different.

I had a week long trip I was leaving on in the morning. I just left everything plugged in and it sat there for about 10 days w/o me doing anything. Eventually I thought I'd try it again to see if anything was different. I had noticed before that after I let it sit for a little while, it would run longer sometimes, so I thought I"d try it.

It ran fine, and never has had the problem since. I now have about 1000 miles on it and it still runs great.

All I can figure is that whatever issue it was it needed time to burp itself or something and when I'd try to start it, it would reset it. Makes no sense.

But that's my story, and at least it's running now.

Indyjc

iTrader: (1)

I only hope mine will fix its self when the time comes. Have fun.