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8.1/LS swap no start issues, help needed

I spoke with Alex last night. I feel he is on to something with the potential issue you are chasing a resolution on related to the CMP. Anxious to see how that works out

IMO if anyone is going to figure out a device or wiring issue it's Alex. Dude is just wicked smart like that and he's kind of like a dog with a bone on these types of things. He can help get this sorted out and operational. When it comes to "tuning" he can help a great deal but I know he isn't the most comfortable with it and isn't going to try to say he "tuned" it.

As far a tuners go, it's my experience that any tune beyond a super basic stand alone tune to get it fired up and running can have some issues. If you want a "performance" tune that has no issues you need to spend time on a Dyno with your tuner of choice. Then understand that you may need to do some actual Data logging and work with the tuner for some period of time to get it spot on. When we did the race car tune the guy did the basics to get it close then started dyno pulls, part way through we were amazed at some of the numbers he was getting, but when we asked if that was really where we were headed his reply was sort of, that's kind of a Dyno queen tune. It's somewhat driveable and would live for short duration Dyno pulls but isn't all that good. Once we started making sure it would handle being 200+ degrees, eating crappy 100+ degree air at full throttle for long periods of time we lost some HP but gained safety.

As far as the bashing of other tuners I wholeheartedly agree with Larry, each one bashes the next. I deal with that in Construction all the time, every general contractor bashes the next's work it's just the way it is, it might not be right but that is what happens.

What I hate and I'm laying it out there right now; Is the vendors, suppliers, etc. who flat out bash their competition (specifically saying names and things like they really have their heads up their asses) like has been done in this thread and numerous others. That really rubs me the wrong way and I will not use nor recommend anyone who does that no matter how good they are perceived to be. You can keep that to your private interactions with your customers.

If you want to help, state that you think you can help them and you have some ideas about what is wrong and if they would like to speak with you they can call, text, PM etc. When your advertising product it's acceptable to me to say your better than the competition because you don't simply turn off this that and the other thing you build a tune that doesn't look at those things, or excludes them etc. But you don't have to say Howell sucks and has their heads up their asses. Clearly they can't suck as bad as you think because they have been around for 20+ years and seems to be doing ok. I can fully understand that they leave something on the table so they limit liability issues.
 
Fwiw I data logged with Josh and it took about two weeks of files and tunes where we stripped the tune all the way down and built it back up with logged files. Rebuilt the volumetric efficiency tables and MAF and spark.

I did a video over on my channel.

Josh went out of his to help me out. I kept throwing a knock sensor code and could not trace it. At KOH he took an hour to help n troubleshoot and traced it down to a bad MAF signal (even though it wasn't throwing a code)

I will echo the refrain that there is soooo much that goes into a tune beyond changing some air fuel and timing etc. Thing is people don't want to pay for it as there are tons of cheap options out there


Sorry for the hijack
 
I spoke with Alex last night. I feel he is on to something with the potential issue you are chasing a resolution on related to the CMP. Anxious to see how that works out

Alex tried to call me last night (probably after he talked to you on the phone) but I was tied up at dinner at my in-laws house and we didn't connect. Hopefully tonight we can talk more.

Even though the guy who I bought my motor from (who I still keep in contact with) said this is a 2002 motor, from what Alex and I were looking at with a little camera and looking at the timing gear, we were pretty convinced it's actually a 2001. The stock cam sensor I pulled out of it has a 2001 part number on it. I talked with the guy who sold me the motor again, and he said it was his dad's truck he bought brand new in October of 2001, though the VIN# of the truck was a 2002 truck. I've heard of GM doing this before so that doesn't surprise me too much. I was lucky to find a replacement 2001 cam sensor (as you know Larry is a kinda difficult to find on a 2001...later on I might swap everything over to a 2004+ to be done with it...we will see). I don't know/think that will solve my issue, but it's nice to know I have an extra one just in case. Hopefully I can talk to Alex some more tonight and hear what you guys talked about with regards to my weird situation...

IMO if anyone is going to figure out a device or wiring issue it's Alex. Dude is just wicked smart like that and he's kind of like a dog with a bone on these types of things. He can help get this sorted out and operational. When it comes to "tuning" he can help a great deal but I know he isn't the most comfortable with it and isn't going to try to say he "tuned" it.

I'm not going to lie, after a couple hours of messing with my motor and trying every different combination of things to try and get it fired up, it was at least re-assuring to me that Alex looked a little stumped on this one as well....even though I wanted it to start, it at least made me feel like I wasn't going crazy that someone else who is WAY better at electrical than me was stumped too. I'm hoping we all can figure this out soon....I want to drive this truck so badly it's not even funny, haha
 
I feel you on the "not alone" part about being stumped. There are enough smart heads involved in this, you'll get it figured out. I want to see this thing outside of that dang garage!
 
So I got internet while flying over the pond and this is really sad. All I see is settling for good enough. I really see a huge lack of tuning knowledge that is causing very biased decisions and answers. Being led by an ocular impaired leader with high google fu makes showing, describing, educating on the matter relatively pointless. There is no point in even forming any type of rebuttal to closed ears. I could go into deep detail on ecm processing and proper setup but why should I share or help when its going to go no where.

In other words, peace out, good luck.... Just think for yourself and not with the herd. Please, jab away. Anyone that knows me can attest it means zero as I am confident in my ability and very comfortable with my clientele. Arrogantly interpret as you will. Hell, smile and call it a victory if it gets your rocks off.
 
http://lt1swap.com/8100_harness.htm
If I were in your position,
A-ECM should not be the issue due to same issue with another one.
B-Coils are also not the issue due to same issue with other coils.
C-Power and grounds sound like they have been eliminated also in testing.
D-Doesn't sound like a tuning issue due to same prob with both ecms unless the first one hasn't been set up correctly and also the second one too.
I would either check the wiring harness pinouts according to OEM wiring schematic and make sure the correct pin at ecm goes to correct pin at sensors and coils and also load test each one. (this will take time and be kinda sucky for someone who doesn't do this stuff on a regular basis) or pull the harness and send back to Howell and make them figure it out since it sounds like an issue on there stuff. Again, I wish I were closer cuz I would love to help. I love electrical crap like this and getting it figured out.
 
Little update...tried one more stupid trick that Howell told me to do...I hooked the 12v switched wire to a completely separate battery and confirmed that I had exactly 12v on that wire while cranking...and still freaking nothing.

So I pulled the harness out of the truck and boxed up both harness and computer and shipped it back to Howell this morning. I called them and said to be looking for a box full of my stuff and they are going to double and triple check everything in the harness and computer to see what's up. At this point....I CANNOT think of anything else it can be. I have tried everything about six times with no luck....my best guess is there's a short in the harness somewhere that is causing all the coils but one not to fire.

So hopefully in a couple weeks after they get my shipment and start doing some test we can figure something out
 
sounds like when my and my buddys swap an ls into a 94 chevy truck they built the wrong harness to the computer. took three phone calls and had to call back raccoons broke in and ate all the pencils.
 
FiTech? That'd be cool, FiTech on an 8.1L swap....
 
sounds like when my and my buddys swap an ls into a 94 chevy truck they built the wrong harness to the computer. took three phone calls and had to call back raccoons broke in and ate all the pencils.
What did I just read?
 
hahaha, should have heard his accent had to get him to repeat alot,they were out of Arkansas
 
If howell fails to find the issue, have them ship the harness and PCM to me and I'll look it over. I've seen some shoddy work from them over the years...

I may take you up on that depending on what they say!!
 
FiTech? That'd be cool, FiTech on an 8.1L swap....

That may be difficult to accomplish as the throttle body position is on the front of the intake angled forward...pretty sure FiTech doesn't make something to adapt to that. Either way, once we figure out what the heck is going on with this, it's going to freaking fire up
 
I send you a harness to tinker with Russell but you might hate me afterwards lol. 98 LS 5.7 it's for my Chevelle project that got side track so no rush.
 
That may be difficult to accomplish as the throttle body position is on the front of the intake angled forward...pretty sure FiTech doesn't make something to adapt to that. Either way, once we figure out what the heck is going on with this, it's going to freaking fire up

I know it's just bench racing, but the only way you'll get a fitech unit running on an 8.1 is by ditching the stock intake. Somebody makes a carb intake for an 8.1 you could use with the fitech throttle body.

I think going to a throttle body based system as nice as those look is a step backwards to a multipoint setup. I bet they find something stupid. It will get fixed and you can move forward.
 
I know it's just bench racing, but the only way you'll get a fitech unit running on an 8.1 is by ditching the stock intake. Somebody makes a carb intake for an 8.1 you could use with the fitech throttle body.

I think going to a throttle body based system as nice as those look is a step backwards to a multipoint setup. I bet they find something stupid. It will get fixed and you can move forward.

That's the hope...I don't have any intention of running anything else but the stock injection setup. It works good and that's what I want for this truck. I would not be surprised if they find something small and stupid when they start diving into the harness
 
I was just trying to see if I could hijack Steve's thread with a FiTech discussion just like I did Mark's. :whistle:

Figured Steve needed a distraction from the frustration. LOL!
 
I wondered why there was so much fitech talk going on. Now I get it. Nice touch.
 

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