She won't fire up. Please help me! I"m at a complete loss!

[jorgensensc]

I'm really at a loss guys. I could sure use your help.I got the l92 /6l80e installed in the burb a couple of weeks ago. I was very careful wiring everything up so that I would be able to fire the bad boy up the first try. Guess what, no go. The engine cranks nice and strong. The fuel pump primes, then runs while cranking. everything seemed ready for the tune. The tuner came over last night and couldn't get HPtuners to see the ECM. There were no High Bus signals. There was power and the grounds, but nothing else. So after jacking with it awhile he left. I stayed up till 1 am and figured out that the computer is sending the can bus signals to the transmission first, then the transmission sends the signal out to the Data Link Connector. The signal is not making it past the tranny for some reason. the signal gets to the tranny, I verified that. And the wires from the tranny to the DLC are good, I verified that. The tranny just won't pass the signal on. There is power everywhere on the tranny connector that there should be. So I read somewhere that if you get the ECM bench tuned, it will wake the tranny up and fix the problem. So I went and had it tuned by the guy that came to my house last night. Got it back home, hooked up, and no joy. cranks, but won't start.

So here I am, confused, and really frustrated. If the internal tranny TCM is malfunctioning, or not waking up in the correct order, would it cause the engine to not start?
Where else can I look?
I don't have a scanner. Should I get one? Will it really help? A couple of tuner guys said it probably won't help.
I'm looking for any solutions or ideas guys. This is my daily driver, and I need to get it up ASAP. I've been driving the '56 Bel Air for the last 2 weeks and it just broke the exhaust manifold yesterday. So now we are down to just one vehicle that runs.
Thank you guys for all of your help.
Shawn

[truckdude239]

Unplug the tranny and see what happens
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[Hart_Rod]

I have no answers Shawn but am interested in the solution. I would recommend you call John at Speartech or Mark at street and performance. Both are usually around on Saturday and will answer questions even if it isn't their harness. good luck.
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[Hart_Rod]

http://www.pro-touring.com/showthrea...-LY6-6L90-Swap

[jorgensensc]

Thanks for the responses guys.
Truckdude,
I unplugged the tranny, still cranks, but won't start.
Hart_Rod,
Thanks for that link. I had read one of the threads, but not the other one.

Does any one know if the l92 will start without the tranny looked up? Seems like it should in my mind.
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[68GMCCustom]

I can't answer that for you....but my having a Aeroforce Interceptor scan gauge and a copy of HPTuners helped me supply info/scans to my tuner to help correct things. I can't imagine now not having tools to see whats going on with my system.

I just wish he could fix my vibration!

[BR3W CITY]

Originally Posted by jorgensensc

Thanks for the responses guys.
Truckdude,
I unplugged the tranny, still cranks, but won't start.
Hart_Rod,
Thanks for that link. I had read one of the threads, but not the other one.

Does any one know if the l92 will start without the tranny looked up? Seems like it should in my mind.
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I"ve seen one in a boat, so I imagine they are able to run without a conventional trans attached. I don't know much about boats but I don't think they have vss sensors or anything for the computer to reference.

[D.FENS]

Have yet to do an LS swap, but I'm a veteran of many late model engine swaps into older vehicles.

If you're doing an OBD2 swap of any kind you NEED a code scanner or a laptop with some means of reading fault codes, and wonder why a tuner would tell you otherwise.
I can't imagine tackling a swap flying blind.

Does your software guy have a known-good PCM to make sure the problem isn't your PCM (or his flash program)?

[jorgensensc]

d.fens,
He tunes corvettes all day at the shop. it is a very well known and reputable shop from what I understand. RPM Motors out of santa clarita, ca.
So I'm looking at the innova 3130c. Is this a good tool to use? Overkill? Barely good enough? will work fine?

[rob32472]

I had similar problems with mine..... went back to the basics.... AIR, FUEL, And FIRE. I was not getting injector pulse..... A blown fuse due to a wiring issue was what I found.... You can check alot without a scanner or computer.....

[chebyshortbox65]

Done a few harnesses wire your datalink strait to the ecm the trans is suppose to tie in at the body controller or some have there own seprate wires from ecm to tcm im building a 6.2 erod crate engine and putting in a 6l80 and yes it will run without the trans hooked up
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[jorgensensc]

Ok guys, I bought a scanner and this is what I found (innova 3130c):
Found the APP pedal was wrong. Had to switch two wires on the connector (evidently PSI had it wired for the camaro not the Escalade pedal). That fixed that code. I have run and rerun, disconnected the battery and tried to start. No joy. I have no codes. (except a low voltage ac refrigerant sensor which I am not using).
So I ran the live scan stuff. This is the only thing odd that I can find. The Fuel Pressure PSI shows 0. Even though I know I have pressure at the rails. I even relieved all the pressure, cranked, and checked again. Good pressure. I went out and rented a fuel pressure gauge,got it home, only to find out it is missing a part to connect to the fuel rail, so I can't verify exact pressure, but I know the fuel pump is working in both run and start.
The only other odd thing is the ecm thinks I'm going 158mph. I've read that is a problem that others have run into, but shouldn't affect starting at all.
The Throttle opens and closes with the pedal action, the live data verifies this.
I rented a noid light, but have no injection action. The fuses for the injectors are good and getting power. I verified that also.
I show rpm's while cranking also.

So if the ECM doesn't think it has fuel pressure will it not start? How am I supposed to convince it that it has pressure?
Any other ideas? Thanks for the help everyone!
Shawn

[Hart_Rod]

Can u tell if the injectors are firing? Do u know if you have spark? Have you pulled the plugs to see if they are wet?
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[Hart_Rod]

http://www.ecmtogo.com/ECMTips2.htm
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[jorgensensc]

Hart,
The noid light I rented for the injectors is not coming on when I crank. So I don't think the injectors are firing. I didn't check the coils or the spark plugs yet. Will do that next.
Here's a dumb question. What is acceptable voltage drop to the ECM while cranking? The scanner shows 11.89 volts before cranking. Then drops to 9.75 while cranking. That is even jumpered to another car to verify I hadn't killed the battery. Goes over 12 volts, but then drops below 10 during cranking. Have read a couple of places that voltage drop to ECM can cause no start? Is this too large of a voltage drop?
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[Hart_Rod]

I think it should stay around 12v. You still need to verify fuel pressure at the rail to eliminate that as problem. Is the transmission in park? Are you getting any oil pressure reading? Just tossing stuff out there for you to check. Check this out:

http://www.painlesswiring.com/faq.ph...el%20Injection
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[Hart_Rod]

Can you hook the wire up to a source that will give it a constant 12v?
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[BR3W CITY]

I had a very interesting failure a few days ago that may or may not help.

When testing my hydroboost brakes, I put the pedal down hard and came to a very abrupt stop, causing the rpm's to drop rapidly but leaving load on the engine. This causes a bog and the engine stumbled; but here's what I'm getting at.

If at any time you have a severe low power scenario (misfire caused by non-spark issues, but retaining fuel pressure and oil pressure i.e. no catastrophic failure), it can handicap the engine. Its not really the regular "limp mode", because it CAN take away TAC/pedal function, but it does not always, instead it seems to act like it just pulls fuel. Its a really really really strange scenario, but the hit and miss way it acted and affected multiple systems, kinda makes me wonder if there is anything like that at work.

It threw three unrelated engine codes, basically stating a "low power pedal scenario", although I can't remember them. I cleared thge codes, unplugged all the pedal/tac plugs, discon the battery, then re-warmed the truck up not touching the pedal for a minute or two. Basically gave the system a reset and re-sync the pedal and worked out just fine. Just figured I'd throw it in for thought.


If you hard ground the ECM case to the body, does it change anything?

[jorgensensc]

Thanks guys. After I get the little people down for bed I will check out the case grounding and supplying full 12 volts. To ECM.

How does the ECM determine fuel pressure? Does it need to see fuel pressure from a switch in order to give the ok to run? Does it tyty and run regardless of fuel pressure?
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[68GMCCustom]

I had some starting issues with mine, some related to harness issues because of differences between '07 and '09 wiring.

Have you tried spraying some fuel or something flammable down the throttle body and spinning it over to see if it fires off/coughs/etc.?

[jorgensensc]

Ok guys. Here is the latest. I've got no spark, no injector pulse. I grounded the case of the ECM. I gave it full 12v power. Still no luck. All fuses are good. For the injectors. For some reason the computer does not want to fire the coils or injectors? I'm baffled.
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[truckdude239]

Do you have the vats removed????
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[jorgensensc]

Supposed to be. I took the computer to the tuner and he did a bench tune on it. Said he removed the VATS.

[jorgensensc]

SUCCESS!!!! Well, partially anyway. She runs! Doesn't drive yet, but runs. I called the tuner up this morning after double checking that the injectors and coils were getting power. Asked him to look at the tune again to verify VATS was off. He insisted it was off, but said he would look again. Called me back 20 minutes later and said it was his mistake. He turned it off but didn't rewrite all. So, another 45 min drive one way, got the computer tuned again and I got home. Put the computer in and she fired up and died. Couldn't get her to stay running. Then finally she caught and ran for awhile till I turned her off. I was getting a MAF code. Everytime I would clear it the engine would die. Then I would try and start it 10 times or so before it would fire up again. Finally went and checked the MAF connector. PSI had it wired incorrectly. I repinned it correctly cleared the codes, and she fired right up no problem! Also had to repin the oil pressure sensor too. I'm very irritated with PSI right now, but I won't get into all the things I had to redo on this harness in this thread.

Now on to the next major problem!! It won't shift into gear. I think I know what the problem is but am not sure how exactly the best way to fix it is. I thought I bought an08 escalade pull out. Come to find out the engine and computer were an 08 escalade, but the tranny was from an '11 silverado. Didn't think it would be a problem, but evidently it is. Apparently the '08 ECM won't talk to the '11 TCM in the tranny. From what I understand I need to get an '11 ECM and have it programmed for the '08 engine and the '11 tranny. Then supposedly it will shift. Started figuing their might be an issue with the engine/tranny mismatch when the tranny wouldn't pass the can bus signal along and I was getting 158mph speed on the scan tool. John at speartech agreed that I need to get a '11 ECM and that will fix it. Unless any key has any other great solutions ?
Anyone have a tranny connector pin out for the '11 tranny so I can see if I can maybe make the tranny go into limp mode and drive to the exhaust shop?
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[rob32472]

Glad you got it running.... feels good to hear them run!