I really need help here. I'm not real tech savy on these and am facing a deadline to have this ready. I'd hate to hand it to GM to troubleshoot, but if I need to Monday/Tuesday I will.

The donor is an 08 Sierra 5.3/4L60E and I had Speartech rework the OEM harness to make it standalone w/emissions and gauges brought out.

The motor cranks, I have fuel pressure, but no spark. When cranking it for periods of time, I do not smell fuel, so I don't believe the injectors are firing either. There really is no change in the way it cranks with power to the PCM or not, so it really seems like it is making absolutely no effort in starting.

At this time, I do not have the emissions stuff hooked up - canister vent valve, fuel tank pressure sensor, fuel level gauge, etc. I do not have the rear o2 sensors, but they have not been deleted from the tune.


Any thoughts? I've gone over everything and it appears that everything is plugged in - knock sensors, crank/cam sensors, etc. What should I look for? Tune or hardware...

Thanks!!

 

Got a DVM? Start checking for 12v at injectors, coils, etc.. Make sure grounds are all properly connected too.

 

1) Make sure the pink ignition wire stays hot while cranking. It's a common mistake to hook the ignition wire up to an ignition line that is hot with the key on, but dead while cranking. Use a meter or test light to confirm that it stays hot while cranking.

2) Make sure the crank sensor is plugged into the sensor behind starter. We had one the other day that had the crank sensor connector plugged into the OIL PAN sensor. It's hard to troubleshoot over the phone when the guy swears that everything is plugged in where it belongs. It's easy to miss the actual crank sensor since it is partially hidden by the starter.

3) Make sure the injectors aren't stuck. This is fairly common on engines that have sat around for awhile before the swap takes place. The fuel evaporates from the lines and injectors, and the varnish left behind dries up like glue down in the injectors. You can take a ground wire and 12 volt wire directly to the injector and see if it clicks.

4) When the computer hasn't been programmed here, that can be suspect too. The new ECM's are a little different than the older stuff and yours is an 08.

The thing in your favor is that EVERY harness done at Speartech Fuel Injection runs on an engine here with a Tech-2 monitoring all of the running parameters, before being shipped. Since your harness worked perfect here, it should do the same for you.

I think one of the above steps should pinpoint your problem.

 

Good point on the grounds. The truck harnesses have multiple ground lugs at different locations. Make sure you got 'em all bolted down.

Also check the fuses in our fuse block and make sure they are all good.

 

BTW, who flashed your PCM? I noticed on HPt forum that you posted an 02 Sierra file. Is that what is flashed in? What year PCM is it?

Here's the OS screen snapshot of the file you posted there:

 

edit: nevermind.. def not an '02 file, just looked at the file size again. Must be a newer style ecm file.

as posted above, the vats are enabled, but it should still do something.. now the "starter checks: enabled" I'm not sure about. Perhaps that's something that should be looked into more.. along with what John suggested of course.

 

If that's the file from the ECM, that's the problem. VATS is still on bigtime there. They will not run that way.

 

John, I've never had to deal with vats myself since I always delete it first with my conversion projects, but won't it at least start and then die?

Either way, I agree, needs to be disabled. He needs the latest 'beta' HPtuners software to do it though. The HPtuners version he's using right now doesn't show him the VATS options for that particular OS since it's so new.. It does show up using my software though, as posted above in the snapshot.

 

My bet is its the coil ground that bolts to the driver side just above the oil pan middle of the block. On a stock truck it would be a 10"-12" or so ground sticking out of the larger loom that goes under the front of the motor just behind the crank pulley. Forgot to bolt that ground once and it did the same thing cranked all day and no spark found i had missed it bolted it up and the truck fried right up. Spent 3 days trying to figure it out checking the tune, VATS, crank sensor and who knows what else.

 

Wow! Thanks for the help guys!!!!!

Nobody has programmed the ECM yet. Speartech did by mistake, but I assume they put it back to stock before shipping - I purchased HPTuners to do it myself and they thought I wanted them to do it because I sent in the PCM with the harness, when I only included everything so they would have it all.

My 2.22 version of HPTuners doesn't show any of those settings under the OS>General tab. I've emailed support to see about getting the later 2.23 beta version.

That's great that it's been run already! Did you run it with my ECM/TCM/DBW Pedal, or a shop setup? That really leaves out question that the harness is missing something - unless you have other sensors and etc. But now it opens up question about sensors on my motor being good. I do not have all of the external wiring hooked up yet - tach, speedo, evap vent, fuel tank pressure, etc. In that harness all I have hooked up are the battery, ignition, fuel pump. I'm assuming the other wires won't stop it from starting? The starter solenoid wire isn't hooked to anything on either end right? It is labeled as 'optional'.

CUrrently both hot and ignition wires are at the battery, because I thought what you pointed out might be happening where I had it before.

Checked the fuses and they all 'look' good. I did not ohm them out to be sure.

It's been a little while since I installed the harness, but if I remember right there are two sets of ground wires to bolt up. One at the front of the head on the passenger side and the other down near the oil pan on the drivers side. Think I'm missing some?

I checked the cam and crank sensors, and they are both hooked up. I also checked the knock sensors while I was under there. It doesn't mean they are good, but they are hooked up. Under VCM Scanner the tach does show ~120 RPM's while cranking.

When I got the motor nearly 3 months ago now, there was still fuel in the rail. And I'm pretty sure when I pulled the hose off to hook up my braided line a few weeks ago, that I had gas spillage.

I'll check the few things you guys have mentioned today, but if you think of anything more....

 

I don't know what I'm looking for, even if I saw something. Does GM supply 12 volts to everything and switch the ground to actuate the item? Or do they supply a ground and swith the 12 volts to actuate the item?

 

anyway to get rid of vats completly without a tune?

 

On HPTuners someone mentioned to switch over to Advanced view to see VATS. I did and per 98blackss/John's recommendation, I disabled Vats1, Vats2 and starter check and it fired right up! THANKS GUYS!!!!!!!!!!!!!!!!!!!!!

 

I believe there is a way with wiring, but I don't remember how as I don't have the OEM connecters any more, which is what the directions used.

 

Needs at least a full flash with HPT or EFI on late models to do it. No need to tune, that's optional.

 

Hi Wayne sandking from PBB here too!!
I am working on the same '07 5.3 for my Blazer.
I promise I wont bug you for parts here though
Post pics of your conversion.

 

lol Then I'd never be able to log in over here

Took it out yesterday and beat on it pretty good. Bounced it off the rev limiter (set at 6k rpm) a few times doing some sandy hill climbs Sounds mean! But now I have a stuck exhaust valve in #8. So I've gotta figure that out... It doesn't shift down after hitting 4th gear, either, so gotta tune that. The alternator is making a lot of squeeking noise, gotta fix that. The shift linkage came off the trans once, so I'm not sure if it just wasn't on all the way or if this will be something to fix.