No start issue after rebuild.

I've got a 2002 5.3L engine from a flex fuel Suburban that I put in a '69 c10. I had the engine rebuilt with a BTR stage 2 truck cam. 4L60E trans rebuilt with HD internals and Circle D 2800 stall converter. Attachment 96635 Attachment 96636 Got it all installed and it won't start. I've put a noid light on all injector plugs and get light. Spark tester gets spark on all coils. Fuel pressure is adequate. Vats turned off. Put a new factory replacement intake manifold on. It came complete with new throttle body, injectors and all sensors. The only two sensors on the engine that I haven't replaced are the cam and crank, as the engine ran before I took it out. Only has two O2 sensors, intake uses the truck MAF/IAT sensor, has the flex fuel 33lb injectors with the return style fuel rail. I'm just trying to get it started so I can get it to the dyno tuner. I've attached the tune and scan log while cranking. Any help is greatly appreciated.

Is it backfiring in the exhaust at all? I had to take a ton of fuel out of my cranking ve as well as took out some of the mutiplier for the cranking fuel tab. you need to scale your injectors probably. the tune you have shows 30lbs not the 33lbs. I also added 2 degrees of timing to my entire cranking timing table and that helped a bunch. I have a 6.0 with the BTR truck stage 2 as well. Disclaimer on this is I am very green when it comes to all this, its just what worked for me.

Just a little sputter, not even close to starting.
I'm seeing 33lb on the tune and on the scan log. Where are you seeing 30?

my mistake, I have mine set to 30 instead of 33 since I only have 50psi at the rail. I was looking at my file for a compare. holding the throttle at 100 percent shuts off the injector (flood clear) after cranking for a second you might try and hold the petal to the floor and see if it fires off, mine was getting flooded. I guess you could turn off the injectors in the scanner and spray some starting fluid in it to see if it fires, that would at least narrow down if its a fuel issue or a spark issue.

Tried all of that. Didn't do anything. Injector shut off is at 80% tps on the tune.

Maybe someone else has a better idea, any chance you got the cam and crank off time when you swapped it out?

I had the engine rebuilt by a reputable builder. Not to say it can't happen, but probably very unlikely.

Does it sound like it is making compression? Have you tested compression? Only other base engine item that you didn't mention testing was leakdown. If all was good for fuel, air, and fire, then it should light off. Fuel quality was not mentioned, but fuel pressure was. Maybe bump the base idle up to 800 or so given the cam. If base engine is indeed good, next step would be PCM. If you posted a tune, guessing you can read it. Any codes? Did you rig up a CEL? Would be kinda cool.

It does sound like it's making compression. I have not tested leakdown. Fuel is prob 3 months old. Had idle set around 900 without any difference. Replaced pcm already. Even put a pcm that had an sd tune on it and got the same thing...nothing. Plugs are wet when removed, noid light signaled on all injector plugs. Spark plug tester shows spark on all plugs. No codes with hp tuners or a hand held obd2 code reader. It does have a cel light rigged up to the instrument cluster. I'm going to replace crank sensor, retrace all coil and injector wires from the connectors to the pcm plugs and rework the grounds and see if it makes any difference.

ok, was watching your log, only cranking around 100 rpm. I may be wrong, but that is too low. if you have spark, you most likely have a working crank sensor. RPM showing up on log indicates working crank sensor. Start with testing, costs nothing if you have the tools. Battery connections, cables good, grounds good, starter is good. battery itself is good.

Just did a cranking test on my truck, cranked at 150rpm. Is a 5.3, battery is 6 months old no mods. Would definately start with battery, cables, grounds as stated before. Also a detail I noticed, your vin says from a silverado with a T vin engine, meaning not a flex fuel. That may not matter. Was the vehicle running with this engine/trans/ecm combo before? May also want to disconnect the MAF.

Pcm is from a silverado. It's been retuned with the flex fuel injectors. No other parts of the flex fuel system are used. Vehicle was running with the same trans, but a different pcm with an sd tune. I've put that pcm on it and same result. Engine had 225K miles on it and smoked. Engine wasn't just freshened up with new gaskets, it was cnc honed, new rings, new cam bearings and btr cam, head job with new valves/springs. Battery is less than a year old. I'm cranking with a charger attached, I've noticed the rpm is low, but the voltage stays high. I've read the crank sensor can send rpm signals and still be bad. It has to run to actually throw a crank sensor code. I've had several people say it sounds like a timing issue, which is why I'm considering changing the crank sensor. I've tried to crank without the maf connected, but it has the all in one maf/iat sensor. With the MAF disconnected the iat reads -40F. It has sputtered a little and an occasional backfire through the intake.

In my dealership daze, for a cranks-no-start I would always want to see it run before seriously diagnosing anything. In the situation you've described - has spark, has injector pulse, plugs wet - what I would do is disable the fuel pump, bleed off any pressure, and try to make it run on carb/brake cleaner. If you do that and it runs, you have just proved you have a fueling issue. If you then re-enable the pump, spray it again, and it won't run, you just proved it's getting too much fuel. Once you know what's causing it to not run you can then diddle the tune accordingly.

I did unplug all injectors so they wouldn't fire and squirted starting fluid into the intake. It sputtered a little. I actually did it twice. Since it has fresh rings on the pistons, I'm hesitant to do it too much plus I really don't want the first start to rev up to several thousand rpms. I was hoping one of you advanced tuning guys would see something in the tune or the scan log that looks wrong.

So, I missed the wet plug comment in your reply. With the sputters and backfires plus wet plugs, I would pull all plugs and run compression, key off using a remote starter switch of some sort. Cranking with the key will just wash down the cylinders even more than they have been already. Of course unplugging all injectors and cranking with key would be just as good, just unplug the coils too. Knowing you have good compression takes that off the list. This could just be overfueling or bad fuel timing due to the new cam, but need to rule out the basics too.


The low cranking RPM does still bother me, but I may be barking up the wrong tree with that.

I would remove some fuel from it. Your injector pulse is way up there. When it is warm your injector pulse will probably be like 3 ms and when it is cold like 7ish.

Check the flat braided ground strap from firewall to engine block behind driver side cylinder head.
I forgot to bolt it back on when I rebuilt my tranny.
Same no start problem
Check your wiring harness ground too. The little black wire at the back of the passenger side cylinder head.