87SS

Finally after 2 years I was ready to hear this thing purrrr this afternoon, but no dice. I didn't expect it to fire since this is my first LS swap and figured I had something off, but it would have been nice.

Quick summary: 87 Monte SS, 07 LY6/4L80e with Speartech harness, other than tube headers it is stock. Wanted to get stock motor going then start with the mods. Motor cranks but no firing. Have not had computer retuned so I know VATS is an issue, was at least hoping it would kick for a couple of seconds.

Since I replaced a previous SBC setup, my start procedure is a little different. I have a push button to spin starter (good for bumping motor over) and a separate switch for the A1000 fuel pump in the trunk. Since I had this already wired, I decided to keep it that way.

Anywho, I really want to get this started, but also want to learn how to troubleshoot. I have fuel at the rail (truck intake with Aeromotive regulator and return line) and pressure seemed to be a little low when I had the pump on alone (will look into adjustment). Other than that, I have seen using a noid light to test injectors. Since this motor has sat for almost 2 years, there is a good chance injectors could be clogged. Planned on trying the 9volt battery for the click.

What I am looking for is any other tips/webpages that may help detail how to look deeper. For example, what is the best way to test for spark? Disconnect plug wire and see if it arcs while spinning motor? Since I have separate starter and ignition setup, I would need to work both to test.

On top of all this, I have been on the fence of sending the ECM out for a tune, or just picking up HPT. I planned on getting HPT within the next few months, so I may use the tune cost and put it into HPT. I can then knock out the VATS possibility, but will HPT allow me to troubleshoot anything else without it running? Would it show a bad sensor (crank,cam, etc)?

Thanks, just a newb trying to learn something along the way, and get this POS running after sitting for too many years.

FatfreeGTO

Do you have 12v to your ignition relay during cranking?

87SS

Yup..

troy2285

mine would not fire without vats removed. Pull a plug and check for spark. Also check all grounds.

1quickirocz

VATS will deff need to be disabled. Its a no go without that. If the fuel rail and injectors sat for 2 years with any amount of gas in them then the injectors are also most likely clogged. When i put mine together i had clogged injectors from sitting for a few years. I ended up using GM top engine cleaner to free the injectors and now they are good as new.

87SS

Thanks guys.

Tried a couple of injectors tonight with a 9v battery, they clicked when I touched the jumper to them.

Grounds are good. Looks like my best bet is to get the VATS taken care of to eliminate that as the cause. I figured it would have fired for a few seconds at least. Oh well.

LS1MCSS

iTrader: (18)

It would if that was the only problem. VATS won't stop it from starting, just keep it from running more than 2 seconds.

87SS

That is what I was afraid of, couldn't be as easy as shutting off the VATS for me.
I think I am going to order HPT this afternoon and at least eliminate the VATS and start getting familar with the software. Need to do more research to see if the software helps identify bad sensors, injectors, etc.

MaxxMitchell

iTrader: (15)

Make sure any old/bad gas is out of the truck rails as they hold quite a bit. Use the noid light on the injectors to make sure they are getting a signal to pulse. Check for spark as well. You can always pour a couple table spoons of fuel down the intake and crank it again, if it lights off for a second or so then its fuel or vats related.

I have also pulled the rails before with the injectors installed and plugged in and cranked to make sure they are spray an even amount if you think they could be clogged.

87SS

Thanks, need to find a place to get a noid light. I was thinking of sending the injectors out to be cleaned/tested as well in case, believe there is a sponsor here that does them for under $100.

Will try testing for spark tonight.

MaxxMitchell

iTrader: (15)

I rent noid light kits from Oreillys.

bczee

iTrader: (12)

There could be many issue, but Take care of the VATS, that would be a good Start.

Check to make sure your getting voltage to both the Coil and Injector circuits.

Are you getting constant Battery 12v and Ign 12v to the PCM as need and for as long as the key is in the start/run positions ?

check your grounds (can be critical) and connectors are tight and seated.

If you can just use a ODBII Scanner from one of your buddy's or rent one. That should be enough to do some problem isolation. It should show that your getting voltage / singals from all of the senders, MAF, TB, O2, crank and Cam Sensors while your cranking it over or with just Ign on.

I beleive that FICINJECTORS is an sponsor/vendor on this site. from what i read of them and heard from other guys, they do great work and good turn around time. User = FICINJECTOR, http://fuelinjectorconnection.com

Just a few things to check or do.

Good luck, keep us posted or ask your questions.

BC

87SS

Thanks bczee. I completely forgot I had a scanner for my Silverado, will try throwing it on and seeing if there are any codes.

Are there any secrets or explanation on how to test the coils or injector circuit? Again, I am new to all this and while not happy it did not start, am looking forward to learning how to diagnose each of these items so I can help others if necessary.

87SS

Got the following codes:
P0449
P0443
P0452
P0463
P0615 starter relay circuit

Looks like the first group are emissions stuff that needs to be turned off in the ecm, need to look into the last one more. Decided to order HP Tuners, now I can then remove the VATS, rear O2 sensors, emissions and whatever else to help narrow down the issue.

-TheBandit-

iTrader: (1)

Look for buddyholly's thread on his GMC swap. He gave a pretty good run down on what he had to do using hptuners to get his LY6 to fire stand alone.

87SS

Awesome, will do.
Thanks

87SS

Ended up disabling the VATS with HPT and she started. Took a little bit to get her going, still think the injectors need to be cleaned. Buddy coming over shortly so we can check fuel pressure, was around 40 when car wasn't started but pump was on which seems low.

cam

iTrader: (9)

Its normal for them to run a little gnarly for the first run or so but glad to hear you got it fired. Im almost there myself on my L92 swap... very close now

87SS

Thanks.

Just messed with the fuel pressure, running at 50psi during idle. Will try getting it up a little, need to run out for more gas

Good oil pressure, 40-50 psi at idle. Heard a little funny squeal, need to see if it is just the belt or something from the motor. Will try to get video later.

After sitting for many years, I have a grin from ear to ear after hearing it start. Long time coming.

FatfreeGTO

That's great good job! Does it seem like HP tuners will be easy to use?