Starting new Tune on new motor install

Discuss General Motors (GMC, Chevy, Pontiac, Hummer, Cadillac, etc) tuning topics here. Request definitions, discuss parameters, etc.

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Byteme
Posts: 3
Joined: Thu Sep 15, 2016 4:52 am

Starting new Tune on new motor install

Post by Byteme »

1994 Camaro Z28 LT1, new Opti, wires, plugs, all sensors, except MAF.

Car has been a pain on second install of a new motor, "first one had lifter chatter on all lifters so the warranty department sent a new one but didn't want to pay full price for install so Mechanic doesn't give a damn how it runs so I having to fix this stuff my self", so I have a few questions for starters.

First the Mechanic ran the car out of gas on test drive of new motor and now it has low fuel pressure, started at 30lbs replaced the fuel filter and got it to 36lbs at idle and 40 with the vacuum line off, it does increase as RPM goes up so I know the regulator is working and they're mostly bullet proof but could it also of gotten contaminated or do you guys think the pump is the issue?

Also at only 36lbs how much is actually being lost and what would the PCM show on a scan while it's trying to compensate for the pressure loss? BLM's are in the 108 range and I have what sounds like real spark knock is this also due to the low pressure?

Next is the car has a shudder from 2000 rpm on up, could this be related to the low fuel pressure or should I look else ware?
Byteme
Posts: 3
Joined: Thu Sep 15, 2016 4:52 am

Post by Byteme »

Though no one has answered this post yet going back to your basic troubleshooting on these motors will fix most of your problems, plus not for getting that Low BML's mean your car thinks your running rich not that it's lean.

108 BLM's mean either your tune is way out your if everything checks out, but did everything check out? 20 i/m is right, right? well if your a dummy like me and don't also take the car to at least 2500 rpm and see if it goes back to norm you fail, yep I fail.

Next problem is when you have a Mechanic who is pissed he's only getting half pay from warranty company, check behind him, THOROUGHLY!!
All 4 center intake bolts not torqued, just snug, "get out old trusty torque wrench, set to 35 lbs work pattern" BAM problem gone!!!

Moral, don't assume anything always check and double check.
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