engine starts but wont hold idle or rev without dying

[98tadriver]

I put a 2001 LS1 in my 99 Z28 recently, everything seems to be hooked up properly, the fuses are all good as well. but heres the problem

it threw one code, a P0103 Mass air flow, high input voltage or something like that

the car still runs rough when i unplug the MAF and it will throw a P0102 code

it threw the maf code and then i put my t/a's maf on it, and it still threw the p0102 code.

for you tuning guys, the fuel trims arent even registering on hp tuners when i scan it and look at the gauges on the laptop

EDIT- also, im using the original 99pcm and wiring harness with the 01 LS1. i was told the pcm will work with 99-02 LS1s

itll crank over and start but then it barely holds a 400rpm idle. when i go to give it gas, it just bogs and eventually dies unless i tap the gas a lil. it wont hold rpm below 3000-3500rpm and it seems to be really rough but it seemed to hold 4500 RPM or higher somewhat smoothly

dont know if this means anything, but the floor seemed to get unusually hot where the cats were. hot enough to the point where it smelled like the sound deadening was almost getting cooked a lil. even when my t/a had a full interior and cats, it never did that!


i changed the fuel filter, and its getting 55-60psi when cranking so thats good.

spark plugs are NGK TR5's gapped at .040 (recommended on the box)

[GrandmasterCow]

what wiring harness or pcm u using? if its not the same pcm that came with the engine, did u relearn the pcm for the crank sensor?

[Formulalt1]

You are running very lean, thats why your exhaust is getting so hot. You have clogged injectors (or something else going on with your fuel delivery)or something is causing your car to lean out the fuel mixture to a extremely low rate by the sound of it.

Edit- Sorry skim read it the first time,thats it. Your MAF is telling your pcm that you have hardly any air coming in and your computer is barely pulsing the injectors.

Ok to go more indepth. The MAF uses the cooling effect of the passing air to tell how much air is passing (being sucked in). If the Wires stay too hot (voltage stays constant) the PCM assumes that there is little or no air passing and then leans out the injectors to make up for little to no air passing.

[98tadriver]

thanks for the fast response guys. I used the stock Maf that came with the car, then after it threw the code, i used the one from my trans am (which never gave me any problems) and it still did the same thing. i also used the tb from the trans am as well, ill note that in the op. i was told a 99 pcm will work with 99-02 LS1s, the only difference being that the 01-02s can pull a few degrees more of timing

[Formulalt1]

You have to reset the PCM when it sets a code. If it set the code for the MAF then you fix the problem it will still show that code in its memory. You need to clear all codes, swap the MAF from the other car then start it up and see if the code comes back, if it does come back but its the opposite code of your original , that is pretty weird but you might have a wiring issue to the MAF from the PCM.

[98tadriver]

Originally Posted by GrandmasterCow

what wiring harness or pcm u using? if its not the same pcm that came with the engine, did u relearn the pcm for the crank sensor?

how do i relearn it? i also have the original 01 pcm that came with the motor

[98tadriver]

Originally Posted by Formulalt1

You have to reset the PCM when it sets a code. If it set the code for the MAF then you fix the problem it will still show that code in its memory. You need to clear all codes, swap the MAF from the other car then start it up and see if the code comes back, if it does come back but its the opposite code of your original , that is pretty weird but you might have a wiring issue to the MAF from the PCM.

i cleared the code the first time, then changed mafs and it still threw the same code almost immediately after.

[Formulalt1]

Did you clear it the second time when it threw code P0102?. That is the code it throws from the MAF being disconnected.

P0101
Mass or Volume Air Flow Circuit Range/Performance Problem

P0102
Mass or Volume Air Flow Circuit Low Input

P0103
Mass or Volume Air Flow Circuit High Input

[98tadriver]

yessir. i cleared the code before i unplugged the maf, then i cleared the code after the maf was plugged back in, then it threw the P0103 code again. i have the 01 pcm sitting here, should i swap them out?

[Formulalt1]

Does your PCM show ID 9354896 or ID 12200411?

[98tadriver]

where would it show the ID? on hptuners? im still new to tuning. i dont know too much about it lol. if you can, could you jump on AIM? i see you have a s/n. mine is listed on here

[Formulalt1]

Yeah, I will go on but there should be a tag on the PCM.

[98tadriver]

UPDATE

after talking to formulaLT1 and finding out only certain 99 pcms work with 00+ i swapped my 99 pcm to my 01 pcm and its alivveeeee and idling. it threw a bunch of automatic trans codes since i have a 6spd and only one engine code a p0356 (ign coil cyl 6) which i will take care of tomorrow. thanks John!

[98tadriver]

i havent went to bed yet. looks like ill be waking up at 1pm lol

[Formulalt1]

Originally Posted by 98tadriver

UPDATE

after talking to formulaLT1 and finding out only certain 99 pcms work with 00+ i swapped my 99 pcm to my 01 pcm and its alivveeeee and idling. it threw a bunch of automatic trans codes since i have a 6spd and only one engine code a p0356 (ign coil cyl 6) which i will take care of tomorrow. thanks John!

No problem man, I am glad we got it figured out. Get some sleep, lol.

[98tadriver]

im up, i figured id be ok on like 6hrs of sleep lol

[crainholio]

There's a guy in Morristown who can re-flash the PCM with the right software, he gets $50 last I checked. Give a shout if you want his contact info.

[98tadriver]

thanks, but i will be taking the car to RPM in claymont DE, its fairly close to me

[camaro2you]

Ron when are you making the trip? Do you know how much for a dyno tune there? Feel free to take this to a pm or phone call.