ProchargedLT-Score

Hey Everyone, I'm new to the LS1TECH Forums and I am hoping for some assistance. I am just finishing up my Procharged LT4 build and I am having issues with it cutting out under load (seems mostly when it's warm). I have a P0100 Code (Mass Air Circuit) and I have already Changed the MAF and deleted the Mass Air Signal Massager from the Circuit. Still nothing. It seemed to run fine the 1st 2 days after the build and now this. Everything else seems to be in check and I really wanna get this thing out on the road.

Here is a link to my thread in the Vette Forum but not getting a whole lot of help. Everything is in this Thread and the Thread it's Linked to.
Thanks!!!

http://forums.corvetteforum.com/c4-f...post1582599586

MasterTomos

iTrader: (15)

IF you already replaced the MAF with a new one, I would think that there is a break in the circuit somewhere else (wiring). Have you checked the wires for frays/breaks? Also, maybe the connector (on the wires) is dirty. Might be worth a shot to clean it with some electronics cleaner.

nitrous2fast

iTrader: (2)

Mass Air Signal Massager??? educate me on what this is please....

96capricemgr

iTrader: (1)

Is it a Mass Air Translator?

Have you checked that the plumbing didn't come loose?

How is this tuned?
Can we have a complete mod list please?

Alex94TAGT

It's a band-aid device for when the MAF sensor gets maxed out on OBD2 vehicles. Procharger sells them.

The stock MAF sensor is code-limited to 512 g/sec, and the OBD2 PCMs throw a hissy fit when that happens -- usually by way of cutting the injector pulsewidths in half, resulting in a sudden lean condition at WOT. Obviously not a good thing to have happen under boost.

It's for this reason that many forced induction guys swap back to an OBD1 PCM. The MAF will still max out, but there are no tantrums to work around. In any case, fueling beyond that point is just added via the PE tables.

Alex94TAGT

Without any further information, I agree with MasterTomos.

Judging that you're getting a P0100 and not a P0103, I'd venture this is NOT a maxed-out MAF problem (i.e., unrelated to the MAF massager/forced induction). Sounds like you just have a physical problem with the MAF circuit -- either the wiring, electrical connector, and/or the sensor itself. I'll assume you do not have any form of datalogging/scanning software to verify the MAF g/sec output readings, but you should perhaps look into getting something of the sort. It helps out a lot.

Digging through your post history at the corvette site, it appears that the MAF code predated your forced induction install? I found the thread where you had two similar connectors and weren't sure which was for the MAF. If you're not certain, then go buy yourself a multimeter with continuity check (if you don't already own one), and trace the wires back to the PCM pinouts. This will also verify that there are no faults in the wiring.

Assuming the Y-body OBD2 PCMs are similar to the F-body OBD2 PCMs, then you need to probe the MAF Yellow Wire -- > Pin 19 on the Black PCM connector. If you instead get continuity to Pin 1 on the RED connector, then that's actually the crank sensor pigtail. (I don't even remember what the AIR pump connector looked like, but I believe it was similar in appearance.) You can also test this yellow wire for +5 VDC with the ignition key in the 'on' position (not run), MAF disconnected.

You should be able to probe the two remaining wires for power/ground (+12 VDC). I'm not entirely certain where they lead, but likely Pin 16 for ground and either Pin 28 or 29 for the power wire on the BLACK PCM connector. Make sure the power wire isn't shorted to ground. Also inspect the female terminals within the electrical connector itself -- sometimes the little terminals snap off and prevent connectivity when plugged in (in which case, the pigtail needs replaced).

If all the wiring checks out, then I'd suspect the MAF sensor itself. Perhaps swap with a buddy if you know of any other local 'vette owners, reset the PCM, and see if the MAF code comes back.

Stay off the throttle until you get this figured out.

BIGCAT7274

you can max out a ob1 pcm. mine reached its limits when we switch to the ysi. ended up switching to fast.

WS Sick

The ign module, coil and maf plugs are in the same area and are very simular, at one time you could have plugged them onto the wrong sensor/module and damaged the plug and or the sensor/module, check for a blown fuse, and also loo the connectors over for bent pins or damge where the pins would nmate into the sensor/module.

Alex94TAGT

I know. I said that in the same post you quoted.

Personally, I switched to a 2-bar MAP / SD tune on the stock PCM. Car runs better now that it has since I've owned it -- I'll never go back to MAF.

popo8

IM gonna go a different direction...

Is the dryer hose set up used on the corvette application?

ProchargedLT-Score

First off, I REALLY appreciate all the help. Before we dig in I'll post the Mods List
-LT4 w/ LT4 Hotcam
-42# Injectors and an Inline Booster Pump
-PCM Tuned by PCM4Less
-P1sc
-MSD Opti and Coil

That is the Bulk that matters anyway.

Alex, I am definitely going to look into all the wiring. Been really busy at work lately and you are correct; when I was reinstalling the connectors I lost my tags and couldn't figure out which plug went where (Knock or MAF). Rookie mistake, I know... I plan on trying to data log this weekend. Never tried it before but a buddy has an SCT Flash Programmer and a Laptop so we are gonna do some logging this weekend. I will let you know what I find. I am gonna try and trace the wires back to the PCM and see if my connectors are actually switched up. (Which btw I appreciate the honest searching and digging help. Very helpful indeed. )

If the connectors are backwards would I not have some issues with the knock sensor not being hooked up correctly??? Timing issues? I can still Free Rev the Engine just not under load.... No idea.

ProchargedLT-Score

Not sure what you are referring to so maybe not.?.?. Elaberate please... I followed the Procharger install guide with very few and minor deviations.
Thanks!

popo8

On the fbodies the inlet to the blower is what looks like 4-5" dryer hose

96capricemgr

iTrader: (1)

The underhood plugs are all rather different. You could say swap O2 sensors from right to left or something but the MAF and KS plugs are COMPLETELY different and in fairly different areas of the harness.

Many wont like this comment but I am known for calling things as I see them. Your mod list reads like a magazine build it will just make most guys who know what they are doing cringe. I am going to say you dove into this way too inexperienced and you are going to find something you did wrong because of that inexperience.


Maybe I missed it but are there headers and good catback?

ProchargedLT-Score

The MAF and KS plugs both split from the harness in the same spot on my car (right hand side of intake at the front of the engine). They are also identical plugs with different color wiring. I had them labeled but we all see how well that went...

As far as my mod list, I can elaborate.

I purchased the entire kit from a member of the Vette Forum and he shipped it to my door. The inline fuel pump is one that comes with the kit from procharger. The Injectors are 42# Ford Green Top injectors I purchased rebuilt from a friend. I am not using any FMU because my tuner (who I asked for advice due to my lack of experience with superchargers) recommended I run larger injectors and he can handle the fuel tables in the tune more effectively than an FMU (which can be dangerous). The intercooler, blower and all the piping is installed as the Instructions explain it which is pretty cut and dry. The car has a Hotcam installed as well as the MSD Opti Spark and coil. There are no headers on the car, just stock manifolds, but I am looking for headers now. I have seen many cars setup identically with stock manifolds (even though it's obviously restricting). I have a factory exhaust with a resonator delete (straight pipes in place and no X-pipe). I have larger drilled and slotted rotors all the way around, an ACT clutch which seemed to hold up good last trip to the track Naturally Aspirated. Stock rear gears and the Tuning, like I said is all done by the Vette Specialist at PCM4Less.

I hope that explains it slightly better. I apologize for the lack of "meat and taters" in my last post. I am very inexperienced with Superchargers, just not cars. But I'm learning the fastest way I know how and that's by doing it.

"Experience is the name everyone gives to their mistakes. ~Oscar Wilde"

96capricemgr

iTrader: (1)

Having made mistakes along the same lines of what you have and then later putting the car together well I am going to say you did things assbackwards doing the cam before the headers. I did the same thing, it was wrong.
I also spent money on "ignition upgrades" that was wrong too with the boost you might benefit from an ignition box and the safety of a spark based rev limiter is nice but the MSD opti is no upgrade and neither is the coil.

I would not do a booster pump. Racetronix 255lph kit would be better.

After all the troubles I had with pcmforless on a much milder setup I would not even consider letting them mailorder tune a boosted car. I know they have a wonderful reputation but as you gain experience you will see reputations don't always really match a shops average results. Sure they put the effort into a FEW cars that endup running well but you will find just as many guy at the complete opposite end of the spectrum with very mild cars where the spark and fuel were so far off it broke pistons. I have sent used stock replacement pistons to MULTIPLE folks who had exactly that problem with Herter.

Now since it drove OK at first the tuning is not likely the cause unless it actually did engine damage but I would still find someone more local to tune it.

I have never wrenched on an LT1 Vette but far as I know the KS and MAF plugs are completely different.

I know some of the stuff I am saying I wouldn't do came with the kit, but those kits are meant for simplicity and adequate is all they need be, doing things well takes a little extra effort.

I also understand you thought you were buying very good on everything you bought but the HOT cam is a CHEAP setup, it can be decent but most guys will tell you for the effort why not use something vaguely modern valvetrains have come a long ways. With the boost trying to open the valves you certainly need something more than LT4 springs. The LT4 springs are OK with LT4 valves because those are so light but are really at their limits with that cam, they were in the GM parts bin so they were "good enough" 5psi or whatever trying to push the intake valve open means you really should run a little more spring.

Before anyone else says it no I don't have a blower car, but that doesn't stop someone from understanding what does and does not work and what it takes to get things to work right.

Lgoldtop

^ Damn. I learn more and more from you 96capricemgr. Everyday I learn from you lol

Alex94TAGT

I believe he meant to say crankshaft position sensor, not knock sensor (as they were discussing on the 'vette site). The MAF and crank position sensor use the exact same pigtail.





Above all else, a mail-order tune just isn't going to cut it on a forced induction car. Getting it tuned locally would be #1 priority.

95zpro

That 'orange' hose is virtually useless, get rid of that and fab something solid in its place.

nitrous2fast

iTrader: (2)

sorry but are you running a boost ref pressure reg?