Popping when maf is plugged In

[casey20000007]

Ok guys I got a delima I start my car and almost immediately it salt arts popping I unplugg the maf and the popping quits but my car starts bogging down a freind thinks my air fuel mixture is off what do you guys think?

[96LT1355Z28]

Are there any codes, can you try a MAF from another car?

[casey20000007]

No the check engine light don't come on until I unplug the maf and i got this maf yesterday becAuse the original one crapped out and I tried the new used one on a freind of mines ta and no probs.

[zooguy]

its not like i am batman or superman:batman: ... you can say my name here. i think that its the TPS sensor not being aligned correctly. when he gets off work i am heading over to do some more trouble shooting.

[96LT1355Z28]

Did this just pop up or was something changed?

[casey20000007]

I started baving problems the day I ran it outta gas I've change injectors tank pump lines and still nothing but it didn't start the whole "backfire/miss" till I had it retuned for the injectors

[MoeHorsePower]

Stock injectors? did you tell your tuner the brand and was sure of the size? what about your FP

[zooguy]

Well right now he is running open headers and I personally think that the O2 sensors are getting a false reading by air flowing back up into the collectors .... this would cause a lean reading making the computer want to add more fuel. Also when he unplugs the MAF it seems to help it run a little better ... I know this makes the car run on speed density and rely on the O2 sensors more. One more thing to add to the equation is he has replaced his TPS and we're not 100% sure what the voltage is ... I know it needs to be in the .45-.75 volt range but how do you check that with out a laptop and cable?



he will have to confirm this next stuff but from what i know about the car:
stock intake and elbow
stock TB
stock intake manifold
new injectors ... i dont know the #
383 CID
cammed ... dont know specs
head work ... i dont know
rocker arms ... i dont know
newer MSD opti
newer plugs
newer fuel pump
new fuel lines
new fuel tank
newer O2's
open LT headers
built M6
PCMforless tune

[casey20000007]

The injectors are bosch 3 #42lb
Rockers are liberty roller rockers
The cam Is 548 lift 108 Lsa
Tranny is still stock until I can get this prob figured out
I have minor porting on factory heads
I called pcmforless and they told me a vacuum leak will cause a "piping noise" to come out of the exhaust
WE WILL GET HER FIGURED OUT

[zooguy]

best way i know to find vacuum leaks is to get some starter fluid and spray around all vacuum lines and ports and listen for the motor to rev a little bit.

this will be hard with open headers but once it is more quiet you could tell better

[black heartbeat]

just as a btw I check alldata and according to them. The tps sensor output is supposed to be outputting approximately .6 volts. hope this helps. Also I doubt it would be this big of a difference but could you be putting a MAF in with a ram air tables rather than a "na" one?

[casey20000007]

Alldata? And the new used MAF came off a 97 Camaro. I have some mechannics comming over either today or tomorrow depending on what time I get off work, they're gonna run a scanner and set the tps and check AIC

[casey20000007]

Ok here's an update I got the x pipe dumped in front of the a axle then I took it to B&R performance to get tuned on the Dyno I'll let you guys know if I have any problems after the tune

[casey20000007]

Well got bad news the tuning shop said That popping was a miss and is pretty bad and would not be able to tune it until it was fixed so they will be diagnosing and trying to figure out what's going on with it prob for the next week or more 😡

[gregrob]

One thing you really need to do is check the fuel pressure...

I've seen a car run better without the MAF, due to the speed density part of the tune commanding much more fuel than when using the MAF tables.

Verify you have solid fuel pressure and go from there.

[casey20000007]

Here is an update the car is at the shop still and they still have not figure out what's causing the miss they said fuel pressure won't cause it to miss It's gotta be something else personally I don't think they know what theyre doin lol but yeah, does anyone know of any shops that are good with ltx cars or anyone that will work on it I'll pay whatever