Bad MAF sensor or vac leak?

P

pablon2

Registered User
I'm pretty sure I have a vac leak at the IC side of the intake elbow b/c the car idles higher when starter fluid is sprayed around that joint. Would this alleged leak cause the car to idle poorly? The car idles better (almost normal) when the MAF sensor is unplugged. The question here is, if I have a vac leak and unplugging the MAF sensor seems to fix the idle problem, does this mean the sensor is bad or could it still act this way with a good sensor that is unplugged but with a vac leak on the IC tubes?

In other words, if there is a vac leak resulting in poor idle and unplugging the MAF sensor makes the car run better does that necessarily mean I have a bad sensor OR does unplugging the sensor merely diminish the effects of a vac leak at idle?
 
Compensating

Unplugging the MAF could very well change enough to compensate for the vacuum leak just by luck.
Yes a vacuum leak will cause poor idle and reduced performance.
If large enough it could cause detonation VERY BAD.
The first step is to fixx all of the vacuum leaks before changing any sensors.
Good luck!
Bill
 
More info...please help.

blue94sc said:
Unplugging the MAF could very well change enough to compensate for the vacuum leak just by luck.
Yes a vacuum leak will cause poor idle and reduced performance.
If large enough it could cause detonation VERY BAD.
The first step is to fixx all of the vacuum leaks before changing any sensors.
Good luck!
Bill
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I have an update with more info. I reassembled the IC tubes and checked for leaks. I am 95% sure I have no leaks. Anyhow, the car runs better than b4. Here is what my vac pressure reads: 18 when idling good in Park, 13 when it is idling rough and in Park, and when the car is off it reads 3 or 4 (doesn't go to zero). Is this all normal? Is the fact it goes to 13 from 18 when it is having problems idling a sign of vac leak? Also, I have 42lb injectors in with an adjustable FPR, but have the stock pump in (until tomorrow). When it starts to idle poorly I notice the fuel pressure rises at the same time, then it dies when it hits 40-43psi. Could it be getting too much gas? I have no idea. Please help put my mind at ease. :)
 
Anyone?

Don't mean to be a pain in the arse here...but can anyone help out? I do value all input I get. :)
 
Have you tried cleaning the maf? and chacked all the plugs and wires? And you are absolutely sure you have no leaks? If all that stuff is good, id go cam sensor, or motor mounts as i recently learned.

Tyler
 
T@Sound-Xtreme said:
Have you tried cleaning the maf? and chacked all the plugs and wires? And you are absolutely sure you have no leaks? If all that stuff is good, id go cam sensor, or motor mounts as i recently learned.

Tyler
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I've got new cam sensor, plugs, wires, and mounts. So, most likely a wee leak or a dirty MAF sensor? (I have a K&N filter).
 
Ok get some electronic cleaner and clean that little Bi#$. That is prolly the problem.

http://www.tccoa.com/articles/intake/index.html#

not sure if that link works, but theres an article at tccoa with the how to, you dont need to take it all apart liek that though, just get the maf in your hands the metal casing and you can see the wires from there, spray away just make sure you dont hit the wires.

Tyler
 
T@Sound-Xtreme said:
Ok get some electronic cleaner and clean that little Bi#$. That is prolly the problem.

http://www.tccoa.com/articles/intake/index.html#

not sure if that link works, but theres an article at tccoa with the how to, you dont need to take it all apart liek that though, just get the maf in your hands the metal casing and you can see the wires from there, spray away just make sure you dont hit the wires.

Tyler
Click to expand...


My bad....forgot to mention that I only have headers on right now. Could that affect idle, I am assuming it would do to back pressure issues.
 
Yup FF is right , since the o2 sensor on your cat is outta the question now, i will prolly through it off? why not bolt the exhaust back up?

Tyler
 
Here's the deal

T@Sound-Xtreme said:
Yup FF is right , since the o2 sensor on your cat is outta the question now, i will prolly through it off? why not bolt the exhaust back up?

Tyler
Click to expand...


Okay, here's the deal. I will be getting my new exhaust by 4/20. (I currently have no exhaust.) I'll then hook it up and see if that fixes the issue. This way I'm not wasting everyone's time with my half baked posts. :eek:

More to come.....
 
z90sc said:
..this may seem like a dumb question but is your maf programmed for the 42# injectors?
Click to expand...


I have a 76mm C&L with a purple sample tube. So, I believe it is set for 42 pounders.
 
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