Experienced a little nitrous backfire the other night and it burnt the MAF. I replaced it but now the car will start to idle and go up to 3k RPM and just kinda stay there. Any idea what else may have messed up that would call the car to rev that high in Neutral?

I tried to look at the intake as best as I could for any cracks but I can't see any. I may need to remove it from the car and take a closer look.

 

I had one a couple of months ago... Damaged MAF, blew air filter off, intake tube off, blew a HUGE whole in the back off the intake, piece of intake knocked off oil pressure switch, and it blew the map sensor out.... I would make sure the map sensor is still in and if not I would pull the intake... Might be cracked in the back...

 

I guess I'll have to do that sometime today. I just looked at my scan gauge and it's throwing different codes today. Yesterday it was just MAF related codes now the codes are P1111, P0113, and P0507 which seem to be all Intake Air Temperature related.

 

seen this happen once, turned out the TB butterly was not closing all the way - go figure.

 

this on a wet shot?

 

I bet you may have blown one if the hoses off the back. There's a TINY hose coming off the rear passenger side that operates the a/c air diverter, and there's of course the brake booster hose, and the MAP sensor.

 

Map sensor, tiny line and brake booster hose are all still plugged into the back of the intake. I replaced the maf since the sensor were burned off. Could it have anything to do with the sensor on the throttlebody? Maybe that got burned too. I cleared the codes and the IAT one seem to have gone away but the p0507 is still there and the car still is idling between 2500-3000.

 

id pull the manifold and make sure its not cracked or a peice missing somewhere. also check the blade in the tb. seen those bent also. btw what happend? why did it backfire?

 

I would agree high idle is because of a big vacuum leak somewhere.

 

u need to get a omes meter n check ur throttle position sensor

 

you have a serious vacum leak. Brake booster, something is loose, or the intake is broken.

 

I would agree with this comment. This is the first place I would go.

 

thats what id do first process of elemination

 

P0507 (idle speed to high)
Your idle air control motor can no longer control your idle because you have a vacuum leak.

Start the engine and spray brake and parts cleaner around the intake and wait for your idle to drop, you more that likely have a cracked intake or blown off vacuum line. (propane works better and is safer if you have it available you can make a "wand" out of rubber hose to better control where you are introducing it), remember arching plug wire + brake and parts = fire so stay away from your plug wires as best as possible. If you don't find any leaks start blocking off vacuum lines, including that monster that heads to the brake booster as you can rupture the brake booster internally with a large enough backfire.

If you don't find anything check your TB to make sure that the tb cam is making contact with the stop indicating it is closing completely.

Might just be time for a 90/90 setup

 

Been there done that, lol. Reach around the back of the intake, down really low and you may just find a nice little hole. It's hard to get to, and i had a GM engineer point mine out, and yep a hole. So, like was said, you have a nice big vacuum leak from something, somewhere. Once I pulled the intake, another big piece of intake fell off that holds the brake line and map and also blew the oil sender apart. My MAF and TB where fine, though my filter melted down in my Vararam. Going with an aluminum intake this time around, as I feel lucky that it didn't dislodge the fuel rails and burn the car, and also glad it was a dry shot as a wet could have been much worse. It sounded like a sonic boom, and everyone in the pits said, yea I knew that was you, lol. Good luck, and I hope it's not to bad, let us know what ya find out.

Oh yea, I was throwing all kinds of codes too, a new intake, a borrowed ls1, and they all went away.
Robert

 

also check your throttle blade...make sure it isnt bent/deformed from the blast. but theres a strong possibility for the hole in the back of the intake...its usually down low like Robert said.

 

I replaced the MAF, and I believe the IAC(sensor on top of the TPS), and the MAP senor(had one laying around). All codes went away and car drove fine. I did end up pulling the intake later just to be sure and no cracks or holes in it. TB blade was fine also. Thanks for the help guys.

 

Wow that's great news. I tried that on mine, but to no avail, lol. Good that you checked your intake though, now you know all is well. Did it blow the hose off the MAP sensor? if so that may be the source of the high idle, or open vacuum leak.
Robert

 

had the same thing happen to me about a year ago definatly pull the manifold and check it

 

Quite a few intake backfires, and there certainly are more than will say. Here's my new plan to keep the burning to the ground at bay, an aluminum single plane and this bad boy that pops at 60/90psi.

Robert