brett.higgins3

ok so i was racing the other day. and after shifting a gear i heard a little pop almost like a backfire. then the car was kinda jerking so i down shifted to see if maybe it were just that gear but it happened in all gears and it ran rough. i pulled over and put in neutral but the car died. went to start it back up and it would start but at idle the boost would build up on the gauge and once it hit 30 the car would die. what could this be?

Slowbalt2000

iTrader: (1)

You mean the vacuum reached 30"??? its impossible for the engine to run if it is not getting any air.

brett.higgins3

no on the guage it went to 30 psi boost.

brett.higgins3

https://www.youtube.com/watch?v=_S6F...ature=youtu.be

tylerjclance

iTrader: (7)

Lsj?

brett.higgins3

tc lnf

CobaltSS 16

iTrader: (3)

its an lnf since lsjs stock boost gauge only goes to 20psi.

never seen that before. any codes?

could be boost actuator or throttle body

brett.higgins3

p0087 and p0137 low fuel pressure in rail and map sensor but i unplugged map sensors wouldnt it make the car run atleast? with them unplugged

Slowbalt2000

iTrader: (1)

sounds like a bad map or bad wiring/connection somewhere

brett.higgins3

but if i unplugged the maps wouldnt the car still start normally?

Slowbalt2000

iTrader: (1)

Most gm cars would but idk about the lnf. Probably will flip ****. Try it

YelloEye

iTrader: (3)

Plug your MAPs back in, neither of those codes reference the MAP sensors at all.

P0087 is low fuel pressure at the rail after the HPFP.
Can be caused by a bad fuel pressure sensor, faulty injectors, a bad HPFP, a worn intake camshaft fuel pump lobe, bad fuel lines, fuel pump relay, or fuel pump. Check that your fuel pump is turning on when the key is turned on, you should see 57-67psi and a decrease of less than 5psi a minute. First thing I'd check is your fuel pump fuse.

P0137 is your 2nd o2 sensor, the post cat sensor.
That code indicates that there is a short to ground. The book references replacing the ECU a lot and replacing the o2 sensor once. Are you running the stock downpipe?

tomj77

iTrader: (2)

Well for one the gauge does do its opening dance where it goes to 30 and back to 0, could be just happening in sync with ur car dying. Turn the key and don't start it and it will do the same, could just be a coincidence. Check for popped off charge pipe, even if u didn't get the p0101, of u can scan and check map sensor, could have popped that

brett.higgins3

ahhh sorry for the wrong code its not 137 i was trying to go off memory its p0107... sorry about that

brett.higgins3

maps are plugged bback in i tried all situations with maps un plugged and plugged and still does the same thing.

brett.higgins3

i think im going to buy a map and see if it fixes it if not ill just bring it back lmao gunna need to upgrade anyway but need car to run to get a tune. and im pretty sure fuel pump is good wqhen i turn key to on i hear the winding noise thing. my batery is low due to having doors open and leaving hazards on and not being able to run car for a long peroid to recharge it. so the pressure might not be gettingbuilt up enough from that. also i notice a little black smoke and smells rich. when starting and what not

Slowbalt2000

iTrader: (1)

theres a high pressure fuel pump as well, but if its running really rich you may have a bad high pressure fuel sensor

YelloEye

iTrader: (3)

P0107 is for the MAP sensor on the manifold. Should have a 5v wire, a ground, and a return/signal wire with the ignition on. I'd test those before outright replacing it.

brett.higgins3

how do i test those? snd what are they exactley lol

firehawk618

iTrader: (2)

Check one for 5v with the key on.

Check one for near 0 ohms key on or off.

Check the other for near 0 ohms from the sensor to the pin on the PCM.

brett.higgins3

still no clue i need like a how to for dummies lmao

firehawk618

iTrader: (2)

Unfortunately if you're not sure on this one, don't do it. You can cause more damage than what already exists.

brett.higgins3

ahh okk.... hopefully its justa map sensor lmao. boost just builds and shuts off its so wierd. at idle

YelloEye

iTrader: (3)

Real easy to test. You'll need a multimeter.
The black lead needs to be connected to a good ground, the valve cover or intake manifold should be fine if they're bare metal.

Test for 5v:
1. Turn on car without starting.
2. Turn meter to DC 12v.
3. Unplug MAP sensor.
4. Test all 3 pins in the connector for voltage. One should show 5v. If you have trouble getting in there use a paperclip.

Test for ground:
1. Leave car off.
2. Set car to OHMS, any setting is fine.
3. Unplug MAP sensor.
4. Test all 3 pins. One should show the same reading you get if you touch your 2 leads together.

Mr Mall Cop

iTrader: (1)

oh oh spaghetti O's