Mechanics

CHEVY TROUBLE STARTING WITH A MAP SENSOR ERRO

1999 Chevrolet Suburban

Engine Mechanical problem
1999 Chevy Suburban V8 Four Wheel Drive Automatic

My Suburban is having intermittent issues starting. It will sometimes turn over, roar to life, and then die. Other times is starts fine, but then rough idles. It never has this problem more then once a day.

When I put a scan tool on it, it came up with " P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input.&Quot; Is this a case of replacing the MAP sensor, and if so how do I do that? My car maintenance/repair experience is limited.
Avatar
Japhmi
November 2, 2009.



" If your question is urgent and requires immediate assistance, we have a preferred option; if you elect to donate a small sum of your choice, we will guarantee an answer from one of our certified technicians within 24 hours. If we are not able to help you, we will gladly return your donation. &Quot; It's been 24 hours, and there is no response, I would like my donation refunded ASAP.

Tiny
Japhmi
Nov 3, 2009.
MAP SENSOR CHECKS

First, make sure engine manifold vacuum is within specifications at idle. If vacuum is unusually low, there may be a vacuum leak (leaky hose connection, intake manifold or throttle body gasket, power brake booster, etc.), an exhaust restriction (clogged converter), or an EGR leak (EGR valve not closing at idle).
A low intake vacuum reading or excessive backpressure in the exhaust system can trick the MAP sensor into indicating there's a load on the engine. This may result in a rich fuel condition.

A restriction in the air intake (such as a plugged air filter), on the other hand, may produce higher than normal vacuum readings. This would result in a load low indication from the MAP sensor and possibly a lean fuel condition.

Next, check the sensor's vacuum hose for kinks or leaks. Then use a hand-held vacuum pump to check the sensor itself for leaks. The sensor should hold vacuum. Any leakage calls for replacement.

An outright failure of the MAP sensor, loss of the sensor signal due to a wiring problem, or a sensor signal that is outside the normal voltage or frequency range will usually set a diagnostic trouble code (DTC) and turn on the Check Engine light.
check harness or connectors (The sensor circuit is open or shorted.)
Engine coolant temperature sensor may be faulty .
If a MAP sensor needs to be replaced, make sure the replacement is the correct one for the application. Differences in calibration between model years and engines will affect the operation of the engine management system;
you also have a MAF sensor and the MAP as back up in case the air flow signal is lost


http://www.2carpros.com/forum/automotive_pictures/46384_MAF_1.jpg


check that one too.
and your map sensor


http://www.2carpros.com/forum/automotive_pictures/46384_MAP_1.jpg


and the coolant sensor


http://www.2carpros.com/forum/automotive_pictures/46384_coolant_sensor_1.jpg



the 3 sensors , there wirings and connectors are most likely produce the P0108 when diffective.

Tiny
Mathiaso
Nov 3, 2009.
I have no idea where to start with your first thing: " make sure engine manifold vacuum is within specifications at idle.&Quot; I have no idea how to check engine manifold vacuum levels, and I have no idea what the specifications should be.

I expect the charge on my credit card for my donation to be refunded by the end of the week.

Tiny
Japhmi
Nov 4, 2009.
We try our best to help and appreciate you considering us for a donation. We have refunded it and hope we can help you next time.

2CarPros Mike
Nov 5, 2009.