Hi all,

Yesterday I hopped in my Blazer which hasn't had a problem. Started going to work and it was stuttering here and there, then it died. Thought it was the battery, got a boost, went to work and it went fine for the rest of the day.

This morning, I went out to start it, backfired a few times but refuses to start. Sounds like it wants to catch.

I checked the codes, got a PO108 Manifold Absolute Pressure.

I've been trying to get mine off to check it but it seems pretty stuck on. Is there anything else I should be doing to get it off?

Vehicle is a 1998 blazer V6.

I've taken a look around the site, no info on how to remove it. I don't want to break it when I'm taking it off...I can be hamfisted.

Already looked here for info :

https://blazerforum.com/forum/diagno...plained-36764/

 

You don't need to remove the MAP sensor to check it, the flow chart goes through the testing procedure. The MAP sensor pulls straight out, and if you do remove the sensor, DO NOT reuse the old seal. If you went through the flow chart exactly as outlined, and did not find a problem, another possibility is a problem in the fuel delivery system. Here is the flow chart for fuel delivery diagnosis: https://blazerforum.com/forum/tech-a...agnosis-23038/ Low fuel pressure can set any one or more of several DTC's including MAP sensor, MAF sensor and numerous O2 sensor DTC's.

 

I don't have the gauge to check pressure, working with just a voltmeter & ODB2 reader, nothing else. Plus I dont have any money to buy more stuff to test.

Are the seals easy to get and cheap?

 

The seal on the MAP sensor just pulls off. More often than not, the seal tears when it is removed from the intake plenum. The seal is all that holds the sensor in the intake.

A vacuum pump can be used to test the MAP sensor without running the engine, but a vacuum gauge can also be plumbed into the manifold vacuum source and compared with the voltage return from the MAP sensor to the PCM.

 

I've called around, no one knows where to get the seal by itself. Have to figure out how to repair it if it rips. Maybe a small drop of crazyglue.

I have a junkyard local I'm going to get a replacement MAP sensor to try. Since I got the 108 code I'm hoping that will fix it. I heard the TPS can throw this code also.

 

You could try to glue the seal back together, but be sure to clean it to get it free of all oils or the glue might not hold. It would suck to have the lower part of the seal fall into the engine & possibly bend a valve.

 

When I try to start it only backfires. A nice LOUD backfire. Any ideas?

 

A back fire points to timing problems. It is possible that the backfire condition blew the MAP sensor.

I would check the rotor position after aligning the two timing marks on the balancer and ensuring that the engine is on the compression stroke of cylinder #1. For more details, check the EDI Engine Timing thread in the Tech Article (DIY) Index link below (see signature).

 

Where is the balancer? No idea where it is, and it's cold here in Canada, don't have a garage to work in.

 

So the MAP sensor didn't seem to do anything. Tomorrow I think I might snag a new pickup coil and MAF sensor (unless it's the TPS...fooooock). Whatever I don't need I can return, but at least I know I should have working parts in hand.

For the EDI, where is the part I have to turn, and what tools are necessary to do it? It shows a picture, but there's a few similar looking parts from what I've seen.