Howdy,
Today I went for a soft off road and fishing. On my return back, I've encountered something unnatural. I had been parked upward the slope. I've started the engine and put the t/c to "R". I have been trying to move on very slowly, so I've barely step on the gas. The engine ceased. I've started it over again. The RPMs were hunting down from idle. At home I've done some further tests. On "N" or "P" the idle RPMS are steady, so engine is not the case. Whenever I engage the "R", the RPMs start hunting (idle to down).
I have the feeling that the transfer case clutches in the engine to the drive shafts, but as far, as the brake pedal is pressed, the engine gets loaded and RPMs go down.
I haven't explore the Blazer's T/C yet, so kindly asking for help those, who did. What could it be? Should I be aiming on getting the parts and do the repair myself or rather it's complicated/complex and I'd better look for another T/C?
Thanks in advance, hoping for a good news.
Mike

 

What sort of transfer case? 4 or 3 button?

 

4:

• Auto 4WD
• 4Hi
• 4Lo
• 2WD

 

Mike
I'm a little confused here - but at my age that's easy to do.....
you stated you put t/c in R - I'm guessing transmission in R as no such thing in transfer case - In P and N you have no load on engine changing the RPMS what does RPMS do in drive ?

 

Oh crap. Like I said once, sometimes I am totally lost with translations.. I've spend lots of time reading and learning semantics, but I am still capable of stupid mistakes. Thanks for pointing this out. Yes, I meant the transmission of course. In my native language the T/C is called a "reducer" so I didn't even had a chance to notice how far I am Still I am crossing my fingers to get the proper reply even with improperly named thread

 

figured as much - lol - language translations are the easy to figure out a blazer is the pitts - so what does the RPMS do when in drive?

 

Hm.. I think it's similar. Your question brought me a fact from today I did not notice. I've been waiting at the roundabout for my turn to move on. When there was a gap for me, the blazer hesitated for a short period, like a second and then moved on.
...
OK, I went to a garage once more to be accurate here. I've started the engine, it was on 4WD Auto. Then, I've selected "R" and the RPMs drop down a bit. It didn't choke the engine to a complete stop. An engine was cold this time, so it may be normal due to a high viscosity of the transmission fluid. Then I've moved to a neutral. Then, while going to a "D" I've had a loud "clang-clang" (similar to the sound given while actuating the front diff) and a vibration. I've sweep across the t/c options, and my observation is that whenever You change over from R/D, the loud, double "clang-clang" pops out together with a vibration.... And it is not related to what t/c You're on.

 

Hmmm I was hoping for something as simple as a IAC or such,but with the clanging noise in the drive train does lead to t/c, transmission, u joints ect.
Regretfully I don't know enough about the auto 4 wheel drive units to help you any.
I would have somebody do the gear selection so you can be outside and close to under the vehicle to pinpoint where the noise is coming from

 

I went back over again. Just to see the fuel trims. And what I've just seen is even more confusing.
I've started the engine - startup normal, as usual. Then I've had the RPMs hunting and staying low no matter what I've selected P/R/N/D/1/2/3. Checked fuel trims and they all were at maximum, positive 50! O2 sensors completely flat, bottom line. I wish You could see the fuel economy
So, what I did next. I wanted the engine control unit to run in an open loop. I've stopped the engine, disconnected the MAF plug and start over again. RPMs got back to normal, even somewhat negative. like -6...-8%.. So, I've connected back the MAF plug and start over again. And fuel flood again...
That is so confusing now. I've replaced my MAF half a year ago with Delco. I don't believe it went bad. Still I should have the old one. Gonna swap them and check.

 

Okie dokie. A few minutes later I can confirm, it's not the MAF. Swapping with an old one doesn't change anything (the old one was not completely dead, just had an off-set). An IAC is a good option here to check. Although if it was leaking the air fully open, then opening the ECU loop wouldn't stop the air leak and the bad trims would remain. I feel like I am missing something (probably a sleep, it's 1AM here now). And my topic has diverted into completely different fields of exploration