replaced transfer case motor now no start?

anniversaryss

Original poster
Member
Dec 29, 2012
12
Hey guys I have an 04;trailblazer ext. I was having an issue where i was stuck in 4lo. I changed the transfer case motor. It works as far as I can tell I can switch the gears and I hear the motor changing it. I did notice that its having an issue selecting 4lo tho. But my real issue is now my truck won't start. It will just crank and crank no start no codes. Need some info are there any wires or grounds that I may have disturbed maybe a fuse blown anything. Its such a weird problem BC I did not touch anything but the and encoder motor. BTW its the 4.2l 6 cylinder.
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
UPDATE:

OK so I checked all fuses that deal with ignition starting fuel coils etc all fuses are good. I even switched the fuel pump relay with an exact same one still nothing.

Also more info: the night before when the the vehicle was stuck in 4lo I had unplugged the battery to start with the simplest thing. On the way home when I would get stuck at a light or stop sign the idle would just drop and return and drop and return. I figured the truck was relearning itself it would slightly studder when it drive off but no chug chug like it was running out of gas. I've never driven in 4lo so I wasn't sure.

Also when u turn the key to the on position(no start) should u be able to hear the fuel pump from the drivers seat does closed . Should it be heard clearly? The truck has 125k on it.
 

The_Roadie

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Nov 19, 2011
9,957
Portland, OR
Welcome! Glad you made it over from the ghost town at trailvoy.

1) The fuel pump should be audible, but if the fuel pressure is already up from a previous attempt, I'm not sure you'll hear it. Do you have a meter and want to check the fuel pump relay socket to see if the relay is getting power and the right control signal?

2) The ignition switch has a high failure rate, but it would be a huge coincidence to have it go bad at the same time. Again, a meter is the best thing to dig deeper if you're into electrical troubleshooting.

3) The erratic idle is a classic behavior after a battery disconnection. The PCM unlearns the response of a sticky/dirty throttle body and can't adapt as well as it can when the throttle body goes slowly bad over time. Most I6 engine owners have great results by removing it and cleaning the throttle body every 30K miles or so. Your failure to start may be a stuck-shut throttle body plate. The back side of the throat gets as dirty as a wild west bar spittoon after 150 cowboys all spit their chaw in it after a hard month cattle drive. All because GM cheaped out on the I6 and failed to include a proper PCV valve.

How to with video: http://gmtnation.com/f25/how-clean-4-2-inline-6-throttle-body-221/

4) 4LO mode has an interlock that you have to be in NEUTRAL, not PARK or DRIVE. And either stopped or rolling under 2-3 MPH. Just making sure you knew about this interlock. Many owners never rear their manual to discover this tidbit.
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
Thank u roadie. As for the 4lo I didn't know that. It was weird to be BC I've never had an issue like that. Well I have the new motor on now and i hear the motor switch now I hadn't before.

About checking the relay for the fuel pump and Igniton switch can u give me more info. I have a dvom meter. I'm getting a fuel pressure tester and checking it tomorrow I've gotta work. Will the motor still crank even with a bad ignition switch?
As far as the throttle. I pulled the intake tube off and checked it. Its not stuck open or closed
 

The_Roadie

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Nov 19, 2011
9,957
Portland, OR
A circuit on the ignition switch only operates in the START position and this runs the starter relay. Another circuit provides power in RUN and START positions and that runs the engine computer, spark coils, and fuel pump. That's the general way an ignition switch failure can kill the engine.

http://gmtnation.com/f93/how-replace-your-ignition-switch-3430/

Here's the wiring chart:

RED on the ignition switch is 12V, fused by underhood fuse #34, and feeds the following three circuits:

White is hot in ACCY, RUN, START
Orange is hot in RUN
Yellow is hot in START

RED/WHITE is another 12V, fused by underhood fuse #36, and feeds two circuits:

Brown is hot in ACCY, RUN
Pink is hot in RUN, START
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
Thank u . I bought a fuel pressure tester and will check it tonight or in the morning. If I have no pressure its either the pump or relay socket. I don't believe the relay is bad since I used another one to see if it was. Also the fuse box is getting power just have to test the socket. If not that I'll move to the ignition switch
 

Black LT

Member
Dec 4, 2011
211
Coincidences do happen, but I'd check everything that was done lately. You said about the battery disconnect. Double/triple check the connection. Maybe loose or I've seen the plastic cover get pinched between the terminal and the battery post. I know you have some power, but a bad connection may not be enough for the starter.:undecided:
 

RayVoy

Member
Nov 20, 2011
939
As I understand the 1st post, the starter is working just fine. The motor is spinning, it won't start. The problem is no fuel, or no spark.

I agree, it is very coincidental, that this would happen after having a transfer case problem. I also agree with the previous poster, you must go back and check what was done. Somewhere between getting it home and trying to start it, a wire (to ignition, or fuel pump) got knocked off, or damaged.

This may be a silly question; but you did drive home in 4LOW, could you be out of gas?
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
This is the 2nd time I've heard of this, and it seems terribly odd. So I'm wondering if there is something in the transfer case that has to be in neutral or some other position before it will start?
 

anniversaryss

Original poster
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Dec 29, 2012
12
RayVoy said:
As I understand the 1st post, the starter is working just fine. The motor is spinning, it won't start. The problem is no fuel, or no spark.

I agree, it is very coincidental, that this would happen after having a transfer case problem. I also agree with the previous poster, you must go back and check what was done. Somewhere between getting it home and trying to start it, a wire (to ignition, or fuel pump) got knocked off, or damaged.

This may be a silly question; but you did drive home in 4LOW, could you be out of gas?

First thank u guys very much for your responses.

Second as far as the battery terminal question yes I did check it. I took it off and put it back on a few times.

Third yes I drove about ten miles home on side roads. I had just put fuel in it before I went to work. By time I got home I was over half a tank.

When I get up in the AM I'm going to check the fuel pressure and the relay socket. If that don't work then spark and so on. I'll keep u guys updated.

Also I checked all around where I did the work and no grounds or wires to be disturbed only thing close would be that box thing near the fuel filter towards the front of the truck I'm not sure what it is.

As far as the neutral thing the one guy was talking about it may sound weird but I tried it in every 4wd gear and neutral nothing.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
anniversaryss said:
Also I checked all around where I did the work and no grounds or wires to be disturbed only thing close would be that box thing near the fuel filter towards the front of the truck I'm not sure what it is. QUOTE]

I believe that's the ABS control module.
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
Wooluf1952 said:
anniversaryss said:
Also I checked all around where I did the work and no grounds or wires to be disturbed only thing close would be that box thing near the fuel filter towards the front of the truck I'm not sure what it is. QUOTE]

I believe that's the ABS control module.

Thank u wooluf.

Well I checked the fuel pressure when u initially turn it on when the pump is priming it shoots up close to 60 then comes and settles around 50-52. The relay socket was also tested and works perfect. Now I need to check spark and ignition switch

- - - Updated - - -

Wooluf1952 said:
anniversaryss said:
Also I checked all around where I did the work and no grounds or wires to be disturbed only thing close would be that box thing near the fuel filter towards the front of the truck I'm not sure what it is. QUOTE]

I believe that's the ABS control module.

Thank u wooluf.

Well I checked the fuel pressure when u initially turn it on when the pump is priming it shoots up close to 60 then comes and settles around 50-52. The relay socket was also tested and works perfect. Now I need to check spark and ignition switch

I know I'm not a certified mechanic but I can work my way around cars with the he right amount of research lol. But I'm in awe about this. The truck was fine the night before when it comes to starting. Now nothing ...

I just wish I knew if it Started before I change the motor. BTW if anyone asks fuel filter Is fairly new also are the plugs and boots
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
OK so I checked the ignition switch the way roadie had said and everything is a o k . Next is spark but that has to wait I have to work.

If I check it and it has spark what are my next options?.

Also only one more concern that I have. When I hook up my scanner the only thing in to me that seems off is that my tps is measuring 28.6 if I remember it usually reads 0.0 unless u give it throttle. Right or wrong. Is this an anomaly or BC the computer needs to relearn or is this something more and if so how can I test that.... BTW I minds well clean the throttle out the when I check for spark since I'll be in there.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
It would also be easier to see if you had something dark behind it.
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
So after a misdiagnosis of no spark and going through testing fuel pressure to relays to ignition switch and then some. My issue turns out to be what?!!!!!?


RATS! yeah u heard it RATS. Those bastards ended up building a nest near the back of my motor and chewing up my wires to my injectors.

Thank u guys for all your help and info. It was very informative and helped me to count things out.
I'm not sure how this can help anyone else out but I'd say never count out the unordinary.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Thanks for the report back! I will start asking for a full visual inspection of the wiring to make sure somebody doesn't have a mistaken cause->effect connection like that again.

Good news - at least it wasn't a mouse or rat in your HVAC blower impeller. Those are much ickier to clean out.
 

anniversaryss

Original poster
Member
Dec 29, 2012
12
the roadie said:
Thanks for the report back! I will start asking for a full visual inspection of the wiring to make sure somebody doesn't have a mistaken cause->effect connection like that again.

Good news - at least it wasn't a mouse or rat in your HVAC blower impeller. Those are much ickier to clean out.

Your welcome roadie. I could only imagine what that would be like to clean up. I hear of people starting their vehicles where rats/mice even snakes get caught into the fan, belts even intakes of vehicles even cats! I'm like that's gotta be nasty. I guess its time to set the traps again. I have enough trouble when they chew on my wires to my camaro during the summer. We aren't scum or anything, its this damn city but guess it can happen anywhere.
 

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