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2002 chevy trailblazer_lt
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Discussion Starter #61
Thanks for that info. In the mean time. I bought a 26pcs Craftsman ratcheting screwdriver set for $15.00 at LZs. The largest torx head included was T27 and it worked just fine. I did have to remove the dog house and an AC hose retaining bracket (3 - 10mm bolts in all). The old regulator leaked some when it was disconnected, and was full of gasoline. Connection was positive; no leaks.
Still won't start. Just cranks.
ECM scanner doesn't offer any new P codes. There's supposed to be a PC USB interface cable, but, of course, it's missing. I'll return to AZ to try and get one that has the cable to see if the PC interface offers better/additional info. Unfortunately, the ECM has no history because I must disconnect the battery overnight due to a power drain (think it's the instrument cluster) so the reading comes from whatever it detects with the ignition ON. Instructions says to plug into ECM, Ignition ON, Do Not Start Engine.
 

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So I reread through this thread and could not find if/where you ever did the starter fluid test?

Also be aware that when you use a "code reader" you are getting to see only those codes the designer of that device decided you needed to see. On these trucks there are 8 different status' of DTC. $01= immature codes, $02 = current codes, $04 = manufacturer specific codes, $08 = manufacturer specific codes, $10 = history codes with freeze frame data, $20 = old codes that once were current but are not now active, $40 = pending codes, $80 MIL codes that request the service engine soon light be turned on. So when one of these code readers says no codes they are quite likely not showing old codes that remain in the system even after battery disconnect or 'code clearing'.
 

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Discussion Starter #63
I was all out of starter fluid so I subbed blinker fluid; they're interchangeable, right? (I assume you jest..)
 

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Well,,, no. Not a jest at all. Basic troubleshooting. If you want to rule out fuel delivery issues for a no-start condition you supply a little 'fuel' yourself. A standard practice.

Remove the cover to the air filter. Spray some starter fluid on the filter, not a lot, maybe a 2 second burst from the aerosol can. Then try to start the engine, leave the filter cover off for the moment. If the engine doesn't even cough or sputter then you likely have a no spark condition. If the engine fires or maybe even starts for a second or two then you have a fuel delivery issue.
 

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Discussion Starter #66
My apologies..I understand now. I'll give that a shot.
I removed the air filter cover and sprayed starter fluid for about a second into the airway to the plenum. Didn't want to overdue it. The engine started roughly for a moment, but didn't make it to idle. So there seems to be ignition. fuel pump operating at 55 psi at crank with a new fuel filter and fuel pressure regulator. There isn't a test port connection at the fuel regulator/fuel rail so can't positively confirm but fuel was present when replaced. The coil fuse checked out ok. Is there a test for the throttle body? Or any suggestions?
 

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My next thought would be to test for power at an injector and also check fuse #28 in the underhood fuseblock. (Assuming this has not been already checked out) This fuse supplies power to all 6 injectors. By the diagram there should be a pink wire at each injector and it should be powered 12VDC when the key is in run or start position. The PCM will supply the ground side as needed for the injectors to function.
 

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I see now that fuse 28 is the one you just checked! I think I would still check for power at an injector to rule out some misconnection somewhere.
 

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When you first turn the key to the run position, NOT cranking,,,NOT running, does the security light illuminate with the other dash lights for a second or two and then go out when the others do, leaving only the check/service engine light on?
 

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When you first turn the key to the run position, NOT cranking,,,NOT running, does the security light illuminate with the other dash lights for a second or two and then go out when the others do, leaving only the check/service engine light on?
Good catch!
Let's see what the answer is in the AM --- I'm gonna go to-o-o-o-o-o-o-o ZZZZZZZZZZZZZZZZZZZZZZZ zzzzzzzzzzzzzzzzzzzzzzzz ,,,,,,,,,,,,,,,,,,,,,,,,,,,
 

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Discussion Starter #71
When you first turn the key to the run position, NOT cranking,,,NOT running, does the security light illuminate with the other dash lights for a second or two and then go out when the others do, leaving only the check/service engine light on?
Yes, the security light cycles on and off with the other dash lights.
The coil fuse I referred to was #14, but #28 checks out good too.
I couldn't even see the injectors. Are they behind the PCM?
Now when I crank the engine, the rhythm is slightly different. (This is gonna sound silly) It was a steady Tuh, tuh, tuh (starter cranking). Now it goes Tuh, tuh, tuh-tuh.
 

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That is a test port for the EVAP system.It is where you would connect a smoke machine to find a leak in the fuel vapor recovery systems.

As for the coils vs injector power circuits I just confirmed on my 02 the same fuse #28 powers both coils and injectors. While you cannot access the injectors themselves you CAN check the power leading to them here at the harness connector on top of the head rearward of the throtttle body....

Edit: I recently bought a backprobe assortment but you can use a small sewing needle or similar, or disconnect the harness and test there.

IMG_20200724_112048.jpg
 

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While testing the fuse is always good we can never know without testing at the destination that some rodent hasn't been at work at our wiring. Seen here is evidence I have had some sort of visitor!

IMG_20200724_113352.jpg
 

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Discussion Starter #76
That is a test port for the EVAP system.It is where you would connect a smoke machine to find a leak in the fuel vapor recovery systems.

As for the coils vs injector power circuits I just confirmed on my 02 the same fuse #28 powers both coils and injectors. While you cannot access the injectors themselves you CAN check the power leading to them here at the harness connector on top of the head rearward of the throtttle body....

Edit: I recently bought a backprobe assortment but you can use a small sewing needle or similar, or disconnect the harness and test there.

View attachment 55460
Pic 1: Found a disconnected yellow wire. How do I fix that properly?
Pic 2: Also, a small amount of what looks to be oil in the plenum. The starter fluid I used yesterday is clear.
 

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The oil in the plenum is somewhat normal. Towards the front of the engine there is a small short hose that connects to that plenum. It pulls oil vapors from the valve cover into the incoming airstream.

That broken wire is a whole 'nother matter. If that is the harness to the injectors (looks like it) there must be 7 wires and all are essential. One is the power feed and the other 6 are from the PCM to each injector. Couldn't see well enough in your picture to identify individual wires. Will look at wiring diagram.....
 

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The yellow/blk is the control from PCM to Fuel Injector #6. I think it would be in order to test and verify the integrity of all of those connections. Do you have a multimeter?
Screenshot_20200724-160245.png
 

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Can you get a better picture of that connector with the broken yello wire? Look at my posted picture of the same connector. See the top left where I have the probe in the pink wire? That is the power source for all of the injectors. I don't see a wire in that position on your picture!!
 

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Discussion Starter #80
Can you get a better picture of that connector with the broken yello wire? Look at my posted picture of the same connector. See the top left where I have the probe in the pink wire? That is the power source for all of the injectors. I don't see a wire in that position on your picture!!
Yes I noted the missing wire as well, but I could barely reach the connector with one arm to clean it up for a better view. I'll have to lay on top of the engine to get close enough for two hands. It's 103 under the shade tree in DFW with the relative humidity so I'm toast for the day. I'll get a better close up tomorrow.
Yes, I have a multimeter.
BTW, I sprayed some starter fluid in a pan, and when it settled it looked just like stuff from the plenum. Come to think of it, it does have some lubricant in it so any excess starting fluid not burnt off won't break down the cylinder oil. Or so I'm told.
 
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