I have a 2006 Trailblazer with the 5.3 with not spark to ...


I have a 2006 Trailblazer with the 5.3 with not spark to the coils . Will not start . Just put fuel pump on and checked the relay for the fuel pump and it’s good . The pcm fuse is good . So what could it be Mechanic's Assistan...

I have a 2006 Trailblazer with the 5.3 with not spark to the coils . Will not start . Just put fuel pump on and checked the relay for the fuel pump and it’s good . The pcm fuse is good . So what could it be Mechanic's Assistant: How can I help with your Chevrolet? I just asked Mechanic's Assistant: How long have you had problems starting the vehicle? Do you know if the headlights still work? Just started . Yes Mechanic's Assistant: Do you know the approximate mileage? Is there anything else you'd like the Mechanic to know? 180 but just had the mother replaced with one with about 90 on it . Ran fine for a while . Died out out . The fuel pump wasn’t working so checked the relay . It was goo . Changed the fuel pump . Tried starter fluid . Didn’t help . Test for spark off the coil and it has none Chat is completed

Automotive Expert
Hello, and thanks for your question, my name is \*\*\*\*\* \*\*\*\*\* I will do all I can to help. Did it cut off while driving? Also, if you turn the key to the ON position, Does the security light go out like it should? or does it stay on or blink?

While it was idling , twice . Yes it goes out like it should
Automotive Expert
Alright, does it always fire right back up? Or is it not starting now? If you have no spark, then it shouldn't start at all. it will just crank and crank. is that what it's doing now? If you have no spark, then it shouldn't start at all. it will just crank and crank. is that what it's doing now?

No it only started back up once . That was after I messed with the relay . Then it died out again to . Then I changed the fuel pump . And now the pump works I’m just not getting any spark to the coil pack
Automotive Expert
Alright, I follow you, does the vehicle have a tach in it? Reason I ask is, sometimes, (not always) you can see the tach bounce slightly when cranking it, or if you have a scan tool with live data function, you can read the crank sensor RPM's. I'm leaning towards a bad crankshaft position sensor, which is kind of on top of the starter on that model. It's little tricky to get to, you have to pull the starter down. And get to it through the passenger wheel well and take the tire off. Can't say for sure, but check the codes and see if you have any crank sensor codes.

it does . I was thinking that too but I was hoping it wasn’t ? I don’t have a scan too but I’m fixing to get one .Ok thanks
Automotive Expert
If security light goes out, and you have power on the PINK wire at the coil pack, then next step is to check crank sensor rpm signal on a live data scan tool in my opinion, but sometimes you can see the tach jump, or sometimes it will just set a code for a crank sensor. Check and make sure you have power on pink wire at the coil pack. with key on. Thank you .

Is that something that usually goes out after a fuel pump? Because it’s funny it haloed after the fuel pump quit ?Ok thank u
Automotive Expert
I mean it's possible. Seem's awfully coincidental. But if it's got no spark when cranking, then even if the fuel pump was bad, it should still have spark when cranking. You could put the fuel pump 100 feet away from the truck and it should still have spark when cranking .

Well I mean I didn’t check the spark before . Till after I installed the fuel pump . But I know the fuel pump want working before I replaced it
Automotive Expert
I follow you. You checked for spark with a coil pack off and a plug in it and cranking it right?

No I just pulled the coil off the plug and checked it for sparkNo tac does not move all all when trying to start it .
Automotive Expert
Alright, that will suffice, Check the codes next. and we can go from there. right, I'm leaning towards the crank sensor really. Double check that you have battery power on the pink wire going to the coil though .

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