new motor only getting spark on 4 cylinders - LS1TECH - Camaro and Firebird Forum Discussion

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new motor only getting spark on 4 cylinders

 
Old 12-23-2018, 12:06 AM
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Default new motor only getting spark on 4 cylinders

just put a new motor in my car got it wired up and it wouldn't start I'm getting fuel pressure and the injectors are firing but I'm only getting 4 cylinders firing pretty consistently I've checked
fuses and relays good
all grounds I can remember and I've rechecked many times all good
12v at the crank sensor good
signal from the crank sensor to the computer good
12v and ground at all coil packs good
I know I need to make sure the cam sensor is reading the cam and I need to move the coil packs around and see if that's a problem but if anyone has any more ideas I'm all ears I'm ready to finally hear this new motor run
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Old 12-23-2018, 12:37 AM
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It sounds like you already know the diagnostics you need to do. Sorry, but no internet shortcuts here.
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Old 12-23-2018, 12:44 AM
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Originally Posted by gametech View Post
It sounds like you already know the diagnostics you need to do. Sorry, but no internet shortcuts here.
that's what I thought I've been doing alot of googling and head scratching the last 2 weeks thanks
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Old 12-23-2018, 08:19 AM
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Just curious... how do you know that only 4 cylinders are firing? Are the plugs on one bank wet with fuel?

You mentioned that all injectors are firing. Is that because the plugs are wet, or did you use a noid light or something like that?

Did you check if all plugs are firing? Could it be the connector to one bank of coils isn't plugged in all the way? Sometimes the pins inside a connector can bend, then not make contact. Might be worth disconnecting those and inspecting the contacts.

Lastly, can you check if you have any error codes? Sometimes there will be a clue in there (but not always).
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Old 12-23-2018, 09:23 AM
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Originally Posted by computerz View Post
Just curious... how do you know that only 4 cylinders are firing? Are the plugs on one bank wet with fuel?

You mentioned that all injectors are firing. Is that because the plugs are wet, or did you use a noid light or something like that?

Did you check if all plugs are firing? Could it be the connector to one bank of coils isn't plugged in all the way? Sometimes the pins inside a connector can bend, then not make contact. Might be worth disconnecting those and inspecting the contacts.

Lastly, can you check if you have any error codes? Sometimes there will be a clue in there (but not always).
I used a inline spark plug tester to check coil packs and I thought about a bent pin I haven't noticed any but I'll take a better look and I did use a noid light on the injectors I pulled the fuel pump fuse to keep from just filling the motor with fuel until I can get all 8 cylinders to spark and I've checked for codes 5 or 6 times nothing is coming up
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Old 12-23-2018, 09:34 AM
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Ok cool.

So did your injector test show you are getting fuel to all injectors?

Did your spark test show that you are getting spark to all plugs?
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Old 12-23-2018, 11:37 AM
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Originally Posted by computerz View Post
Ok cool.

So did your injector test show you are getting fuel to all injectors?

Did your spark test show that you are getting spark to all plugs?
injectors are pulsing and have fuel pressure and the spark test only showed spark at 4 cylinders and those 4 would come and go it might have been the battery being low from cranking so much tho
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Old 12-23-2018, 06:12 PM
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What engine didnyou put in and what year is the goat.
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Old 12-23-2018, 06:14 PM
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Originally Posted by blackbyrd View Post
What engine didnyou put in and what year is the goat.
its a dart LS next block and the car is a 05
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Old 12-23-2018, 09:08 PM
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Right relucter wheel for the ecm?
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Old 12-23-2018, 09:10 PM
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Originally Posted by blackbyrd View Post
Right relucter wheel for the ecm?
yes we counted it befor we put the oil pan on and I've looked back at pics to double check
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Old 12-24-2018, 01:23 PM
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Are the 4 firing cylinders on the same bank? Or are they random?
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Old 12-24-2018, 01:40 PM
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Originally Posted by blackbyrd View Post
Are the 4 firing cylinders on the same bank? Or are they random?
they are on different banks but the ones that do fire are really intermittent I was just messing with it and checked all 8 coilpacks on the number 3 cylinder and they all worked but 10 min later none worked on the number 3 cylinder
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Old 12-25-2018, 08:41 PM
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Sounds like a bad cam or crank position sensor. Happens I got a harness off a running car and had to.swap out the sensors after I put them into my 414. Would explain the intermittent firing order.
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Old 12-25-2018, 08:44 PM
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Originally Posted by blackbyrd View Post
Sounds like a bad cam or crank position sensor. Happens I got a harness off a running car and had to.swap out the sensors after I put them into my 414. Would explain the intermittent firing order.
I thought about that I've tried 2 cam sensors and 2 crank sensors and I have checked the crank sensor is picking up the reluctor wheel I do need to check the cam sensor a little more
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Old 01-03-2019, 11:21 AM
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Updates on this?
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Old 01-03-2019, 11:48 AM
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Originally Posted by AUS Injection View Post
Updates on this?
not really it's still getting spark on some cylinders and that's still intermitten my tuner thinks it's a ground problem but I cant find any ground that aren't on and we've added a couple ground I think I'm just going to trailer it to my tuner and see what he can do with it
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Old 01-03-2019, 12:37 PM
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Interesting, well let us know if anything comes up. Curious to know what it is
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Old 01-03-2019, 01:04 PM
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Originally Posted by AUS Injection View Post
Interesting, well let us know if anything comes up. Curious to know what it is
I will
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Old 01-04-2019, 09:57 PM
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I finally got the motor to start I have to give it a lot of gas then it will start but I have to keep giving it gas and it misses really bad and its throwing a code p0336 Crankshaft Position Sensor A Cicuit, Range/Performance going to mess with the crank sensor tomorrow
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