Only running on 3 of 6 cyl

GrandmaLS

GrandmaLS

Club Member
Vehicle: 1994 Chevy Camaro 3.4L V6

Problem: I just did head gaskets on the gf's Camaro and now I have a big problem with it only running on 3 of 6 cylinders. Cylinders 3,5, and 6 are dead. I can run it for a minute and the headers for those cylinders are still at 45 degrees. The spark tester says the coil to wire is sparking, wire to plug is sparking, the NOID light (think thats the name) says the harness is telling the injector to fire, and even the plugs are soaked in gasoline. Any ideas?

I am 99.9% I adjusted the valves right but maybe I fucked it up. I spun the crank until the mark came up to 12 o'clock and made sure the neither of the valves moved on #1. At that point I wiggled the pushrods until I felt no play and then spun the nut and additional 1 turn (3/4-1 1/2 recommended). While #1 was on TDC I was able to do exhaust valves 1,2 3, and intake valves 1, 5,6. Then spun the crank 360 degrees and was able to do exhaust valves 4, 5, 6 and intake valves 2, 3, and 4. Maybe this manual I'm using is wrong?

I replaced the plug wires because when I was taking it apart 2 of them seperated the connector from the boot on the spark plus side. I replaced the plugs today (3-19-09) to no difference
 
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Rockers on that engine bolt down. Nothing to adjust. you didn't cross any injector plugs did ya?
 
check your firing order.


GrandmaLS said:
Vehicle: 1994 Chevy Camaro 3.4L V6

Problem: I just did head gaskets on the gf's Camaro and now I have a big problem with it only running on 3 of 6 cylinders. Cylinders 3,5, and 6 are dead. I can run it for a minute and the headers for those cylinders are still at 45 degrees. The spark tester says the coil to wire is sparking, wire to plug is sparking, the NOID light (think thats the name) says the harness is telling the injector to fire, and even the plugs are soaked in gasoline. Any ideas?

I replaced the plug wires because when I was taking it apart 2 of them seperated the connector from the boot on the spark plus side. I didn't replace the plugs but they were done less than 10k ago.
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smooth said:
Did you properly lash the rockers?
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I followed the manual exactly. #1 TDC did x,x, and x intake and x, x, and x exhaust. Spun the engine 360 and did the rest of them. The manual said remove all play and tighten 3/4-1 1/2 turns. I did all 1 full turn after play was removed.

RBOD said:
Rockers on that engine bolt down. Nothing to adjust. you didn't cross any injector plugs did ya?
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Actually they do. You're thinking the 3.1 and 3.4's in the FWD cars or the newer 3.4's. Not sure but both intake jobs I've done on Aztecs they were simply bolted on.

ReiKo said:
Coil is bad...
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That really doesn't make sense to me because the only coil we took off (cyl 1/4) is working fine. The two that were completely untouched are the ones not firing correctly. Plus, the spark tester says all cylinders are firing.


Sean said:
check your firing order.
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How? Each coil is labeled and the wires are ran to the correct cylinder. You can't f it up like a 350.

Duke said:
Check the ignition fluid.
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Should be fine. I changed it like 8-10k ago... :roll:

dave89iroc said:
x2

also, I have seen quite a few with a leaking fuel pressure regulator, just pull the vacuum line off it and see if it has fuel in it
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I'll have to check that tomorrow. Right now its time to warm up and take a shower.
 
GrandmaLS said:
I followed the manual exactly. #1 TDC did x,x, and x intake and x, x, and x exhaust. Spun the engine 360 and did the rest of them. The manual said remove all play and tighten 3/4-1 1/2 turns. I did all 1 full turn after play was removed.



Actually they do. You're thinking the 3.1 and 3.4's in the FWD cars or the newer 3.4's. Not sure but both intake jobs I've done on Aztecs they were simply bolted on.



That really doesn't make sense to me because the only coil we took off (cyl 1/4) is working fine. The two that were completely untouched are the ones not firing correctly. Plus, the spark tester says all cylinders are firing.




How? Each coil is labeled and the wires are ran to the correct cylinder. You can't f it up like a 350.



Should be fine. I changed it like 8-10k ago... :roll:



I'll have to check that tomorrow. Right now its time to warm up and take a shower.
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hopefully all the coils are still in the right place
 
dave89iroc said:
hopefully all the coils are still in the right place
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We only took one off. They are all mounted to a large bracket. Only the lowest coil (1/4) has to be taken off to remove the coil. Like I said before, both those cylinders are working fine. Its 3, 5, and 6 that are acting up.
 
Bump. Still doing it. I've replaced the plugs, cut out and replaced an iffy looking wiring section to the crank sensor, and redid the grounds that are in the same harness as the coils. Noid light says all injectors are firing and spark tester says all coils are firing.

Any way to check for a bad crank sensor other than to replace it?
 
Warning this procedure is dangerous and could result in severe injury or death. Proceed with cuation


do a cylinder drop test. Remove a plug wire at a time and see exactly how many dead holes you have. Better to remove it at the plug.

Then test those cylinders for compression. If you had a bad crank sensor it wouldn't run. Also it would most likely round robbin missfire if it was barely working.

Recheck the firing order. I know I already siad it. But just becuase you only removed 1 coil doesn't mean that somebody else didn't move them all. also there is a way to screw up the firing order and have it run on 3 cylinder. I can't remember how the last guy I saw do it, did it but it can be done.
 
Sean said:
Warning this procedure is dangerous and could result in severe injury or death. Proceed with cuation


do a cylinder drop test. Remove a plug wire at a time and see exactly how many dead holes you have. Better to remove it at the plug.

Then test those cylinders for compression. If you had a bad crank sensor it wouldn't run. Also it would most likely round robbin missfire if it was barely working.

Recheck the firing order. I know I already siad it. But just becuase you only removed 1 coil doesn't mean that somebody else didn't move them all. also there is a way to screw up the firing order and have it run on 3 cylinder. I can't remember how the last guy I saw do it, did it but it can be done.
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Why would I want to do a cylinder drop test? I already know just by touch/thermostat that 3,5, and 6 are dead. I checked, rechecked, checked again, and again about the firing order. The coils are in the right spots and wires are ran properly.
 
bend a valve ? Do a compression test. It would rule out mechanical failures. how long has the car been sitting ?


GrandmaLS said:
Why would I want to do a cylinder drop test? I already know just by touch/thermostat that 3,5, and 6 are dead. I checked, rechecked, checked again, and again about the firing order. The coils are in the right spots and wires are ran properly.
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Sean said:
bend a valve ? Do a compression test. It would rule out mechanical failures. how long has the car been sitting ?
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Well because of the headgaskets/not running right like 3 weeks. Before that its been daily driven for almost 15 years now!
 
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