454 starting issues

[Slooptin]

Hey guys, maybe someone can help me, I'm at a loss. Just did head gaskets on my 454 and went to start to set timing and stuff and nothing. its getting fuel and 12v to the distributor, but no spark. I even swapped a new cap/rotor/coil/wires and still nothing. In theory, everything should work, but i have a spark plug tester on the 1st cylinder and it doesn't light up at all. any ideas what I'm not doing here? it was running fine (fineish) prior to the head gaskets.

Update: it's now backfiring (?) out of the intake and exhaust. still no power going to the plugs

 

[squareton]

IF it is backfiring it IS getting spark, the distributor could be out a tooth or more or it could be 180 out. Did you take the timing chain off?

 

[Matt69olds]

https://www.gmcmi.com/wp-content/uploads/2014/05/HEI-Testing.pdf

Read this.

 

[Slooptin]

Thanks. I've run through pretty much all of those tests except for the pickup coil and the exploratory surge test so I'll try those.

Can someone verify that I'm setting static timing correctly? I'm going mad over here trying to figure out what I'm doing wrong:

1. Turn over engine until the notch on the harmonic balancer lines up with the 0 deg on the timing plate.

2. Set the #1 plug on the cap to the position of the rotor

Maybe I'm overthinking this, but since 2 engine revolutions makes one complete cycle (4 stroke engine) then there are two different top dead center positions. could I have put the distributor in on the wrong "cycle" so to speak? Would it be worth it to remove the distributor and rotate the engine another 360 deg and then reinstall the distributor?

Sorry if that sounds ridiculous, I just feel like I'm going nuts trying to get this truck running. I managed to get my uncle's 68 bronco fired up this weekend and it was sitting in a garage for 10 years and I'm being defeated by a truck that was running a month ago

 

[Slooptin]

IF it is backfiring it IS getting spark, the distributor could be out a tooth or more or it could be 180 out. Did you take the timing chain off?

No, but I did remove the oil pump to do the rear main seal

 

[Matt69olds]

Try this:

Remove the number one plug. Slowly rotate the engine on the compression stroke, stop when the timing marks read your desire initial timing number, say 12 degrees.

Remove the distributor cap, is the rotor pointing to number one plug wire? If so, reinstall the cap. Put the number one plug wire on the plug, and make sure it’s well grounded. Loosen the distributor hold down clamp. Turn on the ignition, but DO NOT CRANK THE ENGINE! Rotate the engine back and forth, you should see a consistent spark from the number one wire. If you go, you have the distributor installed correctly. Turn off the ignition, reinstall the plug and wire. Remove the cap again. Find the triangle shaped “teeth” on both the pickup coil and the distributor shaft. You may have to remove the rotor to see them. Slowly rotate the distributor until the teeth are aligned, make sure the rotor is still pointing at #1. Tighten the distributor hold down, reinstall the cap. Start the engine. When you put a timing light on it’s it should be pretty close to whatever number you stopped turning the engine. The only variable will be slop in the timing chain, which should be pretty small

 

[Slooptin]

Try this:

Remove the number one plug. Slowly rotate the engine on the compression stroke, stop when the timing marks read your desire initial timing number, say 12 degrees.

did this and still no spark. I'm getting 12v to the coil with key on and ~10-11v while cranking

 

[SirRobyn0]

Ok so let me see if I understand this correctly. There is no spark at the plugs. You have 12 volts going into the distributor, you have replaced the cap, rotor, coil and wires. It is recommended to have 10.5 volts or more during cranking at the coil. Which it looks like you probable have.

So if you have read the link Matt posted then have you tested the pick up coil?

Your question: "Maybe I'm overthinking this, but since 2 engine revolutions makes one complete cycle (4 stroke engine) then there are two different top dead center positions. could I have put the distributor in on the wrong "cycle" so to speak? Would it be worth it to remove the distributor and rotate the engine another 360 deg and then reinstall the distributor?"

Yes that's how it works and yes you could have it 180 out, but that would not cause no spark, it would be spark at the wrong time, but you did say at one point it was backfiring which would indicate there is spark, but then you said no spark on the test light. I'm not trying to be difficult but you are contradicting yourself. It either has spark or not and we need an accurate answer to that.

With that said have you put the #1 cylinder on TDC to see if the distributor is in properly? If not you need to do that. If your not sure how to put #1 on TDC accurately let us know and one of us will tell you how.

Double check that you have assembled the coil properly. If it's timed right, you really only have two things left the pick up and the module. You can and should test the pick up, if that's good then it must be the module assuming again that the distributor is not 180 out.

I'm not trying to be a jerk, I'm trying to help so hopefully I come off that way it's just with the no spark / backfiring being a contradiction of sorts it's difficult for me to try to give good advice. But hopefully some of this will be of help to you.

 

[Slooptin]

Ok so i think it was the module in the distributor. Now it will start, but almost immediately dies and is still backfiring through the carb

 

[SirRobyn0]

Ok so i think it was the module in the distributor. Now it will start, but almost immediately dies and is still backfiring through the carb

Well they are not all that expensive, and certainly do go out from time to time. Let us know if that takes care of it!

 

[Snoots]

Pick-up coil. It should read ~900 ohms. BUT I've had them read that and still be bad. Cheep & Easy to replace.

 

[Slooptin]

Ya it was the module. Started after I replaced it but it won't stay running for some reason. I spent the afternoon messing with the mixture & idle screws and the timing and still no dice. I can kind of keep it running if I'm quick with the gas pedal, but it won't idle for the life of me

 

[potent rodent]

Try this:

Remove the number one plug. Slowly rotate the engine on the compression stroke, stop when the timing marks read your desire initial timing number, say 12 degrees.

Remove the distributor cap, is the rotor pointing to number one plug wire? If so, reinstall the cap. Put the number one plug wire on the plug, and make sure it’s well grounded. Loosen the distributor hold down clamp. Turn on the ignition, but DO NOT CRANK THE ENGINE! Rotate the engine back and forth, you should see a consistent spark from the number one wire. If you go, you have the distributor installed correctly. Turn off the ignition, reinstall the plug and wire. Remove the cap again. Find the triangle shaped “teeth” on both the pickup coil and the distributor shaft. You may have to remove the rotor to see them. Slowly rotate the distributor until the teeth are aligned, make sure the rotor is still pointing at #1. Tighten the distributor hold down, reinstall the cap. Start the engine. When you put a timing light on it’s it should be pretty close to whatever number you stopped turning the engine. The only variable will be slop in the timing chain, which should be pretty small

i do the same thing with timing ,only i turn my dist and watch for the num 1 plug to fire pretty close without a timing light

 

[SirRobyn0]

Ya it was the module. Started after I replaced it but it won't stay running for some reason. I spent the afternoon messing with the mixture & idle screws and the timing and still no dice. I can kind of keep it running if I'm quick with the gas pedal, but it won't idle for the life of me

Any luck or do you want suggestions on the idle issue?

 

[Slooptin]

Got it sorted out. Thanks all!