Hello everyone, i have recently build a 351w i threw some bosch style 21 lb injectors 185cc alluminum hydraulic roller heads from jegs as well as speedmaster full roller rocker set. i also have an msd coil and cap n rotor. not so sure how familliar you guys are with the years but my truck has the TFI module/ spout connector on the driver fender. when adjusting the valves I went to top dead center compression every 90 degrees in firing order 1-3-7-2-6-5-4-8 turned the adjuster until just got some drag on pushrod then half a turn. yes i replaced my pushrods had them measured perfectly and centered nicely. all new plugs and ford racing 8.5mm wires. anyway started the motor up timed it to 10 btdc it wasnt too happy until 16 btdc after a drive or so noticed it was a bit shakey and lacking response and some power anyway i finally noticed the header on cyllinder 4 and 5 were bone cold. after testing spark and seeing some fuel in the 2 cyllinders i figured well guess i messed up the valve adjustment so I went back threw #5 tdc compression re adjusted and nothing. soo i started testing liike a mad man first I swapped plugs between a good cyllinder and 5 nothing, did the same with wires and nothing, isolated the wires so they didnt touch any others and nothing, i got a inline spark tester and with the motor under operating conditions still had solid spark consitently identical to other cyllinders. as i said earlier there was a little puddle of fuel in both cyllinders so I know it has fuel. anyway to make sure I cleared the cyllinder of fuel unplugged the injector and cranked, no fuel coming from the injector so its not leaking, keeping the injector unplugged i sprayed some starting fluid in the cyllinder and cranked it up, after a second removed the wire at the cap and idle doesnt flinch still not contributing , so thats ignition and fuel confirmed present? now im thinking maybe compression got 150 compression static and 50-75 psi running I checked with a good cyllinder and it has 50-75 psi running. it has compression so it should run? this pretty much brought me to my last idea maybe the intake runner gasket failed and is sucking umetered air making the cyllinder lean? checked all around the intake runners with carb clean and no idle. This made me think maybe timing? with the cap off and the motor at 1 tdc compression the rotor lines up perfectly in the middle of tower 1 and the crank mark is at 0. I really have no clue atp if someone could help please messege me thanks everyone

 

Do you have the factory cam in it still? What brand heads? Did you confirm valve seating before install? Are you using spark plug recommendation from head manufacturer? I would ground the spark plug directly to the head and see if it’s sparking.

 

yes factory cam is in, the heads are according to jeggs they are jeggs heads they dont recommend any plugs to use so I stayed with the stock style NGK iridium plugs, and why would it only effect 2 cyllinders? same plugs and wires all around I did use an inline spark tester so it hooks to my existing plug wire and goes onto the plug with engine running the spark was consistent and showing same results as another good cyllinder. but no I did not check for fulll valve seating before assembly as the heads were new and pre assembled i roughly inspected it and sent it

 

You have compressed air? I would pump in the cylinder when at tdc to see if you hear air coming out of intake or exhaust. That will tell you if the valves are closing all the way or not. Spark plugs can matter bc some require a longer plug to reach in the hole. I know it doesn’t make sense to affect only 2, but weirder crap happens!

 

Remove the PCV valve and plug the hole. Remove the 2 valve cover oil fill caps, start the engine and put your hands over the valve covers and feel for a vacuum. That will tell if the intake gasket is leaking in the crankcase.

 

Did you degree the cam?
Cam timing sounds off, should run at 10* not 16*

 

"Stock" plugs are not NGK iridium
Did it ever run good, or on all cylinders?

 

If the basics are good, I would confirm the cylinders can hold/make compression. I prefer a CLT but a compression test would shed some light on this.

 

The big 3
Sounds like you have good compression and might have decent spark
I'd check the injector flow manually from the new ones that might be junk
Test the #5 and 6 injectors by manually firing them while you monitor the fuel pressure drop
Do post 4 and 5 for clues

 

for some reason i noticed she doesnt like 10 the best

 

i have a pcv delete new valve covers so just 1 hole in each cover I stuck a breather in, I will try this next today

 

okay I will try dropping an injector from 6 over to 5 and see if the misfire moves

 

yes before I took it apart it ran good but since the build it hasnt fired 5 and 4 I will call jegs and see what plugs they recommend

 

I will try this today as well

 

Why?
Was it a Jegs motor?
Autolite is the fastest spark plug in the world because they run them in most of the top fuel funny cars / dragsters
I use a Motorcraft spark out of a Ford Ecsort 1.9 in my sons old Honda Elsinore that fouls factory NGK plugs
The Motorcraft never fouls
You can run any plug you want really; I used to just see the HC go up on the I/M machine on anything that was not a Motorcraft when doing emissions tests