6th cylinder not firing

[325issguy]

Hey guys,
I have been trying to troubleshoot a problem with my obd1 m52 swap for the past week or two. I was on the interstate last week gettin on it in 4th gear and noticed it wasnt pulling how it should. I got off the interstate and the idle was bouncy. You cant see it on the tach but you can feel it.

I noticed I have an exhaust leak and the tick is really loud but Im not sure if the leak just got worse because of the vibrating engine.

I started out by pulling the coil packs and the number 6 cylinder did not respond. I swapped the coil packs with no change and then checked for spark. It had spark so I then checked the fuel injector pulse using a noid light and swapped the 5 and 6 fuel injectors being everything checked out to that point.

Still had no change so I then did a compression test and had between 192-210 on all cylinders. I also pulled the valve cover because I was doing the gasket anyways and everything in there looked fine.

Stomp test shows code for 3rd ignition coil but swapping that produces no result as well. I have checked and cant find any vaccume leaks. May be worth noting as well that the plug is dry when I pull it.

[dsobering47]

How are the plugs themselves? Newer? Any of the ceramics cracked? Is it a consistent misfire in one cylinder or intermittent? Have you altered anything recently?

[325issguy]

Constant misfire on 6th cylinder. Havent changed anything recently. Plugs all look ok. Swapped plug on 6th cylinder too with no change.

[dsobering47]

How are you running your CCVV? I've seen OEM ones clog up and cause random misfire issues. If you open your oil cap with the engine running, just crack it a bit, what happens?

[dsobering47]

Also, have you checked to make sure youre getting constant fuel pressure? There is a schrader valve on the fuel rail...

[e30s50dan]

I had to go thru a couple coil packs till I found a good one. They worked at idle but once I r3v the engine the spark would go away .harbor freight has a spark plug tested that works great for under 10 banannas. Found out I had two bad coil packs. Good luck!

[weaksauce]

did you say you were or weren't getting an injector pulse?

[Philo]

Sometimes the wires that sit on top of the injectors to give a pulse back out. I would make sure they are pushed down all the way, and are getting a good connection.

[325issguy]

I am gettin injector pulse. I have unplugged and replugged in the injector harness. Seriously am stumped here. Seems like im not gettin fuel but I cannot think of one reason that Im not.

Thinkin about takin it to the shop and seeing what they say is wrong with it.

[Adrian_Visser]

Sometimes the wires that sit on top of the injectors to give a pulse back out. I would make sure they are pushed down all the way, and are getting a good connection.

This.

I had the same problem when I first got my s52 running, do you have the locking clips installed on the connectors? If not there is nothing holding the connector onto the fuel injector and despite the fact that there is power at the connector it won't fire the injector.

[325issguy]

It ended up being the computer. Swapped one over and she runs great.