Cylinders 3 and 5 running leaner than the rest.
 

So, I've recently discovered an odd issue. I pulled the B8EFS spark plugs out the other day because I'm mostly street driving the car and figured I'd run BR7EF's as I can't run crazy boost on the street anyway. At any rate, I discovered that all the plugs EXCEPT cylinders 3 and 5 looked like they were running too rich. By this, I mean the insulator tips all the way to the tip of the electrode are dark. Cylinders 3 and 5 looked good...white insulator as far as I can see without cutting the plug. I swapped coils...no difference. On the logs, everything looks fine. No super rich areas of the VE. Motor runs great under boost...no issues there. I'm seeing this same pattern with the BR7's as well.

All the plug wires look fine...no burnt areas. Intake is a Vic. Jr.

Any ideas will be greatly appreciated.

Thanks guys.

Clogged/dirty 3 and 5 injectors....

Did you measure the temps of the manifold/header primaries to see if those two are hotter?

You could also swap injectors 3&5 with 1&7 and see if the issue follows the injectors.

Could possible me a difference in compression or heat in those cylinders if the above doesn't show up anything.

But I would take it easy until you get it sorted, in case it has dirty injectors. Don't want it to pop while you're trying to figure it out.

I'm running E85....been doing so for the past 4 years. The car sits most of the time...only 1500 miles on the motor since it was built back in 2015.

I need to get batteries for my temp gun. That's a good idea.

I'll probably just pull the injectors and have them cleaned.


Thanks guys.

E85 and sitting most the time will cause lots of fuel system issues.

Just wanted to post an update. I pulled the injectors on Tuesday. Definitely found the problem.
https://cimg1.ibsrv.net/gimg/ls1tech...4d7eea6e34.jpg
Before.
https://cimg4.ibsrv.net/gimg/ls1tech...5774eb03e5.jpg
After a dunk in some 87.


They're being cleaned today...I should have them back tomorrow. I'll be making a pump gas tune for the car.

check your fuel filters..............

Don't let your motor sit that long without running! especially running E85 or meth

Yuck that's pretty bad.

I had no idea e85 did that. Learned me something new.

Yo, THAT is some NASTY crud! No wonder it was lean on those holes....

I drive the car every other week. I figured that would be adequate.

From what I've found online, this gunk is supposedly from driving the car...the gunk forms when the injector drips after shut down, and it bakes in the radiant heat from cylinder. I'm no authority on the matter, though. Are you saying the pump E85 is just dirty?

Yeah, surprisingly they all looked like that.

How many miles do you put on it when you take if for a drive? or do you just drive it around the block

Actually those injectors can be fouled from oil too. The oil from the valve guides and PCV system vaporizes in the intake when the engine heat soaks and bakes onto the injectors. You may find the valve seals are leaking on those cylinders or the valve guides are a little on the loose side OR if you have ported heads the rocker studs are leaking oil into those cylinders. This is very common on ALL engines not just HP stuff.

I have a set route I use when I take the car out. Some city driving, then I jump on the interstate. It's about 15 miles round trip.

I vent the valve covers to the atmosphere, but the motor does have blow by from the large ring gap. There's also definitely oil getting past the valve stems...I noticed it on decel when the car was on the dyno. Checking the seals and guides probably isn't a bad idea.

So what's the update on this? Did you get them cleaned? Sorry if I missed the post some where.

If you have large gaps allowing excessive blow-by, consider a running a vacuum. It would really help keep that oil at bay.
Do you get plenty of smoke out of that valve breather?

If you drive 15 miles every other week, it should not clog up on you when using E85. Could possibly be an oil issue? Keep us updated, curious for the end results.

Alcohol in the E85 does attract water out of the atmosphere and is why many people won't run E10 in their yard toys - mowers, blowers and chain saws, etc. Yea, I understand the advantages to E85 for boost but I think the idea was to burn it faster with more frequent driving to lessen the moisture problems.

I pay 60-70 cents more per gallon around around here for no ethanol pure gas and its worth every penny when I have to restart things in the spring.

Rick