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Cylinders 3 and 5 running leaner than the rest.

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Old 12-30-2018, 04:17 PM
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Default 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.
Old 12-30-2018, 06:43 PM
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Clogged/dirty 3 and 5 injectors....
Old 12-30-2018, 06:52 PM
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Originally Posted by G Atsma
Clogged/dirty 3 and 5 injectors....
Agreed. Send your injectors off for a flow test and cleaning. And maybe do a compression/leak down test on the engine.
Old 12-30-2018, 09:51 PM
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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.
Old 12-31-2018, 06:49 AM
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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.
Old 01-02-2019, 08:35 PM
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E85 and sitting most the time will cause lots of fuel system issues.
Old 01-03-2019, 07:08 AM
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Just wanted to post an update. I pulled the injectors on Tuesday. Definitely found the problem.

Before.

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.
Old 01-03-2019, 10:00 AM
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check your fuel filters..............
Old 01-03-2019, 10:11 AM
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Don't let your motor sit that long without running! especially running E85 or meth
Old 01-03-2019, 08:11 PM
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Yuck that's pretty bad.

I had no idea e85 did that. Learned me something new.
Old 01-03-2019, 08:35 PM
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Originally Posted by 00pooterSS
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....
Old 01-04-2019, 05:47 AM
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Originally Posted by AUS Injection
Don't let your motor sit that long without running! especially running E85 or meth
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?
Old 01-04-2019, 05:48 AM
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Originally Posted by G Atsma
Yo, THAT is some NASTY crud! No wonder it was lean on those holes....

Yeah, surprisingly they all looked like that.
Old 01-04-2019, 10:12 AM
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Originally Posted by 98Zheadsncam
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?
How many miles do you put on it when you take if for a drive? or do you just drive it around the block
Old 01-04-2019, 11:33 AM
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Originally Posted by 98Zheadsncam
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?
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.

Old 01-06-2019, 09:05 AM
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Originally Posted by AUS Injection
How many miles do you put on it when you take if for a drive? or do you just drive it around the block

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.

Last edited by 98Zheadsncam; 01-06-2019 at 09:10 AM.
Old 01-06-2019, 09:08 AM
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Originally Posted by RockinWs6
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 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.

Last edited by 98Zheadsncam; 01-06-2019 at 02:14 PM.
Old 01-07-2019, 09:47 AM
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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?
Old 01-07-2019, 10:18 AM
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Originally Posted by 98Zheadsncam
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.
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.
Old 01-07-2019, 11:53 AM
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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



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