ZBRA

I pulled both heads off today, and the driver side has major carbon deposites on the head and piston. Obviously running rich.

When I pulled the pass side off, it looked normal. No carbon deposites or signs of running rich.

I realize that the only O2 sensor is on the driver side, but I don't understand why only one side would run rich, especially that side.

All of this happened within only about 5000 miles. That's how long it has been since I put the heads on.

I am going to replace the O2 sensor when I put the heads back on.

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'91 Z28 Blue/Silver ZZ4/ZF6
335.9 rwhp 374.9 rwtorque

[This message has been edited by ZBRA (edited September 10, 2000).]

Guest

I think it would have to be a wiring problem, because the pressure should be equal on both sides, and I really doubt you have 4 bad injectors on just one side. That whole bank however, is wired to the same driver circuit from the ECM, I'd look in that direction first.

WECoyote

ZBRA,
What did the plugs from the drivers side head look like? Where they blackened? A dry black coating on the electrode?

Madmax has a good point. Sounds like the drivers side injector bank is staying grounded longer...ie injectors are open that much longer.

Were all the cylinders (1,3,5,7) carboned more heavily than the passenger side ones?

How did the driver side runner look inside? Was it blackened more/have a thicker 'film' of carbon deposit than the passenger side?

Have you had your injectors flow tested. By some remote 'cosmic' chance you could have some higher flowing injectors on the drivers side.

What type of headers and y-pipe are you using? Any dents or some collapsing on the drivers side exhaust components?

Um.....are you sure you have the same(matched) heads on both cylinder banks? Dont take that as an insult!! I have heard of it happening.....even see 'mismatched' heads for sale at swap meets from time to time! LOL! Different heads would flow differently hence a richer mixture on the drivers side.


Other ideas.......

valve lash set differently

broken valve spring(s) [mis-matched valve springs]

bent pushrods

Mike

[This message has been edited by WECoyote (edited September 10, 2000).]

Guido

One thing no one mentioned. And its a longshot.

Could you have had some fuel rail problems? Possibly it was not sealing good? what I mean maybe the drivers side was running to rich because somethine was blocking it from getting as much to the passenger side?

I dont know what else... hmm

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-86 IROC
Vortech stuffed EFI 406 in progress

ZBRA

OK, the injectors are relatively new set of SVO 24#s bought new as a set.

The headers and y-pipe are fine, as in no dents or obstructions.

The heads are matched TFS G1 Twist Wedges.

One of the valve springs did break, but that was an exhaust valve on the pass side (#8). That is why I pulled the heads back off.

All of the pushrods were fine, but they are being replaced anyway with some slightly longer. This was the recomendation of TFS.

If it is the fuel rail, then installing the Mini Ram is going to fix that.

All of the plugs (#6 Rapidfires) were installed new when I put the heads on. The plugs on the driver side were coated with a dry black film. All on the pass side looked normal, or light tan/yellow.

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That leaves madmax's idea of the driver pulse lasting too long. How do I go about checking that once I put the motor back together? I do have a Actron Scan Tool. I don't know if I can look that up on it or not. Looks like I won't know anything until it is running again.

Cntrvrsy

I wish I had a solid answer, but I remember a few years ago I had a problem with my iroc in which 1 side of the headers would turn cherry red. It turned out 2 be the 1 side of the injector bank wasn't firing. I didn't fix the problem myself, I had taken it 2 a speed shop so I don't know what was involved in the fix. But like MadMax suggested it was ECM related.

scoob8000

doesnt the quad driver control each bank of injectors independently?

-=Jeff=-

ZBRA,

My guess too is the ECM.. each bank is independant of the other.. this could be a problem..

Otherwise there are a lot of great ideas here

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-=Jeff=-
89 Corvette Coupe White with Black Grand Sport Stripe

Check out my mods on My '89 Vette