4.7 running rich

[Spjewell]

Been chasing my tail on this one...

1992 yj, obd1 setup w/ horse shoe (01) intake manifold.
Comp cam 68-232-4
62mm tb
4.2 crank, 4.0 rods, 60 over
Tre 24lb injectors, 40psi on the rail.

Measuring on the summit wide band aft gauge.

I am running rich on idle, but when I get some revs going it starts running a little lean.

10-12:1 at idle, 15-16:1 @2000 rpm

Initially had this problem with some lifter noise, ran a vacuum test and it was jumping from 12-19 in-hg. Ran a compression check and got #6=0psi, 1-5: between 165 and 175psi. Removed the rockers on #6, pulled the push rods, cleaned them, put the rods back tapped on them with a soft mallet to free them, ran a compression check and got 170. Put it all back together, everything ran a lot smoother, still has a little tick. Ran a vacuum test and it holds a steady 20 in-hg.

What do you guys recommend to get this puppy dialed in?

[Cheromaniac]

Just 100 miles or so of drive time for the ECU to complete its adaptive learning process.

[jsawduste]

Dino,
Been working with this guy on another forum.
We can richer up the off idle by adding a bit of FP. The idle richness is what's hurting. While I agree the ECM has some learning to do. Asking it to pull that much fuel at idle seems a bit much.

Is there really that much adaptability to shorten the duty cycle at closed throttle ?

[Cheromaniac]

Is there really that much adaptability to shorten the duty cycle at closed throttle ?

I doubt it. That said, I'm puzzled as to how the engine can run rich at hot idle but yet run lean at 2000rpm.
Something wierd going on.

[jsawduste]

Dino, that's what I am thinking also.
Suggested to the OP to post up here are I am puzzled as well.

[Spjewell]

Looks like I may not have solved the lifter issue... took it out for a drive today. About 5 minutes in my lifter tick came back fully, and it started running rough. When I get home I will run vac and compression tests to see where I'm at.

[jsawduste]

Post up the results.
There are a number of very talented folks here to help. Your case is very puzzling and I am curious as to what is happening.

[Spjewell]

Idle vacuum was at 18 in-hg, @ 210
Needle bounced slightly (17.5-18.5)
@2000 vacuum goes to ~23 in-hg

Back to running richer:
10-11:1 idle
13-13.5 @ 2000

I can defiantly hear something ticking (assuming lifter)

My next course of action will be to run a compression check again to see if anything changed, and tap on all the lifters to hopefully free the stuck one up. Anything else I should check or try?

[Cheromaniac]

A stuck or collapsed lifter won't allow the corresponding valve to fully open and that could be causing all the wierd air/fuel mixture issues you described. It'll also cause a rough-running engine. You may have to pull the head to get to the bottom of the problem.

[Spjewell]

That's what I was hoping to avoid. I did put cheap stock replacement lifters in, if I get to that point what do you guys recommend for a good set that are less likely to have sticking issues?

[Spjewell]

http://s358.photobucket.com/user/spjewe ... 0.mp4.html

Here is a video of the valves... of course once it cooled off, no tick...

[Spjewell]

So I put the valve cover back on... tick is back...
http://s358.photobucket.com/user/spjewe ... s.mp4.html

Here are some pics/bids of what I am seeing...





Vid @ 2000 rpm
http://s358.photobucket.com/user/spjewe ... r.mp4.html

[jsawduste]

You already know that the lifters are going to have to be replaced. Doubt they will magically fix themselves. Not to mention your not doing you cam any favors.

Johnson Hy-Lifts are your best bet. Get in touch with Russ Pottenger for a set. He is on this forum a lot and his contact info is in his sig.

Once you get the lifter business straight lets try again.

You said your fuel system was a custom AN set up. How about a picture of that ? Can you verify the return line is in fact returning ?

[Spjewell]

Fuel system. Center line is the evap passing theough. An-6 feed, an-4 return. Since the picture fuel pressure changed to 40 psi. If it wasn't returning I would be hitting 90 psi constant. Also I had a fuel pressure gauge a while back and confirmed rail pressure matched gauge pressure.

[Spjewell]

Not finding much on the web on Johnson hy-lifts... do you have a username or contact info? Feel free to pass mine on [email protected].