bank 1 rich bank 2 ok

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
lugbolt
Posts: 24
Joined: 2021 Feb 15, 19:03
Location: central arkansas
Vehicle Information: 1992 ford mustang gt A9P 10.5:1 pump gas 408"w AFR205 T56 Magnum 8.8/3.73

bank 1 rich bank 2 ok

Unread post by lugbolt »

92 mustang N/A 408" efi a9l2. Super victor efi 80lb siemens deka (genuine), 10.5:1 93 octane pump fuel. 6061 elbow 90mm TB 4" anderson pipe. PCV is more or less the factory style setup. AFR205 renegades. Ed cam 242-252 at 50 .600+ lift. Pretty common setup.

WBO2 is in the driver's side of the H pipe about 6" behind the collector. right bank (bank 1) plugs show to be really rich. They are black carbon fouled, I have not been wide open with these plugs and they have about 200 miles or so on them, max. Left side plugs look great. HEGO's have a bias but only at certain throttle opening. At 1/4 throttle the hego's show about the same. Just off of idle, CL, the right side shows 1.25+ lambda, left side 0.98-1.02 for the most part. It almost follows high vacuum, which led me to believe that it had a vacuum leak somewhere. But darned if I can find it even with smoke machine. Even went as far as putting 10 psi into the intake tract and using soapy water around the intake, injectors, everything post throttle body and nothing was found, zero leaks. Not even the throttle shaft or TPS which are pretty common.

Smoke tested the intake, zero leaks. I bought a smoke machine to do this before I had to go out of town last year. Re-tested earlier to verify my notes. Engine compression 180 psi on all 8 cylinders hot. 175 cold. The ONLY thing I have found is some real small leaks at the right side header slip fit tubes, and a teeny tiny leak at the flange. I went in and made some makeshift clamps to go around the slip fits and got those sealed up but the flange, nothing I can do about that short of replacing the headers. I didn't like this design from the get-go anyway.

Several questions. Do you reckon the elbow might have something to do with it? I wouldn't think so at low load high vacuum but what do I know? Second thought was PCV. Valve is in front left side of valve cover. Fresh air tube in the left rear valve cover, runs up to the intake tube almost like factory 5.0's were but I used a larger 3/8 dia tube and hose. It's all sealed up good verified with smoke test. Will a tiny flange leak cause the hego's to read lean, and then that side of the motor to go "that" rich? It runs like crap, as if it were real lean but the o2's don't show it. KAMs can get 1.25+ on the right side and stays 1.00-ish on the left side, but again only under really light load and high vacuum. The less vacuum, the closer the KAM's get. At about 1/4 throttle give or take a little they are about equal side to side.

It has fought me for the last year and I'm honestly about ready to throw in the towel. I put a lot of my money into it so it's kinda frustrating.

Ideas?
dleach1407
Posts: 212
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Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: bank 1 rich bank 2 ok

Unread post by dleach1407 »

Is the o2 in the lean bank switching above and below .5v? Sounds like a lazy o2. You could just swap the o2s into opposite banks and see if the problem follows.

An elbow or pcv issues won't cause issues on one bank. Depending on how bad the leak is it could cause a lean condition but a small leak is unlikely to cause a +25 trim.
red5.0fogger
Posts: 27
Joined: 2021 Mar 22, 15:58
Location: Newington CT
Vehicle Information: 1986 Mustang GT, Stock block, TFS 170 Heads , N41 cam, ported cobra intake, nitrous, T5 , 3.73s

Re: bank 1 rich bank 2 ok

Unread post by red5.0fogger »

When you smoke tested, did you block off the intake and exhaust pipes to allow some pressure to build up? ( around 2 psi) I never used one but if there's no pressure build up the smoke has no reason to be forced through smaller leaks or partially sealed areas. It will just go out the air filter or headers.
Also x pipes do something weird to the o2's Running an x pipe? Decipha can chime in?
Brewster
Posts: 44
Joined: 2021 May 15, 15:59
Location: Edmonton, Alberta, Canada
Vehicle Information: 1992 Mustang LX
347 Cui
AFR 185

Re: bank 1 rich bank 2 ok

Unread post by Brewster »

Post a log and tune up. Leaks can be a pain to find and definitely freak out a hego thinking there's a lean situation
Blocmi
Posts: 19
Joined: 2021 Feb 16, 11:13
Location: Connecticut
Vehicle Information: 1995 Mustang GT, CBAZA, 11:1 306, Ported Windsor Sr. aluminum heads 2.02/1.60, Trick Flow Track Heat, 24lb injectors, Comp cams 294/306 (2,800-7,000), Shorty headers, X-Pipe, Reverse Manual VB C4, 4100 stall converter, 4:10, MT ET Drag 26-10-15

Re: bank 1 rich bank 2 ok

Unread post by Blocmi »

A misfire can cause false O2 readings. Any possibility of a misfire on the rich bank?

Also as a quick check, make sure all the injectors are assigned to the proper O2 sensor for each bank.
lugbolt
Posts: 24
Joined: 2021 Feb 15, 19:03
Location: central arkansas
Vehicle Information: 1992 ford mustang gt A9P 10.5:1 pump gas 408"w AFR205 T56 Magnum 8.8/3.73

Re: bank 1 rich bank 2 ok

Unread post by lugbolt »

I swapped the hego's a while back before I left for overseas-no change. Bank 1 still lean. For giggles I reassigned banks in the tune and then bank 2 shows lean, so I don't believe it to be a hego problem.

I don't feel or see any sign of a misfire, aside from the camshaft's idle and low speed running characteristics. Lots of bucking at light loads which I attribute at least partially to whatever is causing this issue with different lambses between banks.

When I smoke tested the exhaust, I did not block off the intake or anything. I didn't get any smoke out of the intake at all that I could find. There was a ton coming out of a few of the header slip fits and of course the flange has a leak on the passenger side (bank 1). H pipe on mine. I made a cap for the other tail pipe, and fed the smoke into the drivers' side only. With the H crossover, it fills both pipes. It had some pressure in it, not a lot. The machine is regulated to 2 psi.

I'll get a log as soon as I can-had a rough day today. Got hit by a tarantula this morning then this afternoon got a bath in oil and all up in my eyes, hair, etc...and it's dyed purple, so I have a purple face for a little while and a little bit blurry vision.
red5.0fogger
Posts: 27
Joined: 2021 Mar 22, 15:58
Location: Newington CT
Vehicle Information: 1986 Mustang GT, Stock block, TFS 170 Heads , N41 cam, ported cobra intake, nitrous, T5 , 3.73s

Re: bank 1 rich bank 2 ok

Unread post by red5.0fogger »

The intake gasket may have slipped out of place or be leaking on the lower side near the pushrods. The paper type 1250 gasket did that on mine. (Black with blue o ring bead) It will suck in oil and unmetered air.
decipha
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Re: bank 1 rich bank 2 ok

Unread post by decipha »

I don't understand what reassigning the banks would do?
lugbolt
Posts: 24
Joined: 2021 Feb 15, 19:03
Location: central arkansas
Vehicle Information: 1992 ford mustang gt A9P 10.5:1 pump gas 408"w AFR205 T56 Magnum 8.8/3.73

Re: bank 1 rich bank 2 ok

Unread post by lugbolt »

Mike I did that a while back and reverted back to where they're supposed to be. I did it for testing purposes only. You had posted to do it on the old forum in another thread (which is gone now).

Finally got a minute to do a quick log. Take a look. Seriously don't know what to do.
718(2).xdl
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lugbolt
Posts: 24
Joined: 2021 Feb 15, 19:03
Location: central arkansas
Vehicle Information: 1992 ford mustang gt A9P 10.5:1 pump gas 408"w AFR205 T56 Magnum 8.8/3.73

Re: bank 1 rich bank 2 ok

Unread post by lugbolt »

red5.0fogger wrote: 2021 Jul 15, 07:25 The intake gasket may have slipped out of place or be leaking on the lower side near the pushrods. The paper type 1250 gasket did that on mine. (Black with blue o ring bead) It will suck in oil and unmetered air.
I looked at that during smoke test. Removed the oil filler cap from the valve cover while smoking the intake tract. I got a tiny bit of smoke out of the pcv hole. In 5 minutes of running air/smoke through it I think I saw a squiggle of smoke out of the oil filler hole. I wrote it off as normal leakage past the rings. Just for giggles I did another leakdown test on all 8 cylinders and got under 5% on 7 cylinders and #4 was right at 5%. Because of the spark plug angle and where #4 sits, there was possibility that I may not have gotten the hose screwed in quite far enough.
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