Still have wide band issues........

[Spence]

what is going on here?

since I have purchased this speed pro/FAST setup(struggling with this problem for 2 years) I have never ever been able to use the wide band accurately. I finally ordered a new WB sensor and installed it and the disc, it seems to show actual reading at idle and off idle, but when I go WOT it still shows 9.19:1 air fuel in closed loop no matter how much we move the VE tables. We have resorted to plug readings, and there is no evidence that its THAT rich, we have been moving in small increments so as not to melt it down again like last month. the EGTs show alittle rich(1300) but not 9.19:1 rich and it does not blow black smoke. What is going on here?, we pulled the jumper harness and checked it against a known working FAST system and its correct.....does anyone have a pin out with colors and numbers for the ECT so that I can double check that? How about the ECU? what is the proper way to check the voltages to see if its properly working? any help would be appreciated......BTW, it has done the some thing with 2 different header and exhaust systems, no leaks in the pipes.

 

[Otto J]

i am running a GN but 1300 sounds WAY rich for full throttle, my egts with a setting of 11.5 to 1 is about 1650
Otto

 

[Spooled]

I think I always heard that your UEGOS value should be about .45 while running. That lets you know if your 02 is working correctly. Where is the 02 placed? And how is the passenger's side YS doing?

 

[Spence]

the Wide band sensor is located in the left collector as far back as I could get it away from where the pipes merge. The passenger side YS did pretty good, but couldnt keep a belt on it, one belt per pass was the norm, it did go 9.20/151.95 tho, I changed it all to the drivers side now and have started back at square one with the tuning, it went 9.37/149.50 this past weekend on an iffy track(BG) but I am sure there is alot left in it, just gotta figure out why the O2 doesnt seem to be reading correctly, with the tune I have now, if I let it correct -5% on the lean side it will melt the gasket or head, this is another problem that I have had resently, thats why I am pretty sure the WB is not working properly(new sensor has 6 passes on it)

 

[Spooled]

Yah, BG was pretty iffy on the starting line, especially the first two days. I'm really not sure what to tell ya about the 02. Did you look at the UEGOS voltage while it was idling? It should be right around .45. Check that out and report back.

 

[Otto J]

spence, just for the heck of it put air temp on your dash and check it ,last week my perfectly tuned car went from 11.5 to 9.19 and i could see any reason why and when i check my air temp i realized the air temp sensor was reading -5.4, even though i have no air temp coorection in it it went totally rich,changed the sensor car ran perfect and the dashboard showed actual temp
Otto

 

[NoSlix]

Spence,

I don't have a wiring diagram, but I will tell you this. When I bought my first FAST(then Felpro) four years ago, I went through hell at first getting it tuned. Turns out the wires for the air temp and water temp were reversed where the wires attached to the big ECM plugs in the harness. Hope you find what's causing that. It sucks to have bought a new sensor to find out that wasn't the problem.

Shane Hill

 

[Chuck Leeper]

Gaskets and heads??

Is the blower plumbed to a stock, side inlet type TB??
If so, I've seen the same problem w/ a local car... He had a Hogan's w/ I/C in it and was blowing in from the pass side.. ANY little bit of lean out would blow the dr head gasket and/or melt the head.. went to ind cyl tuneup and that helped.. Had to add 10% and more at times..
My conclusion was the incoming air was blown into the opposite side head and was LEAN and HOT compared to the pass. Plug readings confirmed this.
Also saw same problems w/ belts..
Solutions were:
Trash the blower, add a T-100 turbo..
Trash the I/C and manifold and go to an under dash I/C and a reversed plenum on a 4 bbl manifold..piped thru the firewall.
Results??
From 8.20/50's to 7.40 at over 190...

Oh, ya.. don't forget to add in a bunch of cash!! ALWAYS enhances the chances for success

 

[Spence]

Chuck, this is a pass side TB with a drivers side YS trim with an Igloo, also had same problem with passenger side YS too. After doin some plug readings we found that the timing was to high, hence this could have enhanced the issue, but before we were running 5 degrees less and it was doing the same thing, if I let the lean side correct 5% it would melt. once I turned this off it was fine as far as not blowing gaskets or melting. this last outing we took some timing out and have taken fuel out according to plug readings, but IMO 9.1:1 would have that thing blowing some serious black smoke, or so I would think anyway. once we did lean it out more this past weekend the a/f started coming up to 9.6:1, and EGT was in the 1300 range, I was told 1400 is where I need to be. with the ETs and MPH it has produced for the mild combo I honestly dont think its 9:1....hehe

 

[Chuck Leeper]

9 to 1??

I run my engine at 11.6 and the EGT stays right at 1600*. ALOT of BUICK guys run even higher than that and stay together.
I see SBC N/A engines we run on the dyno at 1250*...Yours at 1300 seems too cold...
You don't have the closed loop parameters backwards do you??IE: going out of CL at high rpms...[we've discussed that and found mine was backwards at 1 time!(]
I agree.. 9.6 to 1 is a mosquito sprayer and would not run as well as it does IF that were the case.

I run the timing in the 28, down to 24* degree range, depending on boost. The VE map is in the 80's range around the cells that are in use at hi boost..[20+psi] Where does your VE map go to??
What do you have for a fuel system??
Are you running a FMU that could be FUBAR at boost and raising FP to the moon, thus the ?? A/F readings??
W/ the O2 in the leaner side of the engine, could that be the problem??
Just thinkin out loud!

 

[TurboJim]

Chuck:

If theyre not secret, can I see one of your better runing gct files? I just wanna see how you;re doing your timing and VE maps against what I'm doing to see any trends I can pick up on. You know, see how other people do thjings. Somehting from a 3.8 engine if you have it.

 

[Craig Smith]

Spence,

Based on the other posts here, I'd be interested to see what you find if you put the sensor in the other header.

Do you see any traces of oil or any indications of excessive water vapor when you look at the sensor?

As mentioned here, have you monitored the UEGOS voltage during a run? It should be right around 0.45V anytime the engine is running.

I don't think you have an O2 sensor problem but I'll be happy to do what I can to help you figure this out.

 

[Craig Smith]

Spence,

Based on the other posts here, I'd be interested to see what you find if you put the sensor in the other header.

Do you see any traces of oil or any indications of excessive water vapor when you look at the sensor?

As mentioned here, have you monitored the UEGOS voltage during a run? It should be right around 0.45V anytime the engine is running.

I don't think you have an O2 sensor problem but I'll be happy to do what I can to help you figure this out.

Turbo guys, don't forget that your EGTs before the turbo are about 8 million times higher than non-turbo cars... 1300 ain't too far off the mark.

 

[Spence]

UPDATE: Well I think we got to the bottom of this, first thing I found was the IAT was adding 4% fuel over 120°, but this would still not be enough added fuel to take the A/F from 9.19 into the 11s, next thing I did was added another engine ground to chassis, nice big ole welding cable, BINGO!!!!!!, first pass with the same tuneup as before when it was running 9.19:1 the A/F was 11.1-10.9:1 thru most of the range(target 11.5:1), Alternator started charging consistantly and my EGT showed a 90° increase to 1375°, here is the best part, the car went its best ET and MPH ever, on this same tune other than the 4% fuel it went 9.37/149.5 before with small traction issues(1.49) to an 8.99/155 with decent traction(1.43.....on BFG drag radials). Thanks for taking the time to help me look for this problem guys.

 

[AEkrot]

Glad you figured it out - I have 2 big ground cables on either side of my block and one on my tranny mount.

btw: the igloo directly on top of a GT-40 intake or TFS-R intake straightens out the air really well - any intake distribution issues with that setup are directly related to cylinder heads and lower intake, not the igloo or upper. It doesn't matter what side the air is blowing it from with the igloo on top of the intake.

In fact, an in dash or remote mount Intercooler/aftercooler will be more succeptible to partiality" or bias based on the elbow and throttle body location/orientation. Travis Franklin and Mike Murrillo both have had lean cylinder problems when using remote mounted intercoolers and they both me that they attributed the problems to intake manifold/elbow/throttle body position.

The only problem with the igloo is working on the car - it's a bitch sometimes...especially the fuel lines and wiring between the igloo and the firewall...

Alex

 

[NoSlix]

Spence,

I've got a buddy with a T trim that has been having some of the same problems as you. He had just the stock ground strap on his car. It never charged well going downt he track and has "eaten" more than a few alternators. Yesterday, I had him put in a 2gauge ground strap from the motor to the frame and VOILA! His charging problems went away and the car idles and runs soooo much better. I guess it's time for me to do the same to my ol jalopie.