Jacque8080

I just replaced my ECU with one from ZZP. I need to do the crankshaft relearn as a result. I also just switched from the OEM LSJ injectors to the ZZP Bosch 42 lb/hr ones. I'm about to put in the 2.8 pulley from OEM size, when I find a hydraulic press to use.

Oh, and I get a code for air/fuel ration being too rich.

Jesse

iTrader: (4)

Are you doing your own tuning with HP Tuners? The last few tunes I've seen from ZZP have closed loop disabled, which would throw the code you mention if the airflow isn't fine tuned. IMO it is better to leave closed loop enabled unless you have good reasons not to.

Slowbalt2000

iTrader: (1)

Rich could be caused by running the 2.8 tune on the stock pulley

Jacque8080

Slowbalt, I think you could be right. At first, I thought the supercharger integrated bypass valve only opens when you get into boost. And otherwise the engine runs with the valve closed - in naturally aspirated move. But I have been watching my Long Term Fuel Trim. And it mostly runs at -20 at idle. And it climbs to 0 as I approach 0 vacuum. So now, I think you are right. Do you know anyone in Franklin that has a hydraulic press?

Jacque8080

I don't have HP Tuners. I see open loop after engine start, until it warms up. Otherwise, it seems to run in closed loop. The Long Term Fuel Trim seems pretty steady in the negative range.

Do you know anyone with HP tuners that do remote tunes?

southal cobalt

iTrader: (3)

its the other way around. the valve stays open, releasing excess air at idle, cruising, and part throttle. it closes when near atmospheric pressure and allows to build boost.

and you shouldnt be that far off from going up in pulley sizes. maybe during power enrichment, but not during closed loop cruise and idle

did zzp send you the tune for 42s, or did they send you a tune for stock injectors?

Jesse

iTrader: (4)

If they disabled closed loop then the computer will retain LTFT. LTFT will remain until they are reset with a scanner. What are your STFT like? If they are zero you aren't entering closed loop. You still have to buy HP to be remote tuned unless you just send the ECM back to ZZP but that is not optimal.

Honestly I'd email ZZP or find paperwork that will tell you what you are tuned for.

Jacque8080

You are right. I just sent ZZP an email. Their own shipping note said to check the injectors match their tune. I'll check the STFT in the morning. I didn't get a good look at it yesterday because it fluctuates so fast.

Jacque8080

Local shop said they'd swap out the pulley for me for 30 or 40 bucks. I just show up with the M62 pulled already. It is scheduled for tomorrow morning, pending my boss' approval.

Jacque8080

And you are right. I got the 2.8 and stg 2 belt on and the LTFT began to move closer to 0. After 30 minutes, that DTC went away. And then I got the crank relearn done.

Now, the issue is belt slip. Just after 12 psi, I hear a fluttering type sound from the engine bay. There is some power and boost loss. It is reproducible. It happens anywhere from 3,000 RPM and up.

I searched some and saw some folks use belt dressing. The belt was a little dusty when I got it. I might try that after I search some more.

Slowbalt2000

iTrader: (1)

:

Jesse

iTrader: (4)

Belt dressing will do nothing for you. Stg2 belt was designed for 3.1" pulley. Larger tensioner pulley will do you more good: Yella Terra - Oversized LSJ Tensioner Pulley #YT-EP010

Jacque8080

I ordered it. I figured it would be fine because it was super tough to put on the belt. I can't imagine what it will be like with the larger tensioner pulley.

southal cobalt

iTrader: (3)

wouldnt have expected that, but glad to hear it worked out.

did you get a genuine gm belt? or was it zzps off brand thing?

Jacque8080

I ordered the belt from Crate Engine Depot. It came in a GM Goodwrench cardboard package. The numbers match this:

http://shop.zzperformance.com/resize...&bw=600&bh=600

I can't tell if it really is genuine except that's what it says on the box. Also, CED said there is a nation wide back order. And the stg 2 belts are hard to come by right now. And mine was drop shipped from Ohio.

southal cobalt

iTrader: (3)

Okay. You can tell the difference in belts. A number of years back, zzp would sell another brand of belt. They're probably selling the gm belt now. I haven't heard of many people getting slip with a stg 2 belt and 2.8" pulley

Jacque8080

Maybe a chance because it is a new belt? It holds boost up to about 13 psi. Now I wish I wiped the belt down with a clean towel because it looked a little dusty.

southal cobalt

iTrader: (3)

I don't know. But could also be due to the cold. I know you can't now, but did you compare your stock belt to the stg 2 belt to see if the stg 2 belt was shorter? May even be a bad tensioner

Jacque8080

I'll see how tough it is to measure the belt when I get the larger tensioner pulley installed. The box says it should the 1.767 M. I will need to figure out what that is in 'Merica. It did seem to do a little better with 60 degrees out versus 40.

Jacque8080

Solved
It turns out that I am a chowder head. The new pulley came in. But I began having doubts about the belt slipping. I got past 12 psi again and watched the boost gauge. I was in denial. My boost gauge wasn't fluctuating. I just read about it and saw what I wanted to see. Then I read about spark blow out. I figure that I'm overdue for a spark plug change anyway. I took out my old NGK BKR7E. They were all worn down pretty bad. I'll post some pics later. I know I can't read a plug. But the ground strap was worn down. One side of the center electrode of the "V" was worn almost to the valley. And the other side was getting there. As a result, they now measure at 0.053 to 0.055". New BKR7E @ 0.034 and the it runs at 17psi without issue.

I might hang on to the larger tensioner pulley - just in case.

Thanks everyone for the help. You helped your Cobalt brother get from stock power levels to maybe 250 WHP. I just have to figure out what to do about IAT2 for track days...

Slowbalt2000

iTrader: (1)

Meth

southal cobalt

iTrader: (3)

^ thats probably your best bet. with a decent size nozzle