Running lean all the time

[dgoodhue]

Re: Running lean all the time

I realize the wb02 is not the root cause of be issue but its not working.

I would first verify the fuel pressure with the truck running and driving. The fuel pressure should be approx 43psi for a stock chip and it will rise to 58-59 psi (rise 1 psi per # of boost.). I know you say it has a new walbro but their are many knock offs and even real walbro had some failures.

Next I would check to make sure the IC pump is working and pumping properly. High intake temps will cause knock.

 

[DubJG]

Re: Running lean all the time

Do you have a hotwire mod on your fuel pump? I know even after a I put in a walbro and afpr my NB mv's in datamaster were still all over the place with a lot of lean areas until I put the racetronix kit on it. Sounds like you may have another issue but that's what came to mind.

 

[kessler]

Re: Running lean all the time

I have a new Johnsons I/C pump on it and it is hot wired. I can hear it running as well and the cooler is full. My intake temps do get high, but on a cold start, I have the exact same issues. It is lean all the time, every scenerio. I am hoping to have time tomorrow to check the injectors and do a compression test.

 

[dgoodhue]

Re: Running lean all the time

What is your LTerm (aother tern in BLM) fueling correction at idle and cruise?

 

[kessler]

Re: Running lean all the time

Lterm is 119 to 126 at cruise and idle

 

[dgoodhue]

Re: Running lean all the time

A BLM of lower than 128 means the ECM has leaned out the fuel mixture table because the o2 sensor was reading rich during closed loop operation (idle,cruise, and moderate acceleration.). 119 isn't a really rich blm.

you could still be running lean at wot. It just mean the ECM think your running during closed loop operation. If you still convinced the truck runs lean all the time check for intake leaks and check the engine grounds.

 

[kessler]

Re: Running lean all the time

According to Data Master, at 15 psi boost, spark advance is 2.5, spark retard is 12.7, knock 16 is 5937 and knock 8 is 23. Injector duty cycle is 95.1%, IAT is 95.4 and TPS is only 56%.

 

[ItsMyTy]

Re: Running lean all the time

my ideas:
check timing.. verify the balancer ring has not slipped prior. if timing is way off it can cause lots of knock
also, a misfire can drop extra oxygen in the exhaust stream and give false o2 sensor readings.


and my first thoughts after reading this thread...

there is no way the engine is idling at >20:1 afr

if you see the stock o2 switching at idle then actual air fuel has to be around 14.5:1

your block learn numbers are normal.

don't worry about the air leak at the throttle body shaft

 

[kessler]

Re: Running lean all the time

I will double check the balancer ring when I do the compression test. Thanks for all the help, and I will update the thread as I find things out.

 

[kessler]

Re: Running lean all the time

Update:
I checked injectors by pulling one off at a time and all seemed to make a difference. Some more than others, but all made a difference.
I did a compression test as well. All cylinders were between 195 and 200 psi warm.
I looked at the balancer and it looked like it has been replaced at some point.and the rubber ring looks good.
I checked for proper grounds, and added some as well. This made a slight change, but not much.
Since I just got this truck and the info I had on it came from the guy I ghot it from and he had only had it for a short time and didn't really drive it, I pulled the ECM down to look at it. At first glance it looked like it had never been opened. The white sticker was intact. But at closer inspection, it wasn't exactly stuck down correctly. So I pulled the cover off and it flipped open and I could see the chip. To my surprise there was a JET chip in it that says off road use only on it. I am wondering if this isn't the root of all my issues. I started looking things over really well and found ARP studs in the heads as well. The turbo looks new but doesn't have the mounting spot for the stock wastegate controller as it is just sitting there not bolted down. The block has been repainted and is very clean and I could see new gaskets on most of the accessories.
In short, I found out a lot of things, but didn't for sure find my problem. I did double check base timing and it is set at zero.

 

[RealFastV6]

Re: Running lean all the time

I wonder if you've got something funky going on like a 3 bar map sensor with a 2 bar chip.

 

[0966Sy]

Get a stock chip and go from there

 

[kessler]

Re: Running lean all the time

I replaced the map sensor with a stock new one. It ran the same with both sensors. Is there a place to get a stock chip? I was thinking of upgrading chip and injectors, but really want to make it run correctly before I do that.

 

[Quickstop [UK]]

Re: Running lean all the time

What heads are on it? Have you got vortec heads? Stock tune + vortecs = lean?

Good to know the inj and comp came out well.

 

[leadfoot]

Re: Running lean all the time

I replaced the map sensor with a stock new one. It ran the same with both sensors. Is there a place to get a stock chip? I was thinking of upgrading chip and injectors, but really want to make it run correctly before I do that.

There is a complete Sy harness with 7749 ECM and pitbull street chip on E-bay. :2cents: :tup:

 

[johnboy89]

Re: Running lean all the time

I did a compression test as well. All cylinders were between 195 and 200 psi warm.

This seems awful high to me (gauge accurate?), I believe stock compression is around 155 PSI or so. I have around 180 PSI and used to see KR with stock boost levels.

I would be very careful with all the KR you are seeing in getting on it too much.

 

[dgoodhue]

Re: Running lean all the time

I wonder if the motor has higher than stock compression pistons.

 

[kessler]

Re: Running lean all the time

Update:
I removed the JET chip that was in the truck, pulled the ECM fuses and drove it again. Definately a bit better, but still getting knock. Today I removed the stock hard lines to the inter cooler and removed the EGR and installed an I/C scoop. My IATs dropped dramaticly. When I first drive the truck, cold start, it runs great, but as it warms up, I get lots of knock again. I remembered on my way home that I didn't recheck the base timing after taking out the JET chip so I will do that tomorrow. Also, since I reset the ECM, I am getting an IAC code and it idles high. Around 1100 to 950 depending. Data Master shows IAC at 0. I rechecked for vac leaks and still nothing.My injector duty cycle is at 100% after it warms up and shows knock. I ordered an adjustable FPR today as well.

 

[berzerker]

Re: Running lean all the time

I wonder if you've got something funky going on like a 3 bar map sensor with a 2 bar chip.

with ya there .. chip combo mismatch

 

[kessler]

Re: Running lean all the time

Well, I took out the JET chip, put the original back in it's spot. I had changed the MAP sensor previously. Just got a stock replacement, and it ran the same. I changed the MAP before i took out the JET chip. So I have a stock chip ( I am assuming) with the stock MAP sensor now and it runs pretty much the same. I'm not sure how to find out if my chip has been set up for a 2 or 3 bar sensor either.