fishmasterdan

Ok first off I have taken the plunge into tuning (kinda). I purchased a tune and am happy with the current support.

With that said I am trying to learn how to tune and what I am looking at with the logging I am doing.

Here's my delima.
95 5.7 TBI with too many mods to list.

At start up and idle it is pouring alot of fuel into the TBI. I am trying to see what is doing it with a data logger or if it is something outside the tune is going south.

It runs so rich you can see fuel and black smoke coming out the exhaust at start up. The first thing I looked at is O2 voltage. It goes up to 1004 at start up then settles down to 900 at 100 degrees.

Is this normal?

After it warms up to 170 degrees the voltage stays around 900mv?

Also when I pulled the plugs to check richness every other plug was black.
1,5,4,8 were all black and the others were normal looking?

Any info on what might cause that?
Dan

Ronny

iTrader: (1)

start with listing the specs on engine combo. all the specs.

i would start with a calculation or verification of the Base Pulse Constant.

that plus reasonable fuel pressure should get a reasonable idle.

fishmasterdan

Ok 5.7 chev 95 yukon
New throttle body and 1" spacer from here
http://www.rvmorsemachine.com/
Intake was bored to match the throttle body
New Comp cam 12-249-4 specs are here
http://www.compcams.com/Technical/Se...umber=12-249-4
New 1.6 roller rockers
New tune from tbichips.com
K&N air filter
New air intake from here
http://www.cfm-tech.com/catalog/air_...uck_549430.htm
New cold air tube from here
http://www.cfm-tech.com/catalog/air_...___3280272.htm
160 or 170 degree t stat (cant remember exactly) came with the tune.
New high flow water pumps
New long tube headers
New 3" exhaust (no cats shhhh)
New 4 wire O2 sensor
New IAC
New plugs and wires (the cap and rotor are 6 months old)
New Timing chain
New High flow oil pump.
Picked up an ALDL cable and doing some data logging with ttdatasystem (cant rember if that is the exact name or not)

I stared it up this afternoon and I get what looks like raw fuel coming out the exhaust until it warms up also it doesnt run very good until it warms up. I changed amost everything I could think of.

I had them put the O2 sensor as close to the headers as I could.

I have no idea what the fuel pressure is right now should I get some sort of meter?
Thanks
Dan

Fast355

iTrader: (2)

Above is your trouble, below is your problem.

fishmasterdan

Fast355;
Please elaborate. I am not the all knowing but am trying to learn. I used to enjoy messing around with cars but it seems everthing revolves around a tune these days, and from I can figure out there is a HUGE learing curve.

Ronny

iTrader: (1)

OUCH. that hurt.

I dont see hiow anyone can burn a chip without knowing the fuel pressure or injector size. lets assume the chip burner was told by you that info. lets further assume the BPC is correct. On start up the NB 02 sensor is not yet in CL. It is in OL till the coolant temp comes up to around 160F or so. mine is heated so it hits CL sooner(> 3 MPH). my idle is OL as I chose that in tune.

if one used a "generic" OL fuel table I would be surprised if it would be that far off to puke gas out the ext pipe. unless the FP is too high and or BPC is off?

What does Brian say of this?

fishmasterdan

Ronny;

Brian thinks there might be something else wrong with the motor.
It fouls every other plug 1,5,4,8 goes black and the others look normal.
He said he would look at the datalogging info when he gets some time.

I cannot seem to figure out why I am fouling every other plug. Is it the tune or some weird ignition thing? It fouled the plugs before changing the rocker arms and I have not drove it enough to check after I installed the roller rockers but it is still puking gas out (along with black smoke).

BPC? I am not sure what that is.

I have done some data logging but I cant see where anything is way off, but I am new to the tune thing so I am not sure what I am looking at.

What data logging software do you recommend?

Uncle Skeletor

iTrader: (5)

OK, factory dual plane intake matched to TB, right? Check to see if the intake feeds all of those fouled cylinders off of one plane. I'm not intimately familiar with TBI, but I believe you will find this to be the case. Likely scenario is that one injector is goober'd up and is dumping fuel at an astronomical rate while the other is working properly, making this a hardware and not a software problem... That would be my first guess.

HaulnA$$

The stock TBI intake has 1,4,6, & 7 and 2,3,5, & 8 on the same planes so that doesn't jive with the injector theory. Sounds to me like the firing order is not right or the timing is way off.

fishmasterdan

Should'nt I be able to check the voltage and DC at the injectors in OL to see if it is abnormal ?? If that is normal then it should be a timing issue correct?

Could it be a cracked head or burnet valve sending extra fuel back into the motor?? If I had a burnt valve or bum compression wouldnt that show up in the MAP(or which ever acronym deals with the intake vaccum)?? I will do a compression check next time I check the plugs.

Dominic Sorresso

Start with the simple things first. Like timing. The cam is pretty small. I'd take the tbichip out and just run a stock one to get started.

fishmasterdan

I am staring to agree with fast. 180$ and a chip to get you running a little support up front but when there is issues nothing!!! I am going out to throw the stock chip in and see what happens. I have to start it 3 times to get it to run.

I am ready to get the tuning stuff but I cannot seem to figure out what chip I need. Stock number is 1620098

fishmasterdan

I put the stock chip in and it is still doing the same thing. I have convinced myself that it has something to do with the coil/cap/ignition.

Going to start looking around for upgrades. Any recommendations?

Dominic Sorresso

MSD ignition, cap, coil, and 8.5mm wires.

91chevz71

I've used MSD items for about 3 years- never failed once.
Love em

Mike

fishmasterdan

Update;

I upgraded to Standard tried to get MSD but my supplier could not get it next day so they got high end carquest "Standard" stuff and it seemed to fix my problem.

Before I upgraded the cap and rotor the injectors were pouring fuel in at idle and you could hear the TB sucking ALOT of air.
After the new cap and rotor it no longer dumps fuel in and the sucking sound went away.

The old cap was not that old but it was a cheap cap and rotor.

Tommorow I will know for sure if it pours fuel out the exhaust during start up.

I logged before the change and I will log after the change if anyone is curious to what a cap and rotor will do.
Now time to work on the tune.

Dan

Sierra GT

Dan,

I put a rebuilt engine in my truck a few weeks ago, it's similar to yours in that it's a 350 with a small cam upgrade. I'm also running a 95 TBI truck with probably the same ECM you are (16197427). I thought from what I had read and what people told me that my cam (206/212 112lsa) would run with the stock chip and we tried it.

Well, it didn't work quite so well. With the fuel system stock and all sensors replaced for new, it would barely run at idle especially when cold... spitting black carbon out the exhaust. What it did and what we didn't realize was that it was also dumping a ton of fuel into the crankcase going past the rings. In a matter of a few hundred miles the bearings took a 200 thousand mile beating... essentially toasting a brand new rebuild.

So.. we rebuilt it again and this time I just went right into the tuning and started yanking fuel away at low RPMs and low Loads especially on the idle VE table.

My truck has been running for about 2500kms with me taking over 30% of the fuel away down low and it's excellent. I still have some cold idling issues to sort out, but it's very close. When it's warm... it's perfect now.

The only thing that makes sense is that because of my headers and cam upgrade, the engine was far more efficient at low revs and low load that the fuel that the engine would command idling at 30-40 map was way too much for the new one.

I would pretty much stop driving it until you can tune it yourself and make these changes, or get tbichips to make them. If you're interested I can send you a copy of my current running bin file as an example of where you might go with your fueling.

It would only be an example though, and any ideas you get from it you would have to use at your own risk.

Keep in touch...

John
----------
I just went through and clicked on some of your links. You have the exact same cam I'm using. Did you get a bored throttle body? That may affect your MAP readings a tiny bit too, I'm not sure. Can you post your datalog?

Again I'd be careful with driving it. If you have to drive it, don't let it idle cold... you will hurt the motor. Just jump in it and drive taking it easy.

Sierra GT

Actually might be a good idea to change your OIL asap. Also consider running some GM Engine Oil Supplement. I think it's like 10 bucks at the dealership for a bottle. Goes in with the oil, and your cam will like you.

fishmasterdan

John;
I appreciate the info.I cannot get it start again, and when it does it just pukes black smoke.Sounds like I have the same problem as you. I would appreciate it if I could get that bin from you. I need to figure out how to read the bin from the new chip and compare the 2.

I have done some data logging but I dont know what I am looking at. I sent it off to Brian and he says it is running rich until about 1600 rpms.

My rig is not an everyday driver so I will park it until I can get the tune redone.

Thanks a ton for the info.
email is fishmasterdan at hotmail.com
Dan

edit. I cant figure out how to post the data log??
The throttle body is not bored it is new but bigger (so I guess yes its bored kinda) and the intake has been bored to match. The new bore on the intake was 1.833 per hole.

Sierra GT

Hey Dan,

I've got no idea either on how to post images or files on the forum. Maybe someone could give us a hand?

The mail order chip thing is going to be very difficult to do with your issue, so I think it would make the most sense for you to get your own chip burner and adapter. Even though everything seems daunting right now, it's actually not that bad when you get into it. I felt a little (okay a lot) apprehensive about tuning my truck, especially when the damn thing ran likes yours does now but I just kept reading and poking away at it. Now that I've been through it, I should be able to give you a hand with a lot of the stuff to get you up and running and get it on the road at least. I still have lots to learn and I'm nowhere near done tuning my truck, but I'm really happy with the way it's coming.

I'm assuming that you have the datalog cable already because you have logs, so that just leaves a chip burner, chip adapter, and some chips.

Moates.net is the best place to get the stuff, and there's a special adapter for a few bucks that will allow you to read the bin file off the chip that came with your truck. That's the bin file you should be editing.

I'll get a list of the hardware you need and post that later tonight, and as for the changes you need to make to get your truck up and running so it won't hurt itself, I can't do that tonight because my Windows machine is at work. We're not ready for that yet anyways.

John

Sierra GT

Okay here's a list of what you'll need...

-Windows laptop that will run TunerPro and Datamaster. Also has to have USB and shouldn't be something from last century. Our newer PCM's are pretty fast and what I find when I'm datalogging is that even with a Mobile Pentium 4 it takes a chunk of CPU power to run Datamaster. I average about 10 to 15 updates per second on my truck.

-Chip Burner/Reader
-Memcal Adapter + 2 Chips (You need this to be able to insert your own chips in the ECM)
-Memcal Header Adapter (This is what you will use to read the bin file from your stock chip without having to hack it up)
-Extra Chips (Buy a few more of these, they're cheap and nice to have when you're on the road. I've already fried one, and bent the pins on another one)

-TunerPro RT from http://tunerpro.markmansur.com/
-Bin file definition (roadmap to the bin file for TunerPro) and ALDL definition (if you want to datalog with TunerPro) from the TunerPro site.

Based on your truck year I am 99% certain that you have a 16197427 ECU and $0D code. Before you buy anything or downloading anything, can you check behind your glove box for your ecu and post the numbers listed on there? There should also be a broadcast code similar to BJYK or BJYM.

You can email me the datalog file if you like to jgrikes at sympatico.ca.

Catch ya later,

John

Sierra GT

Oh I completely forgot to mention the thermostat. I wouldn't run a 160 degree unit in your truck at all, it's really going to complicate your life with tuning and you will be wasting a lot of gas.

For now I would run the stock 195 degree unit, and if you want later then you could run a 180 degree.

I have my truck running on the stock one and I wouldn't ever change it for a lower one.

Sierra GT

In the meantime, check out the thread called "Come in for a free Tune" in the TBI forum by BMonteSS.

It's not exactly applicable to you, but a lot of it will be the same... just easier .

Give me a shout back on here when you're done sifting through the overload of info... lol.

John out.

fishmasterdan

John;
You are my hero. I will check into that stuff tonight. I am at work now and will dive into later.
Again you are my hero thanks a ton.

Dan

fishmasterdan

John;
I purchased a new usb adaptor and it is a decent one. Also I have a new laptop I am uning so that shouldnt be an issue. I sent you an email I hope you get it. I will order the stuff I need tonight.

I have read some of the thread you are reffering to I need to go back and read the whole thing.

I asked tbichips to burn me a new chip but have not gotten a response yet. I will do it my self I guess. Not to good with computer stuff I guess I am just to old.

Dan