Diagnostic Advise...

[LS1Silverado05]

Hey guys, new to HP Tuners, but looking to use it to help me iron out some issues before I get any deeper into tuning for power etc.

The car since purchased has exhibited a rough idle, almost that of a small cam... a noticable vibration during a neutral rev of the motor, and an overall lack of smoothness. No huge misses or moments of breaking up, just a consistent poor overall running.

The car has a new fuel pump, new fuel filter, new wires, new plugs. I am looking for advise on what to put in my config to log specifically and any other thoughts on the matter.

Not sure if Im dealing with a possible coil issue, or injector etc. The engine harmonics is whats getting me. Its subtle, but present. (I have had the valvecovers off and all appears normal...

Appreciate the advice on setting up my log. Thanks.

[oakley6575]

Post your tune and a log. Log misfires and whatever else is in the stock config

[LS1Silverado05]

Here is the log from driving the other night.... and the tune that I read from the car. Tune is unchanged from what was read from car....

[oakley6575]

Engine specs?

[LS1Silverado05]

The tune...

[LS1Silverado05]

Engine specs?

Far as I can tell, dead stock... no lid, no exhaust, no nothing... now has a Walbro 255 as it needed a pump... Thats the only change to the car... other than the new plugs and wires..

[oakley6575]

Your LTFT are upwards of 20. That is pretty dangerous. Do you not have a wideband hooked up through HPT?

[oakley6575]

Duramax? haha

[LS1Silverado05]

Duramax? haha

LOL not a duramax... Yeah I have an AFX in the car... going to set it up here in a sec and log with it.... just got it installed...

Sorry totally new to all of this..thats why im not changing anything yet. So the LTFTs being 20s would be cause by?.....

[LS1Silverado05]

I should add that this is a 98 car but it appears to have a 99+ motor... so who knows for sure whats been messed with. "appears" stock... but unsure if tune was jacked with

[oakley6575]

Go through the help files and read your ass off! Learn what most of the pids and tables are for. That will make the tuning process much easier for you. Look at ls1tuningguide.com and read the first couple of pages of his free tuning tutorial. It has some critical definitions that will help you.

LTFT stands for long term fuel trims. With a LTFT of +20, it is adding 20% fuel to compensate for a very lean condition. That is dangerous and could hurt the motor, especially with the high timing you are running. Don't drive the car hard until you do a lot of fuel tuning with your new wideband.

[LS1Silverado05]

A 98 f-250 or what?

Thanks for the patience... I have been messing with 4th gen F-Bodies for a long time and just only now getting feet wet with tuning... I understand what the LTFTs do, but is it compensating for some obvious problem im missing in the tune or is something clearly physically wrong with the car?

Thanks again... Going to get this wideband hooked up... Should I address the trims or log some more without going WOT... not sure where to start since im starting with an off base car for some reason... Does the tune appear stock to you?

[oakley6575]

Tune is far from stock. I would start by adding some fuel to the VE/MAF and putting it in open loop. Drive the car very easy with little load and see how far off fueling is. Hook your wideband up and log for lambda error or AFR if you read it that way. I would recommend to learn with lambda. Follow ls1tuningguide's info

Who ever tuned it is a POS. the EQ table should be 1 in all the warmer ECT cells. Insead of actually tuning the fuel tables, he used a bandaid and made the EQ table rich in the warmer cells. Just a heads up

[flame]

Start by cleaning the MAF then reset the fuel trims and see how it is

[LS1Silverado05]

Being new would I be miles ahead to just load a stock tune into the car as a start point for me? if I can find a trusted source....

[LS1Silverado05]

Working on getting the WB loaded... for some reason it read 14.XX on my control box but 9.06 frozen on screen... (one more thing to bang head on wall about)

[flame]

His tune is 100% stock

[LS1Silverado05]

Mine? lol

[flame]

Mine? lol

Yes your tune is 100% stock

[LS1Silverado05]

Yes your tune is 100% stock

Tune is far from stock. I would start by adding some fuel to the VE/MAF and putting it in open loop. Drive the car very easy with little load and see how far off fueling is. Hook your wideband up and log for lambda error or AFR if you read it that way. I would recommend to learn with lambda. Follow ls1tuningguide's info

Who ever tuned it is a POS. the EQ table should be 1 in all the warmer ECT cells. Insead of actually tuning the fuel tables, he used a bandaid and made the EQ table rich in the warmer cells. Just a heads up

So what is Oakley referring to?....