95 4.3 TBI spark table info

[ironwill11]

Hello,

I have a 95 4.3 TBI engine with a 01227747 that for a very long time have had an idle hunting problem. After years of research I couldn't find a solution to straighten out the idle. People then advised me that that firmware in the ecm was out of date.

Then I was introduced to megasquirt. I have since replaced my ecm with megasquirt II, v3.0 and have regretted it for a while.

I am just trying to get this stock engine and it has plenty of power in stock configuration for what I am using it for.

I am using tunerstudioMS (I know there are probably not a lot of people familiar with that) but I am trying to create a spark table and I have no idea where to get started. Does anyone have or know how to create or where to get a spark advance table for this engine?

I can get it to idle, but the idle is around 1500 rpm and according to the spark advance table this is where it should be. Can anyone give me a target idle RPM for this engine?

I am greatly appreciative of any information that I can get and thank you very much in advance for your time.

Will

[skandolis]

first off i don't claim to have any knowledge of the tbi 4.3s, i do have a 95 blazer (CPI) which runs 7427. did the 95 tbi motors have the "vortec" heads? the cpi motors did.(completely different spark requirements from the prevortec heads......) i played around with several different bins for mine, found that the astro cpi tunes had quite a bit more aggressive spark tables than the blazer. made a "bastard child" bin.really woke my blazer up. maybe you could look at some different bins and see how they handled the spark. you cant take the 7427 tables copy and paste, but they should point you in the right direction......
either way, your gonna want to do some data logging to see what your truck really wants. sooner or later somebody with some knowledge will chime in............

have you checked out tunerprort? i believe most of the folks on here will be more familiar with it.....

[ironwill11]

Thanks for the response and clear information.
No I have not checked out tunerprort yet. I just found this site today.
My engine is from a 95 s-10 blazer (or so I am told from the junk yard I bought it at). It is indeed a TBI, according to the research I have done it is a vortec technology and it has the vortec valve covers.

Right now I am stuck with the generic 12x12 spark advance table that megasquirt produces generically. I can only get my idle to go down by retarding the spark with the distributor. Then it does not like to start. Megasquirts information and forum is really quite terrible and I am kind of regretting getting it. I have been trying to get this damn engine to run right for 4 years now. At this point I do not think that the 12x12 table is really even big enough for the table that I need.

I have read online and set my base timing to 0 degrees at TDC, however, with the timing wire unconnected I can't even get the engine to start. Is this really the correct way to set timing?

Is it really possible that there was something wrong with my factory ecm? I question that because I have two of them and the idle used to surge on both of them.

I have been logging a lot of stuff but, right now I am at a point where I don't even know were the advance should be at idle.

Thanks for your response. I will check out that other site too.

Will

[ony]

my std trans idle vareys with different bin files some files 550 most are 600 a couple 750 they are all set different. I had a 95 engine like yours that I replaced it idled good at 600, but I was running a 161288 ecm that is what is in my 1991 truck. the heads are different than swill port but the combustion chamber look the same its not heart shaped like the true vortec heads.12-18.5 degrezz with timming set to 0 should give you smooth idle if everthing else is right with a stock engine. I run 20 at idle with that engine but I do a lot of dirt road driving.here is one file you can open with tuner pro $ao an see what I run in the main spark table.

[ironwill11]

Awesome thanks for the info, I am now learning how to use tuner pro so I can open it and see it. What would I use to connect my ecm to my computer to use tuner pro?

[ony]

that engine was really worn out the balance shaft and cam gears caused a lot of knocks at a steady speed so you could probly add some timming , you need a ald cable I think is what it .isd key board not working. is called. get on moatse web sight they have all kinds of things for data logging and chip tunning.