JayBoCC2

I have been working with this car for a long while and i just cannot get it to run anything better than a stock 350 TPI auto. Heck sometimes i even get run down by them (i run a 9.45 best at the local 1/8mi track).

Been tuning it for a while burning chips etc, and i just can't get it to run "right".

It runs and idles and is drivable (although when driving low speeds like 5-10mph, sometimes the car will start to jerk really bad and i have to pedal it to make it stop).

I have no problems with fouled plugs, or backfiring or even a real rich condition aside from startup. No smoke, no leaks, fresh hone and bore on the cylinders.

Yet i still get very erratic and extreme readings from my sensors (.900s and .0##s).

I just cannot get things to go right with this system and i've been trying for over a year. I'm to the point where i'm about to go carb and just get it running the way it should!

If im not careful i can easily blow the tires off, so it obviously has *****. It pulls hard, it just doesn't seem to keep putting steam through the entire band. As well as i get false knock during regular driving, and NO knock at all during WOT, but 1-5deg of retard. No matter what i do to the timing i cannot get the knock to go away, even tried disabling the knock sensors. I can't help but feel this is where im losing my power. Maybe some wires are bad somewhere causing issues but i dont feel this is a problem and i do not ever get any codes from the ECM, except one when i first started burning which i forget what it even was, as i havn't seen it in a long time.

Please if anybody can offer any advice or help.

extremely frustrated TPI driver .

Michelob

if it's not something in the tune then the first thing i'd reccomend is a new ECM. my 87 w/ 165 6E was having a similar problem where it had no codes but had bad pinging( mainly on warmup ) and also misfiring with slightly higher idle. took awhile and a load of new parts to figure out that the original ECM had gone bad. before i figured it out i also tried another used ECM( off ebay )which seemed to work but would stall at idle once the motor warmed up . that one also wasnt' showing any codes.
finally bucked up and put in a new one and whaddya know... problem solved. 80$ at Autozone.

JayBoCC2

You bought a new ECM or just a new stock chip? i dont believe i could buy a new ECM for $80. As it stands the best i've found for a new ECM is $121 at gmpartsdirect. Though there are used ones for $75 that have been "tested for functionality."

could it possibly be my gutted maf that is the problem?

RednGold86Z

iTrader: (1)

Does it just die off at the top end?? Or is it always just weak?

Probably need to go through and make sure the basics are there, such as fuel pressure at WOT + high RPM.

Do you have a wideband? That'll tell you reallll quick where to (or not to) look.

Do you have a log file of a full throttle blast? The O2 sensor should read >800mV the whole time of full throttle. If it drops off at high RPMs, then it's a lack of fuel that's causing weak performance.

Michelob

Jaybo, yes it was 80$ for a new in box ECM after the 50$ core exchange... that price was at an Autozone in Cali.

Guest

Hows your grounds doing? Make sure all your grounds are good first. Funny stuff happens with bad ground.

JayBoCC2

i'll give it a shot and see if i can get a good log file for ya to look at, Red. We are averaging 20-30deg temps here and she doesn't usually see anything but spring/summer weather. but i'll get her out asap if i can.

JayBoCC2

unfortunately the log i did last week got corrupted somehow and wont show any data or even a proper header... so all i got is my bin... perhaps thats something to start from? who knows it could just be the horrific mess thats causing the trouble.