trying not to scrap it...

[drifterwanb666]

ill start off with this.

1996 chevrolet tahoe, 4wd. l31, 4l60e.

in my quest of just a better daily driver ive gone too far, by accident or stupidity. im not sure.

heres what ive done to the truck;
"RV" cam, (dr.bumpstick), new roller lifters, hardened pushrods, roller rockers, new springs, lapped valves and remanned heads, high volume oil pump. thinking of adapting an LS throttle body since the OE one leaks vacuum thru the shaft seals, also has long tube headmans, 2.5" exhaust with an X pipe. transmissions been rebuilt with a "tow package" since i do haul more then ass with this thing. got a tuned PCM from blackbear and had the rear 02s deleted, NOT the front. EGR deleted. and tuned for my set up. i dont want to go further then what ive done on this tahoe, ill save my "race truck" ideas for another.

now heres the issue; besides the fact shes tempermental, the truck will not idle. (these issues happened before and after tuned PCM) itll almost stall out and then idle way high and come back down to almost a stall. does this until it finally stalls or i start driving it.
now for driving; itll intermintantly run like complete dog ass, missfire every cylinder, barely move down the road, hold RPM way too long, and slam into gear. then outta know where itll act right and shoot my RPMs so high i git 6k cause im basically flooring it trying to go 40mph. now sometimes itll go back to running like dog ass after, and others itll run fine but the idle is at around 2500rpm, and will stay like that until i come to a complete stop, idle drops to around 800rpm, and the cycle continues.
now today i came to a full stop twice and the cycle did not continue. but the rpm did stay around 2500 until i did a coplete stop, went to around 800rpm and took off from there no problem.

ive checked all sensors, all continuity, all resistance, replaced parts, checked powers and grounds, ect. thrown codes for MAP, baro/map, TPS, knock sensor, and both upstream 02 sensors. replaced all, and codes still came back. so i put the OE parts back on. the 02 codes are known, but the others are new with this blackbear PCM.

with this i ask, what in the name of all thats holy am i doing wrong, or missing here? i have this one vehcle and its all i got. im so stressed and angry im tempted to junk it sometimes. plan on calling blackbear and seeing what they say, as im not fully happy with it as it is.

 

[454C2500Longbed]

I will start off with saying I'm no expert, so take what I say with a grain of salt. With the way your engine is acting up, sounds to me like a fueling issue, have you been through your injection system yet? I know those spider injectors can have a host of problems. The way it's driving though, is definitely a transmission issue. Being a 4L60, it's quite possible that it's doing 4L60 things and is in the process of blowing up. But before you panic, you can change a lot about how your trans behaves with the tune. I would talk to Blackbear and see if they touched anything as far as the transmission goes. Hopefully some of the more knowledgable members will chime in on this.

 

[scott2093]

these issues happened before and after tuned PCM

Did you have issues with the original setup on the motor before doing all the other stuff?

 

[drifterwanb666]

I will start off with saying I'm no expert, so take what I say with a grain of salt. With the way your engine is acting up, sounds to me like a fueling issue, have you been through your injection system yet? I know those spider injectors can have a host of problems. The way it's driving though, is definitely a transmission issue. Being a 4L60, it's quite possible that it's doing 4L60 things and is in the process of blowing up. But before you panic, you can change a lot about how your trans behaves with the tune. I would talk to Blackbear and see if they touched anything as far as the transmission goes. Hopefully some of the more knowledgable members will chime in on this.

they were supposed to change some trans things. fuel is good, spiders new new. (4th one)

 

[drifterwanb666]

Did you have issues with the original setup on the motor before doing all the other stuff?

before the top end rebuild i had a lifter going out, and it would stumble real bad off the line, bog down at any throttle to almost a stall and then act fine. was told it was timing chain, so i did the whole top end. when in rome, right?

 

[Sean Buick 76]

What you need to do is create at least 3 or 4 data logs and email them to Blackbear. Do you have the autocal box or did they send you the computer? With a combo like yours they will need to do a few re-tunes to get it right. If you don’t have the autocal box then ship them your computer and then they can try to diagnose it. However at that point you are better off with a local tuner.

An in person tune is the best option vs a mail order tune. I’ve used blackbear on 4 trucks but all 2000-2012 and using the autocal box so I’m able to email them datalogs and they further refine the tune based on the data.

 

[df2x4]

Do you have the autocal box or did they send you the computer?

Unless OP is 0411 swapped, Black Bear can't do the Autocal. The black box PCMs in these trucks aren't compatible.

 

[Hipster]

Kinda stuck at lapped valves being referred to as remanned head's, and leaking shaft seals.? Sometimes you gotta get to the basics that the engine is in mechanically sound shape. Most of these heads I've been in needed all new exhausts at minimum if they weren't already cracked, and leaking shaft seals can be a very random intermittent issue.

 

[drifterwanb666]

What you need to do is create at least 3 or 4 data logs and email them to Blackbear. Do you have the autocal box or did they send you the computer? With a combo like yours they will need to do a few re-tunes to get it right. If you don’t have the autocal box then ship them your computer and then they can try to diagnose it. However at that point you are better off with a local tuner.

An in person tune is the best option vs a mail order tune. I’ve used blackbear on 4 trucks but all 2000-2012 and using the autocal box so I’m able to email them datalogs and they further refine the tune based on the data.

they sent me a pcm, im still using old blackbox so id have to keep mailing it i suppose, i dunno if i can datalog on a blackbox...

 

[drifterwanb666]

Unless OP is 0411 swapped, Black Bear can't do the Autocal. The black box PCMs in these trucks aren't compatible.

not 0411 swapped, but i was considering it until i heard of blackbear.