Wide and o2 to run closed loop?

[Rob 689]

Hey everyone I was just curious is it possible to run closed loop with the 161395 pcm? I know the behavior and voltage ranges are different but I was curious if it were possible. Assuming it’s not how do I tap the wide band into the egr input like people talk about doing? Software changes?

[dave w]

PCM 16196395?
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?337-16196395-PCM-Information-OE

[tayto]

Hey everyone I was just curious is it possible to run closed loop with the 161395 pcm? I know the behavior and voltage ranges are different but I was curious if it were possible. Assuming it’s not how do I tap the wide band into the egr input like people talk about doing? Software changes?
No...

[dave w]

If we are on the same page . . . definition file $OE . . . PCM 16196395 . . . see screen shot below:

I've successfully data logged AFR's closed loop for Definitions $OD, $E6, $OE, and $31 using TWO O2 sensors in the exhaust system (factory narrow band and aftermarket ARF tool like the AEM 30-4110).

I've been challenged (likely other tuners too) with the INACCRACY of Simulated Narrow Band, so I use TWO O2 sensors to data log AFR information.

I use AFR's for tuning only, because engine modifications don't provide optimal performance without tuning.

There's considerable debate about the accuracy of Open Loop AFR Tuning vs. Closed Loop AFR Tuning.

The WBO2 Tuning spreadsheet I posted here: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?5381-WBO2-Tuning-Spreadsheet is for Closed Loop Tuning.

18190

[Rob 689]

If we are on the same page . . . definition file $OE . . . PCM 16196395 . . . see screen shot below:

I've successfully data logged AFR's closed loop for Definitions $OD, $E6, $OE, and $31 using TWO O2 sensors in the exhaust system (factory narrow band and aftermarket ARF tool like the AEM 30-4110).

I've been challenged (likely other tuners too) with the INACCRACY of Simulated Narrow Band, so I use TWO O2 sensors to data log AFR information.

I use AFR's for tuning only, because engine modifications don't provide optimal performance without tuning.

There's considerable debate about the accuracy of Open Loop AFR Tuning vs. Closed Loop AFR Tuning.

The WBO2 Tuning spreadsheet I posted here: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?5381-WBO2-Tuning-Spreadsheet is for Closed Loop Tuning.

18190

Thank you for the help. Yes that is the correct pcm. I actually haven’t determined what bin and mask I’ll use. There’s like four main options right? What are the differences? Why do so many masks even exist and on a side note the hex decimal and prom write locations etc are incredibly confusing the 000FFF whatever stuff. I’m a fast learner I just can’t find any info that explains everything what’s going on. Is $0E my best option? I read the text in that screen shot and it sounds easy enough. I’m assuming that screen shot is of the definition file that is the software “hack”? Do the parameters in the tree change with the mask id? I’ve only played with the craptastic one in the truck so far and it’s pretty basics (I’m away for work at the moment I can’t wait to get back and swap the new pcm in, already ordered more goodies from moates and stuff)

[Rob 689]

PCM 16196395?
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?337-16196395-PCM-Information-OE

Yeah sorry typo. Thank you. The $0E hack at the bottom post in the link what are all the things added or changed in the hack?

[dave w]

$E6 & $OD are for the 4L60E transmission.

$31 & $OE are for the 4L80E transmission.

$OE was also used for Manual Transmission. (posted in this tread)

Definitions $E6, $OD, $OE, and $31 are 64K binary chip files or more commonly called .bin file. The hexadecimal addressing for a 64K chip is address 000000 ~ 00FFFF.

The SST 27SF512 is a 64K chip and a very popular chip for definitions $E6, $OD, $OE, and $31 C2 SST 27SF512 Chip [C2] - $10.00 : Moates.Net (http://www.moates.net/c2-sst-27sf512-chip-p-39.html?cPath=26)

The factory chip for definitions $E6, $OD, $OE, and $31 are EPROMs that require an Ultraviolet Light to erase.

The SST 27SF512 chips are EEPROMs, which can be erased electronically.

[Rob 689]

$E6 & $OD are for the 4L60E transmission.

$31 & $OE are for the 4L80E transmission.

$OE was also used for Manual Transmission. (posted in this tread)

Definitions $E6, $OD, $OE, and $31 are 64K binary chip files or more commonly called .bin file. The hexadecimal addressing for a 64K chip is address 000000 ~ 00FFFF.

The SST 27SF512 is a 64K chip and a very popular chip for definitions $E6, $OD, $OE, and $31 C2 SST 27SF512 Chip [C2] - $10.00 : Moates.Net (http://www.moates.net/c2-sst-27sf512-chip-p-39.html?cPath=26)

The factory chip for definitions $E6, $OD, $OE, and $31 are EPROMs that require an Ultraviolet Light to erase.

The SST 27SF512 chips are EEPROMs, which can be erased electronically.

Thank you I didn’t know the different masks went with the different transmissions. That makes $0E my obvious choice as I have a manual and if I ever did go auto it would also be 4L80 anyways. The chip addressing ive found a thread here on gear head that tells you what to put into tuner pro for whatever chip your burning. I was mainly more curious about hex editor? I know I’m not even close to ready to mess with any of that but I’ve read some stuff about people messing with things for whatever reason like software changes but they talk about writing bits to “addresses” in the chip and they are 000s and FFs etc just like when burning chips and I was reading one time about how the chip burning works for using the full size chip to write say like only 4K bins and how you just write to the beginning gm of the chip and so on and it read like it should be obvious but how does the ordering of the addresses work I guess is what I was asking

[Rob 689]

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1477-Reading-Stock-GM-Chips-Burn-1-Burn-2-AutoProm-TunerPro-Flash-and-Burn

Sorry the “as you can see the buffer gets wrote to the ‘end’ of the chip” not the beginning like I said in my previous post sorry. But anyways I totally figured out how to burn chips don’t need help there I’m just confused as to how the hell do you decipher the beginning and end?! Etc.

[dave w]

Definition files (.xdf) like Advanced $0E TP5 v250.xdf are actually a Hexadecimal Editors that identify parameters and tables. Most, if not all, of the tuning can be accomplished with Definition files (.xdf) like Advanced $0E TP5 v250.xdf The most common parameters updated or modified for tuning are Fuel tables and Spark Tables, similar to changing jets in a carburetor and changing distributor parts like weights, springs, and vacuum advance canisters.

Usually the Moates.net Burn2 will automatically set the 64K 27SF512 Chip Addressing 000000 ~ 00FFFF and the Buffer Addressing 000000 ~ 00FFFF.

Because $OE is a 64K .bin file, the Burn2 does not required offset programming for the 27SF512.

Moates.net Burn2

http://www.moates.net/burn2-chip-programmer-p-197.html?cPath=94

http://static.moates.net/manuals/FlashAndBurn.pdf

[Rob 689]

Definition files (.xdf) like Advanced $0E TP5 v250.xdf are actually a Hexadecimal Editors that identify parameters and tables. Most, if not all, of the tuning can be accomplished with Definition files (.xdf) like Advanced $0E TP5 v250.xdf The most common parameters updated or modified for tuning are Fuel tables and Spark Tables, similar to changing jets in a carburetor and changing distributor parts like weights, springs, and vacuum advance canisters.

Usually the Moates.net Burn2 will automatically set the 64K 27SF512 Chip Addressing 000000 ~ 00FFFF and the Buffer Addressing 000000 ~ 00FFFF.

Because $OE is a 64K .bin file, the Burn2 does not required offset programming for the 27SF512.

Moates.net Burn2

http://www.moates.net/burn2-chip-programmer-p-197.html?cPath=94

http://static.moates.net/manuals/FlashAndBurn.pdf

Ahh I see what people mean when they say hex editor. What even is hex do you know a good source we’re I can do some more reading? Oh and and again thanks a ton for the reply’s and the help. Yeah I got a burn 2 and all that. I got my feet wet a little already one the crap ecm that’s in the truck it’s on a 27sf512 but stock bin still. It was my test subject for learning purposes. My first big task now is this pcm swap to the better one. I got all the moates memory adapter and zif socket etc already ordered and an AEM wide band with the bosh sensor with the kit and the gauge has an analog output for data logging. Kit comes with a harness and weld in o2 bung. And I have headers where is ideal placement? also sensor is 5 wire. Also should I install on same bank as factory narrow band or go to passenger side bank with my new sensor? Also my data logging that I’ve done historyogram blm numbers were average as low as like 90 and shit and higher up in the rpm range I get a lot of 130 and even 140s. I played little and cleaned it up a decent bit but it’s still a bit rough and I’m unsure. Having the AFR guage will be reassuring and I will be tackling the spreadsheet tuning method it seems like the logical path to success and a nice learning aid right? Also thanks again a ton for the help any thing else I might need? Oh and I got spare chips coming now too I can see how that could be nice. Oh and I’m goi g to upgrade my factory narrow band to the heated 3 wire as well for more accurate idling BLM logging and I noticed pulling over and shutting down to change the tune was really inconvenient cus the sensor would cool like seemed like right away or at least I had no clue if it was accurate till the mv got back up to like 8~9 hundred after a couple minutes of cruising. Looking forward to the wide band and the tuning of the new pcm

[Rob 689]

Also how do I know it’s even accurate even after extended cruise with the headers and all? Should I wrap the headers?

[LeMarky Dissod]

Also how do I know it’s even accurate even after extended cruise with the headers and all? Should I wrap the headers?Unless you want the headers to corrode, COAT the headers if you can afford it.
WRAP EVERYTHING ELSE. Anything you can't wrap, get more heat shielding in there.

[Rob 689]

Unless you want the headers to corrode, COAT the headers if you can afford it.
WRAP EVERYTHING ELSE. Anything you can't wrap, get more heat shielding in there.

Coat them with what? Just ceramic header paint? The vht crap in a can?

[dave w]

Ahh I see what people mean when they say hex editor. What even is hex do you know a good source we’re I can do some more reading? Oh and and again thanks a ton for the reply’s and the help. Yeah I got a burn 2 and all that. I got my feet wet a little already one the crap ecm that’s in the truck it’s on a 27sf512 but stock bin still. It was my test subject for learning purposes. My first big task now is this pcm swap to the better one. I got all the moates memory adapter and zif socket etc already ordered and an AEM wide band with the bosh sensor with the kit and the gauge has an analog output for data logging. Kit comes with a harness and weld in o2 bung. And I have headers where is ideal placement? also sensor is 5 wire. Also should I install on same bank as factory narrow band or go to passenger side bank with my new sensor? Also my data logging that I’ve done historyogram blm numbers were average as low as like 90 and shit and higher up in the rpm range I get a lot of 130 and even 140s. I played little and cleaned it up a decent bit but it’s still a bit rough and I’m unsure. Having the AFR guage will be reassuring and I will be tackling the spreadsheet tuning method it seems like the logical path to success and a nice learning aid right? Also thanks again a ton for the help any thing else I might need? Oh and I got spare chips coming now too I can see how that could be nice. Oh and I’m goi g to upgrade my factory narrow band to the heated 3 wire as well for more accurate idling BLM logging and I noticed pulling over and shutting down to change the tune was really inconvenient cus the sensor would cool like seemed like right away or at least I had no clue if it was accurate till the mv got back up to like 8~9 hundred after a couple minutes of cruising. Looking forward to the wide band and the tuning of the new pcm

I think the next step is to post a data log, and start tuning.

[LeMarky Dissod]

https://ccpcoatings.com/portfolio-view/ceramic-coating/

Hope this helps.

[Rob 689]

I think the next step is to post a data log, and start tuning.

What do people mean when they say good or usable data? Are there general practices for data logging or just hook up and drive around?

[Rob 689]

https://ccpcoatings.com/portfolio-view/ceramic-coating/

Hope this helps.

Thanks

[Rob 689]

I think the next step is to post a data log, and start tuning.

I've attached the best logs i have that were still on stock unaltered bin file. I have several short logs i took as i changed things numbered in order as well and i have a few copys of changes along the way and i have a copy of whats in it now which is worse than what had worked up to slowly and then i went to far and ruined it and the truck ran a little rough again and not quite as much seat of the pants measured power. unfortunately i accidentally saved over that tune with what is in the truck now and i screwed with several individual cells at once like a fool cus i felt like i was getting the hange of it and i think i was when i was making the extremely tedious micro adjustments. Ive tuned tons of carbeurators and im not completley lost but im not ready to say i know what im doing exactly yet either.

[Rob 689]

Here is the mask for the bin that is in the truck now. As well as the bin that i pulled of the original OE 2732a PROM chip and as far as i could tell it is unaltered? Also is a copy of the bin i ended up at after playing with the fuel table which i didnt even have WOT disabled i didnt know i did need to do that at the time and i have no idea how close i got but i ended up with a idle at 128 blm instead of fucking 90 so theres that. Ill also throw in the definition files to veiw the logs.

[Rob 689]

I think these two logs are the final altered tune i just uploaded. If not they are from a slight varient from right before that tune.

[Rob 689]

I need to cobble together some sort of tune that will run my truck in the new computer for the swap. I am away from the truck for a little while as soon as i get back tho ill be swapping the better 16196395 PCM into the truck. Probably gonna take the matching harness that i pulled with it and seperate out and remove the auto trans leg of the harness ill save it of course and then my re pinnning re wiring job will be taken care of that way. Unless it really is just as easy as swapping a couple pins around in my existing harness?? My main reason for choosing to swap the whole harness was the memcal and the knock sensor and the electrionic spark control system that is this little external module on top of my intake and the newer memcal takes that external ESC module which is integral to the spark retard knock sensing system and makes it internal correct? so what about all that extra crap on my harness for that ESC module? and the knock sensors are different they make different amounts of ac milivolts and i was wondering how simple is all that really i mean im no slouch when it comes to electrical and this sort of thing but is it worth the extra work of just doing away with all of the old and just swapping in the whole harness?

Anyways as soon as i get back ill be doing all of that ^^^^^^ and attempting to run the truck for the first time on the new computer and I need help maybe putting together a bin that will work as there are not really any stock configurations withe this pcm and $0E with a 350 and a manual trans. similar setups but not the same. Ill start looking around in the $0E and a bin and stuff i have my laptop but just not the truck for probably another week or so.

I did also just now get around to downloading that xdf and bin that were posted up earlier in the thread im taking a look toningt.

[dave w]

The 16196395 conversion IS NOT simple. The 16196395 requires COMPLETELY repining the computer connectors.

Gearhead link to a similar conversion (16197427): http://www.gearhead-efi.com/Fuel-Injection/showthread.php?173-1227747-to-16197427-Conversion-PCM-Swap-with-Wiring-Pinout-Directions!

The .bin posted earlier in this tread is for 7.4 liter. It's likely the 5.7 was not an available with a manual transmission.

[dave w]

I think these two logs are the final altered tune i just uploaded. If not they are from a slight varient from right before that tune.

The data log request was to if you are up to speed with data logging, clearly you are.

Reviewing data logs with the original computer is a-kin to beating a dead horse.

[dave w]

The 16196395 conversion IS NOT simple. The 16196395 requires COMPLETELY repining the computer connectors.

Gearhead link to a similar conversion (16197427): http://www.gearhead-efi.com/Fuel-Injection/showthread.php?173-1227747-to-16197427-Conversion-PCM-Swap-with-Wiring-Pinout-Directions!

The .bin posted earlier in this tread is for 7.4 liter. It's likely the 5.7 was not an available with a manual transmission.

Tutorial for moving computer connector pins: http://dynamicefi.com/RePinHowTo.php

[Rob 689]

The data log request was to if you are up to speed with data logging, clearly you are.

Reviewing data logs with the original computer is a-kin to beating a dead horse.

Yeah I noticed hence why I’m abandoning the original computer lol. Sounds like swapping the whole harness will be the easiest not that I can’t do the re pinning but why chance making a mistake or missing something when I have an entire known good harness that matches the pcm and it all ran when I pulled it apart. I’ll then be able to save the old one as another stand alone unit I could put on a mud buggy or something that just needs to run.

[Rob 689]

I’ve been wondering too since the day I bought this truck if it had an untuned cam swap in it cus it just seems too good to be stock but not good enough that I’m certain it’s swapped and now that I’m data logging is the large spread in my blm numbers does it look like it has a mild cam swap in it? Or could that be caused that drastically by headers? I installed the headers after I bought the truck and it got a little better with power just a little bit but i don’t think the headers are solely responsible at all but I’m not sure and I don’t wanna degree the cam to find out

[Rob 689]

It also had a horribly sooty exhaust a plugged cat fouled plugs and a nasty IAC vacuum leak and about every gasket between the heads and y pipe were missing and the manifolds only had about 39 snapped off bolts to deal with. I fixed all the leaks and it almost immediately had trouble and left me stranded. It was very sluggish and slow till I fixed all of that and hogged out the guts of the cat which also turned out to be plugged and then I fixed everything did the fuel pump rebuilt the throttle body etc it’s in tip too shape now and runs quite well.

It also according to my logs idles pig rich and stays pretty rich for a while up through the rpms

I theorize that the untuned cam swap plus the egr clogged the cat?

Sound theoretically plausible?

[tayto]

could be leaking/dirty injectors

[Rob 689]

could be leaking/dirty injectors

I don’t think so I just recently rebuilt the TBI unit and I cleaned the injectors under pressure with a fuel line hose clamped on the injector the other end plugged with a bolt and the straw off a can of carb cleaner glued into a teeny hole in the side of the fuel line. Holding the sprayer down on the cam giving pressure I tapped voltage om and off of the injector terminals with a battery and literally watched the spray pattern come back to brand new. Rebuilt and cleaned cus they became incredibly noisy and after cleaning they stopped the loud clicking. Also no leaks under pressure voltage removed in or out of the vehicle with my cleaning setup or the vehicles fuel pressure. Possibly they are worn out? Only 200,000 on the truck and they are gm injectors. They seem to have nice spray pattern and no leaks tho. Nice solid cones. No drips or dribbles between injection pulses. They seem to be controlling the fuel adequately at least while in nuetral. Can’t really watch under load obviously. But richness is ag idle…


Is there a sure fire way to tell if there is a cam swap in the truck with minimal work involved. Could the richness be caused by a loose timing chain that’s worn?

I did post another thread when I first started data logging and somebody said something about synchronize and asynchronous fueling that it was maybe going into asynchronous too often and could be dirty injectors also…..

Besides visual inspection of the spray pattern and for leaks what else is there to check?

[Rob 689]

Now that I’ve thought about it the rebuild kit was a cheap o’reilley one and that’s were the fuel pressure regulator came from and no name parts coming from China there’s a lot of room for shitty parts and perhaps maybe a slightly stiffer spring behind the diaphragm could cause richness? I really think it might have had a cam swap in it’s time.

[tayto]

not sure how your cleaning method is any different than running the injector on the vehicle? any place i've ever got injectors cleaned at uses a commercial grade ultrasonic cleaner and then flow tests them after. i have had/seen injectors that "sprayed fine" and cause the BLMs to drop (rich condition). after replacing them BLMs went to normal and the vehicle was able to pass emissions testing.

have you even put a vacuum gauge on?

[Rob 689]

not sure how your cleaning method is any different than running the injector on the vehicle? any place i've ever got injectors cleaned at uses a commercial grade ultrasonic cleaner and then flow tests them after. i have had/seen injectors that "sprayed fine" and cause the BLMs to drop (rich condition). after replacing them BLMs went to normal and the vehicle was able to pass emissions testing.


have you even put a vacuum gauge on?



Yeah obviously i dont have that crap. And i cant put straight carb cleaner through the dam thing while in the vehicle. I thought if the spray pattern was good and it didnt leak while under pressure but not energized it was fine. I did have a vacuum gauge on it while diagnosing it when the cat plugged up. The guy i bought it from kept saying the same thing about a cam. Granted once i figured out it was back pressure and i pulled the o2 and it fired and revved great all of a sudden i never did put the gauge back on it but the whole time i was testing it the vacuum was crap. Again it had excessive back pressure to the point it would barely idle. If you even thought about cracking the throttle it would struggle hard and stumble and the timing retarded aggressively my guess the map reading made the ecm think it was under heavy load hence the retarding timing? Once fixed it stopped retarding and everything.

Im assuming your asking cus a cam creates low vacuum right? Dont know why i hadnt thought of that sooner. Stupid me.

[Rob 689]

Ive also seen a few times hen sebding injectors out to get cleaned they use water and detergent alot of times in the ultrasonic and little bits of water remained abd corroded a couple of the injectors and the pintles got froze.

[Rob 689]

Also how do you figure that the way i cleaned them is no different than running them? Unless your referring to one of those injector cleaners made by otc or like a motorvac machine. Then yeah what i did was about the same but i did it with .2 cents worth of scrap fuel line a four wheeler battery and a can of carb cleaner. All crap i had laying around cus money is a thing that is finite. The only thing bettef would be to replace them. But again expensive. If it is the injectors it would indicate that they are leaking right? Instead of buying new ones for now cant i just tune it out? It also has a cheap no name fuel pump and it puts out about just barely over 15 psi with the new regulator and a brand new fuel filter. The system is 12 to 15 pounds right? The old regulator same pump was at like 13 pounds mabe a touch higher. The okd pump which was original to the truck was 12.5

[Rob 689]

I had thought the fuel pump went out when it first died on me andits a flat bed so i just pulled up a board and shotguned a 30 dolkar pump cus when it died not even starter fluid worked. Then i started diagnosing and turned out the plugs were fouled from the plugged up catalytic converter. Changed them and i got the idle no rev crap condition. But thats why i swapped out a perfectly good fuel pump. I later went back and tested it to see when it didnt fix it thats how i know what pressure it had.

[tayto]

sounds like you have some mechanical problems to fix before we can start pointing a finger at the tune. I would have upgraded to a TPI or vortec pump. the tbi pumps are barely adequate for even stock setups.

[Rob 689]

sounds like you have some mechanical problems to fix before we can start pointing a finger at the tune. I would have upgraded to a TPI or vortec pump. the tbi pumps are barely adequate for even stock setups.

Good to know it needs a new sender anyways its about to turn into dust the metal tubes are paper thin cus of rust. Tank is brand new luckily previously installed before my ownership.

No the mechanical issues have been taken care of.

The truck ran like crap when i got it cus of a vacuum leak snd i didnt know at the time but the plugged cat. Fixed several exhaust leaks a few responsible for melting part of my exterior lighting harness. Fixing those caused the cat to kill the truck. Shotgunned the fuel pump no fix. Changed the plugs and it ran okayish again then it left me on the road. Got towed bew plugs again and then actual diagnoses time. It was 20 below at the time for reference and no garage mines too short due ro washer dryer heater etc. The retarding timing made me think it was the dizzy. I had just got done parting a burbon and had known good parts to shotgun as it was cold and again i had a whole ass nother truck in my garage basically minus the body lol. So yeah swapped a ton of shit and then let it sit over the holidays.

I revisitted it with a fresh mind not frustrated and tried checking if it was the cat and i pulled the o2 sensor and fired it up ran and revved great and a huge cloud if soot poured out the o2 hole in the manifolds. Dropped the y pipe and beat the guts out of the cat very thoroughly with a rod and a hammer. Put it back on and also rebuilt the throttle body and cleaned the injectors replaced the iac solenoid and fuel pressure regulator. Put a brand new o2 in and drove the truck for a while. Ran great. Bought headers for the truck and built and welded up an entire new exhaust for it. Deleted the egr and loaded a new bin that has the egr on minum thresholds set so high it will never ever cone on.

The injectors before i cleaned them during the rebuild they had a poor spray pattern like really poor and dribbly at idle and after cleaning and rebuilding the throttle body the injectors have nice perfect cone patterns and do not show any drops or dribbles with a timing light with the dial hooked up and watching the injector pulse. They absolutely do not leak under pressure de energized.

At 120 plus dollars a peice im not calling those injectors faulty. They are stock gm stamped 350 injectors as well i verified that during the throttle body servicing.

The truck does leak some oil enough to leave tiny occasional drips and still barely ever needs topped off. No internal consumption of oil. Compression is 150 across the board except #1 and #8 were a couple pounds low not much and the cylinders were pretty washed out from me trying to start it a crap ton the day prior. I saw gas running out of the donut between the y pipe and manifold and stopped.

Absolutely no mechanical issues going on.

[Rob 689]

The truck gets blm numbers down as low as 90 full temp closed loop operation. And hits high 140s in the up around i don’t remember exactly where in the rev range but I wanna say like 4500 and up but dont quote me i gotta look at data and crap to check. But surely thats not normal for a stock truck with 200,000 that appears to have been well cared for until the exhaust was neglected and it got sold.

I played with the tune a bit and took out idk guessing here but overall about ish 15 to 20 percent fuel out of the map under i think it was 30 maybe 20 kpa and up to about 2600 rpm and the truck responded really well and its still a little rough im not finished yet. Idle quality improved a ton but felt the power feel slightly greater and mostly smoother.

Could headers alone cause this?? They do scavange quite well. I tested with a dryer sheet and compressed air before i put them on and they definitely do the job. Is it worth seeing if the timinv chain is stretched? If it’s stretched probably has not had s cam. If its not stretched doesnt mean it does but it could be a clue. The truck has always felt strong enough to make me wonder. But I didnt start data logging unti after i already got the headers.

[Rob 689]

Also after playing with it it idles right about 128 full temp closed loop now.

[Rob 689]

Overall the truck does run great but its blms are deffinatly not anywhere near 128 hardly ever

Its also always since day one on a dead nuts cold start also has brand new battery and brand new starter as well. Ive also re done all the ecm grounds engine grounds chassis grounds body grounds etc under the hood. Alternator looks brand new. Again previous owner. No signs of intake gasket leaks, I've sprayed down the sides of the intake pretty aggressively with carb cleaner and starter fluid while its running and no change in idle speed. No coolant on the top of the motor either.

anyways on a dead nuts cold start its always taken a seemingly excessive anount of crank time before it fires. After playing with the main ve table a bit as I mentioned earlier it was improved that slightly but not completely.