having trouble with limp mode , any help apreciated

[Airbrush guy]

Hi all . not sure If its just me been stupid or not , but trying to reprogram eprom from 95 astro with vortec heads and mercruiser inlet and injectors. I pulled the original prom and read in software for tl8662plus programmer , saved and read in tunerpro, updated values etc wrote back to new chip sst27sf512 , popped back into ecu (well zif as buggered the original holder getting prom out so repinned and put a zif in) started up and its all over revving up n down until in gear and stuck in 3rd, removed chip reburn original bin but same issue not sure if its me or I'm missing something in burn program, any help would be appreciated ill include original bin BSWW $0D, and screen of programmer software , thanks again
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[In-Tech]

I've only done ONE with the eeprom and from my memory it does require it to read from the bottom. I just did it as an experiment so my memory of it is vague. It does sound like something similar. The checksum check on key up should flash once and then stay on solid if everything is ok, otherwise will flash rapidly if checksum fail is present. On the 512k stuff, that might be in the code of the chip and not embedded in the firmware, not sure on that.

[Airbrush guy]

Thanks , I tried pulling codes to see if any errors but wont even flash out codes check engine light just on constant , wondering if have a faulty ecu or just messed up as could pull codes before the chip swap old one was a 27C512 , removed ecm fuses and usually when replaced can here iac resetting etc but nothing to be heard atm

first time flashing so thought I must have messed up somewhere along the line

[In-Tech]

I looked at your read and the checksum is correct at address 4006,7(value is 9112 in your bin and is calculated from 4008-FFFF) so that looks like a good start. I would bet you have a programming issue/error. I have only played one time with those eeproms and I sort of remember I had to do something specific to get it to program correctly. Hopefully someone here can help with the details. It's been many years ago and I just did it as an experiment. I'm hoping to feel good enough to get to the shop tonight for a bit. If I do and you don't have an answer yet, I'll pull one out and program it to refresh my memory.

[dave w]

27C512 chip is 64K which has chip addressing 000000 to 00FFFF

dave w

[c5wagner]

What chip adapter are you using? Do you have the chip orientated right with the notch going to the outside? You mentioned re-pinning so did you check for continuity with a voltage ohm meter? That is the right starting address so I don't think it is a programming error, but I never have that "Skip 0xFF" checked14066

[Airbrush guy]

Thanks all , Ive adjusted program with offsets as Dave stated and unchecked skip 0xff and included screenshots, also included pic of re-pin as extended using wires to an ic holder and then zif is connected to that in the correct orientation , continuity checked all ok I know looks rough was my own fault trying to desolder original when having a shaky hands day lol but found a way around using the wires and cables. I was going to buy a G1 adapter but shipping is twice the price of the adapter to get it to the UK so did it this way instead





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[mecanicus]

what happens if you try your original chip?
there is new software for the xgpro on their homepage.
I take those settings when flashing.

[Airbrush guy]

Thanks, don't have original chip atm , a friend has it to read incase just my issue, removed zif adapter and plugged into ic socket , no difference with original bin tried different 0D bin and cel light flashes fast on ingnition on which is more than it was doing but then defaults to limp mode so unless Im crazy it has to be a bin / prog error unless I have a dodgy pcm as motor always seemed a little gutless for a 4.3 ?

do you think it would be worth pulling a 5.7 bin from the list and editing for 6cyl as a base?
thanks again for the input

[mecanicus]

I would by a used memcal, have a look here:http://www.ebaystores.de/RAGGEDS-USED-AUTO-AND-TRUCK-PARTS/_i.html?_nkw=BPLA&submit=Finden&_sid=1102508 then have a look here:http://www.gearhead-efi.com/Fuel-Injection/showthread.php?178-427-PCM-Memcal-Mod-for-27SF512-Chip
build an adaptor between memcal and programmer like this , have a look to the BBClookup and choose the right bin.Read a lot here in the forum and start again!
When ordering a new memcal have one for a 6cyl otherwise the limp mode will not work!

[Airbrush guy]

Thanks I'll have a look , I know original bin file its BSWW but not on here apart from my upload earlier , pcm was updated before I got the van so chevy astro 1995 4,3 cpi L35 , Ive since changed heads to vortec (96), and inlet injectors and throttle body are all from mercruiser , injectors are 24lb hr and are wired up as batch fire , egr deleted and no longer has cpi tune unit obviously , its W motor so better cam than later model and exhaust is 3" straight , believe its 460 trans and have tried BHRJ as that's cpi L35

thanks again for your input:thumbsup:



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[Airbrush guy]

Just wanted to say a big thanks to all for the advice, Ive sorted it now and feel like a right numpty, one of the wires was broken internally original continuity test showed all ok but another test after casing put back showed one wire only connecting when bent a certain direction lol:mad1: on with the tweaking now
Thanks again
Gary