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Try slowing the write down. 100us is the typical value for an EPROM but most programmers allow you to slow things down to get more charge in.

Also be careful on the VPP setting, the absolute maximum is 14V on the normal memcal EPROMs.

Increase the numbers to advance

it shouldnt take 45 minutes to erase a chip if the window is clean and if its got the window pointing at the tube in the eraser.normally 7 minutes is more than enough too much more and the chips get very slow and have issues.i learnt that the hard way when i bought a massive number of 27c010 chips online all programmed and verified fine but limp home mode straight away in an ecu had been erased by the seller for too long

problem found, one of the pins was bridged with the other on my adapter
a chip i made is still going since 11pm last night after i fixed the problem

and it only takes 10 minutes to erase now two crossed pins was probably half my problem and i was erasing them to long

lucky i have 3 spare eproms

Dylan wrote:Increase the numbers to advance

thanks google dosnt always give good information

how would i tune for vt injectors i tried changing injector flow rate from 370 ms/gram fuel to 390 ms/gram of fuel but i noticed that its blowing black smoke am i missing somthing or what

Get the difference in flow as a percentage from old spec to new (treat 1.00 as 100% eg identical flow) and multiply the original injector rate value by that. For best results also look up the injector dead time by voltage and add that data for the new injectors to the appropriate table as well. This will help mostly for idle and the bottom end.

delcowizzid wrote:it shouldnt take 45 minutes to erase a chip if the window is clean and if its got the window pointing at the tube in the eraser.normally 7 minutes is more than enough too much more and the chips get very slow and have issues.i learnt that the hard way when i bought a massive number of 27c010 chips online all programmed and verified fine but limp home mode straight away in an ecu had been erased by the seller for too long

Well, the seller may have abused the chips in some way, but it wasn't by sunburn. The maximum UV exposure is so high, it's usually not even included in the data sheets.

Joe.

PS. After some searching, I finally found a maximum UV exposure figure, in an Intel A27C256 data sheet : 1 week at 1200 uW/cm^2, which is equivalent to 500 erase cycles of 20 minutes (that's the specified erase time at 1200 uW/cm^2) each.

For weaker UV sources, the times increase accordingly. Under-erasure can degrade access time, reduce noise immunity, and give erroneous data at elevated temperature.

antus wrote:Get the difference in flow as a percentage from old spec to new (treat 1.00 as 100% eg identical flow) and multiply the original injector rate value by that. For best results also look up the injector dead time by voltage and add that data for the new injectors to the appropriate table as well. This will help mostly for idle and the bottom end.

where would i find a data sheet for the stock vt injectors i compared the vt and vs program together but everything is so far out compared to the vs that im not game enough to use anything from it

Physically read the part number off the injector and google it. Or where changing from one stock injector to another get both stock tunes and suitable xdfs and copy data between them