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Can I reprogram my tack with GMTDScan?

P

pgguru

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Location
Hamilton Ontario Canada
I am looking to purchase GMTDScan next week and was wondering if I could reprogram my tack with it? I have a Gasser alternator so I read like 1000 RPM at idle. Or is a new pulley the only way to fix it?
Thanks
 
Best, most accurate way is a new pulley. I purchased a new alternator from Pep B*yz and was assured that it was application-specific. After install, my rpm's seemed to be the same as before. Only problem: several of the members here had mentioned that they seemed awfully high for the roadspeeds that I was recording. Compared the new pulley to the one on my old alternator - they were the same diameter. Checked them to the pulley on a Chevy gasser that was here in the shop. Again, identical. Hmmmm..... Called our local alternator shop and asked if they had one. Yup, they did. I went over there, bought it, brought it back and compared it to the other two. BIG difference. 20 minutes later, new (incorrect) pulley off and new (correct) pulley on. RPM's dropped noticeably - I now show 2200 rpm at 65mph.

I have the GMTDScan software and adapter. ABSOLUTELY one of the most cost-effective purchases I've made for my truck. It's helped me verify sensor problems, as well as setting my timing spot on at -1.94. Wouldn't trade for it! However, I've never seen anything in the software that would let me recalibrate a dash instrument. Check the accuracy of the readings, yes. Change how the gauge reads, no.
 
Nope, but it will show you what the true RPMs are, from the crank sensor.

I have the same alternator problem, but I have a high output 140 amp alternator almost ready to go on.

Dave, what is the diameter on the "correct" pulley?
 
How hard is it to pull the pulley and put the new one on?
did you do it on the truck?
Did you use a special Puller?
I to would like to know what size pully to use.

Thanks
 
Acesneights1 said:
IIRC once you take the nut off it should just about fall off.
Click to expand...


Yeah, but first you have to get this nut off ! I changed my alternatorand noticed that the pulley was smaller in diameter than on my old, but it also only had 5 grooves to my old 6 grooves pulley. It was a hard job to get the nut on the 13 year old, stuck with loctite, alternator loose !

Cu,
Sven
 
Jim Bigley's manual says the OEM pulley is 62mm.

My alternator pulley measures just about 62mm across the top of the ribs (my only metric caliper is slide rule so limited precision). A dial caliper across the top of the pulley ribs measured 2.434".
 
Buddy - sorry for the delay in responding. As Smithville and Scwhind have already pointed out, the pulley ID is 62mm. If the belt is on, you can measure the rim OD. At the outermost edge of the pulley rim, you should see 66mm, 3.575", or a shade over 3 9/16", depending on what you're using to measure. I bought the correct pulley from a local alternator shop; the cost was $8.
 
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