Can anyone tell me the difference between Delphi pump# MU1772 and MU1733? I have a 1998 Blazer 4wd, 4dr. Shop installed MU1772 but I thought my truck took the MU1733 fuel pump. I tried looking it up on Rock Auto's site. I'm not sure what a "low lubricity fuel sys" is but I guess this more expensive pump has one is all I can figure. In the picture the seal/o-ring looks different also.

 

Those are both AC Delco part numbers.

To use the MU1772 pump, you should have RPO code K55 (low lubricity fuel system) and not have NE2 (18gal tank). MU1733 should be used if you do not have K55 and do have NE2.

 

OK,does that mean if I have an 18 gallon gas tank, which the owner's manual says I have, that I should have been given the MU1733 pump? I'm still not clear on the RPO codes. How do I tell which one applies if it doesn't refer to the tank size? Thanks for the help. Did not see either K55 or NE2 on the Service Parts sticker in the glove box.

 

Your RPO cides on the sticker in the glove box is what YOUR trick was equipped with when it left the factory. There are a bunch more codes thanwhat is on your sticker.

 

OK then how do I tell which fuel pump code is correct?

 

Go to the dealership service dept and ask if you can get a printout of your RPO's? You'll need your VIN to get them.

 

OK thanks for the tips.

 

They are also in the factory service manuals. Sorry, I have only up to 94 and those codes do not show up. If you know someone with one they can look every one of them up for you or e-bay sells some of the manuals dirt cheap. Or go to the dealer like mentioned above. Here's a set for your truck. Just trying to help man. I find mine worth every dime I spent on them.
http://cgi.ebay.com/ebaymotors/1998-...item53e0e25c78
http://cgi.ebay.com/ebaymotors/1998-...item5ad8e713e0
http://cgi.ebay.com/ebaymotors/1998-...item27b1c689e5

 

Just type your vin into CompNine.com's vin decoder and you'll have the complete list of all RPO codes.

 

OK, I went to CompNine.com for the RPO codes - Thanks swartlkk. Also, I got the 3 volume service manual - Thanx GimpyBlazer.

BlazerForum ROCKS!