My blaze would started immediately upon cranking for the 4 years I have owned it up until about 3 months ago. It will still ALWAYS start but sometimes it will crank for 5-6 seconds before it catches. Eventually I figured out that if I turn the key into the on position and hold it there for maybe 4 or 5 seconds and then crank it will start right up consistently. But if I turn it of and let it sit for an hour or so it will go back to the long crank again. It idles smooth and never dies on me. I also do hear the fuel pump even with the long cranks.

I've read through the forums and going to do some fuel pressure tests but was wondering if anyone had some other ideas. I replaced the fuel filter in the last month and that didn't help. I do have a new PCV valve I plan to put in just for grins. I've read cleaning and replacing EGR gasket might help also.

Thanks for you input.

 

Big thing, pull some spark plugs and see what condition they are in. Also look at spark plug wires, your coils, and how are the Cap and rotor? these things would definetly cause a hard start but if they aren't completely gone they usualy show no symptoms when the vehicle is running.

 

have you checked your battery? what about your connections on the battery?

 

Check the fuel pressure. Just because you can hear the pump run does not mean it is working real well. Normally longer than normal cranking is due to a fuel pump that is going out as it takes more time for it to build the required pressure.
Also check for any loose or broken vacuum lines.

 

So I checked fuel pressure and there are definitely issues there. It was taking way too long to get the fuel pressure high enough to start the car. So it looks like a fuel pump will fix the problem. But I did have issues finding the correct ACDelco pump. I have come across two part numbers. MU1772 and MU112. I called Chevy and gave them my VIN and they told me the GM part number for the fuel pump is 19177257. Can anyone confirm if this translates to the ACDelco number? I am finding this somewhat cumbersome as different autoparts websites seem to have different parts and descriptions and it seems that MU1772 and MU112 are interchangable? Any advice is greatly appreciated.

Also I put in my VIN at ACDelco's part search and it gave me three different pump numbers.

MU1733
MU1755(2 door, so this definitely is not the correct one)
MU1772

 

If you go to Rockauto.com and paste the GM part number into the part # search box, you will find the right pump. I tried it using your GM part number, and the MU1772 pump is the matching pump.

 

Thanks for the confirmation. See this auction. http://cgi.ebay.com/ebaymotors/ws/eB...#ht_2036wt_939

They list out two GM numbers and two MU numbers. I have been in contact with the owner of the auction to get this straightened out. I did the compatibility test on that auction page and apparently doesn't fit my blazer.

Anyone else have luck buying the pumps on ebay? At 169.99 I find it hard to beat.

 

which fuel injection system do you have? The one with the throttle body up front/horizontal (W motor/injection system) or right in the middle/top of the intake (Z motor/injection system)?

I've been told the W uses a high pressure pump (sort of like my TPI Irocs - around 45 to 50 psi). The Z motor uses a 12 to 15 psi pump.

Be sure you get the right pump.

The pump is in the tank. Major PIA to replace. At least it was on my 95 Blazer. The hoses (vents, etc.) are cut so short the tank was obviously installed in the frame before the body was set down on the frame. Almost impossible to get your hand in there to detach or reattach the hoses to the metal tube at the front of the tank. Be careful when removing the pressure hose fitting that you don't damage the metal tube coming out of the tank or you'll have to replace that, too (another $100 - ask me how I know).

Oh, the strap bolt over there between the gas tank and the drive shaft isn't hard to get loose (with an extension and deep well socket) but its hard to get it back together when putting the tank back it - again, hard to get your hand up in there to get the strap, the washer, the nut and the socket/extension/ratchet up there.

You can do it, its just not real easy. Oh, be sure to clean the tank off real well before you remove the lockring and sending unit/pump from the tank. You don't want all that dust/dirt in the tank. And replace the filter bag in the tank, too.

 

81Z4ME, there was only one injection system offered in '98, SCFI. It requires at a bare minimum 55psi to operate properly.

As far as the pump numbers, the MU numbers are AC Delco as stated. Try searching on the two that seem to apply. They have been discussed before.

 

Hey thanks for the help guys. I did get the ACDelco MU1772 fuel pump from ebay and installed it last weekend and everything works great. Car starts right up again. Here are a few pointers.



* Remove spare tire and rear wheel for better access
* I did break the rear rusted frame bolt clip that holds the rear tank strap.
* Took some extra work to remove the 2 rubber hoses off of the rear of the tank. Worked a screwdriver between metal and hose and also loosened with pliers.
* Installing new fuel pump is a tight fit so be careful
* Follow instructions carefully when cutting wires for new connector