A starting issue ???? Any thoughts???
 

On our 98 Blazer 4x4 I'm having an occasional starting issue & would like any thoughts or input anyone may have.
I just had a new Delphi Fuel Pump installed & new fuel filter. I cleaned the T/B. I have not checked the plugs yet. I have no codes. But every so often I will go to start it & I have to crank it sometimes twice to get it to fire. Other times you just turn the key & it fires right off. It was doing this before the new pump. When it starts correctly it starts better than before pump. It use to kind of hesitate then the RPMs came up. Not so now.
I notice it more in the heat of the day. We are in the 115s & over. This morning first thing it fired right off.
Anyway I want to check the plugs & if it doesn't have AC Delco Platinum plugs which are OEM I will install them.
One other thing we get 20-22 mpg on the road & 13-16 mpg in town in this heat with A/C running full blast non stop.
So any ideas would be appreciated. Thanks

No Thoughts or ideas. Come on guys someone must have some input.
Thanks

Make sure the ignition switch is feeding all of the PCM circuits, every time, in the START position.

Have you checked the battery posts for any corrosion?

Thanks for that info.
I wondered about the ignition being a possibility. The battery cables are clean & no corrosion. Is that a common wear item on the 98s? Is there a diagram on testing the circuits?
Thanks guys for the input.

I was noising around under the hood today before it got too hot. We are having 115-120 degree days. Friday we are headed to a cooler climate. Which is when I will mess with our Blazer.
But as I search I find that most ignition switch issues involve dash lights, & other components which I'm not having issues with. But what I did discover was it appears that someone has put cheap standard spark plugs in. It looked like 605 as the number which would be a $1.99 Autolite plug.
That could well be my issue with starting.
But I PM Captain Hook about ignition switch testing. So hopefully I can get to the bottom of this when I get to a cooler climate with shade.
Thanks

AC Delco #41-993 plugs with gap of .060" are the best plugs for this engine.

There is a link on the forum that explains ignition switch operation & diagnosis in the DIY section.

For information on the ignition switch, check out the link at the bottom of my signature. :icon_wink: It's also in the Article Submission/Discussion area.

Thanks Kyle. I hope someone can clue me in on my other post about the correct spark plugs OEM or at least AC DELCO platinums.

I installed a set of AC DELCO 41-993 plugs. Dielectric geased all the connectors plug wires etc.I had a Pro Flo Turbo muffler installed. You guys in Canada should know about Pro Flo Max mufflers they are a Canadian Company. Their mufflers are long lasting & have a nice mello sound. I ran one for 4 years and almost 100K with no problems.
Back to the starting issue. It is better but still is an issue sometimes. I cleared the computer also. So I'm trying the easy stuff first. I guess check cap & rotor.
Any other thoughts???

Connect a fuel pressure tester. In the underhood fuse panel, just forward of the fuel pump relay, there is a single female vacant terminal molded into the fuse panel. The terminal inside goes directly to the fuel pump.

http://i561.photobucket.com/albums/s...154-Copy-1.jpg

Connect a fused jumper wire to battery positive. Touch the other end of the jumper wire to the pump prime terminal. As you touch the prime terminal, watch fuel pressure very closely: It should rise immediately, each time you touch the prime terminal, (pressure will drop when you remove the jumper). Repeat this several times making sure the pressure rises immediately each time you touch the prime terminal. What we're looking for is the fuel pumps ability to consistently pressurize the system when battery voltage is applied to it.


This is also how to check fuel pressure and leakdown: When the pump is running, fuel pressure must be 60psi to 66psi. When voltage is removed, the pressure must remain above 55psi for at least 10 minutes.

Post your results.