'03 Blazer wont start...tried everything I know

[junior7]

First, I am new here and this is my first post. Thanks for having me.

Second, I have just had it with this Blazer. I am lost. It is an '03 4x4 with 64,000 miles. On the way to the doc's the other day, after running perfect all day, it seemed to "cut out" on me about once every couple of miles. The "cut out" was so quick though, it sounded like a knock. Aside from those couple of cut-outs, power was fine and it idled fine at red lights.

Next morning it wouldn't start. Turned over at normal speed but nothing. First I checked all fuses which were fine. Next I tried some starting fluid, but nothing, although it sputtered on the ether. I am chalking that TINY bit of sputtering up to compression based on experience of screwing with engines. I should add that it sputtered that TINY bit without the ether a few times too. The sputtering was after I let off the key too, not during cranking.

So tonight I purchased an Actron CP9175 on the way home from work. No codes. Hooked up a fuel pressure gauge and I have 60 at the schrader right off the bat. Since I am not sure how slowly the pressure should drop on the guage over a few minuites, I haven't done that test yet.

New parts in last 8,000 miles:

cat-converter
plugs
wires
cap & rotor
battery
map sensor

Any help and I would be so, so grateful. Right now I am just going trying to figure out what this could be.

[discnik]

You did not mention if you have checked for spark at the plugs.
If you go to http://www.autozone.com/home.htm You can look up your vehicle and using the menu on the left go into repair info, there is "Product and how to" secton in the left hand menu. I looked up your pick-up coil, and it gives the testing procedure for it. Auto Zone also states that they can test your ignition control module.

Just some thoughts

[blazes9395]

Originally Posted by discnik

You did not mention if you have checked for spark at the plugs.

I agree, make sure you have spark. Could be ignition control module, crankshaft position sensor, etc, etc.

Welcome to AF!

[junior7]

Sounds good. Tomorrow morning I will get cracking on that. What do you cats think the most efficient way to check for spark is? Just toss a new plug in a cap, ground it, and eyeball it while someone turns it over? The truck is outside and its 10 degrees here and a complete frickin blizzard, just so ya know what I am working in.

blazes, my truck looks exactly like yours, and i mean exactly. Black, 2-door, 4x4 and its sitting in about 14" of snow.

Oh, and wouldn't a bad crank pos sensor produce an OBD code? What about a bad ignition mod? Crikey...there are so many things that could be causing it.

Thanks and I will post back after some spark checkin.

[brcidd]

I had a '95 Blazer that sputtered after I let off the key from crank...it was a bad ignition switch--see if you have 12 volts to the coil in "Run" and in "Crank" positions-- mine had 12volts in run- but not crank-- and when I backed off from crank- it got 12volt while the starter was winding down, just enough to make it sputter...I tested it by jumping 12 volt to the coil from the battery- through a fused jumper-- truck started right up.....

[djd99]

Well you could either have a fuel issue or ignition problem. Don't rule out the fuel pump yet until you have this thing fully diagnosed. I also had problem with my blazer just dieing out of the blue and when I put my pressure gauge on it it would read 60 psi. After doing a complete tune up and checking the ignition system when my truck cut out I came to the conclusion that it was my fuel pump. When my truck would cut out there was a nice blue spark. hmmm So every time I put my fuel pressure gauge on it read 60 psi. Then My truck had issues trying to start on a cold morning and once again My fuel pressure read 60psi and would never go above 60. Being I had plenty of spark it could only be the fuel pump. I replaced the pump and never had another problem with it cutting out. Also they make a replacement connector for the fuel pump witch also goes bad that you could check.

So the next time this thing cuts out put a spark plug on number 1 cylinder and check for a good blue spark and if it has spark look into the fuel pump closer. If you don't have any spark look into the CPS, Ignition module and coil......

[usedranger]

I may have missed it but have you changed the fuel filter?

[junior7]

Ok, its got a weak, orange, intermittent spark. I guess I will take the coil and ign mod to Auto Zone and have them tested.

Any other suggestions before I take them off? Would a bad CPS give me those results that I got?

I really appreciate the feedback and help. Thank you.

[junior7]

Whew, what a day! She is running like a champ now!

I kind of made this situation a little harder on myself than I had to. Heres what was up... Like I mentioned earlier, the truck was fully serviced about 8,000 miles ago including a cap and rotor. So when the truck wouldn't fire on ether, doing some spark testing and listening to the pros here, it was obviously an ignition problem. Since the cap and rotor were new, I skipped those and concentrated on the coil, ignition mod, crank sensor, etc...

My mistake. It turns out that the shop that did the work stripped one of the small torx screws that holds that cap on by over-tightening it! Then, just left it like that! It was so green and corroded in there that I am surprised that it made it as long as it did. It would have taken the mechanic 10 minuites to fix.

Runs awesome now. I threw a small bead of Permatex Form-a-Gasket on the bottom of the new cap to be safe. I also put in six Bosh Platinum +4 plugs and a K&N filtercharger. The truck is sometimes on the jobsite parked on the street, so I installed a set of Optix Strobes in the front headlight assemblys and mounted the control box around where your right knee is when driving. The install took about 1.5 hours and turned out great. Sort of nervewracking drilling the headlight housing though! These are not commercial grade strobes, but those are too expensive for me. I am very proud of how it turned out for under $100 and less that 2 hours.

So here is all the small stuff that is on the Blazer now:

2003 Blazer 2-door 4x4 LS 64,000 miles
AVS Ventshades on windows and moonroof, AVS bug guard
Sylvania Silverstar headlights
15% tint all around
K&N Filtercharger
Goodyear Wrangler RT/S meats including swing-out spare
Optix Strobe light kit/w adjustable speed and pulse pattern
Bosch Platinum+4 plugs, Bosch silicon wires

Thanks for all the help!