Won't Start

[gmbwrenchn]

Just recently I was driving along and I had the air bag light go on briefly. At the same time there was a beep inside the dash AND it felt like the car was going to stall. This happened to my daughter while she was driving it, only it did stall.... complete shut down, while driving, but started right back up again for her. Then I'm driving along another day and it shut down completly. Now it wouldn't start. So I was told by other people, that sounds like your ignition switch. I just got done replacing it and it still won't start. She turns over, but nothing happens. Any other ideas please. Here is what else I've done: I have spark. Not sure if gas is getting in. Fuel pump was replaced 3 yrs.ago{ AcDelco} I can hear it working.

[old_master]

Year, make, model, engine, 2WD or 4WD, and transmission would be very helpful

[gmbwrenchn]

Yea! it would Blazer 97 4X4 LT 4.3 Ltr. Auto trans. on the floor.

[old_master]

The symptoms sure sound like an ignition switch, and that's a very common problem with '97, but apparently not the problem with yours

1. Your vehicle is equipped with Passlock security system. Passlock disables the injectors if the system detects a possible theft situation. Usually the engine will start and run for a couple seconds, then shut off, but, the system has been known to do some crazy things when it screws up. Does the security light blink or stay on steady when you try to start it?

2. You said it has spark; if it has a good blue spark, not orange, at each spark plug, the next thing to check is fuel pressure and leakdown. Ignition ON, engine OFF, fuel pump running; fuel pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the fuel pump shuts off.

[gmbwrenchn]

Well my Blazer does Not have the Passlock security system......I don't think..? No security light on the dash. That sound right? Or is it something else. I seen spark by pulling one plug and cranking the motor. Do I need to pull them all? Thanks for the help.

[old_master]

I'll have to double check but I'm pretty sure Passlock was standard equipment on yours.

As for the spark, yes, you need to check for it at all plugs. The distributor cap is another very common problem. Aftermarket caps don't last nearly as long as original equipment AC Delco caps. One of the reasons is if camshaft retard is not within specs, crossfire will occur inside the cap. There are also two vents in the distributor housing that like to clog up and allow condensation to build up on the underside of the cap. When that happens, it'll crossfire to the point that the engine will not start.

[gmbwrenchn]

UGH.......pulling all the plugs is going to be a headach, but I'll have to do it. Thanks for the other info too on the cap. Will check it out. Just may go ahead and replace it. Gonna be tuff this week with work & the holiday. Will get to it and report back. Thanks again for the help.

[old_master]

You're right, GM started using Passlock on 1998 S&T body vehicles.

If your distributor cap & rotor haven't been replaced recently, it might not be a bad idea to replace them now. Any idea how many miles, or how long it's been?

[gmbwrenchn]

Looks like March of 09 on the distributor cap and rotor. Did plugs and wires too. About 14k miles. I know it wasn't a Delco cap. I want to pull it off and take a look yet. Gota do the other stuff too. Thanks.

[old_master]

When the cap was installed, if silicone dielectric grease was not applied to the terminals inside the cap, at 14K miles, it could very well need replacement. It's likely you won't see anything wrong: when crossfire occurs, spark jumps to the wrong terminal and leaves no evidence other than a P0300 random misfire DTC.

[gmbwrenchn]

Well I have used the Dielectric grease but never put it on the inside of the cap. You mean on the tab terminals inside the cap? I've always put it on the outside posts where the spark plug wires go. Come to think of it, past few months before this all happened, it was kinda hard starting. Maybe we got something here. So i'm gonna just replace the cap, {and rotor of coarse} and check the fuel pressure. I'll check the pressure first, when I get a gage, should I check the spark at each plug first before I replace the cap and rotor? Thanks.

[old_master]

If it's been a while since the cap was replaced, and no grease was used, I'd just replace it and don't bother checking spark at this point. You know you have spark... at least one plug does

Whenever the cap is replaced, silicone dielectric grease should be applied to each terminal of the cap, both inside and out. When the engine is running, the current passing from the rotor to the cap will crystalize the grease. If you've ever noticed the crusty stuff on the terminals inside the cap, that's what it is, it's supposed to be there, don't scrape it off. The grease on the outside terminals makes it easier to remove the plug wire boots in the future

[gmbwrenchn]

Learn something new everyday.......all these years I was scraping that stuff off! Will keep you posted, Thanks.

[old_master]

When you get this thing running, (after replacing the cap and rotor and checking fuel pressure) it might be worthwhile to have a shop check camshaft retard and adjust it if necessary. The camshaft retard adjustment perfectly aligns the camshaft position sensor so the PCM can control ignition timing correctly, it also helps increase the longevity of the distributor cap. Spec is zero degrees + or - 2 degrees and requires a high end scan tool to access the data. Not sure what your local shops would charge, but it takes about a half hour to check and adjust it.

[gmbwrenchn]

Boy I hope your right! Ordered cap, rotor & fuel pressure gauge online. Getting the AC Delco. Will let you know the results of the pressure. Thanks.