Mechanics

. . .STILL WON'T START. . .

Chevrolet Blazer

OK now I Fixed my problem with my starter issue by replacing the Ignition Switch, $180 later. Now that I have that out of the way I am back to square one with my Blazer refusing to start! About 2 months ago I was driving down the freeway about 60-70mph when deciding to go ahead & switch into OVERDRIVE, all the sudden the engine shut off quietly. At the time I wasn't sure what had happened but I didn't have time to think about it I was on the freeway. Pulled to the side of the road. The Check Engine light had came on & still to this day I haven't been able to start my truck! So My Question is has anyone have any idea of why shifting from DRIVE to OVERDRIVE would shut down the engine preventing to ever start again or ever came across anything similar? I would Greatly Appreciate any Information you possibly might have! : D? : D

Thanx Nick
Avatar
95Blazer434x4
November 25, 2007.



If the engine light is on what is the code?

Tiny
Pear69
Nov 26, 2007.
I am not avle to pull any codes up @ all! My truck is OBD 1 with a 16 Pin OBD 2 Harness. Using a OBD 1 & 2 Compatable typw scan tool is unable to pull any codes & keep telling me unable to communicate with computer. I have used a jumper wire between the 5 & 6 pin, Check engine light flashes once with a pause & then 2 more flashes with another pause, repeating that cycle. A 12 in my book says it " Dignostic mode", whatever that means still does't help! Other than that I don't know what else to do. There are a couple issues, I'm getting fual pressure, how much I do not know. So im thingking what if I have no Pulse @ my injecters. Other than cranking over the engine & checking to see if there is fual on the spark plugs, is there another way to find out if fual is getting through the regulator & to the injectors? Second what is the proper way to check the Ignition modual @ the distributer? If there is any information that I am over looking or that you can think of would be very helpful! Thank You Nick...

Tiny
95Blazer434x4
Nov 29, 2007.
Ok Nick, first -- I know this is very frustrating but you must keep your head. Do not scatter your thoughts all over the place. Trouble shooting any problem with any computer controled engine is a step by step process. You must first determine if you have spark. If you know how then do it your way, if not get a cheap spark plug tester at any auto store. Preferrably the kind that you hook right up to the wire. If no spark test the ignition module. Remove it and Autozone or a place like will test it for free. If still no spark, check the coil. Take it to the place you tested the ignition module.
I don't mean too say you cannot test the ignition module or the coil yourself; it's just easier to take them to a place where they have the proper equipment and---if it is indeed bad--- you can get a new one right there.
It's probably your ignition module (simple fix). If the engine just stopped all of a sudden going on the freeway I dought it is a fuel issue. So lets rule out a spark issue before moving on to a fuel issue. Fuel issues tend not to happen so suddenly. But ya never know. Don't worry we'll fix it.

Tiny
Pear69
Nov 29, 2007.
OK so I Had My Ignition Modual Tested & they said it was fine. I Had Just replaced my Cap & Rotor, Ignition Coil, Plugs & Wires about 5 Months ago and 2 of those months my truck has been out of comission. I have replaced my Water pump then one off my freeze plugs corroded & started dumping coolent so I replaced that. A week later my Heater core exploaded, yet again dumping water inside the truck. I went ahead & replaced the heater core witch was a project in itself. I have had the Blazer for about 9 months or so, a few months after I had got it I was driving to work & all the suddend It felt like it wanted to die so I pulled into a parking lot and it shut down. After Trobleshooting for a few I had determined that the Alternator had craped out. After replaceing the Alternator & Battery It sarted right up! I have had the stater checked out its fine. I just replaced my Ignition Switch & Coil. Last night I went & exchaged my Wires on a warrenty so I will try that! At this point im kinda stuck on what to do next! I guess my question is although my Neutral Safety Switch apears to be working properly cuzz I am unable to start my engine other than in Park or Neutral. Could it still be the cause of my problem! Is there anything else I could check out?

Tiny
95Blazer434x4
Dec 3, 2007.
Is there any spark at all? Why did you replace the coil? They sell cheap spark plug testers at autozone.
Also you must find out what the check engine light code is. This will get you to the answer quicker. Autozone will scan your truck for free. Stop changing things unless you test them and determine that they are bad. Autozone or a place like that will test many things like coils, ignition modules and almost any sensor for free.
What kind of spark plugs did you put in? Bosch are junk even new ones, I suggest A/C Delco.
I also see that your battery was low and your alternator was bad. Your truck has a security feature from the factory called PASSLOCK. This system works in conjunction with a resistor either in your ignition switch or in a passlock module. This resistor has a specific value that is unique to your truck. Sometimes when the battery is low this resistror fails. The passlock system will not allow fuel into the motor if it is set off or broken. Unfortunatly a chevy dealer is almost always the only shop in town that has the capability to determine if this system is failing.
The neutral switch may be the cause also, but test it before you replace it. Stop changing things just because you assume that they may be the problem. Test them first. Jump out the fuel pump and test the fuel pressure. If you don't know how, there is a fuel pump relay in the- under the hood- relay center. Take it out and look at the wiring diagram. There are two terminals marked 85 and 86. Jump them out with a small wire. This will jump out the fuel pump directly. It should run and you then could test the fuel pressure. Do not worry about how long the pump runs because the fuel is just recirculating back to the tank. Keep me posted

Tiny
Pear69
Dec 3, 2007.
Passlock... Neverheard of it! I have done so much research on my model of blazer & have never came accross anything like that! I am not someone who just replaces parts just because I feel like it! I mean that would be just a waste of money don't cha think!Everything thing I have done or replaced was malfunctioning or no good! Come' on You gotta give me a lil more credit than that! I have been working with cars for 10 years & know enough commen sence on how things work & what is bad! I have fual pressure @ the test port, (first thing I checked) how much I do not know! My truck is OBD 1 compliant with a 16 pin OBD 2 type connector! Running a OBD 1 & 2 type scan tool is unable to pull up any codes from the computer whatsoever! Now if I jump pin 5 & 6 I get 1 Flash & than 2 more flashes after that(repeats) 12 in the book say that it is in Dignostic Mode! What that means I do not know! Now I just did tune up about 5 month ago replacing Plugs(Bosch Platinum 2) Wires, Cap & Rotor! Coil was bad so I replaced it! Ignition switch was bad I replaced it! Neutral Safety switch I thick should still be good! It was 12volt @ the harness & only able 2 start in park or neutral.I'll B Back. My ride is here! : D

Tiny
95Blazer434x4
Dec 3, 2007.
Sorry, passlock came out in 96. In order to get the diagnostic code you have to let the diagnostic mode (12) flash three consecutive times, sometimes four. After that the trouble code will flash out it's sequence.
I do not mean to insult you in any way. I'm just trying to help. If there is no spark ( which you still haven't said) then there are only a few things it could be. If you have a spark tester or an old spark plug try hooking it up directly to the coil wire. See if there is spark there. If there is spark there and not at the spark plug then the distributer is not turning. I've seen the gear on some of these distributers strip out. If the ignition module is good then there is only one other thing that it could be and that is the computer.
If there is spark then hook a noid light up to one of the the injectors. If it flashes then it's a timing issue. If the noid light does not flash then its your computer.

BTW : Bosch plugs are JUNK!

Tiny
Pear69
Dec 4, 2007.
The neutral safety switch will not prevent spark, it prevents fuel from entering the motor.

Tiny
Pear69
Dec 4, 2007.
Thank You so much for your feed back, I will check into everything and wite back with results!
-Thank you.... Nick

Tiny
95Blazer434x4
Dec 4, 2007.
Ok so check this out I went ahead & checked to see if I was getting spark! In the prossess of doing this I checked to see if the injectors were spraying fuel. I cranked over the engine for about 10 sec (Yes there was spark) The driver side (1 3 5) plugs were bone dry! The passenger side (2 4 6) were somewhat wet. That tells me that my problem is in the upper plenum. I guess my Question is What would be the cause of the passenger half of the injector to work & not the drivers side half? Or if anyone has any input on what to do next would be great! Thanks Nick

Tiny
95Blazer434x4
Dec 9, 2007.