Intermittently over the last year or so I have been having a problem where my demon blazer will crank but not start. When I turn the key to the on position you can hear the fuel pump relay kick in and out but then I will crank and nothing. If I crank for a really long time (ultra hard on the starter I know) it will start to catch and will eventually start. Or if it doesn't start if I go away from it for a few hours and come back sometimes it will fire right up. Has been more of an annoyance during the warm months but now with the cold weather is not good at all.

Fuel pump was replaced a little over a year ago. Problem seemed to go away for a while and came back. Replaced the injector spider early in the spring, same thing went away and now is back. Fuel filter has been replaced a couple of times and also replaced the fuel relays in the glove box. Finally broke down and got it to the mechanic the other day after having to tow it there and of course it started for them after a couple of tries where they had the same issue. They were unable to determine the root cause. It is throwing no codes. They suspect maybe the ignition switch and even though the relays are kicking in that the fuel pump is not running and no spark.

My question is could it be the ignition switch, I have also heard it could be the crank position sensor from another guy at work here that had a very similar problem with his. I am really starting to lose patience with this and would like the opinion of anyone around here that may have had similar issues, and what they would suggest as trying for a fix or a way to isolate the issue.

Once the vehicle is running it runs like a champ. The issue has become more frequent since the first time it happened to me last fall.

Any help and guidance is greatly appreciated.

 

Boy oh boy, I have one of these and it sure sounds like you are still having a fuel pressure problem. You need to do the leak-down test with a fuel pressure gage. Key on engine off. On mine it jumps to 61 then no lower then 55 in fifteen minuets.


If it fails that it's going to do all the stuff your writing at least mine did.


The ignition switch on mine manifested with driving along and the motor just dying with the quick ability to restart and a couple of other things. The position sensor should throw a code.


If it fails the pressure test you will need to test it at the filter to see if problem is with the pump or under the plenum. It's good that the filter has been changed so at least connecting the gage will not be a problem. I believe what everyone say's that delco is the only pump to get.

 

Thanks for the ideas, they did the leak-down test on it before I had the spider changed out in the spring. The pressure regulator is changed along with the spider so....it is such a pain

 

Do you know if they did the "nut-kit"(under plenum fuel lines). If you have people doing all this stuff for you on a 95 the $$$ really will start to add up. You do any work on it yourself? Most of it is not terribly hard. A $45 fuel pressure gage would get you started.

 

Yeah they did the nut kit when they did the spider as well. Some I can do myself but with no garage or place to work on it, very difficult.

 

I had a similar problem, and I found the problem by luck, my crank position sensor came loose, it's only held in place by the balancer. and the slot will widen if not held firmly. Just take off the position sensor and reach in with a finger and see if it will move. Dealer posrt only under $30 and then ran like new.

 

Seem to have narrowed things down a bit and it seems like it may be something in the ignition switch or harness. It did the no start thing on me a couple days ago. I put a heater in the cab and warmed everything up and then it fired like a champ. Seems like when it is very cold out it is causing something to not make a great connection. Not sure where to check on that though. Not sure if it is in the locking cylinder or the wiring harness itself. Any ideas?

Is this something I could get the assembly and hook it up temp like just to test?

 

Well that wasn't it. Switched the switch and harness and was fine as long as it was warm but today it is down around 0 again and crank no start again. If I put a heater in the cab for a couple of hours it is going to start fine I feel. Any ideas?

 

If I warm up the cab or if the outside temp is fairly warm the issue is going away. What else under the dash could be causing this in cold weather? I have been putting the heater on the driver's side.