Can you take a couple of digital pics of your engine showing, injector wiring and your burned up relay wiring?
I'm better with carbs, but I've checked for injector signals with an LED test light or a NOID light.

 

I'm not sure about your year blazer but I know the newer ones have a little valve in the fuel line, just before it runs into the injectors where you can test for fuel pressure. Pretty much if you can depress the pin in the center of the valve and get more than a drip your fuel pump is working, or you can buy a fuel pressure gage and check for enough fuel pressure. The other thing you could try would be to disconnect the hose from the fuel filter and send power to the pump, if you get a puddle of fuel under the truck I'd assume the pump is working.

If the bearings are seized in the fuel pump you might get a little bit of buzz from the motor when you apply power, but it won't pump fuel.

 

OK,.i went out this morning to give it another go.
I found the shraeder valve, behing the intake manifold, right by the distributor. I depressed the pin and gas starting spraying out. I held it down until it stopped, and I bypassed the relay to power on the pump and gas started spraying out again. So my guess is that it might be the injectors. Could it just not be powering on or could it just be clogged up? Althought I still dont hear the pump prime up. I wish I had a fuel pressure guage to check the fuel pressure. Maybe the pump is pushing fuel but not with enough pressure? I didnt get to take pictures cuz I couldnt find my camera, until I came back inside. I'm gonna go back and take pictures in a little bit.

I came up with a probable scenario: the day before the car died I had put in a bottle of techron fuel systems cleaner. Could it be that the cleaner cleaned out some sludge in the fuel tank and a fuel lines causing the injector to clog up. And with the injectors clogged up the pumps motor burned out or the bearings seaized because of the blockage in the injectors?

I know its a long shot , but I figured I'd throw it out there.

I would like to take up the intake manifiold and look at the injectors, is there anyway to test them or to even clean them out?
I gotta wait for my brother to come home, and maybe I'll pick up a chiltons manual and a fuel pressure gauge.


If anyone has any input , let me know. I could use all the help I can get . Thanks guys

 

Your theory on the fuel system cleaner clogging injectors is not valid. The fuel filter will catch anything that comes from the tank side. Generally speaking, the lines are pretty clear between the filter and the injectors.

Forgive me for asking (I don't feel like going back through and re-reading this post), but have you had the plenum off yet? If you haven't checked the fuel pressure yet, you could have a failed FPR (fuel pressure regulator) that is all too common in the CPI motors. We have had quite a few discussions on this problem and I believe that Lindertech.com is the place to go for a kit to replace your FPR without replacing the CPI spider.

 

OK thanks for clearing up the theory swartlkk.

I haven;t had the plenum off yet. (i'm guessing thats the intake manifold?) Wheres the FPR located? That defintelay could be a possibility. Will keep trying, and I'll go out and take some pics.

 

The plenum is the upper cover. The FPR will be on the passenger side of the injection spider. If it has failed, the lower intake should be washed clean under the tube coming out of the FPR.

 

If the relay connector melted that would indicate (to me) that there is a short in the fuel delivery electrical system. Check the connectors at the fuel pump to see if they are loose and then check for breaks/chafing areas along the frame related to the fuel system wiring.

Since you have a CPI injector unit there should be two wires going through the front of the lower manifold to the injector body, make sure that they are working properly and have the correct voltage supply, if not then you will need to track down the connection that is not allowing the current to pass...sometimes wires break internally, inside the insulation and look good outside so when you get the DVM check wires for shorts/breaks.

 

hold on i'll get them up here in a sec

*Combining posts*







*Combining posts*

Now heres some pics of the tank and fuseboxes







*EDIT by swartlkk* - combining consecutive posts... Please use the edit feature in the future to add extra information if no one has replied to the thread.

 

Definately check the fuel pressure.
And for future reference, the fuel pump test wire I told you about earlier is the wire right by your trans dipstick, I believe.


[IMG]local://upfiles/2910/5FD7568689FD4D29AEB84FE0B2C8BEA1.jpg[/IMG]

 

Hey guys, I was looking up parts online, and I found a part that was called "fuel pump pressure switch". Do these trucks have this kind of part, and where are they located if so?