I have a 2001 chevy blazer 4.3 vortec. It has the problem where it won’t start very good after sitting for a little while. I just did a check at the valve in the engine bay and the pressure dropped about 8 psi from 54 to 46 in 10 minutes. This was after turning the ignition to on for a few seconds then off. I have replaced the fuel pump with an ac delco. I have also replaced the spider injectors, intake manifold gasket, and cap and rotor. This was all done to just get it running good in the first place. (Coolant was leaking throught the gasket into the oil) Once started or if starting after turning off it runs great. It doesn’t leak any fluids either. Looking into the intake it appears everything is still black and not cleaned by fuel. Fuel pressure regulator or maybe a faulty part? At this point i have no idea. UPDATE: gas definitely in oil. Dipstick smells like gas real bad.

 

A repair needs to be verified after completed like a follow up fuel pressure leak down test like you just did. You should check the leak down at the fuel filter to find out if the problem is in the tank or the intake but judging from the gas smell in the oil its probably a problem up top.

George

 

Update. I replaced the injector with an oem one. Just to double check i tested pressure with the intake plenum off and it passed the pressure test well. No visible leaks either. I threw everything back together and in the morning tried to start it and it did the same hard start. I tested the pressure the same way and it was now leaking quite quickly. What am I changing by having everything assembled?

 

What was the status of the injector electrical connector with the plenum off and the good test. If it was unconnected, what happens to the test if you disconnect it now?

George

 

i had it unplugged for the first test and then I plugged it in. It held pressure either way. For testing purposes I unplugged it woth the plenum installed and still had problems.

 

You replaced the injector (singlular). Can you describe what you replaced, was it the whole spider or one injector. How about the regulator?

George

 

Yes it was the whole spider injector with the new regulator on the back.

 

I got nothin' fancy on why this happened except spider failure or something getting damaged on reassembly.

George

 

I had a similar issue where fuel was leaking somewhere in the plenum (thanks for your help George).

In my case it's possible that I did not have the fuel pipe installed correctly where it enters the spider. In the end, I removed and replaced both o-rings and lubed them well with motor oil, in addition to lubricating the ends of the fuel pipe. The o-rings are held in by a retainer that pulls straight out with needle-nose pliers or a pick.

Also, I think the fuel pipe should be seated well in the spider before tightening the clamp. Give it a good shove downward and feel it seat (but be careful not to bend it). The plenum end of the fuel pipe should be connected before fastening the hold down at the rear of the engine.

One more thing. Any holes in the plenum or intake should be stuffed with rags to prevent falling debris or objects. The two tiny nuts that hold down the fuel pipe are not magnetic, so if you drop them into the intake they can not be recovered with a magnet. Then you will have to remove the intake to find and remove the nut. This is even more difficult if the nut has fallen into the head and is sitting on top of a valve.

I hope this is helpful, I hope it is OK for me to chime in.

PS. Alternatively, my problem may have been spider failure as George suggests above. I tried 3 different spiders until it worked.

 

So I went out this morning and primed the pump about 4 times before trying to start it. It cranked for about 4 seconds before sputtering to life. So either then its the spider still leaking into the intake and flooding it or it isn’t fuel at all correct?