thinking fuel pump - Help

[thomp22]

1994 S-10 Blazer 4.3L cpi (w code). Truck just stopped on me at a stop sign and hasn't started since. I have good spark, I had the ign module checked. Here is where I am stumped, the fuel pressure only comes up to 40psi, I put a knew fuel filter in, not it, I bypassed the fuel relay, and slowly squeezed of the return line to try and bring up the pressure, to no avail still stayed at 40psi. I pretty sure the fuel pressure has to be at a minimum of 54 psi to start the motor. So I am thinking Fuel pump, I guess they can weaken? I was under the impression that if it was coming on it was good, but now I doubt it. The pump is only about a year old. That is why I am questioning that it is bad. The CPI unit in just alittle over a year old as well. There are no codes either reads "12".

Another thing, on the advice of an old timer, he suggested removing the intake boot opening the butterfly a spraying alittle ether in there. It fired right up and ran until the ether was gone.

Sorry for the long post. Thank you.

[Tazmania575]

Here's my understanding after owning two of these. The 4.3 "W" CPI will not start with anything less that 54psi. Check your fuel line for leaks, thus low pressure. If no leaks and you have the new filter placed in with the flow going the correct way then it may be your pump. I dout it would be you CPI unit primarily because your not developing fuel pressure. I have had a new CPI go in just 4 months after having one replace. Luckily the manufacturer stood behind thier product and replaced the unit free of charge. Hope this helps!!

[Jeremy-WI]

If this one is like the 96 and later it could be the fuel pressure regulator, fuel pump, or fuel pulse dampener. Look into the throttle body after cycling the key on, key off 8 seconds, key on and look and smell for signs of gas, if you smell it, it could be the regulator leaking into the manifold

[kmarkgl]

The problem is the CPI unit. The regulator on the side of the unit and thus will not allow enough pressure to open the poppets. Do not use the dealer supplied unit. I went through 3 in one year. Now I run a unit that has been modified with a newer type regulator. Get the unit from Lindertech.com. You will not be sorry. I have had mine for over a year and the truck has never run so good.