Hi!

I'm new here and I have a problem with my S10 Blazer 4,3 1995.
The engine runs just fine when ideling but as soon as I press the acceleration pedal the engine dies.
After that the engine is hard to start again. The vehicle does not move at all when I press the acceleration pedal.

 

I would begin by checking my fuel pressure.

 

Hi everybody in Corona times!

I'm soon about do give up with the Blazer problem.

This is what I have done so far.

The rotor is replaced by new
Distributor cap replaced by new
TPS replaced by new
MAP-sensor, new
Spark plugs, new
Spark plug cables, new
Fuel filter, new
Pump pressure tested and OK
Tank inspected and it looked like new
The ECU is replaced by another

Still the same symptom, the engine starts up, the idle is ruff, but as soon as the acc-pedal is pressed the engine stalls. When that happened the spark pluggs are totally soaked with fuel.

 

What was the fuel pressure leak down like? It shouldn't have lost more than a few PSI after the pump shut off. If it drops all the way to zero, you have a fuel leak somewhere. The CPI engine used in your '95 liked to have internal fuel leaks either from a failed FPR (fuel pressure regulator) and/or from a failed 'nut kit' (internal fuel lines in the intake plenum). If you're opening it up and find one or the other, replace both and while you're in there, replace the connector to the fuel injector as well since that is another known weak point.

 

The leak down was ok, I don't have the exact numbers now but it was several minutes before the pressure was zero. We lifted the plenum also and there was no external leaks from hoses or pressure regulator. We lifted out the complete spider but did not change anything. Why is the spark plugs wet after the engine dies? Could the injectors stay open for some reason? Thats why we replaced the ECU, but no difference...

 

You should hold above 55PSI for 10 minutes, or no more then 5PSI of leakdown in 10 minutes as standard pressure is about 60PSI. You have a leak bud. Throwing parts at a problem is never a good idea. the regulator just controls how much fuel is allowed to return to the sump in the tank and thus controls the fuel pressure inside the metering block, and its the last part to see fuel in the system up front. im trying to figure out a similar issue with my truck (among others although mine is a '99 MPFI system) and a fuel pressure test is the absolute first thing i would check. as its probably fuel starving, then seeing a return to pressure right as it dies off. the hard starting is probably due to the FPR sticking or otherwise doing not-normal things.

 

Another strange thing is that if I remove the fuse to the fuel pump it's possible to rev the engine for a second, then the fuse needs to be replaced for a second, and so on.
The fuel pressur was OK, the leak down time was also OK and with the plenum cover removed we could not see any fuel leakage from the pressure regulator or the connecting hose.

 

Hi!

I did a new leak down test just a moment ago. The pressure is 4,2bar or 61psi when the pump is running. Exactly 10 minutes after the pump has stoped running the pressure is 2,4bar or 35psi.

I have more time now to do some tests because we are not allowed to go back to our jobs for 6 weeks!! Volvo Trucks have shut down all the factories in Sweden and Europe! CRAZY!!

 

that is extremely poor leakdown, even if the regulator is not pissing fuel out the vacuum hookup its probably not holding pressure anyways, as they are cheaper parts then the fuel pump itself i would replace the regulator first if you cant find any fuel leaks anywhere. does the truck start fine outside of its acceleration issues? if so we can somewhat rule out the Poppet valves leaking out, as that would flood the motor and cause a hard start.

 

It doesn't start as easy as a healthy engine, the idle rpm is low and rough. It's possible to carefully rev the engine to about 1200 rpm and then it stalls. If I remove a spark plug it's soaking wet with fuel. It also smells like fuel from the exhaust.