Hello, Dear blazer-engineers!

One day my 96 model blazer just wouldnt start.

I changed the fuelpump because i thought that was the problem, because there were no noise from it no - more.

After the replacement of the fuelpump it still wouldnt start, and im sure its running just fine, but havent checked for the PSI it delvers, yet.

Anyways, i've heard some rumors about faulty fuel pressure regulators, but im not quite sure if thats the problem, how can i test it?

After removing the intake manifoild - i can clearly see that there has been an leakage on the passanger side, ( left side on the picture)

When turning the ignition ON and the pump starts, i cant see any visual leakage from neither the "spider" hooses or the pressure regulator.

(Engine STARTS and runs for a few seconds when using start-gas)


screenshot windows 7

Sorry the bad English - im from Norway!

Greets,

Lars

 

That is a CPI motor so your truck is a 1995 to us USA members.

The fact that the engine runs with a bit of fuel added to the intake means that the fuel pressure is not high enough even after pump replacement.

Whenever there is a concern over fuel supply, pressure should be checked to determine the cause of the concern. You can run through the fuel pressure DIY article which will give you the details you need to know then report back to us with the numbers.

Looking at the washing in the plenum, it does look like the regulator has been leaking. If you find it is leaking by pressurizing the system, then you can attempt to replace just the regulator without removing the spider from the intake manifold. If you remove the spider, you will need to replace the 'nut kit' (internal fuel lines) as well.

 

+1
Track down a Dorman /Help part # 55162.
Fuel regulator. Should fix you right up.

 

Good evening godfellas!

Iv'e now checked the fuel pressure in the fuel bleed behind the intake manifoild and
Also directly from the pump itself and i get the same pressure of 1 bar / 15 psi :/

And this with the new carter pump with direct power from battery...

so im now about to test pressure from the old pump and another new i got my hands on.

thx for all comments!

 

Sounds like the pump you installed was for an older TBI engine. You need at least 55psi at the fuel pressure test port.

 

Lars,

Has the filter been changed? a clogged one would yield low pressure.

 

Hey Lars

I think your blazer has gone totally åt skogen..

there is to much lurium in the motor..

buy a new and better one, and never scruw it up.


regards,

Terje from Sverige

 

HI GUYS! got it working with the new ebay-pump fitting it to the existing pump-adapter.. since the ebay pump was too big it would not fit into the tank... but the pump itself was about the same size.. so now we got fuelpressure at around 4 bar / 60 psi

Thanks for all the comments.. :-)

 

Could you tell me some more about the tpi engine?

 

TBI == Throttle Body Injection

This was used on the late 80's to early 90's GM vehicles before the CPI engine took over in 93. The TBI system required a much lower fuel pressure (8-12psi) than the newer CPI system since they used two much larger injectors that physically sprayed fuel into the throttle body above the throttle blades. The CPI motor uses one fairly large injector that pressurizes six individual lines inside the intake manifold. At the end of each line is a pressure activated poppet nozzle that requires ~55psi to open and spray properly.

You can find even more information through a few quick Google searches.