ENGINE POWER LOSS: ( Bogging, Hesitation, etc.)
Page 2:
prerequisite page 1 done.
FUEL PRESSURE OUT OF BAND ! (aka: out of spec. way low or way too high )
THE ECU is completely Intolerant of bad fuel pressure , I HAS NO WAY , of knowing this fact !
It is up to you to find it.
It's no secret too low causes a lean bog and to high fuel pressure causes flooding and fouling of spark plugs and misfire and bogging.
Read this for the full spec on all 89-98 Kicks and trackers. fuel pressure. ( many reasons !)
Steps ( it's not hard and is the top fail on all EFI cars for bogging)
First relieve fuel pressure by using this procedure.
- Go to Harbor Freight and buy this tool. A fuel pressure test kit., for $20 ( on sale is $14) ITEM# 92699-3VGA
- Attach it to the Fuel filter banjo fitting 6mm test port as this photo so clearly shows.
- Key on the ignition key 3 to 5 times to build pressure ( Fuel pump only runs for 3 seconds each key on).
- The pressure must be greater than. 34psi ( some cars are 36 minimum look here first)
- If the pressure is too low ,then read this first to see of power to the pump is good.
- Then check the Fuel pressure Regulator for it being stuck open ( hit it to unstick it).
- If you have 12vdc to the pump each KEY ON, and the FPreg is good then the pump is bad ( filter is fresh and new right?)
There are 4 imporant pump tests do not skip any of them.
Low Fuel pressure: will cause bogging under any load, and can happen at any load, if pressure is too low.
The Engine is suffering for a LOSS OF FUEL which, causes the BOG.
My fast Pump test page.
A clogged Fuel filter (A tune up item) , next to gas tank.
Clogged Fuel Injector screen (at the injector or inside the injector itself, a10 micron screen size !),
or a bad Fuel Pressure Regulator Stuck open , or the vacuum diaphragm or vacuum line is bad, or the vacuum source)
Order of business:
- A New fuel filter. But that's done already in the
tune up mentioned , above.
- The
check RAIL pressure TEST. or at Filter Banjo fitting test
port .
- Test the Fuel pressure Regulator (FPR) by applying vacuum to the FPR nipple and checking the response, to pressure above. a 25 to 35 PSI range
- A forum member says, DO NOT FORGET TO RAP ON THE FPR, and it will un-stick, then run good for a while, Replace it.
Big Hint 1:
If your car runs good cold and has lots of power up hill WOT, most likely the Fuel pump and injection is all ok. ( a cold and heavy load uses lots of fuel )
Jargon:
Please go here to see the meaning of the common 3 letter abbreviations used here. It's standard SAE , jargon.
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