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I just wanted to share a recent experience with my 1988. Friday evening I was driving around town and suddenly the car started stumbling and appeared to have power loss.
I was barely able to limp back home (it happened on the last half mile from my home, but in a very sense city environment when it would have been hard to stop and pull over). It was pinging and really struggling especially on hills.
Anyway, Saturday morning I measured the fuel pressure (I was waiting for a cold engine) and I could only see at most 20 psi...
I took the sending unit out and as you can see below the pulsator was ripped open.
The fix was easy as I had the old sending unit lying around and put back the old pulsator and the car was back on the road in a blink.
But my question is more why did it fail? Bad part quality? The sending unit is a OE GM restoration part that I installed not even a year ago.
I read in a post somewhere that the pulsator can be replaced with a piece of hose. No idea what that will do. Never tried it. I was digging around but couldn't find the post.
I have read that too.
From what I understand it smooths out the spike in pressure in the rail. I am pretty sure a piece of hose would work but it would need to be ok with ethanol fuel. Plus the two hose clamps required would be another place where it can fail.
I actually also just read your thread.
My pressure also drops almost instantly just after key off with the new old pulsator, but it starts right up and runs smoothly, so I suspect a problem with the pump check valve or a leak near the pulsator.
When I installed the sending unit last year the pressure was holding well.
A piece of fuel hose & 2 hose clamps will work fine, if and ONLY if you use hose specifically for submersion in fuel. If you use the wrong hose
the outer jacket can dissolve and create a lot of problems. Proper hose is easily obtained if you ask for it at your auto parts store. You will not
notice any change when you eliminate the pulsator (that is a good thing).
Alright guys, I was about to order a new pulsator but I guess you convinced me (not very hard) to instead put a piece of submersible fuel hose there! ( I already have a few stainless steel hose clamps for fuel injection).
Any hint about the hose ID? 3/8"?
Alright guys, I was about to order a new pulsator but I guess you convinced me (not very hard) to instead put a piece of submersible fuel hose there! ( I already have a few stainless steel hose clamps for fuel injection).
Any hint about the hose ID? 3/8"?
Racetronix has the hose you need and the kit comes with gaskets and SS bolts so it's a good buy.
Alright guys, I was about to order a new pulsator but I guess you convinced me (not very hard) to instead put a piece of submersible fuel hose there! ( I already have a few stainless steel hose clamps for fuel injection).
Any hint about the hose ID? 3/8"?
I thought it was 3/8.
Fuel feed line is 3/8 return line is 5/16. Pretty sure my Racetronix pump kit came with 3/8 hose.
I couldn't find any autoparts store near me with submersible hose anyway. The people at the counter of both Autozone and Advance don't know anything and said I could use regular fuel injection hose :/
Amazon has 12 in long pieces from gates for ~ $20.
I figure I would rather upgrade to the Bosch pump that is supposed to come with the small hose (and given it's a reasonable brand, I bet the hose is submersible plus I get a spare fuel pump).
Racetronix is overpriced (mostly due to shipping). Gasket and pump kit from Bosch was $55 shipped from Rockauto, compared to 47$ for a kit without a pump and with bits I wouldn't even be using (I already have an updated wiring with an all stainless steel sending unit, including bolts).
Thanks everyone for they advice!
Typically any aftermarket pump like RX or other will tell you to just get rid of the pulsator if you ask them, if you even know to ask the question. RX isn't so good about that part.
I couldn't find any autoparts store near me with submersible hose anyway. The people at the counter of both Autozone and Advance don't know anything and said I could use regular fuel injection hose :/
Amazon has 12 in long pieces from gates for ~ $20.
I figure I would rather upgrade to the Bosch pump that is supposed to come with the small hose (and given it's a reasonable brand, I bet the hose is submersible plus I get a spare fuel pump).
Racetronix is overpriced (mostly due to shipping). Gasket and pump kit from Bosch was $55 shipped from Rockauto, compared to 47$ for a kit without a pump and with bits I wouldn't even be using (I already have an updated wiring with an all stainless steel sending unit, including bolts).
Thanks everyone for they advice!
The Bosch pump is what I just put in my '86, and yes, it comes with the pulsator eliminator hose. Very happy with that upgrade!
Racetronix Walbro pump in my 94' for 5 years now with the submersible fuel line in place of the pulsator. Get rid of that thing, not needed on our C4's. It was a carry over part used on other GM Cars to help muffle the fuel pump sound.They will fail eventually and will bleed down fuel pressure.
06-16-2019, 12:28 PM
Fuel pulsator failure
