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Hello. I have been having a problem where my fuel lines have very little to no pressure.
initially it was from the fuel pump which I replaced 2 weeks ago since then I have replaced the pump 3 times! I have also replaced the strainer before the pump, the filter, cleaned out the tank, and replaced the wiring inside the tank. I’m not sure what is going wrong but something keeps killing my pumps. But every time I replace the pump it fixes the problem for a couple days. When I take the lines off at the tank and turn the key I can see fuel is getting pumped out but I’m thinking the pump just isn’t pushing enough pressure.
what could be causing this to happen?
Do I need to look at injectors or could a failing relay be to blame? Is there anything elee between the tank and injectors that could be getting clogged?
1.) What engine running problems are you getting where you suspected a fuel pressure issue in the first place?
2.) Have you actually measured the fuel pressure?
3.) Have you checked the voltage at the pump? It should essentially be very close to the voltage at the back of the alternator.
4.) Have you checked the ground side of the pump connection?
Note that when you run the pump with the supply line off the tank, the pump isn't going to shoot out fuel like a high pressure garden hose nozzle. It should be a steady stream coming out, but with zero head pressure it's not going to be super vigorous.
1.) What engine running problems are you getting where you suspected a fuel pressure issue in the first place?
2.) Have you actually measured the fuel pressure?
3.) Have you checked the voltage at the pump? It should essentially be very close to the voltage at the back of the alternator.
4.) Have you checked the ground side of the pump connection?
Note that when you run the pump with the supply line off the tank, the pump isn't going to shoot out fuel like a high pressure garden hose nozzle. It should be a steady stream coming out, but with zero head pressure it's not going to be super vigorous.
1.) the first time I was driving along when all of the sudden the throttle would not do anything and the car stalled out and wouldn’t start up shortly after. Upon inspection I noticed the fuel rail wouldn’t have fuel in it when I pushed the test port valve in with the key turned to the on position; Not even if I went to prime the System several times.
2.) this time specially, no not yet. But the second time I replaced it I got an actual gauge hooked up and before replacing it read zero when priming after replacement it would shoot up to around 42-43 psi when primed.
3.) I have not yet checked that, that was going to be my next step as soon as I got the car back home in a few hours.
4.) Yes I replaced that wire and it seems to have a good connection
So from your description, I'd consider the fuel pump relay to be on the fault tree too. I've experienced and intermittent relay failure on the fuel pump before.
So from your description, I'd consider the fuel pump relay to be on the fault tree too. I've experienced and intermittent relay failure on the fuel pump before.
I have just replaced the relay and unfortunately it didn’t change anything.
I did get it started again but only after replacing the fuel pump again and it started right up.
im not sure what the difference is between the brand new pumps and the 5 day old ones but for some reason they seem to be able to get the car started.
sure I could just replace it every time it goes out but I would much rather find out the real cause of this problem
Any more ideas?
What is the part number of the pump(s) you are using?
What is the diameter of the outlet hose nipple?
(You can measure one of the take-out pumps, if they are all the same brand,manufacturer and part number.)
pump outlet I.D. .183”/4.65mm
pump outlet O.D. .3115”/7.91mm
part number E16030
Brand Precision fuel pumps
All pumps have been this same brand, I’ve never had problems with the brand in the past and I got a good employee discount from a friend initially and exchanged them all under warranty so I’ve only tried this brand so far.
After the PCM finishes with the pump priming right after key on, the voltage at the pump will return to zero.
The main thing is what the voltage is with the engine running.
I had my father with the multimeter at the pump connector and he said he never saw the voltage go up when the car was priming, it stayed at nearly zero the whole time.
Have not yet measured with car running will do that soon.
So you've bought all from the same brand. As seemingly unlikely as it may sound, I wonder if they have some sort of issue affecting an entire production and you got unlucky enough to get multiple pumps from that lot.
I use a Walbro GSS340. It's a much higher output than stock, but the pressure regulator manages it just fine.
I ran into that same problem twice. Wiring is old on these cars and resistance at the connectors causes heat and a voltage drop under load. For me, once it was the connector in front of the passenger door, I could see the wire was burnt at the connector. Another time it was at the bulkhead connector going into the tank. I couldn't see anything there but I suspected the wire was broken inside but made contact sometimes. Replacing the tank harness solved the problem. Racetronix has the parts to fix it.
I ran into that same problem twice. Wiring is old on these cars and resistance at the connectors causes heat and a voltage drop under load. For me, once it was the connector in front of the passenger door, I could see the wire was burnt at the connector. Another time it was at the bulkhead connector going into the tank. I couldn't see anything there but I suspected the wire was broken inside but made contact sometimes. Replacing the tank harness solved the problem. Racetronix has the parts to fix it.
I guess it looks like my next step should be to look deeper into wiring and maybe also try a different brand pump if/when this next one goes out.
i vaguely remember this and just throwing it out as food for thought. google "c4 corvette oil pressure affecting fuel pump", the first thing that pops up -- When the oil pressure reaches 4 PSI the oil pressure switch closes and applies power to the fuel pump.. worth a look - you very well could have a faulty sensor or related electrical issue - ?????. i once had a starting problem associated with my 85's fuel pump, pressure, starting sequence and went thru this as part of the diagnostics. from my old man memory, i remember checking the signal at the fuel pump relay connector while cranking the engine. BTW, what year corvette and do you have a factory service manual? if you have a manual, check wiring diagram under MULTIPORT FUEL INJECTION, FUEL CONTROL AND FUEL DELIVERY.
edit: google this - "c4 corvette fuel pressure starting sequence". top of the list --
i vaguely remember this and just throwing it out as food for thought. google "c4 corvette oil pressure affecting fuel pump", the first thing that pops up -- When the oil pressure reaches 4 PSI the oil pressure switch closes and applies power to the fuel pump.. worth a look - you very well could have a faulty sensor or related electrical issue - ?????. i once had a starting problem associated with my 85's fuel pump, pressure, starting sequence and went thru this as part of the diagnostics. from my old man memory, i remember checking the signal at the fuel pump relay connector while cranking the engine. BTW, what year corvette and do you have a factory service manual? if you have a manual, check wiring diagram under MULTIPORT FUEL INJECTION, FUEL CONTROL AND FUEL DELIVERY.
edit: google this - "c4 corvette fuel pressure starting sequence". top of the list --
Hmm, interesting I’ll have to look into that.
Also, I have an 86 and no manuals.
BUY A SET OF FACTORY SERVICE MANUALS! i'm thinking after 85, manuals may be two volumes, with vol 2 being electrical. trying to work on these things without service manuals is akin to pi$$in into the wind.
until you get a manual, this may help. from my 85 manual - should be similar or the same as the 86...
BUY A SET OF FACTORY SERVICE MANUALS! i'm thinking after 85, manuals may be two volumes, with vol 2 being electrical. trying to work on these things without service manuals is akin to pi$$in into the wind.
until you get a manual, this may help. from my 85 manual - should be similar or the same as the 86...
thank you very much
I’ll be trying to get those now that my car keeps breaking every dang week
Help! Fuel pumps keep dying
