maxaud
Active member
Know what wire color that is?freddie":3rsdl2di said:By the way there is a fuel pump cut off wire at the MAF. (no air flow = no fuel flow)
I've been leaning more towards vapor lock myself but will entertain all options.
Know what wire color that is?freddie":3rsdl2di said:By the way there is a fuel pump cut off wire at the MAF. (no air flow = no fuel flow)
maxaud":xhz5btpe said:Bringing this thread back to life. Been a while since I've been on.
STILL having this issue.
Basically, if I drive any long distance or if I drive the car for longer than 30-40 minutes and I shut it off it wont want to start. Simply turns over and doesn't even sound like it's trying to start.
Was told it may be vapor lock in the fuel system but I still encountered the issue with the fuel cap off.
Seems to be fuel related instead of spark.
Any other ideas as to what this may be?
FC Zach":1ds6rt0a said:Last November I diagnosed and repaired an intermittent engine stalling issue (and no start) when my Celica left me stranded in a store parking lot. I suspected it was a fuel pump issue but it was in fact a fuel pump relay that caused all my headaches, I was grateful it was this simple and that I didn't have to pull the tank and replace the pump
FC Zach":1ds6rt0a said:Found that I was supposed to bridge terminals Fp and +B. . . did that and car runs. If I disconnect the jumper wire the car cuts off.
maxaud":2il3moje said:Was having the issue of not starting this weekend so I bridged the Fp and B+ in the diagnostic port and it started right up. Maybe it's the fuel pump relay but if it's going bad, I'm curious if there is something somewhere else that is making it go bad.
yyonline":2il3moje said:Usually it's just the relay that's bad. What usually happens is that something causes its internal resistance to go up (cracked solder joint, corrosion, etc.). When the resistance goes up, it generates more heat. Which causes more damage, which generates more heat, that causes more damage...etc. until it fails.
It's also possible that the fuel pump has high internal resistance which is causing too much current to pass through the relay and that's why it overheated. But the first scenario is more likely.
underscore":1ftvv62g said:In that case I'd just take apart the old relay and gut it, then wire it as the plug for a socket for a standard relay, allowing it to plug in without messing with the factory harness.
FC Zach":3ep8gabm said:maxaud":3ep8gabm said:Was having the issue of not starting this weekend so I bridged the Fp and B+ in the diagnostic port and it started right up. Maybe it's the fuel pump relay but if it's going bad, I'm curious if there is something somewhere else that is making it go bad.
It's definitely your relay. I asked the same question about the cause, this is the response I got:
yyonline":3ep8gabm said:Usually it's just the relay that's bad. What usually happens is that something causes its internal resistance to go up (cracked solder joint, corrosion, etc.). When the resistance goes up, it generates more heat. Which causes more damage, which generates more heat, that causes more damage...etc. until it fails.
It's also possible that the fuel pump has high internal resistance which is causing too much current to pass through the relay and that's why it overheated. But the first scenario is more likely.
alltracman78":oh90gmeu said:There is another option to the relay [specifically the high/low speed pump relay]. In the 5sfe cars there is no relay, they use a jumper so it's always on "high". It pulls right out and plugs right into our cars. Your pump will always be on "high". Not really a problem IMO. The jumper is in the same exact spot as our relay.