BeaksSC

iTrader: (1)

So I've been searching for hours and posted this on Facebook, but couldn't really find a solution. The car is a 1995 Lexus sc400.

"I need help solving what I think is a fuel issue.

Here's what happened:
I was stopped at a red light, when it turned green, there was a vibrating/grinding feel/sound when I pressed the gas. There wasn't any power so I put it in neutral and back to drive, then it fixed itself a few seconds later. After about 45 seconds, there wasn't any power to the pedal so I pulled off into the median. With no power to the pedal at all, I turned it off and tried to turn it back on but all of would do was crank. So then a tow truck came to tow it home.

The car cranks but nothing more than that, the engine turns fine. The EFI relay was very hot to touch so that may be an issue. I'm still searching on CL but maybe someone here can help. On another note, we just did the BFI but I can't see where that would be an issue unless the ecu is compensating fuel for the little more air flow created by the bfi.

The CEL came on along with the oil light. And after it was cranking, there was some sort of smell that could be smelled in the cabin. Thanks in advance."

The CEL codes were 24 and 78.
24 being IAT sensor signal
78 being fuel pump control

We've established some new things since I posted on fb. We replaced the relay that was super hot when the car initially broke down, and that didn't fix it. The fuel pump shows 12v flowing to it at the plug that is reachable by going through the trunk (the one on top of the tank below the fuel gauge plug). When the key is turned to accessory, we can no longer hear the fuel pressurizing/flowing like we used to be able to when the car was running properly. The only recommendation given on fb was to go ahead and do the 12v mod since it was a free troubleshoot method. However, we don't want to just cut wires that may not need to be cut. I've been looking for a way to test if the fuel pump itself is working or not, but all I can find is things related to the fuel pump ecu.

I've read that the IAT sensor is a part of the MAF so I'm not sure that there's a way to 'fix' that without replacing the MAF? Like a said, we recently did the BFI mod, but we are not completely done with it yet. We created a path for the air to flow through the slots next to the passenger fog light, but hadn't masked off the cut air box yet. I'm not sure if this could be why, but thought I'd share.

Both of the codes appeared at the same time. Sorry if that seems a jumbled, just typing what comes to mind. Any ideas will help. Thanks.

BeaksSC

iTrader: (1)

Question.. if it seems like the fuel pump isn't turning on when the key is turned to accessory, is this caused by the fuel pump ecu? is this what the 12v mod is used for?

t2d2

iTrader: (8)

Are you positive the pump turned on previously with the key turned to ACC? As far as I know, the pump should only activate when the key is turned to ON, and only with the 12V mod at that.

BeaksSC

iTrader: (1)

Well we just went to do the 12v mod and apparently a PO already did that. I meant when the key is turned to on, sorry. We pulled the fuel pump and we're not really sure what kind it is. The logo is SEP inside of a globe and says truck and auto parts since 1983 underneath of the logo. Sound familiar to anyone? We pulled a denso fuel pump out of a solara from pull and pay. It looks the same but the prongs inside look different. The denso prongs aren't as wide. However, there's a couple of wires inside the tank that are spliced.... so maybe the PO spliced in a new connector..?

BeaksSC

iTrader: (1)

Car started with the Solara fuel pump I forgot to plug in the fuel pump control before starting it... but it still started. Then it started right up after I plugged the control in. So maybe it was bypassed or something. Someone already did the 12v mod to it so who knows.

t2d2

iTrader: (8)

The only good thing about previous owners is they make the cars cheaper for us.