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After 4 days of driving, I went to start my, car I had just driven 3 hrs. earlier, and it would not start. I am beleiveing that my fuel pump and ECU were not bad to begin with. If I put 12v directly to the pump from battery, it fires right up and runs fine. I have already bypassed the fuel pump ECU.
If your fuel pump is staying on (indefinitely) after the car is off with or without the fuel pump ECU installed, and you are on the stock engine ECU, it is the main relay acting up and you should replace your computer or repair it. I chased down ghost issues for years before I finally replaced my ECU and fixed the problem.
no. the main relay is the relay in the fuse box. open the hood, unscrew the 2 screws on the fuse box and look for main relay. a real quick way to see if it is bad is to switch it around with the other fuse that looks exactly like it momentarily. if you switch it and the fuel pump turns off when you turn the key off, but turns off when the key is on, then the relay is stuck closed.
for the record I never new the answer. i'm just helping codetoad out with the answer.
Would this help me out? Maybe it's a coincidence because it rains so much in the sunshine state, but sometime when I park in the driveway (on an incline) rather than in the garage (flat), the car stumbles to start, but it does start and then it runs fine. And it always seems to be when the car is either rained on or covered in dew. Lol idk if that could possibly cause anything but it does seem to always be present when it happens. Thanks
I'm still tinkering with my TT fuel ecu. Still no luck locating a used factory body harness connector. As mentioned before, even with a part number it was never sold separately by Toyota and the sub harness was discontinued years ago. I've been dogged about trying to exhaust the possibility of getting the TT ecu wired up before looking into the 12V mod (with an added cutoff relay circuit).
So... I started thinking about Ali SC3's suggestion to use female connectors and some solder:
In the above image I've used some common insulated female quick-disconnects from radio shack on the four main spades. Those support up to 14-gauge wires and have hard plastic around them. I don't know how much heat they would endure but I hope melting plastic wouldn't be an issue. The clearance is VERY tight with the four middle miniature spades which I assume must be for control signals rather than full +12V and ground power connections.
And here I've inserted a small .156/396mm KK Header (originally 5 contact points -- I cut off one of them). Says they're rated for 250 volts and 7 Amps. I am not sure if those ratings are enough or more than enough for the smaller connections.
As you can see it's a snug but near perfect fit and the spades are aligned precisely. My plan would be to solder those four connections and then extend about 4" of wiring put into a sturdy aftermarket male and female plug to complete the wiring, including the EFI2 wire required for this ecu. There are eight connections total from this ECU.
It's a bit tedious the way I'm approaching it but I like overbuilding and attempting to make replacement something repeatable in the future.
Obviously this route isn't necessary with most builds but with the stock setup I want to achieve I feel this makes more sense. And I also dislike being roadblocked because of one stupid plastic connector I can't buy from the manufacturer.
Any thoughts? Ali?
Edit: It turns out that (for as long as they are in stock) the correct connector is still available. It's actually referred to as a "female" connector by Toyota when everyone thought it was a "male" connector. The "male" connector IS the connector on the TT fuel ECU and is simply part of the assembly.
I was happy this evening when a box arrived in the mail. I have finally located a used TT fuel ECU connector. It cost me a spare fuel ECU but it's done.
I am going to order some new electrodes from Toyota and see what needs to be done to run the EFI2 wire to the ECU location and where that needs to connect at the front of the car.
Taking my time with this as this as I'm still GE until next year.
I ordered new plug leads today for the used 90980-11362 connector I bought. That connector is actually is available after all, but it's a Japan special order item.
It's been referred to incorrectly as the "male" connector where in fact it is a "female" connector according to Toyota. Ignore how it looks and pay attention to the pin orientation. This is why when anyone has said they need the "male" connector they've been told it's unavailable.
The actual "male" connector is literally the part of the TT Fuel ECU itself that has pins sticking out of it-- so naturally you can't order that. It's part of the TT Fuel ECU assembly and isn't replaceable. It's P/N is 90980-11361 and the only way to get it is by picking up the ECU itself (which has its own part number).
Anyway, wiring comes next. Hope this helps someone out if they want to go this route.
Glad I finally got my fuel system sorted out, mostly ECU related. My cars running great, I did the fuel bypass which seems all good except the fuel pump runs for a few seconds after you turn the key off.
mine does that now. I did the permanent mod with the relay. it gets more power, 14.4 volts to be exact, but it does stay on a little bit after shut off for me too. its normal unless you get a standalone.
I've been meaning to ask for some time now, and couldn't find any answers to the question, is there any reason to leave the fuel pump ECU in place once bypassed? Will disconnecting the plug to it make the main ECU unhappy, or is it already invisible to the system once power to it has been cut?
08-23-14, 11:37 AM
