A Happy ECU (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

MisipLC

MisipLC

Joined
Apr 1, 2014
Threads
18
Messages
158
Location
Winona, Mississippi
I have searched and looked with no luck answering my question. I am trying to figure out what it takes to make the ECU happy. In other words, what signals are required to make the ECU send the "happy" signal that tells the electronic fuel pump to pump and the the distributor to distribute.

Checked all the grounds, all the connections, and the codes says the ECU is having a problem establishing a ground. The ECU is well bolted to the truck. With the key in ON position; CEL, A/T, CHARGE lamps are on.

I really am trying to understand all the triggers that are required to make the ECU - Happy.

I know the neutral park switch has to be working, the plug has to be in the air intake, ECU bolted to the truck, ....

The techs at the dealership talked with the engineers and don't seem to get it.

Oh, and I read Diagnostic Procedure for EFI Related Woe and Strife.

All fuses check with meter. All good.
 
Just trying to understand your "Woe and Strife" question. But first, Is your dash CEL on??? if it is, what are the trouble codes????
 
The CLE is illuminated.
When i say "Happy", there are specific inputes the required for the ECU to allow the engine to crank. Such as, if the ECU does not get a signal from the air flow intake sensor showing the flap is open, the ECU circuit will shut off the fuel pump circuit.

There is a specific combination of condition that must be present for the ECU to be "Happy" and allow the truck to crank.
 
MisipLC said:
The CLE is illuminated.
When i say "Happy", there are specific inputes the required for the ECU to allow the engine to crank. Such as, if the ECU does not get a signal from the air flow intake sensor showing the flap is open, the ECU circuit will shut off the fuel pump circuit.

There is a specific combination of condition that must be present for the ECU to be "Happy" and allow the truck to crank.
Click to expand...
Again, if the CEL is illuminated with the key in the ON position, the EFI system (ECU) is in the ready state. If the CEL is off with the key in the on position, the engine will not fire as there will be no fuel or spark.
When you say "crank" are you referring to the starter cranking the engine? The starter circuit has nothing to do with the ECU.

Perhaps you should explain what the problem is, what was done prior to having the problem, and what steps you have taken since.
 
MisipLC said:
Woe and Strife refers to this set of instruction: http://www.sdsysdesign.com/tlc/images/Strife/3FE EFI Diag.pdf

Yes, got all CEL lit . It blinks three times and then solid, then three blinks, and solid....
Click to expand...


Right out of the gate, that troubleshooting document doesn't apply to your engine. It is for a 3FE and the connectors and pin numbers will all be different for your 1fz-fe

You need to find an EWD for a 97.. if not that 96 should work for the engine. Other stuff like cruise control, auto antenna, and some other minor stuff is different between 96 and 97
 
Not to be the terms police, but to help we need to use agreed upon terms.

Cranking = Starter is running and engine is rotating
Starting = Engine is firing on cylinders, consuming gasoline and responsive to the accelerator pedal

The question is then, is it not cranking or not starting?

If it's a 1997, then what is the OBD scanner telling you when you plug it in and check for diagnostic codes?

How is the ECU codes saying it can't establish a ground? What diagnostic code is it indicating? A flashing CEL light on the dash shouldn't be necessary on an OBD vehicle.
 
The starter is turning over, the engine is not starting. That is using your definitions sbman.

The tech at the dealership said that the code from his diag. equipment said that the ECU could not establish a ground. The CEL illuminates when the key is turned to on, then blinks 3 times, steady, then repeats. We have identified an issue with the distributor and the fuel pump isn't pumping working when the key is turned to start. The circuit closing relay is going to be replaced.

As my dealership is not familiar with the FXJ80 motors, I was looking to make sure i understood the conditions that are required for the engine to start.

Should have the parts Tuesday, so we will see.
 
MisipLC said:
The starter is turning over, the engine is not starting. That is using your definitions sbman.

The tech at the dealership said that the code from his diag. equipment said that the ECU could not establish a ground. The CEL illuminates when the key is turned to on, then blinks 3 times, steady, then repeats. We have identified an issue with the distributor and the fuel pump isn't pumping working when the key is turned to start. The circuit closing relay is going to be replaced.

As my dealership is not familiar with the FXJ80 motors, I was looking to make sure i understood the conditions that are required for the engine to start.

Should have the parts Tuesday, so we will see.
Click to expand...

OK, that helps a lot. The dealership should have the toyota troubleshooting manuals and be following them, we can repeat that here, but it sounds like they've got that in their hands already. I've not heard of the OBD trucks using CEL flashing to show codes, that's a new one on me. The fuel pump should run for short burst when the key is first turned on, if not, problems with a fuel pump relay would be likely. Sounds kind of like a bad ECU or wiring issue to me though.
 
sbman said:
OK, that helps a lot. The dealership should have the toyota troubleshooting manuals and be following them, we can repeat that here, but it sounds like they've got that in their hands already. I've not heard of the OBD trucks using CEL flashing to show codes, that's a new one on me. The fuel pump should run for short burst when the key is first turned on, if not, problems with a fuel pump relay would be likely. Sounds kind of like a bad ECU or wiring issue to me though.
Click to expand...
I seem to remember something about a problem with the wiring harness on the late model trucks, coming out of the ECM being cut by the metal frame that supports the glove box. That problem, IIRC caused problems with the fuel pump, or the fuel injectors shorting out. The OP could check his wiring harness, All he would have to do is remove his glove box, and see if his wiring harness has a hole rubbed in it.
 
Thanks and I have not. Have seen the 80's parked out front of their shop several times traveling between Hattiesburg and Ridgeland, MS.

Will see what we get when we replace a couple of things hopefully on Tuesday.
 
You must log in or register to reply here.

Similar threads

REKCUT
ECU power
Replies
14
Views
1K
CJF
CJF
T
91 FJ80 ECU access?
Replies
2
Views
381
Two 3FEs
T
alia176
Installing a new ECU harness
Replies
4
Views
835
ZackR
ZackR
WhiteyNorge
Sourcing a used airbag ECU in the USA
Replies
16
Views
956
WhiteyNorge
WhiteyNorge

Users who are viewing this thread

Total: 2 (members: 0, guests: 2)

Share this page

Back
Top Bottom