My 1HD-FTE conversion was running great for the last year but I recently had to do battle with an exceptionally frustrating problem. Sometime in February, the truck developed a habit of just randomly shutting off while driving - not cool. Sometimes it would not restart, sometimes it would restart and die immediately over and over, and sometimes it would fire back up and run fine for days or even weeks before reoccurrence. The problem usually didn't trigger a CEL and after ruling out the immobilizer bypass, consulting with a few enthusiasts, and searching on the Private FB FTE Groups, I began to focus attention on the spill driver. The EDU (spill driver) seems to be a frequent source of problems with the FTE which is not really known for lots of problems. Thus, I added a separate heavy gauge earth cable directly from the EDU to the battery post. That seemed to help ... for a while. But the problem eventually returned. I then swapped the EDU with TWO other brand new units I bought from Toyota and the problem persisted; I even tried swapping the ECU for a spare I had on the shelf ... no change. So at this point, I really had to dig into the FSM and learn a lot about how the EFI system is supposed to work. Here's a quick summary:
In basic terms, the FTE's ECU receives various signals from things like the crank position sensor, MAF sensor, MAP sensor, air and fuel temp sensors, diesel engine speed sensor, throttle pedal and others to send the appropriate spill valve control signals to the EDU. This happens through the ECU circuit that sends 5 v square wave pulses to the EDU which in turn takes those signals and, through the use of the DC/DC inverter, outputs those commands at 150 v to the spill valve. The EDU then sends a confirmation signal back to the ECU to complete the process. If the ECU doesn't receive that confirmation signal, it may throw an error code and shut down the EFI system to protect itself. Ok, that pretty much makes sense... of course my truck only actually threw a DTC 97 trouble code once in all the occasions where it randomly died so I was left unsure if the communication error was causing the problem.
After swapping basically everything but the IP, I was becoming more and more convinced I either had a bad spill valve, a bad 5 v signal from the ECU to the EDU (IJF and IJT on the EDU), or a bad 150 v control circuit from the EDU to the spill valve (SPV+ and SPV- on the EDU). If you look at the EWD you'll see the 150 v circuit, as well as the switched ignition power wire to the EDU are also shielded. I was also suspicious of the potential for a problem with this shielding to cause my intermittent problem... - was it possible some RF interference was creating a dirty 5 v signal that was occasionally erroring out the ECU/EDU comms circuit???
To try and isolate the issue to one component or circuit, I ordered a set of new OEM connectors from Corsa Technic (you guys should save that website; it's fantastic) and terminals to make my own "by-pass" wiring harness to completely bypass the factory sub-harness which connects the EDU to the spill valve. @SNLC probably grumbled about this to himself as well... the factory harness uses a total of 4 connectors to connect the EDU to the spill valve and a problem anywhere in that circuit would definitely result in a no-start or intermittent problem (in my case, no amount of wiggling, shaking, or bending the harness could reproduce the issue - which was frustrating). Anyway, I made a stand alone harness to bypass the factory harness between the EDU and the spill valve and after a quick test drive, I still had intermittent stalling. Damn. So I then felt pretty confident the problem didn't lay in the 150 v output circuit between the EDU and the spill valve and it was now down to either a faulty spill valve (or one of the other injection pump sensors (like the speed sensor or the timing control valve (sometimes called the suction control valve in the Toyota literature)... OR! It could be the 5 v square wave signal wire circuit from the ECU to the EDU... OR! the power circuit from the spill driver relay. I double-checked the SPD relay for operation and decided it must be a problem with the communication/power side of the EDU circuit.
I set about making my own stand alone harness to by-pass the existing 5 v signal wires from ECU to EDU. ....and BOOM. Right now that seemed to fix the problem. I put almost 1,000 miles on the truck and the problem hasn't come back. And, again, for those who may need to make their own harness, I really feel the need to give another plug for CorsaTechnic. Their catalog made it easy to source many of the factory EFI connectors and terminals needed for the FTE. I was able to cross-reference the EDU connectors in Toyota literature and used the resulting part numbers to find the commercial counterpart. I spend a solid evening cross referencing p/ns and ordering every connector I couldl find available from their website just to keep as spares for the future.
In basic terms, the FTE's ECU receives various signals from things like the crank position sensor, MAF sensor, MAP sensor, air and fuel temp sensors, diesel engine speed sensor, throttle pedal and others to send the appropriate spill valve control signals to the EDU. This happens through the ECU circuit that sends 5 v square wave pulses to the EDU which in turn takes those signals and, through the use of the DC/DC inverter, outputs those commands at 150 v to the spill valve. The EDU then sends a confirmation signal back to the ECU to complete the process. If the ECU doesn't receive that confirmation signal, it may throw an error code and shut down the EFI system to protect itself. Ok, that pretty much makes sense... of course my truck only actually threw a DTC 97 trouble code once in all the occasions where it randomly died so I was left unsure if the communication error was causing the problem.
After swapping basically everything but the IP, I was becoming more and more convinced I either had a bad spill valve, a bad 5 v signal from the ECU to the EDU (IJF and IJT on the EDU), or a bad 150 v control circuit from the EDU to the spill valve (SPV+ and SPV- on the EDU). If you look at the EWD you'll see the 150 v circuit, as well as the switched ignition power wire to the EDU are also shielded. I was also suspicious of the potential for a problem with this shielding to cause my intermittent problem... - was it possible some RF interference was creating a dirty 5 v signal that was occasionally erroring out the ECU/EDU comms circuit???
To try and isolate the issue to one component or circuit, I ordered a set of new OEM connectors from Corsa Technic (you guys should save that website; it's fantastic) and terminals to make my own "by-pass" wiring harness to completely bypass the factory sub-harness which connects the EDU to the spill valve. @SNLC probably grumbled about this to himself as well... the factory harness uses a total of 4 connectors to connect the EDU to the spill valve and a problem anywhere in that circuit would definitely result in a no-start or intermittent problem (in my case, no amount of wiggling, shaking, or bending the harness could reproduce the issue - which was frustrating). Anyway, I made a stand alone harness to bypass the factory harness between the EDU and the spill valve and after a quick test drive, I still had intermittent stalling. Damn. So I then felt pretty confident the problem didn't lay in the 150 v output circuit between the EDU and the spill valve and it was now down to either a faulty spill valve (or one of the other injection pump sensors (like the speed sensor or the timing control valve (sometimes called the suction control valve in the Toyota literature)... OR! It could be the 5 v square wave signal wire circuit from the ECU to the EDU... OR! the power circuit from the spill driver relay. I double-checked the SPD relay for operation and decided it must be a problem with the communication/power side of the EDU circuit.
I set about making my own stand alone harness to by-pass the existing 5 v signal wires from ECU to EDU. ....and BOOM. Right now that seemed to fix the problem. I put almost 1,000 miles on the truck and the problem hasn't come back. And, again, for those who may need to make their own harness, I really feel the need to give another plug for CorsaTechnic. Their catalog made it easy to source many of the factory EFI connectors and terminals needed for the FTE. I was able to cross-reference the EDU connectors in Toyota literature and used the resulting part numbers to find the commercial counterpart. I spend a solid evening cross referencing p/ns and ordering every connector I couldl find available from their website just to keep as spares for the future.
Last edited:
.