1st Gen Haltech ECU Discussion

Hey guys, I'm running the elite 750 and I've been having a lot of issues with my truck losing it's throttle position more and more frequently. For example, I'll be driving down the freeway and the truck will suddenly fall on it's face as if I've let off the throttle. If I push the throttle further in it catches and will accelerate again but it's as if my 0% throttle position is located at 50%. If I let off and coast for a few seconds the truck will reset it's 0% throttle position back to 0% and then act normal again. This is happening 3 or 4 times everyday within my 20 minute commute.

To try to solve the issue I've reset the throttle position using the haltech software, I've had Gabe reset the throttle position, and I've replaced the throttle body with a brand new oem unit from Toyota.

Any thoughts on what could be causing this and if it's haltech related?

 

This sounds a lot like a wiring issue, have you verified if the pins in the connector are fitting well on the TPS. If your 5v rail was dropping out other sensors would freak out too. Do you have a log of when this happens, maybe we just need to increase the filter on your TPS value if its only a split second blip. Can you post your tune and a log?

 

Are you able to log TPS to see if it's really a sensor Issue?

It sounds like what I was experiencing when my spark plug gap was too wide. I would lose power all over the place as soon as I gave it the beans


You could also try disabling decel completely for the time being since that's mainly what would relate TPS to losing power

Edit to that last point: I see you have an 04. Idk anything about programming drive by wire on these things but I'd look to your pedal sensor & settings instead

 

Oh yeah 04... e throttle isn't fun, means his stock computer is there still to control it and it could be slamming it closed for any number of reasons, the Haltech is only looking at the TPS not the pedal position... the stock ecu could be going into engine protect for any number of reasons... @austinmtb can you pull codes from your stock ECU for us after this throttle problem happens

 

I'll check out the TPS connector on the wiring harness side of things and see if the stock ecu is throwing any codes. The throttle body is brand new so that shouldn't have any corrosion.

Edit: I'll see if I can get some tune and data logging info on here. Unfortunately I had Gabe do all my tuning and I have very little understanding of tuning so I'm not sure how to play with TPS filtering.

 

It can't be that hard to move that function to the HT can it?

 

750 cannot do DBW, only 2500 can and then you have to integrate an output for line pressure control if it is an auto since the line pressure cable is removed on 03-04 in favor of electronic control.

 

Probably, but I don't really know how to use the haltech software much so maybe I'll give Gabe a call and see what he thinks.

In my case I doubt that it's a spark plug issue, it happens very randomly regardless of if I'm getting on the gas hard or not.

 

I forgot you have an e-throttle truck, I doubt it is a wiring issue now. I would be willing to put money on it being a stock ECU problem that's causing it to go into limp mode and limit throttle output. Maybe we can still help you figure it out though

 

Check this thread out, https://www.tacomaworld.com/threads/cant-figure-this-hick-up-out.168680/

I have had similar issues from time to time and the solve in that thread seems to do the trick.

 

Gotcha, I'll pull up my data logging later today. Anything specific that I should be looking for in there?

 

Well first, when this happens can you only reset it by restarting the truck? Do you have a scan gauge or ultra gauge we can use to see the stock OBD codes?

 

I spoke to Gabe at SNP. In particular, I was curious about the materials used in his harnesses. He is extremely knowledgeable and laid-back. Sometime this winter, I will invest in his Haltech Elite 1500 complete harness kit and 58mm pulley, as well as a remote tune from him. On the stock ECU, the truck basically fights to stay at 14.7 while in loop, as we all know, but dips down to 10-10.2 while in WOT.

 

If you need help after the remote tune let us know, I pop over to western WA all the time to visit family.

 

I was actually just about to message you to see if you are open to answering my questions when that time comes so thank you.

As a general question: with the complete harness kit, I don't expect install to be too painful except for rebuilding my dash harness. I know it's a nebulous question but what issues might I expect?

 

There's really not much to do with these patch harnesses, hardest part of the whole process is tucking the new computer and patch section back into the space. It's pretty plug and play thankfully. Mine isn't even a "kit" and I hardly did any wiring changes other than some tidying up for my own satisfaction. I'm happy to lend a hand if you need it, I assume your tuner will get you lined out well but if something isn't right or needs improvement I'm sure we can figure it out. Ask SNP for the wiring pinout sheet from Boomslang if you can. It makes solving issues much easier for the next guy.

 

So, since I am deleting the OEM ECU but not the OEM instrument cluster, I need some way to send data to it for monitoring. That being the case, I will need to either a) build a custom harness for speed, coolant temperature, etc., or b) purchase a pre-made harness from Gabe. When I think about potential issues, that -- instituting new harnesses for reading data from the cluster -- is where my mind wanders.

 

Your cluster is wired independent of the ECU, you won't have to do anything to have it function, thank Toyota for that lovely design.

 

Just as a head's up, he basically only will help you up to getting the truck started and running (which he dragged his feet on when I could have used the help), the rest is paid and it's a pretty high rate for what he offers imo.
But as mentioned we're all here to help.

 

Thank you; that's actually a huge piece of input for me.

Out of curiosity, though - the ECU in my truck definitely relies on speedometer data. I know that because removing the speedo (it's a long story) resulted in a problem code. How would that happen if independent of ECU? Perhaps I can answer that question by tracing the rear circuit panel on the cluster and reading the pin / connector diagram . . . .