Throttle wiring
- Thread starter PeteB
- Start date
Speedway Motors made a harness extension for me. You should give them a call, let them know which engine you have, and how long you need the extension to be. They'll make it, and send it right out to you.
Mike
DBW portion of the harness is more than long enough to reach the pedal box, unless you did something weird like putting the ecu at the very rear of the car.
Several business sell dbw extenders, but based on my research from ls1tech I sure wouldn't extend it - it seems to be hit or miss. May work, may trigger a REP error or, worst case, may brick the ECU. Seems the ECU/throttle body is very sensitive and has numerous checks built into it (e.g., making sure pedal and throttle body are matched, resistance of wires) and bad things have the potential to quickly happen when you start getting creative with it.
Btw, you'll probably find you'll need to pre-load the gas pedal with a bolt or similar - there's a dead area in the pedal travel, IIRC the first 10% of the pedal travel has 0% throttle response in the ECU ..... it can tuned out, but there's a chance of bricking the ECU and there's no way to know when it will happen (it may not even happen during tuning, could happen weeks later) ..... basically doing anything different with the gm dbw setup has the potential to brick the ECU, lol.
Several business sell dbw extenders, but based on my research from ls1tech I sure wouldn't extend it - it seems to be hit or miss. May work, may trigger a REP error or, worst case, may brick the ECU. Seems the ECU/throttle body is very sensitive and has numerous checks built into it (e.g., making sure pedal and throttle body are matched, resistance of wires) and bad things have the potential to quickly happen when you start getting creative with it.
Btw, you'll probably find you'll need to pre-load the gas pedal with a bolt or similar - there's a dead area in the pedal travel, IIRC the first 10% of the pedal travel has 0% throttle response in the ECU ..... it can tuned out, but there's a chance of bricking the ECU and there's no way to know when it will happen (it may not even happen during tuning, could happen weeks later) ..... basically doing anything different with the gm dbw setup has the potential to brick the ECU, lol.
Current Performance Wiring LT1, LT4, LS1, LS2, LS7 Engine Wiring Systems
Saved from a prior thread - it was said they do not list it on the site but you can call and order one to length.
I had read all the warnings that the DBW was so sensitive that you should only buy a wiring extender from a reputable supplier. Then I spoke to a few who had successfully extended the harness themselves.
The DBW sensor is indeed sensitive, but it also has a safety backup system so it won't allow a runaway throttle situation. Basically, there are 2 position sensors in the throttle unit. These 2 sensors connect independently to the ECM via 2 separate sets of wires. If the ECM detects any difference between the 2 DBW sensors, it automatically puts the motor in a low idle limp mode.
I figured I had nothing to loose by extending the DBW harness myself.
I've had no problem with my extended harness. The sensor sends very little current down the harness so just use good quality copper wire and ensure the wires are all about the same length.
The DBW sensor is indeed sensitive, but it also has a safety backup system so it won't allow a runaway throttle situation. Basically, there are 2 position sensors in the throttle unit. These 2 sensors connect independently to the ECM via 2 separate sets of wires. If the ECM detects any difference between the 2 DBW sensors, it automatically puts the motor in a low idle limp mode.
I figured I had nothing to loose by extending the DBW harness myself.
- Wires are wires and I can splice in longer wires as well as anyone
- If it didn't work, I'd end up buying the same extender harness anyway (no risk)
I've had no problem with my extended harness. The sensor sends very little current down the harness so just use good quality copper wire and ensure the wires are all about the same length.
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That's not entirely true - it's possible to get unlucky and brick the ECU.
I was also informed of the "potential issues" regarding the extension of this wiring connection. I spoke at length with tech reps at GMPP. The advice was that, "if I had no alternative due to insufficient wire length" then have the extension made by a reputable source".
I did, and I've had no issues what so ever with mine. It runs very smoothly through all throttle positions. When I release the throttle, it backs down very smoothly. As well, there were no signs at all of any problems when the engine was Dyno tuned.
No drama at all.
Mike
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I opened the harness back to the ECM which I mounted on the rear drivers side of the bulkhead, there was plenty of DBW to reach the throttle assembly.
Dimi Terleckyj
Lifetime Supporter
Hi Guys
My training is as an electronics technician and from experience any problems with extender harnesses usually comes from the connectors not making proper contact.
When I have had to extend any harnesses as I did in my 40 I cut the wiring and soldered in the required extension and covered the joins with heatshrink tubing and each join was staggered away from any other join so there was no chance of shorting out.
Doing it this way eliminates any possibility of bad connections in the joining plugs and or connectors.
Dimi
My training is as an electronics technician and from experience any problems with extender harnesses usually comes from the connectors not making proper contact.
When I have had to extend any harnesses as I did in my 40 I cut the wiring and soldered in the required extension and covered the joins with heatshrink tubing and each join was staggered away from any other join so there was no chance of shorting out.
Doing it this way eliminates any possibility of bad connections in the joining plugs and or connectors.
Dimi
I've cut and solder-spliced/extended those wires on plenty of cars.....no issues. I see no way that the ECU is going to see a difference unless you're splicing in a ridiculous length of wire. I would agree that as long as you do a good job of splicing the wires there is zero risk in doing this.
