75% throttle limited

[Rustychops]

Hi,

I used Adcel scanner on my 2.3l Duratec HE 2008 Mondeo because I'm suffering slow acceleration at around the 100kmph mark.

The scantool came back no errors but when I graph the throttle body it sits at idle 12% ish and maxes out at 76.5%.

I have tried numerous resets drain battery(engine caps) methods checked the throttle body physically internal and external, the accelerator pedal.

I can find no fault with them but not saying there isn't one.


Can anyone tell me what's happenings, is it normal? Some hints?

Thanks

[cobrin]

What you've described is a dead spot and the issue lays with the throttle body. I wouldn't even get you to try and fix it, you're better served with replacing it. Used or otherwise, as long as it checks out through the full sweep.



Using a multimeter on Ohms across the TB connector will give you the similar behaviour and is a quick'n'easy check if you have one to test in your hand (thinking wreckers) or doing it whilst it's still on the engine. You just want a constant reading from closed to fully open is all.


So test the TB for the deadspots and if that's alright do the same test for the pedal, cause if it's not the one it'll be the other. Or get an auto-sparky to do.

[Rustychops]

Thanks for that.

I presume I would check it between the 2 contact points inside the throttle body cover?

If so I might try that and see what it reads, just to be sure, they are not cheap, well here anyway.

[cobrin]

Not inside the TB, only the connection to it. You'll have three or four terminals on the TB side, you'll need to check between two of them, and you'll know which ones because you'll get a reading as you open/close the butterfly. Move the one probe to the next terminal in line and test again till you have it.


edit: I should stipulate, you'll be moving the butterfly yourself with your fingers, the TB will be disconnected and there's no need to have the key on. It's all powered down at this point.


I have a similar problem with a Honda Civic only it's dead at 20% and back at say 30% when using an OBD2 adaptor. Checking it at the TB it shows an Ohms reading then open circuit then back to a reading. Just verifies the issue is with the TB and not the pedal sensor.


The symptom is minimal, thankfully, only showing up more with the A/C on and typically two or more occupants, so a bit of load on the engine. At least this is at a lower rpm and I can 'drive around it' so to speak.

[Rustychops]

Originally Posted by cobrin

Not inside the TB, only the connection to it. You'll have three or four terminals on the TB side, you'll need to check between two of them, and you'll know which ones because you'll get a reading as you open/close the butterfly. Move the one probe to the next terminal in line and test again till you have it.


edit: I should stipulate, you'll be moving the butterfly yourself with your fingers, the TB will be disconnected and there's no need to have the key on. It's all powered down at this point.


I have a similar problem with a Honda Civic only it's dead at 20% and back at say 30% when using an OBD2 adaptor. Checking it at the TB it shows an Ohms reading then open circuit then back to a reading. Just verifies the issue is with the TB and not the pedal sensor.


The symptom is minimal, thankfully, only showing up more with the A/C on and typically two or more occupants, so a bit of load on the engine. At least this is at a lower rpm and I can 'drive around it' so to speak.

Cool, I'll try and find the pins tomorrow I have 6 pins, it's an electronic throttle body. But I should see the Ohms move once I find the right 2.

Good tip with that I can be sure it's the TB.

[Rustychops]

Just an update,

I did an ohms test on the throttle body the ohms/resistance drops to .8 from 1,8 and then stop changing with the butterfly open marginally .

It's a great reply and I definitively found my fault and will swap out the component. Thanks Cobrin.

[cobrin]

Hey that's a great outcome, don't thank me, I figuratively/literally only lifted a finger lol. You did all the work yourself.



Happy hunting the part down. If you do find a replacement part, pull apart the old one and see if you can fix it. I'd be interested to know. It's not like you're going to reuse it, so it doesn't matter if it's damaged further lol.

[Rustychops]

Originally Posted by cobrin

Hey that's a great outcome, don't thank me, I figuratively/literally only lifted a finger lol. You did all the work yourself.



Happy hunting the part down. If you do find a replacement part, pull apart the old one and see if you can fix it. I'd be interested to know. It's not like you're going to reuse it, so it doesn't matter if it's damaged further lol.

I ordered one today from a dismantler, should arrive sometime this week. I'll let you know if I have "unlimited power" when it arrives.