Low Rev Throttle Response, at a loss now!

Hi Guys, I really need some help with this now, so all and any advice welcomed!

I've a 1999 Defender TD5, mapped to stage 1 recently by Empire Tuning. Here are the basic symptoms that really need addressing:

1. Very little response from low revs from throttle
2. Huge amount of surging past a certain amount of revs (around 1500/2500)
3. When cold, she REALLY struggles to get up a relatively steep hill, I have had to stop several times and rev HIGH before being able to change into 2nd gear....then she struggles before having to stop, handbrake on and another hill start with high revs.....
4. Once warmed up and driving she is fine....toodles along not unlike my Disco TD5.

Here's what I have done to date:

1. Change Wastegate Actuator - set to what I believe is standard 12/14 threads)
2. Fuel filter change
3. Air filter change
4. Change MAP Sensor - no change
4. Changed MAF sensor (also disconnected) - no change

I have heard others allude to the TPS being at fault, seems to make sense, but I am finding it difficult to both locate it and/or find a replacement??

All I can say for sure at the moment is that the main issue is the surging is palpable and there is little throttle response for the first few inches after depressing it.....hence having to stop and gear down when under load much more noticeable when cold!

I have just had a Nanocom arrive, all good to go, but its new to me so not sure how to record outputs yet (any help in that respect is welcomed too as the is little or no documentation available)

Thanks so much for your patience and any help you can offer!

Recent remap? Take it back.

tottot said:

Recent remap? Take it back.

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I would agree with this.
Did it work fine before the remap?

Anaconda said:

I would agree with this.
Did it work fine before the remap?

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It's not that much better to be fair.....

<bump>.....any takers on this?

*** Update ***

Gave her an oil change

New Injector Loom and Gasket

New LR MAF sensor

Lengthened Wastegate arm


Its a lot better, which is inspiring as I feel like I am getting closer to a solution....drives great when up and running. Pulls great up hills now and does so in 3rd which is a massive improvement. But still prone to surge and not a smooth take-up at all

All thoughts welcomed!

Did you speak to the tuner?

Anaconda said:

Did you speak to the tuner?

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Yes, Empire Tuning. Apparently, 'Stage 1' ....though I'm not sure what that involves. I was hoping for some sort of documentation to give me more details but sadly not. They have said they would 'send me a chip' if I didn't want to send the ECU for a third time. But I'm not sufficiently well versed to do it myself.

Can't really tell you much more really, she's a lot betterz but still Bunny Hops,worse when cold and worse in 2nd gear...always below 2k RPM.

I am not sure it can be solved with more remapping, instinctively I think it's something to do with the throttle not responding at low revs.

Thanks....

I think what people are asking is - did this happen straight after the remap? If not, did it happen before or after? And finally, why the second remap?

boguing said:

I think what people are asking is - did this happen straight after the remap? If not, did it happen before or after? And finally, why the second remap?

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No, problem was worse before remap - struggled to get her up even a moderate hill. Now she performs as I'd expect. No issues there. The initial remap made no discernable difference in terms of the 'Jumping' I describe which is still present. Empire Tuning asked me to return the ECU and said that they had made more changes inline with my requests.

One thing I have noticed is that turning the Wastegate Actuator back to stock - i.e. around 12/14 threads hasn't made any difference at one way or the other. Nor does lengthening or shortening the arm. The arm on the wastegate is loose and flicks back and forth unrestricted too, so not 'stuck'.

Will get the Nanocom on it later and put up the results.

tweedandbriar said:

No, problem was worse before remap - struggled to get her up even a moderate hill. Now she performs as I'd expect. No issues there. The initial remap made no discernable difference in terms of the 'Jumping' I describe which is still present. Empire Tuning asked me to return the ECU and said that they had made more changes inline with my requests.

One thing I have noticed is that turning the Wastegate Actuator back to stock - i.e. around 12/14 threads hasn't made any difference at one way or the other. Nor does lengthening or shortening the arm. The arm on the wastegate is loose and flicks back and forth unrestricted too, so not 'stuck'.

Will get the Nanocom on it later and put up the results.

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So if I’m reading this correctly. You had a major running issue that your are trying to solve with a performance remap?

Sorry to say it and not trying to be a dick about it. But I think you need to focus on repairing the fault as opposed to modding. A completely standard vehicle should run and drive perfectly fine. So if the issue was there pre-remap. You need to find the actual cause. Which could be any number of things such as the throttle pedal, fuel rail, wiring loom, other electrical or fuel related issue.

Are any error codes being triggered and have you replaced or checked any other parts of the engine?

300bhp/ton said:

So if I’m reading this correctly. You had a major running issue that your are trying to solve with a performance remap?

Sorry to say it and not trying to be a dick about it. But I think you need to focus on repairing the fault as opposed to modding. A completely standard vehicle should run and drive perfectly fine. So if the issue was there pre-remap. You need to find the actual cause. Which could be any number of things such as the throttle pedal, fuel rail, wiring loom, other electrical or fuel related issue.

Are any error codes being triggered and have you replaced or checked any other parts of the engine?

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You're not being a dick, I don't think.

I had it mapped as it was displaying almost identical issues as the Disco I have, subsequently rectified by a Stage 1 remap. Different vehicles yes, but you can see my rationale to a point. Now, I can't focus on the fault as you suggest, as I don't as yet know what the fault is.

The Nanocom, that I spent nearly £400 on has given me nothing but problems too, with errors, left right and centre resulting in having to do factory resets several times.

That too is getting flung back as I'd expect just a little bit more from the TD5 device of the century.

Hope that helps....

Attached Nanocom File fault file - didn't have time to take the old girl out this morning, so readings are from an idle...

I am wondering if (21,6) PROBLEMS DETECTED WITH DRIVER DEMAND (LOGGED) suggests rewiring the pedal to the ECU?

Not an uncommon issue, rewire kit to be had, try the Ebay.

tottot said:

Not an uncommon issue, rewire kit to be had, try the Ebay.

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Thought as much - I wonder if this is the cause of the issues I described?

tweedandbriar said:

Thought as much - I wonder if this is the cause of the issues I described?

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Maybe, replace the loom and see what happens. You can read the operation of the pedal in live data I should think.

Anaconda said:

Maybe, replace the loom and see what happens. You can read the operation of the pedal in live data I should think.

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Just getting to grips with the Nanocom... I'll have a look when I have (tried) fitting this door seal!!

I am not that well versed in the Td5 issues but it may well be so. Try giving the wiring a wiggle while running, if engine management light comes on it points that way. Throttle pot may be another source but start with the simple cheap stuff.

Would a faulty Crank Sensor have the same effect?

tottot said:

I am not that well versed in the Td5 issues but it may well be so. Try giving the wiring a wiggle while running, if engine management light comes on it points that way. Throttle pot may be another source but start with the simple cheap stuff.

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If it's a carbon pot that could well be the problem. If it starts to break up the output goes haywire. It's the reason volume controls on analogue audio makes the scratchy noise. (And can be fixed on audio gear by grinding the bits down with repeated twisting of the knob - not reliably enough to fix a td5 though I suspect).

boguing said:

If it's a carbon pot that could well be the problem. If it starts to break up the output goes haywire. It's the reason volume controls on analogue audio makes the scratchy noise. (And can be fixed on audio gear by grinding the bits down with repeated twisting of the knob - not reliably enough to fix a td5 though I suspect).

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Carbon pot?