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Certainly looks like the MAF is giving some pretty variable data.
Low Rev Throttle Response, at a loss now!
- Thread starter tweedandbriar
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Anaconda
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Can you explain track 3 please.
I understand track 1 and track 2 should add up to 5v, rising and falling with throttle position.
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I've change my mind about the airflow. Here's airflow and rpm. Just what you'd expect.
Some td5 are only 2 track
Airflow going up and down is to be expected but when pushing on it should get up around 600. That’s why I thought values were low
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Fair enough, I've no idea what the absolute values should be but having thought af was spikey, I now see that it's in keeping.
Anaconda
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Thanks for the reply. I know that but wondered what the readings indicate in regards to the other 2 tracks.
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I'm way out of my depth on how the td5 works, but are these tracks the resistance circles in the potentiometer? Just recalling that the dead Citroen I mentioned had two, and it was one of the wiper brushes that had fallen apart.
Anaconda
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As far as I understand it track 1 and 2 show the voltage seen by the ecu. It's 5v total so track 1 and 2 readings will be 5v total, each reading a different number depending on throttle positioning.
I don't know about track 3 readings and what they correspond to.
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Got it. The potentiometer has two or three tracks, depending on age of the car. In both, track A goes from low resistance throttle closed, to high resistance when fully open. Track B does the reverse, and as you say the values should sum to 5v. Track C gives more accuracy, but checking its value needs to be done on the graph as far as I can tell. I'll have a look later. Lunch calls.
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Actually, I couldn't wait. The third track is all over the place, and should never show 0v or 6v. I think that's at least part of the problem.
Anaconda
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That's why I was asking, the readings are very erratic and I couldn't see a reasoning to them.
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You can see that 1&2 are doing exactly what they should here, and 3 (yellow) is in cloud cuckoo land. I've no idea what the sampling rate is but it looks very slow, and I bet yellow would be far more interesting if the rate was higher.
Anaconda
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Hopefully someone will come along and solve the mystery for us.
tweedandbriar
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Thanks for looking at this guys, your knowledge by far supersedes mine!! However, I took her out for a longer run last night and have attached a link to the CSV...hope that offer some more insight?
On another note, I turned the Wastegate Actuator right back to 20 threads, it made a palpable difference inasmuch as pulling away was much smoother as was creeping up to lights etc in 1st or 2nd, a lack of 'jumping' too - still there but significantly less noticeable! But.......she struggled to get up the hill to the farm. So I have turned it back to around 17 threads now and its got more power, but also more prone to 'jump'again.
Nanocom #2
On another note, I turned the Wastegate Actuator right back to 20 threads, it made a palpable difference inasmuch as pulling away was much smoother as was creeping up to lights etc in 1st or 2nd, a lack of 'jumping' too - still there but significantly less noticeable! But.......she struggled to get up the hill to the farm. So I have turned it back to around 17 threads now and its got more power, but also more prone to 'jump'again.
Nanocom #2
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The track 3 output is, if anything, worse than the first dataset. That would point to the potentiometer breaking up, but the fact that it hit 8v means that can't be the (sole) problem because it only gets 5 in. The MAF is low. They both connect to different plugs on the ECU, so the only common point for them would be the ECU earth.
I think I'd be looking at wiring. What state is it in around the ecu?
I think I'd be looking at wiring. What state is it in around the ecu?
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tweedandbriar
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Hi, just got back from a short break in Cornwall (didn't take the Landy). I'll have a look over the ECU tomorrow as booked myself some time to dig deeper. Will report back, thanks again for advice/pointers
tweedandbriar
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....in the meantime , here the latest Nanocom readout after turning the Wastegate actuator out to 17 threads....some improvement but still jumping badly, it seemed altering the boost doesn't improve things one way or another.......Nanocom
I can replicate the jumping if I either:
1. Drive slowly up hill, back off the revs then increase them gently... = Jumps
2. In 1st or 2nd driving slowly, gently accelerate then again back off and gently accelerate again.... = Jumps
Cheers....!
I can replicate the jumping if I either:
1. Drive slowly up hill, back off the revs then increase them gently... = Jumps
2. In 1st or 2nd driving slowly, gently accelerate then again back off and gently accelerate again.... = Jumps
Cheers....!
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I'd leave the fiddling until the electrics are sorted!
tweedandbriar
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I know, just frustrating...got a day off tomorrow, will hopefully find a little more to report.
