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Crasher
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R32, AMM analog or digital?

2007 Golf 5 R32, BUB engine.

I am fitting an FIC8 to this car which has had a turbo conversion in the past and also at least two different types of piggy back controller plus a remapped ECU and I have had to sort out a LOT of very poor wiring and strange bodges such as the AMM air temp wire having been disconnected and run off to a dead end!

This uses the 07D 906 461 Air Mass Meter (AKA MAF) which is a Bosch 0 280 218 073, a Hot-film air mass meter HFM-5-8.5. I cannot establish whether this is an analogue or digital AMM and I am struggling to make sense of the output from Pin 5, which I believe is the output.

With the signal going straight in to the FIC, the ECU immediately flags up a MAF error so Pyng Thai at AEM suggested a pull down resistor after studying the output of the AMM and the output from the FIC but even making sense of the signal has me puzzled as I have never had to do this before, does anyone have any advice?

 

AEM_NS
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Not sure what a Mk5 R32 has

Not sure what a Mk5 R32 has for a MAF but I know for sure that Mk5 2.0T FSI had digital MAFs. I've heard that Mk5 R32's are more like Mk4 R32's than other Mk5 chassis cars but who's to say that the Mk5 R32 didn't get a digital MAF like the 2.0T? Either way, looking at the signal on an oscilloscope should tell you exactly what it is. Also be aware that a digital MAF uses different input pins on the FIC than an analog MAF would use and you can't mix them up (digital MAF to analog MAF pins on FIC and vice versa).

Crasher
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This is my first AEM (but not

This is my first AEM (but not my last) and so I am still getting used to the differences to what I have used in the past. I was unsure about the AMM into the FIC but the instructions are not very clear on this, no mention of analogue or digital AMM’s, just in figure 16 the mention of a frequency based AMM so that could do with revising anyway. The signal I have been able to see from the AMM is a sine wave, not square, I will post a screen grab later. This is a wiring diagram of the AMM I was trying to post last night

NOW this has made me concerned about the lambda sensor, I have connected it up as per figure 9 but I think I have seen the LSU4.9 described as digital?

AEM_NS
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I'm guessing you're not

I'm guessing you're not scoping it correctly if you're seeing a sine wave. Sounds like the probe may not be properly grounded. Figure 6 in the instructions covers analog MAF connection. Unfortunately that diagram doesn't give any indication as to what the MAF sensor is. LSU4.9 sensors are not digital.

Crasher
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I will check the probes

I will check the probes grounding next week, thank you for your help.

Crasher
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After some fiddling around I

After some fiddling around I have thse results

Too high

Too low

At 21.8 Ohm

What do you chaps think?

AEM_NS
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If that 1us/div is right, I

If that 1us/div is right, I think you're way too far 'zoomed' in. Scope should be setup for like 10ms/div. You're zoomed in 10,000 times too much. You also don't mention what the two channels represent nor what 21.8ohms means.

Crasher
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I have just noticed the

I have just noticed the channels are on differnt divisions, start again!

Crasher
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Struugling to get this to

Struugling to get this to work, the diagnostic screen says no AMM flow.

I have tried a 0>2K resistor start to stop on the output of the FIC to earth and I can't get any sensible change to take place. The signals in and out of the FIC are masisvly different, roughly 1.5v in and a few mV out. Plug in the bridge and all is as it should be. What do you need me to show from the scope to help? Beginning to pull my hair out a bit, the customer wants his toy back.

AEM_NS
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Have you determined if the

Have you determined if the MAF is digital or analog yet? You've yet to provide a scope trace that concisely shows if the signal is digital or analog. In my eyes, you're just guessing and trying different (possibly wrong) things to see what they do. How can you know what to do and expect any kind of predictable outcome if you still don't know what the base signal is?

Crasher
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I am pretty sure the AMM is

I am pretty sure the AMM is analogue but as you say I need a conclusive trace from it which I will try and get the time to do later. Thankyou for you help so far.

Crasher
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I have to put this down for a

I have to put this down for a few days now, Mrs Crasher insists I take a few days holiday so back to it next Monday.

AEM_NS
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FWIW, after looking at some

FWIW, after looking at some diagrams on AllData, the R32 MAF is most likely analog. The Mk5 2.0T GTI MAF, which is digital, is shown as being a 3 wire setup whereas the Mk5 R32 is 5 wire. One thing to be aware of is that my AllData covers North American spec cars only. Being in the UK/EU may introduce other differences that I won't be aware of. Since it's likely that the MAF is analog, you don't really need a scope and should be able to check the voltages with a simple multimeter.