Power steering readings. Do you seeanything strange?

[Breezy_Pete]

I think the part number for that cable on your car is 1K0917250, assuming you have 5/6-speed manual gearbox? Info from here. If you're lucky it may have a part number written on it somewhere.

Lots on ebay here, and maybe not that expensive new? Let me know if you want me to try to source one here and post it over to you.

[dm222]

I think the part number for that cable on your car is 1K0917250, assuming you have 5/6-speed manual gearbox? Info from here. If you're lucky it may have a part number written on it somewhere.

Lots on ebay here, and maybe not that expensive new? Let me know if you want me to try to source one here and post it over to you.

 

Thank you for the offter, I will try to find it here because it's faster, and if I can't do it here I will let you know. I will let you know how this ends, I hope to solve this next week.

 

Still trying to understand what is the implications when there is resistance in the negative side of the circuite of the alternator. I mean the positive is easy for example if you have 14V and a resitance of 0,5V on the alternator cable only arrives 13,5V to the battery, but the negative side is tricky... How much does it affect the voltage/amps the alternator generates?

 

A practical example, don't know if they are the correct values

 

Voltage: 14,00V

resistance 0,05V

 

Headlights on drops to 13,80V

Resitance 0,15V

 

AC on drops to 13,60V

Resistance 0,30V

 

Does this mean the resistance was responsible for the drop of 0,10V when turned the headlights and 0,15 when turned the AC on?

Edited 15 August, 2015 by dm222

[Breezy_Pete]

You effectively have a fixed voltage source - let's call it V_alt (alternator) in series with a resistance, call it R_s caused by your bad cable/connection. Whether its in the 'positive' side of the voltage source or negative makes no difference, I think. You treat the combination of voltage source and resistance as a 'black box' with just two connections.

 

When you connect that combination to a load (the combination of everything electrical in the car) - let's call it R_L, the voltage produced across that load will be V_L such that:

 

V_L = V_alt  x  (R_L/(R_L+ R_s))

 

For any non-zero value of R_s, V_L will be less than V_alt

[Updown789]

You effectively have a fixed voltage source - let's call it V_alt (alternator) in series with a resistance, call it R_s caused by your bad cable/connection. Whether its in the 'positive' side of the voltage source or negative makes no difference, I think. You treat the combination of voltage source and resistance as a 'black box' with just two connections.

When you connect that combination to a load (the combination of everything electrical in the car) - let's call it R_L, the voltage produced across that load will be V_L such that:

V_L = V_alt x (R_L/(R_L+ R_s))

For any non-zero value of R_s, V_L will be less than V_alt

Ahhh, volt drop calculations lol. Finished college 3 months ago and already forgotten them :P

[Breezy_Pete]

I measured some  voltages around my (Polo) engine bay earlier. Interesting.  I've always thought it charged a little worse than it should, but focussed on the alternator, rather than the cables...

 

So with engine idling, cabin fan on max, headlights on, I measured between alternator case and battery negative, almost 0.6V!

It's a bit tricky to access the ends of the main earth cable that links the engine to chassis, but as dm222 has found, that seemed to be where the problem was for me too.

 

I grabbed a selection of 13mm spanners, disconnected battery neg., then disconnected both ends of this earth wire for inspection.

Not too bad to look at, but a bit 'dull' in appearance on the face of the engine end crimp terminal, where it clamps up against the starter mounting stud. Wire brush and brillo pad type thing, and everything was shiny again. Bit of Vaseline to keep the elements at bay in future and bolted back up.

 

Re-measured with same loads on, and now only 0.08V between alternator case and batt. neg. Result.

 

Quick spin round the village to get a new plot, and everything's shifted nicely rightwards.  Lights weren't on, so the best comparison plot is the one I did on Tuesday lunchtime, here they are side by side (Tues on left, just now on right):

 

 

 

Terminal 30 (battery) voltage on the x-axis in each case, PAS pump current up the y-axes.

 

 

Thanks dm222, you helped me to mend my car.

[dm222]

Nice, looks like you have more voltage now and the pump using less amps to operate, wich indicates the assumptions we made were right, less voltage more amps. I'm curious to check mine after replacing the cable.

 

 

Meanwhile I've found why my voltages changes sometimes, my voltages are higher when the engine is cold (at least when idling, I've yet to do a PAS log with the engine cold).

When it's warm it drops to 13,70/13,90, and I think yours does that too in your log you posted tuesday, so must be normal..

 

 

Today did some testing in the postive side (only the cable) and I have also some resistance, 0,42V wich I think it's in the limit of acceptable 0,50V (I readed somewhere the limit acceptable is 0,50V postive, 0,01V negative).

 

 

Also did a test to the PAS case wich gave a 0,00V.

Edited 15 August, 2015 by dm222

[dm222]

Well today did another log... Found one more strange thing! 

At the car start the pump reached 72.0A at 11,10V. I saw yours and the maximum you had was 41A

[dm222]

And since my second pump burned when I started the car like 3 or 4 times in a row thats a possibility

[Breezy_Pete]

That could just be caused by sample timing. To get the vey highest peak  current, the sample would have to be taken at just the right time, and we're only taking two or three per second, so could easily miss the highest value.

Your current/ampere numbers do seem to be generally higher though.

 

I took a couple of logs from her Fabia yesterday, which are similar to the Polo ones, and do illustrate a temperature dependence, the second short log was started with everything fully warmed up.   That may be by design, or it may be just showing that bad connections get even worse when hot?

 

First log plot:

 

 

Second plot, engine fully warm:

 

 

I couldn't measure any similar  (to Polo, or your car) voltage drop in the earth side of the alternator circuit when I measured today, so it must be the positive wire or the alternator itself that is losing some volts when warm on this car.  Positive connection on the alternator on the 1.2 Fabia is a bit hard to get a probe on, so I couldn't really conclude that investigation.

[dm222]

I believe its by design. Maybe temperature related, maybe battery charge related.

The high amps could just be my way of driving or a problem indeed or even the tire pressure.

I will replace the cable and then hope it doesnt happen again, its not in my power unfornatly.

[Updown789]

I imagine that the increase in current flow when warm is due to engine bay temps increasing causing expansion of poor joints which leads to higher resistance. As an experiment, you could try logging with the engine warmed up and bonnet shut, and then after a drive at high rpm but low gear to increase the under bonnet temps and see if this makes the current flow rise?

[dm222]

I been thinking a lot this days and just marked with the garage because I want them to check the cable and also check the G250 because although I don't have any erros now, both times the pump failed it had sensor erros, and now can't get any value on block 0004.3 wich I believe is not normal.

 

These were the errors:

Reference Voltage; Steering Assist 

Short to Ground

 

Power Steering Sensor (G250) 

 Faulty - Intermittent

 

Saw another thread who had the same problem and turned out to be the sensor,

 

Note: Reference Voltage; Steering Assist is precisely block 0004.3

Edited 17 August, 2015 by dm222

[Breezy_Pete]

Can anyone reading this thread who has VCDS please log measuring block 4 of the steering assist module for a few minutes while driving?

Similar to dm222, I don't get anything except "too low" in column 3; but I think that's OK, as neither car currently, or historically has had PAS trouble.

My speculation is that only Koyo systems with completely different, 4 wire sensor see anything in that 3rd column.

[dm222]

When the first pump failed it was "too high"

[dm222]

Left the car at the garage and they told me that they charged the battery the last time the pump was replaced. The week after leaving the garage the steering was really light and got progressible heavier, and got heavier again when I started driving on high rpm so one more point to the possiblity of the alternador.

[dm222]

When I said heavier again I meant ligher again

[dm222]

Just came from garage steering is a lot lighter. They just tight the bolts. Lets hope its solved

[dm222]

And heavier again, I give up :(

[Breezy_Pete]

Don't give up!

 

I'm going to ask this again, in the hope that someone out there in the Internet can spare 5 minutes to investigate the block 4 column 3 question:

 

Can anyone reading this thread who has VCDS please log measuring block 4 of the steering assist module (in chassis tab) for a few minutes while driving?

Similar to dm222, I don't get anything except "too low" in column 3; but I think that's OK, as neither car I've logged currently, or historically has had PAS trouble.

My speculation is that only Koyo systems with completely different, 4 wire sensor see anything in that 3rd column.

 

Maybe I'll start a thread about it in the "Ask a Tech section" too.

 

Remind me which engine code your car has, and how good/bad the access is to the ends of the earth cable between starter and chassis? Photo(s)?

[dm222]

I'm sorry I thought I mention, repaired now I didn't, I have an Ibiza BXW, I'm really confused, this is really affecting me, I asked here because your car uses exacly the same system and I can't find any help anywhere else.

The cable now doesnt have any voltage drop, although I want to replace it. I think I need to change the garage, they always say it's everything good and don't want to replace anything.

They said me today "if there isn't any error then there is no problem". They didn't even knew the car had a sensor...

 

My engine is like this one:

http://i.ytimg.com/vi/LL6SDqQb1-M/maxresdefault.jpg

 

The cable it's like yours, one cable in the edge of the starter motor and goes to the same place in front of the battery, the cable looks good, but the problem, if there is a problem, is inside the plastic case.

 

Really tempted to change the sensor because:

 

 - When the last two pumps failed the first symptom was still power steering but heavier and PAS light on, and then after a while the whole system failed, wich sugests the first thing to stop working was the communication with the sensor.

 

- The second pump had the same light/stiff varition as this one (third), I'm tempted to say that maybe it is the sensor that is burning the pump, causing at first the communication with the sensor inside the pump to burn, and eventually all the system fails.

 

- When the first pump failed at first I went to SEAT and they wanted to replace both the pump and the sensor for 1400€, a lot of money for me and then I went to another garage who only replaced the pump for 950€ (the same garage I went today).

 

- I have a paper that SEAT gave me when they diagnose the first pump, who says "too high" on that particular field, I have an VCDS print screen of the second pump who says "ERROR" on that field, and the thirth pump doesnt' show anything on that field.

 

 - When the second pump was still intermitent, before failing permanently I did some testing, as my car has both G250 ang G85, and I programmed the pump to use the G85 instead and the steering was so much better, so easy to drive, like a different car, but because I don't know the long term impacts of it I changed back to the G250.

 

The errors I scan with VCDS when the second pump failed, sugests sensor wiring fault or sensor fault, already changed the cable from G250 sensor to the pump without results, the paper from SEAT (first pump) also shows the same errors.

2 Faults Found:

01290 - Reference Voltage; Steering Assist 

29-00 - Short to Ground

00816 - Power Steering Sensor (G250) 

37-10 - Faulty - Intermittent

-  http://wiki.ross-tech.com/wiki/index.php/01290

- http://wiki.ross-tech.com/wiki/index.php/00816

 

Edited 20 August, 2015 by dm222

[dm222]

Also I had warped brake rotors in the past wich made my steering to shake a lot, probably not good for the sensor.

Edited 20 August, 2015 by dm222

[Breezy_Pete]

OK, that's interesting. It sounds like the pump unit is going into 'emergency operating mode' where it still gives some assistance, but not full function.

 

So the car still has the G250 that it was built with? But no errors about it in VCDS with the latest pump unit?

No "01290 - Reference Voltage; Steering Assist 29-00 - Short to Ground" error with the latest pump unit?

 

Have you ever 'caught' the steering going heavy while logging with VCDS?  Might be worth trying to get this data if the answer is no.

 

I've looked at the Self Study Programme documents about these systems on Fabia and Polo, and they are slightly different, so maybe it would be worth you registering on erWin Seat and downloading their version (for an hour's downloading it's just 7 Euro + VAT) which may be slightly different again.  In the Fabia one, there is no mention at all of the G85 sensor. In the VW one, it says that G85 is only fitted to cars with ESP, and that when it is fitted, G250 is not fitted... That suggests to me that going back to your arrangement with only G85 in use should be safe.

[dm222]

http://www.partsbase.org/seat/ibiza-st-ib-eu-2009-6j-9-000-001-42330-steering-gear-track-rod-for-vehicles-w-out-electronic-stabilisation-program/

Does the w/out means with/without or just without? I believe the are some cars in the middle who fitted both, using G250 for PAS and G85 for ESP.

No I dont have any errors in the new pump and no light.

Yes I dos logs, the data is similar, no diferente at all.

[dm222]

I just realized it means without, well, that's odd, I'm sure my car has both, I replaced the cable between the pump and the G250 so I'm sure it has that sensor, and my car has ESP. Confirmed with VCDS that I have the steering angle sensor G85 while measuring blocks at the ABS.

[dm222]

Duplicated

Edited 20 August, 2015 by dm222