Well, my 1993s (240/940) don't have this issue, nor my 1975-244....I'll just keep puttering around, without this issue:-)mrbrian200 wrote: ↑14 Jul 2018, 23:51So the 'cheaper' aftermarket TBs don't even last a full year! ..probably my whole point to this post.
Why do Bosch type throttle bodies fail so often on Volvos? A theory..
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93Regina
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Re: Why do Bosch type throttle bodies fail so often on Volvos? A theory..
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jimmy57
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Bosch throttles have little trouble until they are disconnected.
My personal car is a 2004 V70 R with 250K and never a throttle problem. The throttle has been unbolted and set aside but never unplugged.
The gold plating on the pins is the thinnest plating possible applied to control corrosion on circuits where there is almost zero tolerance for contact resistance. Unplugging it several years on scrapes the plating off.
My personal car is a 2004 V70 R with 250K and never a throttle problem. The throttle has been unbolted and set aside but never unplugged.
The gold plating on the pins is the thinnest plating possible applied to control corrosion on circuits where there is almost zero tolerance for contact resistance. Unplugging it several years on scrapes the plating off.
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mrbrian200
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The plot thickens.
Jimmy57, your 2004 R has been 'well maintained' it's entire life, yes?
Turns out the original TB off the V70 in question was turned over to that mutual friend (who owns a small independent auto parts counter in town). Looks like the replacement TB was a Bosch unit: the original failed TB was in a new looking bosch box part number ending 131. The mutual friend hadn't recycled or disposed of it yet - but squirreled it.
Further inspection: the internal gears (off a car with ~180k miles) showed zero sign of the plastic gear wear that took mine out at less than half the mileage. On this one the TP sensor failed. The sweeps were not physically bad, it was contaminated with dirty engine oil that started getting gummy and interfered with contact.
I'm convinced now that the problem with these are various forms of contamination that get pushed inside under boost conditions. Non plastic safe TB/intake cleaners and possibly some oil additives can soften and take out the plastic gears. PCV gasses (engine oil) can take out the TP sensor. Probably faster on engines that 'aren't well maintained'. For turbo applications these style TBs really needed some sort of seal between the throttle plate and the internals.
My sister's old VW that used this basic design-style Bosch TB, was clean, dry and still like new inside at 180k. However that car was naturally aspirated, PCV gasses were introduced strictly after the throttle plate. No boost. To my knowledge no 'throttle body cleaning' was ever deemed necessary/ever performed.
Jimmy57, your 2004 R has been 'well maintained' it's entire life, yes?
Turns out the original TB off the V70 in question was turned over to that mutual friend (who owns a small independent auto parts counter in town). Looks like the replacement TB was a Bosch unit: the original failed TB was in a new looking bosch box part number ending 131. The mutual friend hadn't recycled or disposed of it yet - but squirreled it.
Further inspection: the internal gears (off a car with ~180k miles) showed zero sign of the plastic gear wear that took mine out at less than half the mileage. On this one the TP sensor failed. The sweeps were not physically bad, it was contaminated with dirty engine oil that started getting gummy and interfered with contact.
I'm convinced now that the problem with these are various forms of contamination that get pushed inside under boost conditions. Non plastic safe TB/intake cleaners and possibly some oil additives can soften and take out the plastic gears. PCV gasses (engine oil) can take out the TP sensor. Probably faster on engines that 'aren't well maintained'. For turbo applications these style TBs really needed some sort of seal between the throttle plate and the internals.
My sister's old VW that used this basic design-style Bosch TB, was clean, dry and still like new inside at 180k. However that car was naturally aspirated, PCV gasses were introduced strictly after the throttle plate. No boost. To my knowledge no 'throttle body cleaning' was ever deemed necessary/ever performed.
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mrbrian200
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Did a little experimenting with the throttle body off that V70. Plugged it in to the vehicle harness on my car as such:
The mechanical pots are happiest when they stay clean and dry. I opened/reassembled it several times experimenting with several substances including engine oil dielectric grease.. Spray the rotating sweeps with MAF cleaner, wipe off the resistive pads with cotton soaked in same and bam! Sweep test looks like a new one:
I played with the throttle pedal and 'tested' it for over half an hour while watching Vida. I think it can go back on that V70. I'll check the harness/connector on it. I don't have problems with that not staying seated on mine. But I put bulb grease in there so that the weather pack seal doesn't get caught up and prevent the connector from fully seating. Unless you broke the locking tabs that's probably all most people need to do. A squirt of silicone grease that doesn't cause an issue vs a $40 pigtail plus the trouble of snorting into bay harness...I'll take silicone grease for 10 cents please.
Edit. I wasn't going to mention this because it sounds crazy. But a recent new topic viewtopic.php?f=25&t=86003 got me thinking about it enough that I'm deciding to put it out there. During one of the 'substance' experiments earlier today, specifically bulb/silicone grease which had a similar consistency to the gummy engine oil that originally fouled the TPS, along with DTCs for the TB/TPS and 'reduced engine performance' displayed on the DIM at KPII, a persistent active DTC for the brake pedal position sensor (out of range) popped up. Very persistent: through key off cycles and also after clearing with VIDA it came right back. I have not had any recent issues with the pedal sensor. That pedal sensor fault went away after I cleared the grease out of the TPS contacts, reconnected the TB and continued my experiments. There is a chance that the pedal sensor is about to go bad and it was just a coincidence. I drove the car a couple times later in the day, cruise worked fine like it always does. I use it a lot. No system warnings..nothing.
- TBPic.JPG (44.9 KiB) Viewed 512 times
Edit. I wasn't going to mention this because it sounds crazy. But a recent new topic viewtopic.php?f=25&t=86003 got me thinking about it enough that I'm deciding to put it out there. During one of the 'substance' experiments earlier today, specifically bulb/silicone grease which had a similar consistency to the gummy engine oil that originally fouled the TPS, along with DTCs for the TB/TPS and 'reduced engine performance' displayed on the DIM at KPII, a persistent active DTC for the brake pedal position sensor (out of range) popped up. Very persistent: through key off cycles and also after clearing with VIDA it came right back. I have not had any recent issues with the pedal sensor. That pedal sensor fault went away after I cleared the grease out of the TPS contacts, reconnected the TB and continued my experiments. There is a chance that the pedal sensor is about to go bad and it was just a coincidence. I drove the car a couple times later in the day, cruise worked fine like it always does. I use it a lot. No system warnings..nothing.