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D2 - Fuel and Exhausts Everything to do with getting fuel into the engine, and fumes back out again |
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#1
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Advice needed passenger side exhaust downpipe.
Hi All,
Newbie advice required. Currently removed the nearside manifold (bit of a PITA) but have left the downpipe in situ. Yes I have probably attacked this arse about face but it seemed logical to me at the time . I found that there must have been a previous removal and replacement as the gasket is split and some seal has been applied. All removed, cleaned and a new gasket ordered. That should alleviate the blow from the exhaust. Now being the curious type I thought I would send my camera into the downpipe to have a look at the CAT internals. Now I am pretty sure it is a cat as the coding underneath says its a CAT (I googled it) but my camera just went sailing right through - Its empty!! Is that right? Funnily enough I remember a rattling coming from this side of the engine a while back, and then it disappeared.... So, I am assuming the downpipe will need to come out - will help with the F125 later....... Question: 1: On the downpipe I find two O2 sensors (lucky me) and can locate the connector affixed to the bulkhead for the pre-cat sensor, but Im struggling to locate the rear connector. I am looking at the tight tangled mess of pipework in the way and thinking why did I start this Can anyone advise where to spot the rear sensor connector? I am thinking once found to run some string through connected to the cables, as I have no other method of re-routing upon replacement? Otherwise, is it a good idea just to unbolt the sensors from the exhaust, leave them in the car and take said exhaust away?
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Paul Gosport UK ________________________ Audi S8 2002 FE Avus Silver / Extended Red Leather. Daily Driver: BMW 3 series GT - Just more practical for my camping trips! |
#2
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If thats an AMX then yes there should be something in that can. I guess the rattling was the matrix disintegrating and going out of the tailpipe. Does yours have cats under the gearbox too? Someone has hacked about with mine and it just has pipes where the V8 has cats, but I can't remember whether the 2.8 is supposed to have a second set as I don't see them very often. It may have just been someone changing the flexi pipes.
The connectors for the secondary O2 sensors are underneath the trim panel behind the airbox. Interesting that yours has a heat shield between the cat and gearbox cooling pipes. Mine doesn't have that. |
#3
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Behind air box, right I will go hunting tomorrow for that. Many thanks
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Paul Gosport UK ________________________ Audi S8 2002 FE Avus Silver / Extended Red Leather. Daily Driver: BMW 3 series GT - Just more practical for my camping trips! Last edited by strummagnet; 13th June 2020 at 05:12 PM. |
#4
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Mm I thought mine should have cats there too. No wonder it just barely passed the MoT emissions test Odd that it has the post-cat sensors after the pre-cats rather than the main ones though.
You may find the remains of your missing cat jammed in the front of the lower one, unless it made its escape before you had that done. |
#5
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Guessing it is prudent to do the other side as well..
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Paul Gosport UK ________________________ Audi S8 2002 FE Avus Silver / Extended Red Leather. Daily Driver: BMW 3 series GT - Just more practical for my camping trips! |
#6
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Quote:
The postal route would involve cutting the cables to the existing sensors, removing downpipe, source new downpipe and source new sensors. I have had a look online and prices vary for the sensors so advice welcome on this course of action as well. As always, many thanks for your input.
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Paul Gosport UK ________________________ Audi S8 2002 FE Avus Silver / Extended Red Leather. Daily Driver: BMW 3 series GT - Just more practical for my camping trips! |
#7
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It would be a shame to cut the wires to good sensors. You may be able to fish it out from underneath?
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#8
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Now the original part numbers on the sensors are: NS Exhaust Lambda Sensor parts: Pre CAT:078906265M - approx 500mm cable length Post CAT:078906265R - approx 1600mm cable length I cannot seem to find an exact match, maybe there is not one anymore? I have been offered BOSCH Equivalent 0258010073 to suit pre and post positions. Can you advise this is the best course of action / component?
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Paul Gosport UK ________________________ Audi S8 2002 FE Avus Silver / Extended Red Leather. Daily Driver: BMW 3 series GT - Just more practical for my camping trips! |
#9
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Interesting seeing the difference between the years. The pre cat sensor is in the same place my ACK engine (bit fiddly to untangle but I managed to winkle it out) but mine is a lower (older) emission standard so I don’t have an after cat sensor. The cat looks quite different, I only have a small resonator box and flexible pipe at the manifold flange and a bigger single cat after the gear box. However for my ten penneth, the U bolts on the cat to main pipe joint are utterly useless at sealing those pipes. They’d been on mine for ages and every few months they’d leak and need new sealant and tightening back up and we’re frankly nothing but a PITA. I replaced them with a constricting band type like originally fitted (significantly more expensive than u bolts) and they make a much better seal. Worth every penny to save me having to crawl underneath with 13mm spanner’s and a tube of exhaust sealant! But looking at your pictures that could be because the down pipe has no supporting mount (like yours has after the cat) and a flexible pipe at the manifold joint so it moves more and pulls the pipe joint.
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PF late '97 D2 2.8 Aluminium Silver. Solar roof, Full Heated Leather, Double Glazing, 17" wheels, Sports Steering Wheel, Cruise, Blinds, Bose sound. Fiat Tipo diseasel econobox with all the buttons and none of the soul that now does all the heavy lifting. Ford Capri Laser: noisy, slow, thirsty, bouncy, no buttons but it always sounds like it’s REALLY trying and I can’t help but chuckle when it parps and boings along. And people of a certain age stare at it with a wistful look in their eyes that clearly says…I had one of them. And I sold it because of the kids |
#10
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That appears to have a 1700mm cable, but looks like a standard 4-pin connector so it ought to work in both positions. You'll just need to tie up the extra 1200mm for the pre-cat sensors.
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