coupe quattro running issues after welding...

Started by slowburn, November 21, 2018, 09:29:01 AM

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slowburn

i had an exhaust leak,i foolishly took it to a local workshop and they welded the exhaust up for me,but not all the way around....they couldn't get to the top of it as they left it on the car. i don't know anything much about welding but you are supposed to disconnect the battery eh? anyways,i watched them weld the exhaust and with the car running so they could find the leaks easier>? also one of the mechanics noticed the banjo on the fuel pump was weeping slightly and he tightened it up. when i drove the car back to work it was barely able to be driven and was stuttering on acceleration ,if you gently increase speed its fine,but if you give it anything it bogs down,badly....i am not gonna bother taking it back to them as they are neanderthals and i shouldn't have gone there in the first place. they've fried something,any ideas as to what? she's been running like a champ for years now and i don't know what they could have done.... waiting to hear back from powerhaus so they can take a look at her.....kicking myself.....all i wanted was the exhaust leak welded up...would have been happy for the exhaust to come off and be welded off the car....fml
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

Trofeo

Is it possible they've turned the bolt on the fuel pump far enough to restrict flow? Symptoms sound like lack of fuel. Some need to be correctly aligned. Not sure on your particular car if this is the case.
2015 Amarok 4WD auto
2018 Golf R-Line Tsi

slowburn

that could be part of it as i did slacken the bolt back a touch on the banjo and it was better...the line between weeping and dangerous and running right must be so small
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

slowburn

http://audifans.com/mirror/www.isham-research.co.uk/quattro/torque.html

found some torque settings in this table that might be relatable?
10NMs? on the fuel pump fittings....worth a crack....
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon


slowburn

its not that bad....but thanks for your advice  :P
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

90_B2 Quattro

The weeping could be from a worn copper washer on the banjo fittings?
If over tightened it could close the orifice of the pump up enough that it would starve it of fuel?

slowburn

ah,this sounds likely....thanks 90,that will be my first port of call,because he didn't do much and it went from being perfect and running strong to completely damned...i think the electrics are fine
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

user2154

#8
Yes you need to replace the crush washers, they deform to seal when tightened and cannot be reused 'generally'.

That is the obvious place to start before you start replacing sensors, but it sounds like you are on to it.

Then I would start checking alternator voltage, voltage at fuel pump, fuel pump wiring, inspect fuel hoses, test fuel pressure regulator, change fuel filter... down the slippery slope..

Just a stab in the dark but did they ground the welder to the exhaust or somewhere else?

Audi do

Quote from: user2154 on November 25, 2018, 10:17:19 AM
Yes you need to replace the crush washers, they deform to seal when tightened and cannot be reused 'generally'.



You can reuse them, you can also re anneal them, heat them to red hot and let cool. I have done so in the past when I haven't got the size I needed in my copper washer kits.

slowburn

yup, they grounded to the exhaust, close to where the down pipe meets the rest of it. I think it will be the washer, its been running like a champ for a few years now with zero problems. sounds like a tractor on roids at the moment. will get the whole exhaust dropped and fixed properly. and then work out the washer and perhaps the voltage at the pump. everything electrics wise is working as per normal.... but correct voltage for the pump and the kjet to work correctly are crucial. hoping its just the washer, feeling better about it to be honest as its a familiar problem from a few years back that was remedied by servicing the areas you mentioned in your post. I think the guy just yanked the fitting too hard and messed up the line.

thanks for your suggestions....why do you ask about the welders grounding? I know nothing about welding ...yet
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

user2154

Sounding like a tractor on roids is a good indication that you still have an exhaust leak. If so it should get louder as RPM increases.

Just wondering about the welding as you don't want the current going through any sensitive electrical components. But it sounds like they grounded it right. I don't know anything about welding, just what I read online.

slowburn

got it fixed properly,also the engine/fuel problem has disappeared(for now).....have a list of things,new subframe bushes in the rear. some wiring to tidy up.
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

RobClubley

Good news!

I have a pair of brand new front lower ball joints for you too.
1985 ur quattro
1992 Ford Courier - the sensible daily

slowburn

you rule.......and the fueling problem is back....is sweet until it warms up and after a while if you apply more gas it stutters,is all good if you slowly add the gas ...but alas is just gonna be "fun" for christmas.....like clock work....
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

90_B2 Quattro

Oooh it sounds very similar to the issue I had on my last 90q.
It was a sick injector and the injector seals were toast.
Could be worth a check.

slowburn

thanks for the tip,i'll add it to the list of maybes....how's your hunt going for a replacement whip?
or are you fixing the 90?
99 B5 S4 Avant
85 coupe quattro
72 fiat 124 coupe
97 corolla wagon

90_B2 Quattro

I've got an '88 b3 90 quattro that's pretty mint but needs some suspension work and some cosmetic paint work. But it's going well.
Blue one is on hold until mid next year,  I'm not giving up on it, although I'd like to reshell it of possible.