Re: Zel's Fleet Blog...Citroen, Mercedes, Sinclair & AC Model 70
Posted: Sun Mar 20, 2022 10:13 pm
Time to do a bit more investigation into the EGR system issue we've been having with the Caddy.
A friend came over with a half decent diagnostic tool a while ago and we confirmed that there were two codes stored.
01283 - Motor for intake manifold flap (V157) - Sporadic - Open/short circuit to ground.
Also P1441 - EGR Valve (N18) Open circuit or short to ground...but that's because I have unplugged it as the system is plainly misbehaving at the moment. So that code is expected.
Not expecting it to make any difference but it seemed worth cleaning up the intake manifold throttle valve which I'm assuming is something to do with the EGR system as I can't see why else you would have a throttle on the intake path on a diesel. Well other than the flapper on the old Detroit 2-strokes - but that was an emergency stop feature rather than something used in normal day to day operation.
If anyone knows these SDI engines inside out I'd be curious to know what the theory of operation for this and the whole EGR etc is. I've virtually zero experience with diesels involving any real level of electronic control and even less with direct injection systems...so I'm interested to learn.
The one thing I do know though is that diesel EGR systems make a horrible mess...like this.

Intake manifold itself looks somewhat grim too compared to what I'm used to, but to be honest isn't that bad - I've seen cars where there's like a half inch thick crust on all sides.

I will probably pull this at some point and give it a thorough clean as I want to give the top of the engine a good clean and the inlet manifold is kind of in the way.
I noticed when pulling the throttle assembly that it rather conspicuously rattles which is rarely a good sign.
I wouldn't really call it clean but it's a whole lot better than it was.

Unsurprisingly absolutely no different. The once-per-second engine speed "twitch" is back, and huge clouds of unburned diesel out the back on light throttle.

Until I unplug the EGR solenoid, at which point it goes into whatever fallback mode it has, just leaves that intake throttle open and idles smoothly and stops smoking.
Given that we have a definite fault code stored for this assembly I think it's the first thing we need to try to sort. One other reason I pulled it out was to find a part number, helpfully stamped on the front...but I completely missed and thought it was underneath. Derp.

A quick look at the internet did turn up a few immediately matches.

Ouch.
A bit further digging turned up a (supposedly) good used one for £30. We'll try that first I think. If that doesn't at least change the behaviour a bit of further digging will be needed. This may end up being a "get a specialist involved" job at that point, though at least VWs are reasonably well catered for in that department.
For now the EGR solenoid has been unplugged again to eliminate the James Bond style smoke screen - though obviously that's not a long term solution and I'm not a fan of running like that anyway.
One of the very first thing that happens to virtually every car to arrive on my driveway is a decent clean...the poor Caddy was washed for the first time since I got it this afternoon, two and a half months and nearly 3000 miles in. I feel guilty!



Getting a bit of paint on the wheels and the front bumper will make a big difference I reckon.
I don't think areas like the door shuts had ever been cleaned since the day it left the factory. Still needs properly wiped down in there, but looks a lot better.



There's a lot of light scratches in the paint all over, but I'm not too bothered about that given my intention once the few rusty bits have been attended to I'd like to get it either wrapped or painted anyway. The Harlequin idea is still my favourite. I'm still really quite liking the little van too so that's still very much on the cards.
This was the first real test for the new pressure washer.

I really wish I'd bought this thing about 15 years sooner. So, so much better than the cheap electric ones. Aside from the power available from an 8hp petrol engine, just having 20 odd metres of hose to work with makes life so much easier. Also doesn't matter if the odd bit of spray goes towards it, I don't have to worry about extension cables getting wet and our overly twitchy RCD plunging half the house into darkness.
The onboard detergent tank is definitely on the list of things you don't need but is really nice to have too. Especially if cleaning something the size of the camper where just drowning the whole thing in snowfoam is basically step one after a rinse.
I'm glad to report that having blasted a substantial amount of moss and organic slime out of the seal between the windscreen pillar and driver's door closure that the annoying whistling noise at speed from that general area has vanished. Wish I'd done that *before* driving all the way to Glasgow and back...
A friend came over with a half decent diagnostic tool a while ago and we confirmed that there were two codes stored.
01283 - Motor for intake manifold flap (V157) - Sporadic - Open/short circuit to ground.
Also P1441 - EGR Valve (N18) Open circuit or short to ground...but that's because I have unplugged it as the system is plainly misbehaving at the moment. So that code is expected.
Not expecting it to make any difference but it seemed worth cleaning up the intake manifold throttle valve which I'm assuming is something to do with the EGR system as I can't see why else you would have a throttle on the intake path on a diesel. Well other than the flapper on the old Detroit 2-strokes - but that was an emergency stop feature rather than something used in normal day to day operation.
If anyone knows these SDI engines inside out I'd be curious to know what the theory of operation for this and the whole EGR etc is. I've virtually zero experience with diesels involving any real level of electronic control and even less with direct injection systems...so I'm interested to learn.
The one thing I do know though is that diesel EGR systems make a horrible mess...like this.

Intake manifold itself looks somewhat grim too compared to what I'm used to, but to be honest isn't that bad - I've seen cars where there's like a half inch thick crust on all sides.

I will probably pull this at some point and give it a thorough clean as I want to give the top of the engine a good clean and the inlet manifold is kind of in the way.
I noticed when pulling the throttle assembly that it rather conspicuously rattles which is rarely a good sign.
I wouldn't really call it clean but it's a whole lot better than it was.

Unsurprisingly absolutely no different. The once-per-second engine speed "twitch" is back, and huge clouds of unburned diesel out the back on light throttle.

Until I unplug the EGR solenoid, at which point it goes into whatever fallback mode it has, just leaves that intake throttle open and idles smoothly and stops smoking.
Given that we have a definite fault code stored for this assembly I think it's the first thing we need to try to sort. One other reason I pulled it out was to find a part number, helpfully stamped on the front...but I completely missed and thought it was underneath. Derp.

A quick look at the internet did turn up a few immediately matches.

Ouch.
A bit further digging turned up a (supposedly) good used one for £30. We'll try that first I think. If that doesn't at least change the behaviour a bit of further digging will be needed. This may end up being a "get a specialist involved" job at that point, though at least VWs are reasonably well catered for in that department.
For now the EGR solenoid has been unplugged again to eliminate the James Bond style smoke screen - though obviously that's not a long term solution and I'm not a fan of running like that anyway.
One of the very first thing that happens to virtually every car to arrive on my driveway is a decent clean...the poor Caddy was washed for the first time since I got it this afternoon, two and a half months and nearly 3000 miles in. I feel guilty!



Getting a bit of paint on the wheels and the front bumper will make a big difference I reckon.
I don't think areas like the door shuts had ever been cleaned since the day it left the factory. Still needs properly wiped down in there, but looks a lot better.



There's a lot of light scratches in the paint all over, but I'm not too bothered about that given my intention once the few rusty bits have been attended to I'd like to get it either wrapped or painted anyway. The Harlequin idea is still my favourite. I'm still really quite liking the little van too so that's still very much on the cards.
This was the first real test for the new pressure washer.

I really wish I'd bought this thing about 15 years sooner. So, so much better than the cheap electric ones. Aside from the power available from an 8hp petrol engine, just having 20 odd metres of hose to work with makes life so much easier. Also doesn't matter if the odd bit of spray goes towards it, I don't have to worry about extension cables getting wet and our overly twitchy RCD plunging half the house into darkness.
The onboard detergent tank is definitely on the list of things you don't need but is really nice to have too. Especially if cleaning something the size of the camper where just drowning the whole thing in snowfoam is basically step one after a rinse.
I'm glad to report that having blasted a substantial amount of moss and organic slime out of the seal between the windscreen pillar and driver's door closure that the annoying whistling noise at speed from that general area has vanished. Wish I'd done that *before* driving all the way to Glasgow and back...









































































