Alfa Romeo Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
160 Posts
Discussion Starter #1
1) If the EGR has been mapped out, does the throttle body therefore need to be taken off and cleaned?

2) What does the throttle body actually do?

3) Worthwhile also fitting an EGR blanking plate? (Sometimes I get the stutter hesitation around 200rpm)


Have so far taken off the MAP, MAF and cleaned them with MAP cleaner. Taken off the electrical plugs and given them a good clean too with electrical contact cleaner. Sprayed the bearings of the swirl valves with WD40.

4) Any other sensor need a good clean too?
 

·
Registered
Joined
·
4,802 Posts
1) If the EGR has been mapped out, does the throttle body therefore need to be taken off and cleaned?



2) What does the throttle body actually do?



3) Worthwhile also fitting an EGR blanking plate? (Sometimes I get the stutter hesitation around 200rpm)





Have so far taken off the MAP, MAF and cleaned them with MAP cleaner. Taken off the electrical plugs and given them a good clean too with electrical contact cleaner. Sprayed the bearings of the swirl valves with WD40.



4) Any other sensor need a good clean too?
1. Yes I'd give it a good clean, shouldn't need to again, but it will be covered in gunk
2. Not 100% but it seems to control the air coming into the manifold, I've seen images and it can severely restrict this
3. Yes, loads of stories of leaky EGR valves
4. Not as such, I sprayed EGR cleaner into the manifold and ran the engine, a fair bit of smoke came out after, obviously loosened some of the gunk. You may also consider fitting a oil catch can.







Sent from AutoGuide.com Free App[/color
 

·
Registered
Joined
·
2,028 Posts
It would be best to remove the inlet manifold, give it a thorough internal clean (throttle body alone won't do a lot - inlet tracts get obstructed with oily soot too), remove the swirl valves completely and blank the holes, then block off the EGR completely. That lot will remove a whole bunch of common, recurrent problems and potential for future trouble. And it'll run better.
 

·
Registered
Joined
·
160 Posts
Discussion Starter #4
The EGR would be mapped out to be in the closed position. And the Stage 3 map takes out all of the other engine fault codes. However, the EGR could be stuck slightly open on remapping. Supposedly the soot and stuff would close the EGR eventually. But is closing the EGR closing the throttle body or does the throttle body play an important function seperate tot he the EGR?

The remapping, modifies the swirl valve parameters. I thought the swirl valves play a good role in mixing the air/fuel. Besides I like their sound of whooshing. I am not keen to take the inlet manifold right now.

Anyhow took the car for a good blast and any hint of stuttering (which was only occasional in the first place) did not show its ugly head. Fingers crossed.
 

·
Registered
Joined
·
2,028 Posts
As far as I know the throttle body is only used to generate inlet vacuum while the EGR valve is open, so that exhaust fumes pass into the engine rather than the rest of the induction system. So with no EGR, the butterfly is pointless. But carbon/oil gum build-up in the throttle body and inlet restricts the overall breathing ability and limits power. ISTM a bit contradictory to map the engine to produce more power without ensuring it can breathe properly first.
 

·
Registered
Joined
·
701 Posts
Throttle body/valve, should/could also be there to avoid a run-away condition where the engine eats its own oil (Due to too much oil or diesel in engineoil due to regens). Only way to stop such a condition is to block the inlet, although im not 100% sure the valve is strong & tight enough to protect the engine this way.
 

·
Registered
Joined
·
160 Posts
Discussion Starter #7
As far as I know the throttle body is only used to generate inlet vacuum while the EGR valve is open, so that exhaust fumes pass into the engine rather than the rest of the induction system. So with no EGR, the butterfly is pointless. But carbon/oil gum build-up in the throttle body and inlet restricts the overall breathing ability and limits power. ISTM a bit contradictory to map the engine to produce more power without ensuring it can breathe properly first.
A stage 4 remap delete of dpf cost around 830 Pounds in Oz. You can say around the same for a proper clean of the inlet.
 

·
Registered
Joined
·
4,802 Posts

·
Registered
Joined
·
2,028 Posts
830 quid to remove and clean an inlet? It's not a fun job, but that's extortion. If I had to do it again now, I reckon I'd have it off within 2.5hrs, take about an hour to clean it (petrol, brake cleaner or acetone work well on the black filth, kerosene doesn't), 2hr to put it back. That was the 'plastic' Magneti Marelli manifold on a 4cyl, the Pierburg inlet on a 5 would take a bit longer. Still easily do-able in a day. A pro would be faster.

Although combining it with a cambelt change is a good idea, there's no need to disturb the cambelt as the HP fuel pump pulley can be bolted to its support bracket, holding the belt in place and tensioned, whilst the pump is removed. At least on the 4, it can, but I'd expect the same on the 5.
 
1 - 10 of 10 Posts
Top