Confirmation of 1976 350SE Euro Vacuum Advance Retard

[calvin streeting]

Hi Can some one (maybe another 350SE owner, or anyone), help me confirm the Vacuum Advance Retard tubes

At present, I have a white pipe coming from the front hole on the throtle body and a red pipe that lead to the side (right if leaning of the radiator) of the throtle body.

The reason i ask is that someone gave me part of a jetronic and it had the remlants of a read pipe coming from the throtle body front.


Also i am wondering if i should check the ignition timing as the distrabutor seems to be very advanced. dose this look right.


I am just trying to get this old girl back up an running propley. at present she will hesitate if accelerating when warm. and wonder if someone (PO) tunned it with vacuum pipes around wrong way.

[oscar]

Calvin, is your 350 a k-jetronic or d-jetronic?  Although 76 is k-jet there's always a few anomalies and from your photos I can't 100% be sure it's k-jet.

So, as far as I know for d-jet, mine has the red line, advance, to the front of the throttle body.  White line, retard, goes to vacuum switch on firewall then another white line to the rear of the throttle body. 

Whether it's the same for k-jet I don't know, however, all you have to do is if you've taken off the air filter housing already, take a close look inside the throttle body noting where the vacuum ports open into the throttle body when the butterfly is at rest.  The retard line should come from the port below the butterfly, advance should come from slightly above the butterfly.   In other words, as the butterfly opens the retard port which is otherwise hidden is now revealed, and the advance port now becomes obscured.

I agree, the distributor does look too advanced.  Mine's between there and halfway.

[calvin streeting]

mines a K-jet (must be an early version)

Not sure if i have a vacuum switch on firewall (i think thats a d-jet thing), My has red going to the side and the white to the front.. I think this is wrong 

I got a funny fealing some one has tryed to tune it with vac lines around wrong way... so i going to get my time light out and see what it is (without any vacuum lines), and then try and work out which one is which.

calvin.

I am also going to spend sometime tracing them all, make a drawing and post it here.

also i am wondering if its a early version k-jet were there any tweeks/bits merc did to these over time?

[oscar]

I forgot you can't see the throttle butterfly too well with k-jets due to the air flap.


Anyhow....

My has red going to the side and the white to the front.. I think this is wrong 

I was flicking through the emissions section (14) in my manual and there are a number of variations between k-jets which seem to be purely emissions related with increasing number of inclusions like EGR, air injection, charcoal cannister and so on.  All seem to have white, yellow, or yellow/purple lines regarding retard and all go through a vacuum switch.   All have red as the advance line.  Some go direct from throttle to distributor, some versions tee off to other things.  If anything seems safe to go by it's the throttle picture which appears below.  Not sure if it's definitive for your version and I'm not to sure what to make of the absence of the vacuum switch.  I'm also not sure which way this thing is oriented but I suppose you'll be able to tell what is front and what is side.

This is the online version but mine was a tiny bit simpler.  No mention of EGR, just white to (1) and red to (2) and (3) to charcoal cannister.  Hope it's of some help.



Uploaded with ImageShack.us

[koan]

The retard line should come from the port below the butterfly, advance should come from slightly above the butterfly.   In other words, as the butterfly opens the retard port which is otherwise hidden is now revealed, and the advance port now becomes obscured.

Don't think the retard vacuum supply to the firewall switch connects to the throttle body, it comes off the manifold.

There are three drillings in the throttle body, lowest is distributor vacuum advance, the upper two connect to the carbon canister purge line to give progressive (well two levels) of suck.

koan

 

[calvin streeting]

ok here is a diagram of what is there at present (drawings assembled from EPC diags)


so both the advance and retard come from throttle body  

[TJ 450]

The retard side (to switchover valve) connects onto the contour hose at the auxilliary air valve on later cars. This diagram is unfamiliar to me, but I am aware that there are several configurations.

Do you have a switchover valve on the firewall?

Tim

[calvin streeting]

no I dont have switchover valve

[koan]

so both the advance and retard come from throttle body 

Don't think the retard vacuum supply to the firewall switch connects to the throttle body, it comes off the manifold.

OK, I am ashamed, contrary to what everyone (including my wife) might think this is the first time in my life I have ever been wrong about anything

koan

[calvin streeting]

ok..
So for the record the diagram i drew was "made up" of parts of EPC, drawn as per my car as it stands to date.. (in no way nessesarly correct). once i have it figured out i will draw another and label it correct.

So why am a i looking at this. I have a few issues .
1. the car starts ok (now cold and warm), but after the cold start stops. the idle drops right down, and you sometimes have to nurse it with the peddel to keep it alive
2. after she has warmed up she will run ok. until every now and then she will hesitate while acelerating, or clinbing hill. this will slowly get worse, but if you pull over and relax (for about 5mins), she will be back to normal.

so as you can tell i am just crosing things of the list. so i want to know if how she is "is correct" or if not "correct it"

many thanks.

[oscar]

Well it's a convincing diagram.  I read you were putting one together but didn't realise it would look so ex factory.  With the retard line, I suppose it doesn't really matter if the changeover switch is there or not.  Once the throttle moves, retard stops sucking as advance comes into play.

Anyway, a quick test to get round this business of the retard and advance line.  Disconnect both lines at the distributor.  Have someone else start the engine and you put the hose ends, one on each cheek. Use your fingertips perhaps if it's unsafe to use cheeks (face), I used my tounge but my vac lines are longer in a d-jet and my face was nowhere near fanbelts etc.   So, at idle only one line should be sucking which will be the retard line.  Get your assistant to accelerate a little, the first line should let go and the other line, the advance line, should start sucking.  Arrange hoses back on dizzy depending on findings.

For your two points,a couple of guesses;
1.  Could be a number of things but at first glance I'm guessing your auxillary air valve isn't opening fully.
2.  Could be fuel supply issue, clogged fuel filter type of issue.  But also could be your over advanced ignition.  Are you getting any pinging when you put your foot down after the engine's warmed up?  The warmer the engine is and the more load is put on it by accelerating or going up hill, the greater the chance of detonation as the air/fuel mix burns too soon and you loose power.  Cooling down for 5mins might make increase the threshold for detonation but I'm guessing it wouldn't take too long on a warm day for it to happen again if stressed again through a little bit of heavy duty accelerating or going up a steepish hill.

[calvin streeting]

Anyway, a quick test to get round this business of the retard and advance line.  Disconnect both lines at the distributor.  Have someone else start the engine and you put the hose ends, one on each cheek. Use your fingertips perhaps if it's unsafe to use cheeks (face), I used my tounge but my vac lines are longer in a d-jet and my face was nowhere near fanbelts etc.   So, at idle only one line should be sucking which will be the retard line.  Get your assistant to accelerate a little, the first line should let go and the other line, the advance line, should start sucking.  Arrange hoses back on dizzy depending on findings.

will do this.. as a god simple test

For your two points,a couple of guesses;
1.  Could be a number of things but at first glance I'm guessing your auxillary air valve isn't opening fully.

I did check it but might double check

2.  Could be fuel supply issue, clogged fuel filter type of issue.  But also could be your over advanced ignition.  Are you getting any pinging when you put your foot down after the engine's warmed up?  The warmer the engine is and the more load is put on it by accelerating or going up hill, the greater the chance of detonation as the air/fuel mix burns too soon and you loose power.  Cooling down for 5mins might make increase the threshold for detonation but I'm guessing it wouldn't take too long on a warm day for it to happen again if stressed again through a little bit of heavy duty accelerating or going up a steepish hill.

whats pinging. i was going to test the timming, but my timing light gave one flash and gave up the ghost.. 

[koan]

So for the record the diagram i drew was "made up" of parts of EPC, drawn as per my car as it stands to date.

Well, it fooled me. I now understand it your use of "assembled". It looks like a page lifted straight from the EPC, very convincing, so much so I'd suggest it be labeled prominently as wrong so it won't mislead others who may come across it.

Deleting it altogether would be better.

Is it normal to have a vacuum retard distributor without the firewall change over valve?

koan

[calvin streeting]

ok.. fair point i have added some text to point out it is (not necessarily correct).. I will add one that is correct when i figure out what is correct.. so that anyone in the future can follow the whole story, and find the conclusion (I hate forums that go "fixed", and  dont say how)..

Is it normal to have a vacuum retard distributor without the firewall change over valve?

koan

I had a look on inet and did find another one, but cannot find it again. mine is a 1976, and thus a early k-jet. maybe they added it latter?

calvin

[oscar]

whats pinging. i was going to test the timming, but my timing light gave one flash and gave up the ghost.. 

pinging is pinking is detonation.  All three terms mean the same thing but basically it's fuel igniting too early.   You want it to ignite early so that the flame front from the explosion hits the piston on or just after TDC.  When the explosion of the air/fuel mixture happens too soon the flame front hits the piston whilst it's still rising on the compression stroke.  When it happens it causes a noise similar to a rattle of a nut in an empty tin can and you loose power.  You might not notice it at idle or slow driving.  Like I said before, heat, hard acceleration, ignition too advanced or loading the engine like driving up a hill are condtions that will bring on pinging sooner.  Remedy is to ease the advance on the dizzy to something smaller.