Hey teeners
ok here is the scoop.new complete rebuild of my 74-2.oL with parts from you guys(thanks) but i am having huge hesitation issues from first to third and not so bad in 4-5th. i have all new vac lines to install except that from my distributor to my throttle body i can't put a line because there is only a blank spot where a line should connect.
Why is this.When i bought this from the club i asked for a 2.0l throttle body and it works well except with this vac line issue.
should i swap this for one with the connection or make the connection myself?
What do the guru's advise.

i only have another 4 weeks tops before i have to put her in storage till next year (come out in may) so i am hoping to remedy this ASAP.
help.
Cheers
andrew in the Soo

tell us your FI part numbers (ECU,MPS, etc) as hesitation can be a lean running condition and not a dizzy issue.

that said, your advance plate could be sticking so pull the dizzy apart and clean clean and lube the underside of the plate so the centrifugal advance works smoothly/

ya don't really need the vac advance

Ditto on what Geoff said. I pulled the vac advance on my 2.0 a long time ago. Need the centrifugal advance though.

Here's a quote from the Bosch "Ignition" technical guide on the purpose of the vacuum advance:
--------------------------------------
"EARLY" (advance) adjustment system

The lower the load, the earlier the air-fuel mixture needs to be ignited since it burns more slowly. The percentage of burned but non-exhausted residual gases in the combustion chamber increases and the mixture becomes leaner.
--------------------------------------

Thought it's not explicitly stated, it appears the function of the advance is to improve efficiency and reduce emissions under steady part-load conditions. I doubt it has any significant effect on throttle response. VW/Porsche removed the system in later 914's. Why? No idea.

Here's a tip - most owners haven't checked the condition of the points plate in their dizzy in years. Often, they're clogged with grit and need cleaning and lubrication for the vacuum adv/ret device to work properly.

As you have stated they deleted the vac adv so the mixture became leaner for emissions.

I have re-installed the vac advance on my Djet setup and it gives you a very slight improvement in on/off throttle low rpm response.

hi All
Sorry took so long to reply
I will get the numbers off my units so i can get more info but what is a dizzy? is that in my distributor or is that on the throttle body?
Also you say i don't need my vac advance? then what do i do to eliminate it and get rid of the hesitation.
Do i just plug all the lines?
I will get numers tonight from my throttle boddy any others i need?
My idle is at 2000rpm and won't come down.
Andrew

I Think you should check for a vac leak. Take some carb cleaner and spray around the base of the manifold and all lines. Listen for a change in RPM. check your fuel pressure. I think its about 32-36 psi needed.

Hey Bley
So i don't need the advance? do i just plug it and keep the green line from the back of the distributor vacuum and plug the front or vise versa?
also my idle is way up there in the 1500 - 2000 range and my idle adjuster is turned all the way down? will eliminating the vac adv. fix this. also my dizzy is fully functional and has been cleaned (that is the parts in the distributor right?)
cheers
andrw

Keep the retard vacuum hose connected to the back of the vac can on the dizzy.

If you don't have a small vac port on the throttle body thats above the throttle plate, just plug the hose for the vac advance.

For your high idle, get some PB Blaster and squirt a bunch of it into the AAR valves two ports. Let it sit and some more as the AAR valve is a rotary valve and it does rust abit and sticks open usually.

Check your timing, should be exactly 27 degrees at BTDC at 3500 rpms

Check your fuel pressure as that is at 29lbs not 32-35 lbs (too rich)

I meant for you to remove the dizzy and take out the advance plates an clean and grease them where they pivot on each other. The old grease drys up and sticks after its 30 yrs old.

hey bley
thanks for the quick reply.ok here are my #trottle body 039 133 067 vw
ECU 0280 000 037 and 022 906 021E
MPS 0280 100 007 and 311 906 051C
the ecu and the mps are from my old 1.7 L (bus engine) that froze up on me so i did the rebuild on the 2.ol with some parts from my 1.7 and bought parts from the club (throttle body)
I blocked off the vac advance and left the vac retard in place like you said.
let me know what you think. I will be on the site on Tuesday.
i will have to check my psi later with help from the mech who installed my engine.
thanks for the help have parts if you need some let me know. for you almost free or even free if we fix this with out me paying 95 bucks an hour for my mech.
Cheers
Andrew in the Soo and the only teener lover with in a 8 hour drive.Sucks to be me all alone up here except for you guys.

You are running a 037 ECU which is from a 73 1.7l or 73 2.0L
You are running a 007 MPS which is from a early 914/411 1.7l and is too lean a AFR.
You should be running a 017 CHT with the ballast resistor (270ohm)


You should locate a 043 ECU (74 2.0l) and a 043 MPS 2.0L for your car.


The hesitation you mention is probably due to the lean mix you are running.

Good analysis, Geoff!

hey geoff
sounds like you know your stuff. I thought there might be an issue with my mix and match parts.
What is the CHT with the ballast resistor? where would i find that on my 2.OL geoff?
Any leeds to who in the club would have these and who might want to trade?
cheers
andrew

CHT = Cylinder Head Temp sensor located by Cylinder #3 plugged into a a plastic connector into the FI wiring harness. IF you have a ballast then there is a black tube like thing inbetween the CHT and the plastic connecor (not likely).

Pull out the CHT to look at the number on it using a deep socket and a 3/8th extension with one corner ground off so the wire pulls thru it. Dont lose the washer!

There are ECU's in the classifeds. The proper MPS is hard to find although I have rebuilt ones from time to time.

You can't mix and match parts in Djet no matter what people say. Its a Myth that you can use any parts together! Well, it will run but not well or right.