Hi All

Still having issues with my 1984 M28/22 4.7L ROW. One day I would like to drive it (I have owned it 9 1/2 years so far)

Idles when cold @ 2000rpm
I have replaced the throttle switch (same Bosch part number but from a Volvo 240) as the old switch, when removed was open circuit throughout all travel on idle speed contact. (Full load contact tested out ok)
The replacement switch only switches to 0.1 ohms when rotated past the mounting screws, so is always open circuit.
Could this be due to the spindle in the throttle body not fully closing thus giving me a high idle as well as the switch not being able to be set correctly ?
I have purchased a smoke machine and found a split in a hose to the splitter under the wheel arch for the carbon canister and that brought the idle down from 2500 ish rpm to 2000rpm.
The MAF has been rebuilt by Andre along with the LH being tested.
Throttle cable disconnected to make sure that wasn't the cause, throttle screw is wound in tight and still idles @ 2000rpm. I am thinking that the throttle is somehow jammed open, which would make sense giving the high rpm and throttle switch not switching on when throttle is at idle.
Is there a stop which I should be adjusting so the spindle on the throttle switch rotates round further say 3-4mm in order to mount the switch in the on position. ?
Thanks for any advise again
Glen

 

Am not an emission controls expert but shouldn't there be a vac operated checkvalve and an actuation valve that would prevent carbon canister from seeing pressure during a smoke test? Maybe the diaphragm in one or both of those valves is compromised? And or, if the check valve isnt closing when blowing in smoke, then smoke would enter carbon canister thru the collection hose.

Suck on the vac port on those two valves to see if they hold. Blow into the checkvalve via collection tube to see if it closes.

This is top of mind since I did it 2 days ago hunting hi idle on 85.

The way I see it, cracked hose near carbon canister isnt a cause but above actuators could be. If fixed hose now ensures that gas scavenging has to pull thru canister again it seems that extra restriction could have helped but not solved.

Actuator valve that on 85 clamps to x brace is stupid money according to roger. I think it is same setup on 84 16v. Seems 951 shares same actuator nd same checkvalve, so look towards 951 or 944 for parts if needed. My replacements for both on sunday came from a pile of 951 parts.

Yours is ROW so I'm not sure how it was federalized and what parts were used where. Could be missing parts.

Does 16v ROW use two limit switches or one combo tps switch on throttle body like 32 v?
Either way, setups are in various wsm or CD troubleshooting supplemental procedures. I can hunt them down if necessary to help you.

I have had throttle springs hang up on 84 USA due to corrosion from mice. Had one hang wide open once during road test.

Sorry not remember how S2 throttle adj is setup, maybe others can help

 

I have the one switch (Bosch 0 280 120 308) which does both idle & full load via three wires)

The smoke was coming from a split hose to tee before the charcoal canister, but I will see if valve holds a vacuum.

Thanks

 

Ok, if euro has single switch, setup is similar to 32v car. Two screws, slotted, so rotate such that you hear audible click with slight movement of throttle.
Linkage has to be free to return to close switch.
On 85 86 32v car there is a harness from the sensor to a test plug, but I don't remember seeing that on euro 84. With test plug one can check for whether switch is closed for idle, open, or switched to WOT.

My 86 is clicking when cold, but when hot the throttle isnt returning far enough to click the switch it seems.

Sorry I don't know more about your setup to help.

 

If you manually pull the throttle butterfly does it close further than it does on its own and bring the idle down further?

Mine was hanging so I put a helper closer spring on it to close it with more force and that resolved my issue, but my setup is different as it's a 79.

 

Found the fault and it was my fault.
When I sent the MAF away to Andre I must of stuffed a rag down the air intake & forgot to remove before reinstalling the MAF as when I accessed the throttle body there was a rag caught in there stopping the throttle from fully closing and stopping the switch from switch on.
Thanks again for kind peoples input, this really is an invaluable site for knowledge as much as inspiration and to reaffirm interest on a project.

Glen

Now what else will go wrong ? As I have owned it nearly 10 years and spent >$13k on the engine alone so far (many many wrong turns)

 

To err is human to forgive is divine - now forgive your dumbness!

We all have our favourite stories about the dumb things we have done. Remember working on a friend's motorcycle engine some 45 years ago. I was tightening the head down and felt something was not quite right- took a careful look and found a washer on the stud trapped between the barrel and the head. Sh*t happens- it knows no boundaries be they geographic, political or religious.