tminihan

It was supposed to be an easy day. My fairly new to me (3mos) 81 was running great but I noticed the green wire connector had crumbled away. So today was supposed to be simple and quick, green wire, rotor, cap. I put at TDC, marked distributor at the clamp. No issues during the replacement. It all went back together fine but ran like crap. So I reviewed threads here and tried to start from square one.
- I set my timing at 23deg at 3000rpm with retard and advance hoses removed from the distro and plugged.
- The retard vacuum reads 20" at idle and drops to zero pretty quick, say 1/8 throttle
- The advance vacuum reads 0" at idle and seems to max out at 5" (note, before I started the day, the advance was connected to the port adjacent to to the retard port on the TB and was 20" at all engine speeds).
- The car seems to stumble around 1000rpm, herky jerky from start until you hit the higher RPMs.

I'll be ordering plug wires and a coil tomorrow but I wanted to get some thoughts on a few things:
- Is 5" max vacuum low for the upper end of vacuum advance? With everything connected, at 3000rpm I only see the 23 mechanical, I don't feel the vacuum advance is contributing but seems to run fine at the higher rpm. I "think" I'm on the right source, pass side, rear of TB
- Anything come to mind related or unrelated regarding the stumble at 1000rpm? The car appears to be original, so every time I breathe on something it breaks, so I've been slowly replacing vacuum lines, hoses, etc.
- The car ran well before I started this morning, with I believe the incorrect vacuum line setup. I did return to the "before" state with the incorrect vacuum lines with no improvement. Although I placed at TDC and marked the distributor, I regret not measuring the timing before I started the work.
- My timing light shows good firing above and below 1000 rpm, in the 1000-1400rpm range, a lot of misses in the light.
Thanks in advance for you input. Tom

Mrmerlin

Hold on there pardner, will you please tell us what brand of green wire you got?

NOTE if its the URO version then the chance is good the engine might run or might not run./
NOTE the new Uro wire connector at the distributor has been improperly molded with the wire leads,
and once the spacer is removed from this connector end,
then wires will be smashed into each other , this can short the wires or damage the pickup coil ion the distributor
why not reinstall the old green wire see if it works

NOTE only use Bosch parts for the electrical system, this includes the Green wire
NOTE if you pulled the distributor up and then the rotor turned then the static timing should be checked first.
put the engine at TDC, verify both cams line up
then remove the cap ,

the rotor should be centered at the hash mark of the distributor

tminihan

Thanks for the quick reply Mr. Merlin. The new wire is the URO brand, I will replace with a Bosch unit. The old green wire connector on the controller side crumbled upon removal - I had to carefully pick the pieces out of the female connector, so it wasn't reusable.
I will try a Bosch unit and if that fails I will pull the upper timing belt covers.
Thanks, Tom

Mrmerlin

a Bosch wire should fix the problem
please note did you have to force the wire connector into the distributor to seat the anchor plate.

NOTE you can install the old green wire for testing just plug the exposed wires into the cleaned out female connector make sue they dont touch.
You will how easy the original connector inserts and seats into the distributor.

Petza914

Is your 81 a us or a Euro and if a Euro a 4.5L or 4.7L S. If you don't know, are your fuel injectors simply mechanical with a fuel line or do they have an electrical connection on them too.

Depending, you may need to raise your timing a bit. I think I'm running 28 degrees advance on my 81 Euro S at 3k rpm and both vacuum hoses removed.

belgiumbarry

i remember that i had to push really hard to get it all the way in the distributor and mount the anchor plate .... (a spare set for the rally car. )
Bought it from Rose Passion.... so must be a URO one i assume.
Tested it and it worked.... now i doubt if reliable.... ?

Mrmerlin

Let’s put it this way if you got a Bosch it will easily slide right in and the alignment slot will be perfectly aligned with the metal anchor plate

Roger is reporting that URO has fixed their wire so that it fits properly

I haven’t seen it yet but that’s what’s been reported
I would get a new version of the URO wire or get a Bosch

tminihan

I don’t recall having any issues seating the connector in the distributor but Roger has a Bosch unit on the way. I did unseat and reseat both ends to make sure nothing was jacked up and I should know by the end of the week if the Bosch wire fixes the problem. I have the US 4.5. Thanks, Tom

tminihan

Ok, today I installed a new Bosch green wire and the car runs great - again. Thanks to all that weighed in!

One lingering issue is the vacuum advance. In my original post I mentioned that during my troubleshooting I noticed that the advance vacuum was coming from the front of the TB and was 20" at all engine RPM. This was the configuration I received the car in and it runs great, starts easy. Having said that, the correct advance should come from the rear port of the TB , which I'm measuring as 0" at idle and 5" from 1/8 throttle and above (unloaded, sitting in the driveway). Right now, the idle timing is about 30 BTC with hoses connected (I didn't measure timing with hoses disconnected). During my troubleshooting last weekend I notice the car seemed to start best around 10 BTC with the hoses removed.

This weekend I plan to investigate more to see if I can get to the correct advance vacuum source so I can put this to rest.

Thanks again for everyone's help, Tom

Mrmerlin

the vacuum lines are not right,
10 BTDC is a good idle setting.

NOTE use the WSM for idle and timing setting.

I think you got a bad Uro green wire,
glad that parts fixed

Billu

The front tb hose goes to vacuum retard, the rear controls vacuum advance

Petza914

OP, and if you're distributor only has a single vacuum port on it (some do and I'm not sure they changed to dual until 83 but could be wrong on the year), that's for vacuum advance, and there is no retard.