i need a pic of the EST connector for a carburetor 305 engine LG4 (all i could find is for TPI). i wantd to check the timing on my car but i noticed a green connector sticking out of my main harness right in front of my blower motor and i have a feeling that is my connector. if that is the case my connector is not connected and the ECM timing is bypassed, i cannot find the other end of the connector either

would the timing bypassed would the ECM throw a code?

 

Large cap distributor? Pretty sure you unplug the 4pin connector.

 

this is what my distributor looks like IDK what a large cap one looks like. its got 3 wires coming out of it

 

What Drew said, connector is at the distributor. The green connector is likely for the MCS dwell. And yes, code 42 will get set with the EST/BYPASS open on a running engine.

RBob.

 

i figured pics would do better justice then me trying to describe.

first pic shows the connector in question. it comes out of the main harness right before it leaves engine bay into the fender. the female part of the connector is gone

second pic show the distributor i have. there is actually 2 connectors on this distributor, one has 3 wires that go to bottom of distributor, other connector has 2 wires that look like they go behind the distributor. im not sure what type of distributor this is besides a HEI. that cap is quite large though and has the coil mounted on top

 

There is a four wire connector to that distributor that goes into the base, will be behind the dist a shown in the photo.

The green connector is a diagnostic lead for reading the dwell of the mixture control solenoid. The dwell meter would connect to it when adjusting the carb.

 

FYI

your carb has been tinkered with. the tamper proof covers have been removed and the idle mixture screws do not look correct for that model carb. the idle bump solenoid has also been removed.

if you're not getting 20+ mpg you may benefit from a dwell check to ensure everything is calibrated.

 

its a replacement carburetor from National Carburetor so those caps were never on the carb.

i was the one who turned those screws but that pic was taken when i first got the car i turned the screws all the way in then 3 turns out. i do not have a pic of the carburetor after i replaced the MCS and carb adjustments

where is the idle bump solenoid supposed to go? the car runs pretty decent right now after i replaced the MCS and the CTS seen in my "oxygen sensor" thread

update: i found where its supposed to go, but i read its used to increase idle speed when you turn ac on. my ac does not work, in fact the compressor, accumulator, and hoses are gone. do i still need this solenoid?

 

Throttle BUMP solenoid would mount where the 2 TORX bolts are shown at the driver front of the carb. No Need for it unless you're still running AC.

 

http://performancedistributors.com/p...-distributors/

Yours is like the one on the left.

To "set" the "timing", you are supposed to disconnect that 4-wire connector that's shown in the foreground. In reality, it comes out of the bottom of the base, at the rear; and plugs into a similar plug that breaks out of the big harness that goes over the top of the bell housing. It's usually laying behind the back of the motor behind and under the dist between the top of the trans and the trans tunnel.

Yes it will throw a code when you unplug it. After which, the engine will run like crap for the next 50 run cycles, unless you disconnect the battery to clear it.

But all of that is a total waste of time. Adjust it to where it runs the best and move on.

The green connector near the blower motor is a convenient point to check the mixture control solenoid duty cycle, using a dwell meter. There is not and never was a "female part" for it.

 

OH, now I learn this after poking straight pins directly into the MCS wires.

 

Shoulda asked...

Been awhile since I was last in Meriden. I've been in New Haven, Trumbull, Stamford, Torrington, and some other places up there in the last coupla months though. Used to go there sometimes when I had to work at ESPN.

 

Shoulda asked...

I could not ask 20 years ago. The internet was in it's infancy and I'm sure this forum did not exist.

 

I've been on it off and on since the late 90s sometime... there's a buncha folks here that know ahelluvalot more than me that have been here longer...

 

There's a thread here somewhere in the past where Damon reported that the dwell readings taken directly from probing the mcs wires were reversed-in that increased dwell at the mcs connector was shown as decreased dwell at the diagnostic lead. Not really an issue in setting dwell, the turns on the IAB were just the other direction.

never tried it myself.

 

Naf:

That depends on how your particular dwell meter can be hooked up.

The green connector is just a pigtail off of the MCS wire.

The actual MCS duty cycle is the fraction of the time that the wire in question is grounded by the ECM driver. Therefore if you hook your dwell meter between +12V and that wire, it indicates right. OTOH if your dwell meter is the kind that only can go between ground and the thing you're measuring, it'll read "backwards", in the sense that at 100% duty cycle, the wire will be at +12V 0% of the time, and vice-versa.

 

my dwell meter is not powered, connect red lead to green connector and ground to a convenient spot and reads correctly at the green diagnostic lead.

Damon's meter was self-powered. Read correctly at green diagnostic lead, incorrectly at MCS probe.

but I get it.

That was back in 08.

 

Actually... 1997 is about when this forum started. It didn't look like it does today, it started with a black background and red/yellow/white text and didn't have half the fancy features.

You might have even got an answer, between all the 350 5spd t-top 1986 Iroc threads.

 

lol this thread ....

it turns out im reinstalling the AC in my car so im on the hunt for the bump solenoid.

i looked it up on ebay and was shocked to see 113.00 for one of these, is there a place i can get it lower?

also what color wire goes to this solenoid? the damn PO chopped it out and need to get the connector for it as well

 

Rock Auto $59 plus shipping or $67 for the AC Delco one.

 

Got a link? I tried there but could only find IAC

 

can't pull up RA at work now but I found it under air/fuel delivery for an 86 camaro