El Camino Central Forum banner
1 - 20 of 35 Posts

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #1 ·
Wanted to start a new post here for clarity.

Have been working through and replacing vacuum lines on my 87, while trying to work to the diagram on the shroud:
Font Wood Art Tree Schematic


The lines I mainly have issues with are:

PCV - a 3/8 line coming from the valve. The diagram does not make it clear what port it should join to on the carb. It is currently connected to port T, via a T piece, which is blanked off:
Automotive fuel system Motor vehicle Automotive exterior Auto part Gas


The diagram further shows this PCV line making a T to the Air Management Valve and the TVS.

Currently the Air Management Valve is connected to Port B via a further T piece, which the air cleaner also connects to.

The TVS is currently not connected to anything.

Can anyone point me in the direction of a schematic drawing for the carb and ports, or provide some knowledge as to what should be connected to where?

I do apologise for the complete ignorance on my part. I'm learning on the fly here, with very limited mechanical experience, and no experience at all of US engines.
 

·
Registered
87 Caballero Amarillo, original 305/200-4R, QJ
Joined
·
1,504 Posts
Pcv goes to L. At the tee, there's a smaller loop down to a split, one side goes to a check valve to the air management on the left of the engine, the other side goes to the top of the EPE/TVS (funky thing next to the thermostat housing). T comes out to a check valve right before it hits the bowl valve.

Best to take a good pic with a cell phone and zoom way in. Clears things up some. Figure all lines are straight, if there's a tee, it'll show in the pic as a small white area not a solid black cross.
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #3 ·
Pcv goes to L. At the tee, there's a smaller loop down to a split, one side goes to a check valve to the air management on the left of the engine, the other side goes to the top of the EPE/TVS (funky thing next to the thermostat housing). T comes out to a check valve right before it hits the bowl valve.

Best to take a good pic with a cell phone and zoom way in. Clears things up some. Figure all lines are straight, if there's a tee, it'll show in the pic as a small white area not a solid black cross.
Right, thanks for that.

It looks as though the T and L ports are switched then.

Unfortunately the label is a little deteriorated with age, so zooming in doesn't help all that much.

Incidentally, the car is running super rich. Is this likely to be due to these lines being all mixed up? The carb is flooding which would suggest to me a physical problem. I'm considering buying a replacement float as a matter of course.
 

·
Registered
87 Caballero Amarillo, original 305/200-4R, QJ
Joined
·
1,504 Posts
Artifact Font Art Wood Pattern
B for the aircleaner is by itself, although mine has a metal tee at the carb and also goes to the choke pulloff. L is large tube, goes to tee (pcv) and small tube tees (tvs top - smog pump). K(low) goes to tee (purge/bowl top valves). T goes to the inline check valve to the bottom of the bowl valve. H goes to top of the purge valve.

As far as being super rich, that'll have more to do with the choke settings and idle/air screw settings. Factory settings for idle mixture screws is from seat back out 3-⅜ turns. Air bleed screw (big brass screw on top, in front of the choke plate) is from down seat back out 4 full turns. Make sure your choke is properly adjusted, timing is set to 0° (tan/black stripe wire disconnected and idle less than 1000rpm with hot engine) and the fast idle when choke is engaged is barely on the first step (that'll be @ 1400-2000 rpm).

That's the basics settings, there can/will be some small! adjustments after as each engine is slightly different, but changes are very small, ⅛ turn on the air bleed or idle mixture screws can have a noticeable impact.

You'll also notice your adjustments go in circles. You'll change the air bleed, which can change the idle screw needs, which can change the idle mixture screw settings, and go round and round as you dial it in, which can change the engine rpm and will require checking the timing, again.
 

·
Registered
87 Caballero Amarillo, original 305/200-4R, QJ
Joined
·
1,504 Posts
Oh, one other really small, talking Tiny, detail if you have occasion to change the gas filter (be very careful with this, the steel gas pipe twists far too easily) make sure the filter has the small rubber check valve on it. Without that check valve, gas from the bowl will siphon back to the pump, and possibly a good ways back to the tank, so if the car sits for several days/week it makes for a very long start time and requires basically repriming the bowl.

If you Google long, hard starts it almost always comes back as a timing issue, and that'll drive a person crazy. (many filters do not have the check valve, or ppl remove them thinking it obstructs the flow of gas to the carb).
 

·
Deputy Regional Director, Region 6
Joined
·
2,387 Posts
thank God for people who have the knowledge we sometimes need and are willing to share it.
 

·
Registered
87 Caballero Amarillo, original 305/200-4R, QJ
Joined
·
1,504 Posts
No kidding. For the most part cars aren't hard to fix. Couple wrenches, sockets and screwdrivers will fix about anything. It's the knowing of what and where and when to fix that's the hard part. I've learned more about my car in the short time reading these posts than a year spent in shop class. 👍
 

·
Registered
Joined
·
1,558 Posts
No kidding. For the most part cars aren't hard to fix. Couple wrenches, sockets and screwdrivers will fix about anything. It's the knowing of what and where and when to fix that's the hard part. I've learned more about my car in the short time reading these posts than a year spent in shop class. 👍
You have a different reason to learn.😊
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #10 ·
Amen to the RT's post above.

I've never been one for getting my hands dirty and always considered anything mechanical to be far beyond my ability. That may still turn out to be true, but having this old classic, in England with very little professional help available to me, I'm gonna have to sink or swim!

The knowledge base here is incredible, and I'm in awe of the guys that can both do the work, and share that knowledge in a way that makes sense to the rest of us.

Very much appreciate those of you that have responded to my various posts.
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #11 ·
So I got the float swapped out, and routed all vacuum lines as per above. The carb no longer floods, and no more black smoke from the exhaust, so that looks to have solved one problem at least.

Was running rough though, but before I could get into anything, the alternator belt snapped and shredded itself.

I think I've now reached the limits of my ability here and will be arranging for a responsible adult to do the work. I've found a Rochester specialist down in London who is happy to get her tuned up and running.

It sucks, but I just don't have the time, knowledge, or ability to keep on like this.
 

·
Registered
87 Caballero Amarillo, original 305/200-4R, QJ
Joined
·
1,504 Posts
You found a Rochester specialist? Wow, that's Gold. They are getting rare. I asked the kid in my local parts store for a fuel filter adapter for a quadrajet and he asked me if that was a kind of 4-wheeler atv. 😬
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #13 ·
I know right? I think he might be the only one in the UK. He emailed yesterday to confirm the carb number and to assure me he was happy with dealing with the computer carb. I've a feeling this could be an expensive solution, especially with shipping the car down there, but I'd rather spend more and get it done right.
 

·
Deputy Regional Director, Region 13
Joined
·
6,775 Posts
I know right? I think he might be the only one in the UK. He emailed yesterday to confirm the carb number and to assure me he was happy with dealing with the computer carb. I've a feeling this could be an expensive solution, especially with shipping the car down there, but I'd rather spend more and get it done right.
anyone can claim to be a Rochester specialist", especially in a foreign country with foreign cars. have you checked his references ? I don't want to pay specialist rates for the yob/pfy to learn on the job
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #15 ·
Yeah, the guy was recommended to me by several folks on a UK forum. He's well regarded over here. Unfortunately, I don't have the luxury of being picky either. I'd rather not transport the car 100 miles away but there's literally nobody else in the country that I know of.
I'll keep y'all updated.
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #16 ·
Got the car back yesterday. The carburettor was replaced with a reman unit. The old one had a bad cold start solenoid apparently, and was thoroughly crudded up with rust and debris. She now runs like a dream, and after 6 months since i bought the car, I'm finally able to use it!

This has also highlighted a whole host of other issues that I can get stuck into now haha
 

·
Registered
87 Caballero Amarillo, original 305/200-4R, QJ
Joined
·
1,504 Posts
Wait a sec.. They sold you a reman carb because of a faulty cold start solenoid? There Is no such thing as a cold start solenoid. The choke is entirely responsible for starting when the engine is cold, even freezing, and has no solenoid at all other than for air/fuel ratio under the blue connector on top of the carb. Which has little to nothing to do with starting.

The only other solenoid apart from the MCS is the idle-stop solenoid which has 1 or 2 functions depending on the carb. 1st being to raise rpm 200 or so when the ac compressor is enabled, stops the motor from bogging out at redlights. The 2nd being a damper in case you go from WOT to no-gas pedal instantly, it stops idle drop for 1/2 second or so. There's 2 small screws holding it to the driver front of the carb.

From what it sounds like, they had absolutely no clue how to fix/rebuild/diagnose or tune your QJ, so simply replaced it in hopes that would fix the issue.

I have a vintage hooziwhatzit, would be perfect for installing the blinker fluid you'll need every 5k km, and am really tempted to put my Title to the Brooklyn Bridge up for sale on eBay....

There's only one reason to take a QJ and replace it. It's warped beyond simple repair. Saying that it needed to be replaced because of a faulty part.. Ludicrous.
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #18 ·
That's taken the wind out of my sails somewhat. This guy was my second choice to look at the car as the Rochester specialist in London was booked up until Easter.

I guess having very limited mechanical knowledge and very limited access to Chevy parts in the UK has bitten me in the ass. Idiot tax has been duly paid.

For reference, I've attached a copy of his email
Font Screenshot Circle Number Parallel
 

·
Registered
Joined
·
2,681 Posts
Get your original back from him. He may whine and say he turned it in for a core (or owes the core charge until he does) but act quickly. Pay the core charge if you have to. (Best case scenario is that he found the 1/1000000 winner of the rebuild roulette; you still should keep the core. You might want to send it out for a proper build before the ‘new’ one fails.)
ALSO—that rust is likely still floating around in your tank. Plan to change inlet filters somewhat frequently and possibly plan to flush or replace the tank.

Patrick
 

·
Registered
1987 Stock 305. TX car in the UK
Joined
·
236 Posts
Discussion Starter · #20 ·
Get your original back from him. He may whine and say he turned it in for a core (or owes the core charge until he does) but act quickly. Pay the core charge if you have to. (Best case scenario is that he found the 1/1000000 winner of the rebuild roulette; you still should keep the core. You might want to send it out for a proper build before the ‘new’ one fails.)
ALSO—that rust is likely still floating around in your tank. Plan to change inlet filters somewhat frequently and possibly plan to flush or replace the tank.

Patrick

I'll contact him and see what I can do.

The tank had been flushed and ultrasonic cleaned by the dealer, but he left the old fuel filter on which was just full of crap. I'll plumb in a couple of in-line doohickeys to keep an eye on the issue.
 
1 - 20 of 35 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top