What we are dealing wth:

Freshly rebuilt 87 305 roller engine. New bearings all around, stock crank, rods and pistons (new rings, polished dishes), port and polished 081 heads, XR258HR cam from comp, stock refurbished lifters, stock pushrods and rockers, screw in rocker studs, polished and back cut valves, stock dist. main parts with msd cap and rotor and accel 35362 ign. module, msd street fire coil, new AC r43tsk spark plugs and accel wires and new o2 sensor. Stock carb, stock tranny, stock ECM, hooker headers, timing set to 0*.

I think that just about covers the parts to help diagnose this.

Got the engine back in the car a few weeks ago, had some trouble with the starter, but I got the engine to fire yesterday. It fires and runs, but only by continually giving it part throttle. Before I get as far as cranking the engine, I can hear a very loud constant click, click, click, click noise coming from the carb (presumably), and I have no idea as to what is making this nose, or even if it's supposed to be there. I does go away after a while if I leave the ignition on. Look at the linked video at the bottom of this post and tell me what you think. The noise goes away as soon as I start cranking and comes back when the engine dies. The engine will crank forever unless I give it some gas. The OPSU has been removed as it was leaking oil at an alarming rate. The relay for the electric in-tank fuel pump does not engage when I start the car, but it does engage when I short the OPSU connector with a paper clip. The petrol currently in the tank has been there since September 09. I have no idea when the fuel filters were last changed and I do not know what kind of fuel pressure I'm getting. The car starts eventually, so I'm presuming my timing isn't that far off (at least it's not 180 degrees off). I haven't gotten as far as to check my timing since I cannot find the EST wire (will search thoroughly tomorrow), but I can't really see how I'll be able to determine my timing if I can't get it to idle without dying. I suppose it's worth mentioning that I have always had difficulties with cold start and keeping it running before it warmed up.

Another thing is when the engine is running and I give it a constant part throttle, the rpms will steadily decline till it dies. I have to rev it up to keep it running. And when I do hit about 1000-1500 rpms the engine will backfire through the carb. The first few times it did that it was just a back draft sort of event (quick pressure burst through the cab), but the last time it did it the flames were licking steadily out of the carb.

Here is a video of one of my first start up attempts. There is no backfiring in this shot. Sorry for the poor quality.

http://picasaweb.google.com/lh/photo...eat=directlink

What do you guys think? I've deduced a few different possible culprits:
1. Timing off
2. Low fuel pressure causing lean conditions
3. Improperly adjusted carb
4. Improper lifter preload setting

Also, if I ever do get the engine to idle, where would you set base timing with my cam?

Thank you!

 

Timing order will cause backfire, so will timing if it is retarded too far. The reason that you have to rev the engine so high may be the previously mentioned problems, or a large vacuum leak. I had a similar problem when I used an improper carb gasket with my quadrajet. If I were you, I would check the order of the plug wires on the dist cap first. Then try to find a way to check timing and vacuum.

The clicking is the mixture solenoid on the carb ( if its a quadrajet). It's actually a good thing.

I just watched the video. Why is there a guy with his finger on the carb the whole time? It kinda looked like you flooded it out and the car was struggling to get air. Also, the idle seemed a little low. Are you sure that your fast idle is set correctly? That was definately a mixture solenoid ticking. Hook up your timing light and losten your distributor next time you get it started like that and have one of your buddies advance the timing until it is around 20* advanced with all of the wires on the dist hooked up. There is no EST wire on your car. There are two plugs at the base of the distributor on the drivers side. The one closest to the fire wall (3 wire I think?) is the one you need to remove to set timing. If you can't start the car now, there is no way you will get it started with the plug unplugged though. Maybe check to see that that is plugged in.

 

Hello 87_LG4!!

The clicking noise might be your mixture contol solenoid.

Did you get any codes????

 

The more I watch the video, the more I think that your carb just needs to be adjusted. The fast idle screw is on the passenger side of the car under the choke stuff. Use a 1/4 inch socket on an extension and screw that thing in a couple of turns.

 

The guy fingering my carb is making sure the choke is working as it should. It won't operate properly/haven't been adjusted properly when it's cold. Haven't really gotten that far yet, and I'm not sure how many turns it takes to adjust the choke lever correctly. For that matter, I'm not really sure the carb is properly adjusted at all. At one point when I was away last year my dad bought a rebuild kit and took the carb apart, cleaned it up a bit, installed the new parts from the kit and put it back on the engine, this was to try and remedy the cold start problems I'd been having. IMO though, the car ran just as it always had, but I'm not sure if my dad adjusted anything else while he was at it. So if anyone could make a simple number by number list of how to adjust the carb to factory specs, so that at lest I have my grounds covered there, that would be tremendously helpful.

Now, about the timing, your saying I should advance it to 20*. This is just temporarily, right? Till I get the engine running properly again? After that, where should I set base timing?

Haven't checked for codes yet, but I'll check tomorrow.

 

I say 20* because that is about where mine sits with the dizzy all plugged in. The computer advances the carb when the 3 wire plug is plugged in. Mine is set at 8* advanced when the 3 wire is detached, so iw ould say that if you adjust yours to 16-20* with the 3 wire attached, you will be ok to get the car running. Then after it is running well, unplugg the 3 wire and set timing where you want it.

I would say that the carb is a majority of your problem. When I first put a rebuilt carb in my car (Ive done it a few times unfortunately) i guess I generally follow these steps.
1. Make sure the idle adjustment screws in the front of the carb are set to 3 3/8 turns out.
1a. Make sure the electric choke closes the primary throttle plates.
2. Adjust the fast idle screw until the lever between the carb and the choke snaps throught the fast idle settings. There are three different warm up settings before the fast idle cam steps out of the way and lets the normal idle screw take over.
3. Set the normal idle once the car has warmed up.

This should get the car running assuming that the carb was rebuilt correctly. There are other settings to adjust once the car is willing to start and stay running. Is your choke pulloff working correctly?

 

I got code 41, which according to the FAQ article is Fault at cam sensor OR Cylinder select error OR Tach input error. Not really sure what any of it means or how to address them.

 

Did like you said Razor, turned the fast idle screw in two full rotations, then tried to fire it up without giving it any gas or manually fiddling with the carb. First time around it just sprayed a bunch of gas out of the carb. Second time around it started, ran for a few secs with very low idle, then died.

Low idle speed

I also measured voltage on the choke heater at 2.05V. Is this correct? If I'm correct in assuming that the idle adjustment screws are located on each side of the base plate on the front of the carb, then they are still factory capped off by metal plates, so should I assume that they are still correctly adjusted from factory, or should I try to remove the caps and re-adjust them? Haven't gotten as far as timing yet, but it's kinda hard when it won't idle. Is there any way I can increase idle speed?

 

Found this on the back of the carb:



Could have sworn I attached a vacuum line to that, but now I cannot for the life of me find it. Where does it come from? Can I route an alternate vacuum line from the source, or does it merge with other vacuum lines?

I also found this:



It was dangling at the rear of the engine on the driver side. Anybody know where it's supposed to plug in?

 

Engine runs, timing was off, but I still haven't figured out the objects in the last post.

Help please.

 

The vacuum line is the most important line on this carb. I can't remember what its called though. The vacuum line will be a small black hard plastic line and it should be behind the distributor sitting above the bell housing. The plug is a puzzle to me as well. I had the same plug hanging around in my engine bay a while ago. It ended up laying on a header at one point and getting destroyed. If you figure out what it is let me know. The code 41 doesn't sound right to me. I think I get that code when I unplug the 3 wire plug at the distributor. make sure that they are both plugged in. Without that vacuum line plugged in you should get a code 34 as well.

My guess would be that if you find that vac-line, your idle will improve drastically.

 

Would be nice to have a steady idle. As it is now it idles at about 1200 rpms when in park, then goes down to 4-500 when in drive, although I'm not sure i trust my tach, as it has a tendency to tell me the rpms are below zero when the engine is just about to die. It also tells me that it shifts at 1000rpms, when I'm pretty sure the stock converter shifts at 1200 or so. But when in wot it does shift at 4500 rpms dead, which I believe is about right.
I'll do my best to hunt down that missing vacuum line, but it's probably receded into the plastic sleeve covering the wires, making it all the more difficult as they are all shoved nice and deep behind the engine. Wish me luck.

 

Mess with that fast idle screw (once you get the vac line on) until you get about 1500 rpm idle when the car is cold. Then mess with the slow idle screw on the opposite side of a carb to get about 750 rpm idle when the engine is warm and the choke fully open. I'll go see if I can get a pic of where that vacuum line comes out of the plastic cover real quick.

 

Yeah, its a real PITA to get pics back there. The vac line does go into one of those plastic wire covers though. One of the two large ones. Let me know if you find it and if it fixes the problem.

 

I believe the plug went to the smog controls.

 

Did you get it working?

 

It's been pouring down from above the last couple of days, so I haven't gotten around to it. I do however have an appointment with a GM specialist mechanic in about an hour, so hopefully he'll be able to help me figure stuff out and adjust the carb correctly.