Timing and Tune Up Q's

[msg]

I am working on getting the 350 running right and I am new to doing this.

The engine was ID'd as a 350 from a 1973 pickup from the casting numbers
Partial Vin: C5A146997
Engine ID Code: V0507TJH
Manufactured: Flint plant on May 7, 1973
Casting Code: 3970010
Engine type: 350
Year: 1973
Type: Truck

Carb: Quadrajet 17059206

...so with it being in my 66 I wasn't sure which forum to post this.

Here are some pics. I did take some carb cleaner today and clean things up but didnt update the pics yet. The open port on the carb was uncapped, but I did cap that today before running tests.




The issues I have been having with the engine mainly is cold cranking and holding idle. Takes a series of 8 to 12 cranks to finally idle. So checking the vacuum and timing is what I have been told to do, so I started today by doing the vacuum test from a port on the carb as well as a timing gun test.

My questions are:
Am I going about this the right way, in order to solve the cranking issue?
Is there a good process of elimination series of steps/tests I should follow?
Does anyone have specs on what this engine should be running, meaning timing, rpms etc?

VACUUM
I had it running for a while and then connected the vacuum gauge that read a shift between 14 and 15 inches. It was a slow shift that repeated. When throttled it dropped low and then came back to fluctuate slowly between 14 and 15.

I only ran the Engine Condition Test in the Vacuum Gauge instructions, havent gotten to testing cranking vacuum, PCV test, Distributor advance, Fuel pump test yet. I assume that I need to do all of these since the reading fluctuated between 14 - 15.

TIMING
I ran the engine a while til hot and pulled and capped the distributor vacuum advance and ran the timing light. The timing tab isnt marked but I assume that the timing was at 8 degrees BTDC based on other tabs that have marks of 2 degrees per 45 angle.

Here is a pic of where I saw the timing mark read.



Here is pic from another thread of what the tab looks like


Before I mess and re adjust something I shouldnt I wanted to ask you all.

[LVPhotos]

Are you getting a full 12 volts to the coil on start up? I had to bypass the harness to get 12 v to coil.
Posted via Mobile Device

[Corts60]

14-15 is a bit low for vacuum. Does the engine have a bigger than stock cam? You should be getting around 18-21 inches of vacuum if the engine is healthy. I would start checking for vacuum leaks. The pics you showed for timing seem to be about right.

Is it hard starting cold or hot, or both?

[msg]

Originally Posted by LVPhotos

Are you getting a full 12 volts to the coil on start up? I had to bypass the harness to get 12 v to coil.
Posted via Mobile Device

I am not sure, in fact I am unsure where the coil is. I'll take a look in the a.m. and see and figure out how to use the multimeter to test.

Does the engine have a bigger than stock cam?

Not sure, but I have had someone ask the same thing when they hear it running. I'll try to get a video clip loaded up of it running if it helps.

I see no mention of the choke. Has it been checked? It could also be a carburetor problem.

I believe it has an electric choke, since the cable that extends from the firewall is unattached. How do I check the choke?

[PoDuck]

Originally Posted by msg

I am not sure, in fact I am unsure where the coil is. I'll take a look in the a.m. and see and figure out how to use the multimeter to test.

The coil is in the distributor cap. It appears you have an HEI distributor. If it were a points type with the separate coil, you wouldn't want 12 volts to it, you would want only 6.

I believe it has an electric choke, since the cable that extends from the firewall is unattached. How do I check the choke?

It does have an electric choke. First thing you can check is that it is getting power when the ignition is turned on only.

To check the choke, when the engine is cold, and the key is off, the front (smaller) holes of the quadrajet should have the plate closed. If it isn't closed, open the throttle all the way and release it and see if it closes. If not, it is out of adjustment. To adjust it, you will want to loosen the three screws on the electric choke and turn it until it just barely closes. After that, and get the engine running. As the engine runs, the choke should open slowly until the plate is vertical.

It wouldn't hurt to rebuild the carb, since it is of unknown condition. It's not like you removed the carb from a known running engine and it worked fine. If you open it up to check things out, you will probably damage gaskets, which you'll need a carb kit to replace anyway, so I would personally just get it over with.

[msg]

The coil is in the distributor cap. It appears you have an HEI distributor. If it were a points type with the separate coil, you wouldn't want 12 volts to it, you would want only 6.

I was looking through the manual of my multimeter and had trouble with what I have vs whats in the manual for Ignition System Testing. Any idea on how to test the distributor coil?
Here is the unit

and the instrux it shows for coil testing.

First thing you can check is that it is getting power when the ignition is turned on only.

So with the multimeter I have - would I be measuring DC current? It mentions that the unit measures 0 to 10A and if anything exceeds it it will blow the internal fuse. Wanted to make sure I had it right before I tried hooking this thing up to the tab that the blue wire connects to on the choke.

To check the choke, when the engine is cold, and the key is off, the front (smaller) holes of the quadrajet should have the plate closed. If it isn't closed, open the throttle all the way and release it and see if it closes. If not, it is out of adjustment. To adjust it, you will want to loosen the three screws on the electric choke and turn it until it just barely closes. After that, and get the engine running. As the engine runs, the choke should open slowly until the plate is vertical.

The smaller holes you mentioned,I am confused on where they are. Do you mean the 2 smaller plates that cover the intakes should be flush when cold?

[awbrown]

The best way to help us diagnose this is if you could take a video.. if the inital timing is close then most of it is in the carb/choke .. if someone messed with it I suspect the choke pulloff is either not working or is adjusted to open the choke too far upon start up ... if you simply pushe accelerator once and turn the key ,does it start then stall?? but it will start again and do the same thing?? that would indicate the choke is opening too far ,you will need to adjust the choke pulloff and go from there....like I said , a video of it starting would help ,especially if the air cleaner is off so we can observe the choke...

[PoDuck]

I see no mention of the choke. Has it been checked? It could also be a carburetor problem.

[dracko]

Rather than worrying about the timing marks, try to get the timing set where the engine runs the best or has the highest vacuum. The idle speed will increase.

Sometimes the rubber in the harmonic balancer will dry out over time and crack...then the balancer rotates on the crank and your marks are out of whack. I'm not saying that happens to every old engine, just that it can happen.

With the engine running, spray some carb cleaner around the carb to see if air is getting past under the Q jet, they get really hot underneath and stuff can warp over time....especially if carb bolts are overtightened. The idle will increase if there is a leak.

The hard cold starts might be from leaking plugs in the fuel bowl. They slowly leak gas til the fuel bowl is empty and then you have to crank the engine to get the fuel pump (mechanical) to refill the bowl.

Its normal for the vacuum to drop to about 5Hg when you rev the engine, but it should return to about 20Hg or 21Hg.

[msg]

Originally Posted by dracko

Rather than worrying about the timing marks, try to get the timing set where the engine runs the best or has the highest vacuum. The idle speed will increase.

I'll give that a shot tomorrow.

With the engine running, spray some carb cleaner around the carb to see if air is getting past under the Q jet. The idle will increase if there is a leak.

If air is getting past will the carb cleaner bubble up or get drawn in? Just making sure I know what to look for.

The hard cold starts might be from leaking plugs in the fuel bowl.

So is this a carb rebuild to fix that if that is the case?

i had a hell of a time getting my choke tension/choke pull off squared away when it was -40 up here

-40? That is rough.

Thanks for the help with this everyone, much appreciated!

[dracko]

Like PoDuck mentioned, definitely wanna check that the choke is working when the engines cold. i had a hell of a time getting my choke tension/choke pull off squared away when it was -40 up here...

[dracko]

If air is getting past will the carb cleaner bubble up or get drawn in? Just making sure I know what to look for.

Yeah spray it where the carb meets the manifold. The carb cleaner will get sucked in by the vacuum and idle speed will pick up momentarily. also spray it around where the manifold meets the block and heads while you're at it.

So is this a carb rebuild to fix that if that is the case?

Unfortunately, no. If you Google, Rochester leaking fuel bowl plugs. You'll find a number of ways and pictures on how to fix them.

It sounds like the only way to permanently fix the problem is to drill out the plugs, tap the hole, and screw in plugs sealed with 2 part epoxy. But sometimes that doesn't even work.

Some folks claim to use just 2 part epoxy but typically that will degrade over time from the fuel. Marine Tex 2 part epoxy sounds like the best if you want to try that.

8 degrees btdc is alright. you could try slowly rotating the distributor counterclockwise while the engine is running to get it to 10 degrees and see if it runs any better. don't go too far advanced with it though.

To ensure your timing marks are correct, turn engine over til #1 piston is at top dead center on compression stroke and mark the balancer to align with "0" on the pointer. Then check that the distributor is in correctly and the rotor is pointing to #1 plug wire.

heres a thread with a few ideas on how to find TDC #1.http://www.wikihow.com/Find-Your-Engine's-Top-Dead-Center-(TDC)

Does the engine idle fine after its warmed up? is there power throughout the rpm range?

[PoDuck]

The videos are not showing up for me. I'm not sure what is wrong.

The pcv valve grommet won't be what the problem is, since the vacuum is on the carburetor side of the pcv valve. The pcv valve could cause an issue if it is stuck open, which can usually be checked simply by shaking it to see if it rattles. If it doesn't, spray some carb cleaner in it on both sides and see if it will loosen up. If not, replace it. (Cleaning it out is a good idea even if it rattles.)

If you are running lean, as was said (I can't see the video), there are multiple things that could be wrong, most vacuum related. You could have a vacuum leak in one of the lines, a leaky gasket (carburetor, EGR or intake), some gummed up jets, bad timing, or a bad EGR. I don't see that you have an EGR valve, but if it is a 73 engine, it came with one and probably has a block off plate that may have leaks if it is the manifold that came with the engine.

To check for leaks, use carb cleaner at all those points, not just on the carb. Spray along the intake manifold mating surface, around the base of the carburetor, around any vacuum lines at the carburetor and at their components (The distributor, brakes and transmission should be the only things on an old truck that vacuum lines connect to), and around any EGR block off plate if you have one. If none of that produces an increase in RPM, it is probably the amount of fuel coming out of the carburetor, which can be caused by mixture screws or by clogged up jets, but it could still be timing (out of time or crossed spark plug wires).

If the problem is a mixture screw, you can adjust them out. Loosening the mixture screws riches the mixture and tightening them leans it out. Run the engine, until it gets up to temperature. Adjust one of the mixture screws until you have reached the highest idle you can with it. Then adjust the other screw until you get the highest idle you can with it. You can also use a vacuum gauge to get the highest vacuum pressure if you can't tell where your highest idle is. That should get you the perfect mixture.

Once all this is done, if it is still running crappy, the carb probably needs a rebuild.

The only other thing that you might want to do to completely rule out anything else is you may see if you can borrow a known good quadrajet from someone and see if everything is the same. If it is, you have something wrong that isn't going to be fun, but no use thinking about it until you have ruled everything else out.

Hope that helps.

[198plus]

Timing is probably your first problem. Set it at 16 to 18 degrees initial timing and the Hei distributor should have at least 20 degrees built in, so that would give you a total of 36 to 38 degrees of timing. Also set your spark plug gaps to .045 for the Hei.

[PoDuck]

It certainly sounds like it is running lean. It also sounds like you may have some other things going on. It doesn't sound like it is missing, so it's not likely got any cross wired spark plug wires.

There is a cold idle adjustment by the choke on the passenger side of the carb, and an idle adjustment on the driver side. You may want to adjust the cold idle up a little so it gives more fuel when it starts.

The cold idle is only engaged when the choke is closed. As it opens up, the cold idle stops being engaged, and it will drop down to the lower warm idle that you set with the driver side adjustment.

Your choke is working though, and it appears to be set properly.

Have you adjusted your timing for the highest idle speed you can get yet? (not with the timing light) That will be good in terms of getting things working with the carb for now.

I would adjust the cold idle a bit out, let it idle until it gets to operating temperature, then adjust the mixture like I explained. If the idle gets too high, adjust the warm idle down a little.

That carb may escape the rebuild bench. It doesn't sound too terrible.

[PoDuck]

By the way, you may need to get a carburetor adjusting tool from the parts store to adjust the mixture, and the screws may be blocked off so you can't access them. I haven't seen a quadrajet in years that has them still blocked, but if they are, you may have to cut your way into them.

[msg]

Update on todays work, I replaced the fuel filter and the fuel hose that was really dried out just to help fuel make its way a bit better. It didnt solve the issue though, so I will next go through some of the steps that I have read here.

Thanks for all the help, it's alot to piece together but hopefully I have the intrsux and the correct order of operations. Here goes.

Check timing

Should I pull the 1st cyl plug and bump the ignition til the piston reaches TDC and see where the timing mark lines up. If so, whats the simplest way? Bumping the ignition and inserting a flathead screwdriver each time into the plug port til it feels to be at TDC?

Adjust Timing

Set it at 16 to 18 degrees initial timing

If I am at 8 now, would reaching that 16 to 18 be advancing off of the timing plate? I may be reading the timing plate wrong, new to this.

Have you adjusted your timing for the highest idle speed you can get yet? (not with the timing light)

I have not yet loosened the bolt that holds the distributor and rotate it counter clockwise (I would think ) to increase the idle, I will definitely do this but unsure if I do this before/after/instead of the TDC check with the timing tab. Sounds like its best to try the idle first.

Adjust the Cold idle a bit out
I watched this clip and this guy was calling it fast idle, but if its the same then am I turning the screw counter clockwise to make it go up a little? Is this something I do before I crank it? And how many turns maybe?

Adjust the fast idle speed
This screw I should adjust once the engine is warmed up right? And turn it till the idle rises up how much you think?

Check lines for vacuum leak
Line from brake booster
Line to the vacuum advance
Which others?

Carburetor gasket and manifold gasket
I sprayed around the carb and intake manifold with carb cleaner while it was running last and didnt see any idle increase, I will try this again

EGR gasket or delete plate
Would this be on the intake manifold?

Gummed up jets
Is this checked by removing the carb? I did spray carb cleaner into and around the carb previously although I cant say I targeted the jets.



Hope to get to this tomorrow, might be a day or two.

[198plus]

The timing tab on the engine has marks for only about 10 degrees, you should use a dialback timing light.

[PoDuck]

Originally Posted by msg

Check timing

Should I pull the 1st cyl plug and bump the ignition til the piston reaches TDC and see where the timing mark lines up. If so, whats the simplest way? Bumping the ignition and inserting a flathead screwdriver each time into the plug port til it feels to be at TDC?

The piston will be at the top twice during the cycle. You will have a compression stroke and an exhaust stroke. Without having some way to check there is pressure, you will have a 50% chance of having the wrong side of the cycle and being 180 degrees off. The timing mark on the crank will line up with the tab on both strokes.

The easiest way I have found to find TDC is to have all the plugs out and turn the crankshaft by hand while putting your thumb over the #1 plug and wait until you feel pressure. That will be the compression stroke. Then turn the crank until the timing mark lines up with zero on the timing tab.

Since taking all the spark plugs out isn't as easy, I rarely do that, because there are easier ways to do it, but they are slightly more problematic.

You can do the same procedure without taking all the plugs out, but it is harder to turn the crank by hand.

You can disconnect the power to the distributor and do the same procedure while having someone tap the starter. With this, you risk overshooting your mark and possibly missing it.

I don't generally recommend putting anything into cylinders like screwdrivers. you run a higher risk knocking debris into the hole, especially on a motor that isn't completely clean.

Adjust Timing


If I am at 8 now, would reaching that 16 to 18 be advancing off of the timing plate? I may be reading the timing plate wrong, new to this.

If you are sure you are at 8, there is no reason to get the engine to TDC. The only way you'll get to 16-18 is to get a timing light with an advance built in.

If you know you're at 8 though, there is no reason to mess with the timing at this point. You can get into that more once you have it running and are trying to more accurately adjust your overall timing, and mechanical and vacuum advance.

I have not yet loosened the bolt that holds the distributor and rotate it counter clockwise (I would think ) to increase the idle, I will definitely do this but unsure if I do this before/after/instead of the TDC check with the timing tab. Sounds like its best to try the idle first.

If your timing is at 8 degrees, leave it alone for now. You should be fine for getting the engine running better at that point.

Adjust the Cold idle a bit out
I watched this clip and this guy was calling it fast idle, but if its the same then am I turning the screw counter clockwise to make it go up a little? Is this something I do before I crank it? And how many turns maybe?

I call it cold idle when talking to the uninitiated because it is easier to understand that it is something to do with the choke.

As for what to do with it before you crank it, I would open it (tighten it) about half a turn before trying to start it. Then once the truck starts, adjust it to 1200 rpm at the choke. Once it warms up, knock the throttle and the fast idle will drop and you should adjust the warm idle screw until the engine is about 700 rpm. (hopefully you have access to a tach. It will make life easier.)

Check lines for vacuum leak
Line from brake booster
Line to the vacuum advance
Which others?

Depending on your transmission, you may have one going to the transmission from the back of the carb. If not, just follow any vacuum hose from the carb and check both sides, even if it just goes back to the carb itself.

EGR gasket or delete plate
Would this be on the intake manifold?

Yes, on the passenger side, under the carb. I'm sure you don't have one from the pics and video, but I can't tell for sure if there is a plate there or if it is an older style intake that doesn't have the hole at all.

Gummed up jets
Is this checked by removing the carb? I did spray carb cleaner into and around the carb previously although I cant say I targeted the jets.

You won't be able to clean the jets without pulling the carb apart. In my opinion, at that point, it is time to just rebuild it and get it over with.

[msg]

As for what to do with it before you crank it, I would open it (tighten it) about half a turn before trying to start it. Then once the truck starts, adjust it to 1200 rpm at the choke

Which is the neg side of the primary coil? It would be the black wire (neg) from the coil to connect to from the primary ignition coil right? Trying to use the multimeter to get the 1200 rpm check you mentioned.

[PoDuck]

That white connector on the right side of that picture is your tach connection. You can disconnect that and attach your tach. That makes me ask though, where is your brown connector? You obviously have it, or it wouldn't have run at all.

[msg]

That white connector on the right side of that picture is your tach connection. You can disconnect that and attach your tach.

The only connectors I have are the ones that come with the multimeter which are alligator clips (below) that I can measure rpms with. No specific tach device unfortunately.

That makes me ask though, where is your brown connector? You obviously have it, or it wouldn't have run at all.

There are 3 wires that are bundled in the plastic coil to the left of that white clip that connect underneath. When I pull back on the coil like cover I see 3 wires and one looks brown.

[PoDuck]

You don't have to take the cover off to access the tach connection. The white connector that is connected to the distributor can be removed and you can put your positive alligator clip on that blade that sticks down. You connect the negative clip to a ground.

[PoDuck]

The connection on the bottom here is your tach connector.

[msg]

When I disconnect the white plug and clip the pos alligator cable from the mutimeter to the metal tab I wont turn over. Once I plug the white connector back she fires up.