[markpj23]

Originally Posted by "QUICK-SILVER"

Factory intake doesn't have a "left bank" mixture screw.

Guess I could have worded that much better. Meant driver side idle adjustment screw had no effect.

I had no clue (obviously) about the EGR ports having been blocked off, but it makes sense because this engine was a transplant from an early 70's car.

So it looks like I'll spend my saturday verifying TDC and pulling a carb.

[steve25]

While you’re confirming TDC also check how much slack is in the timing chain!

["QUICK-SILVER"]

Originally Posted by steve25

While you’re confirming TDC also check how much slack is in the timing chain!

I'm thinking botched install of a multi keyway timing set.

Would almost bet on it if the TDC mark checks out good.

That would explain the running better with initial timing way off.


It wouldn't be the first
Clay

[NeighborsComplaint]

Honestly, that soot is just a car warming up with the choke on. It's a nothing.

Forget the timing light you have since you are just getting erroneous readings anyway and have no measure of where TDC is to calibrate from.

Here is a simple method to get you in the ballpark. Attach you vacuum gauge to full manifold vacuum. Start the car and when warmed up, adjust your throttle to a comfortable high idle. Loosen you distributor and rotate it to the highest vacuum reading at idle. Back off an inch of vac by rotating the distributor counterclockwise from the highest vacuum setting. Lock the distributor down, readjust your curb idle speed and drive the car listening for any rattling (pinging) at light throttle under load and note if hot cranking with starter is slow (caused by too much advance and resulting pre-ignition kick-back). Both indicate too much advance. If so, retard the timing by slight counterclockwise rotation to another inch less vacuum. Drive and check, repeat until until you have no ping or hard start.

Then move on to your carburetor. With the throttle closed (no throttle input) look own the primary throttle bores at the transfer slots (a single groove that run down the side of each bore/venturi. The top pf the throttle blades should be just slightly lower than top of that slot (carries idle bypass air around the throttle plates to the engine at idle) If the length of the slot above the plates is longer than it is wide, adjust your idle speed screw until the slot appears as a square. This is called "squaring up the transfer slots".

If the transfer slots are already "squared off" at idle, then your problem lies elsewhere, but I'd be willing to bet you will find too much transfer slot exposed in your current condition.

If you were to start the car, in all likelihood it would idle too slow to run as you do not have sufficient idle air bypassing the throttle blades. However, if you raise the idle by the screw, you uncover more of the slot and create a vacuum signal that induces an over-rich condition. This is where you take the carb off, flip it over and add idle air through the secondary idle speed screw concealed under the carb (to keep the "kids" from tampering with it). The easiest way and best place to start is to loosen or tighten the screw until you can slip a .015" inch feeler gauge between the throttle plate and the secondary venturi wall.

Reinstall the carb, start it up, adjust the curb idle speed to normal and then adjust your mixture with the vacuum gauge.

If you find you have to add excessive turns to the curb idle speed screw to get it to idle, you may have to repeat using a, .020" feeler gauge and reinstall but typical that .015" setting will get it right and only a slight curb idle speed adjustment will be needed.

[markpj23]

Originally Posted by NeighborsComplaint

... Forget the timing light you have since you are just getting erroneous readings anyway and have no measure of where TDC is to calibrate from...

I was able to compare my timing light against another and it's fine. Still the question about TDC....

I spent some time adjusting the idle mixture screws today, taking my time and watching the vacuum gauge. Not sure what that 'mechanic' did but I was able to get the thing to stall when the mixture screw was run in all the way. He had told me it had no effect. So much for that guy.....

Anyway, I was able to make a slight improvement but the thing still runs like crap - misses, smells gassy, etc. Nearly impossible to drive at a steady speed without bucking along. Accelerates OK but still crappy overall. No pinging heard at any throttle.

Interesting that during the adjustments I increased the idle speed screw setting to keep it from dying so quickly, then tried to reduce the idle speed to near stall, but it NEVER got to that point even after the screw was backed off all the way.

Originally Posted by NeighborsComplaint

...Then move on to your carburetor. With the throttle closed (no throttle input) look own the primary throttle bores at the transfer slots (a single groove that run down the side of each bore/venturi. The top pf the throttle blades should be just slightly lower than top of that slot (carries idle bypass air around the throttle plates to the engine at idle) If the length of the slot above the plates is longer than it is wide, adjust your idle speed screw until the slot appears as a square. This is called "squaring up the transfer slots".

If the transfer slots are already "squared off" at idle, then your problem lies elsewhere, but I'd be willing to bet you will find too much transfer slot exposed in your current condition.

If you were to start the car, in all likelihood it would idle too slow to run as you do not have sufficient idle air bypassing the throttle blades. However, if you raise the idle by the screw, you uncover more of the slot and create a vacuum signal that induces an over-rich condition. This is where you take the carb off, flip it over and add idle air through the secondary idle speed screw concealed under the carb (to keep the "kids" from tampering with it). The easiest way and best place to start is to loosen or tighten the screw until you can slip a .015" inch feeler gauge between the throttle plate and the secondary venturi wall.

Reinstall the carb, start it up, adjust the curb idle speed to normal and then adjust your mixture with the vacuum gauge.

If you find you have to add excessive turns to the curb idle speed screw to get it to idle, you may have to repeat using a, .020" feeler gauge and reinstall but typical that .015" setting will get it right and only a slight curb idle speed adjustment will be needed.

This makes sense - I'll take a look.

Thanks for the input!

[NeighborsComplaint]

Did the car run that way when you bought it? Have you replaced the distributor cap and rotor or plug wires? Don't overlook the obvious, check the firing order. I am sure everyone has done that once in their life.

[geeteeohguy]

Originally Posted by NeighborsComplaint

Did the car run that way when you bought it? Have you replaced the distributor cap and rotor or plug wires? Don't overlook the obvious, check the firing order. I am sure everyone has done that once in their life.

You need to baseline the car or take it to a mechanic that knows how. The firing order needs verification, as does the distributor installation. The timing needs to be set and the curve checked. And on and on. Very basic stuff.

[steve25]

This needs to be double checked.

[Gary H]

After reading your comments on the timing, and the fact that the engine runs so poorly if you try to adjust the timing to the proper 12* mark, I would place my money on the timing chain being installed improperly. Timing chain sets with the multiple keyways on the crank gear are sometimes installed incorrectly resulting in the camshaft being retarded. I've ran across this several times over the years when troubleshooting customer's cars. The symptoms have been the same as yours. The engine runs poorly and won't idle when the timing is set to normal specs. And the engine has poor power when it does run.

[markpj23]

I did verify the firing order already. Will need to spend some time verifying timing, etc. I have found a rebuilt quadrajet for a good price and will pull the trigger on that this week. Next week is toast but when I get back will dive in.

Many thanks for all the input / tips / suggestions!

[markpj23]

Today I pulled the valve covers and rotated the engine to TDC. The rotor was pointed to the #1 plug wire connection, and both the #1 intake and exhaust valves were closed. I know this because I could wiggle both rocker arms and they were not under tension.

While I was in there I checked rocker arms on all cylinders and here's what I got:

CYL INT EXH
1 C C
2 C C
3 O C
4 C O
5 O C
6 C O
7 C C
8 C C

I know that Closed is subjective, and the valve spring could be just starting to compress or release.

Took the distributor cap off and it looks far from new. Pretty worn contacts and the rotor looks the same. Off to NAPA for new ones.

I also pulled all the spark plugs to see what they look like. No big surprise they are pretty fouled. Picture shows them 1 through 8 left to right. Noted that #1 and #7 look the worst - not sure if that's significant or not.

Checked the gap while I was at it. Read:
1 .040
2 .045
3 .042
4 .023 (PO must've dropped this one...)
5 .042
6 .038
7 .042
8 .042

From this I'm guessing they should all be gapped to .042 - .045

Plug wires look to be newer silicone hi-temp, 8mm gray jacket. Are these OK or dumpster food?

[markpj23]

Amazing what a basic tune-up will do! New cap, rotor and plugs. Car runs much better and has a steadier idle. Still bucks a bit while holding steady speed, like a mild miss.

Gonna pull the Holley off and see what the rebuilt Qjet does for me.

[ZeGermanHam]

Just curious, do you have manual choke?

[steve25]

It does not take much crap / dirt to restrict or even block off a Holley idle bleed passage on the top of the throttle body!
Ask me how I know this!

[NeighborsComplaint]

Originally Posted by steve25

It does not take much crap / dirt to restrict or even block off a Holley idle bleed passage on the top of the throttle body!
Ask me how I know this!

Me too! I put on my QFT Slayer 750 after spraying it with Sharkhide coating. I placed the plastic shipping “hat” on loosely instead of masking before I sprayed. I fired it up and thought “we’ll, that isn’t right. I took the carb off and sprayer the bleeds with carb cleaner and compressed air and then it ran right. I knew I got lazy and shot myself in the foot.

[markpj23]

Originally Posted by ZeGermanHam

Just curious, do you have manual choke?

No is an electric unit that seems to work as it should.

[markpj23]

I had posted this in another thread but no answers there.

I have a rebuilt Qjet ready to bolt on. It's apparently not from a Pontiac. Have a few connection ports that I'm not sure what they connect to, and I'm wondering if you guys know what the ports are for? The ones circled are the ones in question.

Can I just cap them off?

[ZeGermanHam]

Originally Posted by markpj23

No is an electric unit that seems to work as it should.

Gotcha. Only reason I asked is because my brother had been chasing down a mild skip that would occur every so often while cruising with steady throttle. Every few miles, the engine would hiccup very slightly. He couldn't figure it out for years, but then recently discovered that his manual choke was not fully disengaging. Once he readjusted it, the hiccup disappeared.

[Holeshot71]

Originally Posted by markpj23

I had posted this in another thread but no answers there.

I have a rebuilt Qjet ready to bolt on. It's apparently not from a Pontiac. Have a few connection ports that I'm not sure what they connect to, and I'm wondering if you guys know what the ports are for? The ones circled are the ones in question.

Can I just cap them off?

The big one in the front middle goes to the charcoal canister. If you don’t have one just cap It. The one to the left of that is for the choke pull off. You don’t have the pull off or the linkage that goes to the secondary air flap. You should have them both for cold start-up and to control the rate of opening for the secondary flaps. The other small one to the right is for ported vacuum to the distributor.

[markpj23]

Originally Posted by Holeshot71

The big one in the front middle goes to the charcoal canister. If you don’t have one just cap It. The one to the left of that is for the choke pull off. You don’t have the pull off or the linkage that goes to the secondary air flap. You should have them both for cold start-up and to control the rate of opening for the secondary flaps. The other small one to the right is for ported vacuum to the distributor.

Thanks. This one has the electric choke. Do I still need the pull-off and linkage? If so could you post a picture?