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Morning folks, I could use some advice. My 66' Toronado was running awesome until yesterday and I'm kinda lost trying to figure out where to start.
Quick backstory: I got my rebuilt carb back from the rebuilders a couple weeks ago and I installed it on the car with no problems and, I have to say, it has never run better after putting that carb on. Quick start ups, the throttle felt snappy and smooth, and the choke was working perfect, pulling off almost exactly on the money......great right? Well a couple days ago I started up the car in my garage just to give it a quick run (not out for a drive, just a quick garage start-up) and, again, it ran perfectly. Smooth, snappy, etc. I shut er down after about 5 mins and that was that.
Fast fwd to the next day and I had just received a replacement vacuum driven headlight actuator which I was going to throw in and see how the headlights performed. I installed it, but accidentally left one of the vacuum lines off (the little actuator on top that releases) and when I started the car it kinda revved a bit too high and when I kicked off the fast idle it started to fall on its face. I realized I had left a vacuum line off and I reattached it. Since all this happened, the car has run like absolute dog s***. Perhaps all that is unrelated and something else has happened, I don't know.
Anyway, the car starts up alright but it's wanting to die all the time. You give it gas and it stumbles like crazy and it kinda reminds me of my old snowmobile when it would run on one cylinder rather than two,.....just seems lifeless or something. It sounds off, not smooth like before. I did notice when I pulled the choke over to the near-closed position that it smoothed out a bit and revved up.
So, what have I tried so far? I wanted to rule out fuel delivery to the carb so I watched for the squirts of fuel from the accelerator pump. Two strong streams of fuel coming out so that's good. I also hooked up a fuel pressure test rig and started the car. The PSI ranged from 7-9 roughly depending on throttle position, so that's not ideal but ok I think. I also capped off the vacuum port that feeds the headlights and HVAC system, just to rule out any vacuum leaks in that system. Still the same result.
Anyway, I'm pretty new to this and am learning as I go. I was going to have a look at the ignition next......just to check the timing, clean the points, swap in a replacement condenser. I actually had replaced the points and condenser about a month ago and it was running great since then. Maybe something going on there? God, I dunno guys....I'm pretty lost. I really don't want to crack into my freshly rebuild carb!
Last edited by ourkid2000; March 25th, 2023 at 05:20 AM.
I dunno guys....I'm pretty lost. I really don't want to crack into my freshly rebuild carb!
It's vacuum related. Don't get carried away. Logic suggests >>> What is the LAST thing you did PRIOR to this occurrence? Leave the IGN along, leave the timing alone, leave the carb alone, etc.
It's vacuum related. Don't get carried away. Logic suggests >>> What is the LAST thing you did PRIOR to this occurrence? Leave the IGN along, leave the timing alone, leave the carb alone, etc.
LOL, great advice. I found myself getting carried away so I've stepped away for a bit to get my head together. I find when I get carried away like that I end up breaking things by accident. Learned from my mistakes over the years.
It's vacuum related. Don't get carried away. Logic suggests >>> What is the LAST thing you did PRIOR to this occurrence? Leave the IGN along, leave the timing alone, leave the carb alone, etc.
So I took a good look around. I can see nothing out of place.
The headlight system runs off vacuum so I already tried capping off the line on the manifold that feeds vacuum to the lights and HVAC with no change in engine performance. All the other lines appear to be connected and in good condition.
So start by eliminating ALL vacuum lines to the engine. Cap each one. If the engine still doesn't run right, you've eliminated that as a potential cause. If it DOES run right, reconnect one at a time until it doesn't. That's your problem.
So start by eliminating ALL vacuum lines to the engine. Cap each one. If the engine still doesn't run right, you've eliminated that as a potential cause. If it DOES run right, reconnect one at a time until it doesn't. That's your problem.
Ok that's good advice. Just a question about my particular engine though......mine has the K19 AIR system, can I cap off these ports without something god awful happening? I don't even know what this contraption does honestly.
The two lines behind the carb is what I'm referring to.
Then use a stethoscope (or a long screwdriver held to your ear in a pinch) and listen to your valvetrain by putting the stethoscope tip above each set of rocker arms. You'll hear the rocker arms operating. Note if any sound strange.
You can also listen around the timing cover to see if something has in fact gone wacky with the timing set. Remove belts for a short time to eliminate water pump noise if needed.
Stethoscope/long screwdriver is a useful diagnostic tool.
So I capped off every line except for the K19 stuff. No change. I had the brake booster capped, the headlights/HVAC, PCV, and the carb ports. Felt like my hand was going to get sucked down into the carb!
In the video, the transmission vacuum signal is still hooked up....missed that one. But I capped it after and tried again with the same result.
Vacuum is a little low and reasonably steady. Doesn't look like a rocker arm has come loose, but never say never.
Is the A.I.R. system intact and operational?
Use a length of fuel line to listen around the check valves on the metal injector manifolds going to the heads. They're the round things on the manifold tubes. One end of fuel line to your ear and move the other end around the check valve and tubes with engine running. Listen around all connections and valves associated with the A.I.R. system. Careful as if it's a bad leak you may get some hot exhaust gas thru the rubber tube.
Read Section 6L in your 1966 CSM.
I hate to suggest disabling or removing an intact and functioning A.I.R. but if you find leaks or something not functioning properly that may be your only option if you can't find replacement parts.
Vacuum is a little low and reasonably steady. Doesn't look like a rocker arm has come loose, but never say never.
Is the A.I.R. system intact and operational?
Use a length of fuel line to listen around the check valves on the metal injector manifolds going to the heads. They're the round things on the manifold tubes. One end of fuel line to your ear and move the other end around the check valve and tubes with engine running. Listen around all connections and valves associated with the A.I.R. system. Careful as if it's a bad leak you may get some hot exhaust gas thru the rubber tube.
Read Section 6L in your 1966 CSM.
I hate to suggest disabling or removing an intact and functioning A.I.R. but if you find leaks or something not functioning properly that may be your only option if you can't find replacement parts.
Yeah, I had that gauge on the car last week and it was pulling a steady 18". I noticed it was much lower on the gauge today.
Vintage Chief has a good vacuum reading diagnosis chart he's posted before. Since idle vacuum has dropped some and is moving a little, might pay to dig into that some.
Vintage Chief has a good vacuum reading diagnosis chart he's posted before. Since idle vacuum has dropped some and is moving a little, might pay to dig into that some.
I don't suppose you have a location for that? I had a quick search but couldn't find anything.
I'd consider the (below) diagram a very good GENERAL guide in helping to address/assist which direction might be chosen next w/ more specific diagnoses.
Right, I printed that sheet off and went down to garage and hooked up my vacuum gauge (put it on the PCV hose and capped the PCV). Started the car up.......completely different car now. Running exactly as advertised. See my two videos below, first one I had just started the car and it was up on the fast idle with the choke on. Second, I had lowered the fast idle cam a notch and snapped the throttle a few times:
Your vacuum readings look good. I would not tear into anything until you first replicate the point which got you here in the first place. Logic, once again, dictates you changed THIS:
Fast fwd to the next day and I had just received a replacement vacuum driven headlight actuator which I was going to throw in and see how the headlights performed. I installed it, but accidentally left one of the vacuum lines off (the little actuator on top that releases) and when I started the car it kinda revved a bit too high and when I kicked off the fast idle it started to fall on its face. I realized I had left a vacuum line off and I reattached it. Since all this happened, the car has run like absolute dog s***. Perhaps all that is unrelated and something else has happened, I don't know.
Put the old vacuum driven headlight actuator on the car - and then see how it runs.
Your vacuum readings look good. I would not tear into anything until you first replicate the point which got you here in the first place. Logic, once again, dictates you changed THIS:
Put the old vacuum driven headlight actuator on the car - and then see how it runs.
I get it, but you can see in that earlier video, and I did mention it earlier, that I capped off the entire headlight system with no change. It must have something to do with that PCV system as that was the only thing I messed with in between the car running like crap and then running right. Either that or there's an intermittent vacuum leak somewhere around the carb, which is possible I guess. I did just install the carb recently.
Well, no I'm not 100% convinced but I think I'm narrowing things down and hopefully I'm on the right track! I haven't disregarded everything you guys have suggested, however. You have all been extremely helpful and I am very thankful for your help on this one. I will update this as I go.
I don't like the manner in which you performed the throttle snap-back test (upper LH test of the diagram I provided). There is NO reason to place your hand on the top of the carburetor. Why are you doing that? Stop it.
The ONLY test is w/ the engine vacuum stable (yours 'looks' OK) but you're NOT performing this test correctly. The test specifically states: "With the engine warmed up & idling is normal" - it does not state to put your hand over the top of the carburetor. It states to very simply perform a throttle blade snap-back. NOTE: The vacuum reading should drop to 5"Hg or LOWER & then return to its stabilized normal reading. I mention this solely for one reason. You're expecting the carburetor rebuild to function exactly as it should after someone rebuilt your carburetor. That's fine. However, in reality - you need to ensure your A/F mixture screws are adjusted correctly for YOUR vehicle. I don't visualize from your videos any significant instability of the vacuum at idle. But, I can't see if your throttle blade snap-back test demonstrates the needle swinging down to 5"Hg or LOWER. If it wanted you to perform this in some other manner, it would clearly state this. It does not. If you're getting too much air, you're likely not getting enough fuel. This can influence engine performance. I'm not stating this is your issue, but I'd much more like to see you perform this test correctly. Don't rush it. Get to a stable warm engine idle. Don't move the throttle blades up & down like I see in your video(s). Yes, perform the test repeatedly but stop after each snap-back throttle test until engine idle stabilizes (then perform the exact same throttle snap-back again). The vacuum should immediately go to 5"Hg or LOWER. "If" you can't demonstrate a throttle snap-back to 5"Hg or LOWER, my next suggestion would be to adjust each A/F mixture (independently) with vacuum gauge installed. I DO NOT want to send you on a goose chase here, but if it were my engine and I just received a newly rebuilt carburetor, the VERY FIRST thing I would do is establish the A/F mixture is set correctly. With that said, before you make any adjustments to the A/F mixture screws, ensure you see your vacuum throttle snap-back test go to 5"Hg or LOWER then stabilize. Perform this test several times. If your vacuum does not fall to 5"Hg or LOWER, you're getting too much air, and too little fuel.
This quote pretty much sums it up. However, please note - you want a "balance" of air to fuel, so that when air is increased the fuel increases in proportion to amount of air. If you begin with too much air and not enough fuel, you're in a lean burning condition/state, and as stated this CAN influence engine performance.
A lean fuel mixture occurs when there is too much air or not enough fuel in your engine. This can result in your car's engine not operating optimally. Since there isn't enough fuel being burnt, your car may stall, operate roughly or struggle to accelerate
Oh I wasn't doing any of your tests at that time of filming. I had intended to, but the car was clearly operating much better after I started it. Previous to that, placing my hand over the carb made it speed up and smooth out. I was only placing my hand over the carb to compare from before, if that makes sense. Previously, snapping the throttle made it almost cut out and shut off.
I will do the tests correctly this evening. I followed the instructions on how to set the idle mixture screws a couple weeks ago right after installing the carb. I used my vacuum gauge to do it and the car was starting and running great up until a couple days ago. They should be set pretty close IMHO.
Last edited by ourkid2000; March 27th, 2023 at 11:37 AM.
I followed the instructions on how to set the idle mixture screws a couple weeks ago right after installing the carb. I used my vacuum gauge to do it and the car was starting and running great up until a couple days ago. They should be set pretty close IMHO.
Good for you. Listen, I understand it's tough negotiating a precise setting by listening to engine RPM &/or watching a vacuum gauge. Truly the absolute best would be to measure Lambda via a wideband O2 (AEM) sensor (if you have one). I've learned to watch how far the vacuum needle falls when conducting that test. I've learned to trust that part of the test by evaluating spark plug condition (white, sandstone, or black) & acceleration. Just dropping the transmission into any gear can sometimes demonstrate a tell-tale condition (especially lean), since at idle in Park there is no load on the engine. If the engine starts to fight you when you do nothing more than place it in any gear (e.g. starts to run rough), for me it's a tell-tale sign the vacuum is not set correctly (although, yes, there could be another issue - timing, vacuum advance canister, etc.). But, I try to get the vacuum dialed in really, really well and I pay attention to how far the vacuum needle falls on the snap-back test. Good Luck.
I like the manner in which this guy talks - no B.S. no loudmouth know-it-all stuff, nothing more than basic how-to stuff and he's dead-on correct.
The readings look better and are tracking throttle. Is the engine running properly now?
Yes, running tip top. I checked the dwell today and it's drifted to 33 deg (new points recently). I'm gonna re-set the dwell and check the mixture screws again using the vacuum gauge. Other than that it's running great.
An acquaintance mentioned to me that it could possibly be the carb base gasket that was causing the vacuum leak. I'm wondering if something like that could be intermittent? My gut instinct is that a problem like that would be always present, but maybe not? If that's not really possible, it must have been some kind of vacuum leak that I missed somehow.
You said it's running like a top. The carb base gasket was NOT the issue - leave it alone. Your vacuum is spot-on. NEVER and I mean NEVER set the dwell and then set your A/F mixture. A proper tune-up is ALWAYS in this order:
(1) Set Dwell;
(2) Set timing;
(3) Set A/F mixture.
Did I mention that is ALWAYS the proper sequence to follow?
Follow the procedure in the CSM - don't forget to plug the vacuum when performing the tune-up exactly as described in the CSM.
You said it's running like a top. The carb base gasket was NOT the issue - leave it alone. Your vacuum is spot-on. NEVER and I mean NEVER set the dwell and then set your A/F mixture. A proper tune-up is ALWAYS in this order:
(1) Set Dwell;
(2) Set timing;
(3) Set A/F mixture.
Did I mention that is ALWAYS the proper sequence to follow?
Follow the procedure in the CSM - don't forget to plug the vacuum when performing the tune-up exactly as described in the CSM.
Yeah, I'm not 100% sure about where to set the timing. The manual says to go for 7.5 deg BTDC but that would be using 1966 era premium fuel. It's currently set to 5 deg BTDC, for whatever reason. I wonder will it ping using the fuels available today if I set it to 7.5?
Yeah, I'm not 100% sure about where to set the timing. The manual says to go for 7.5 deg BTDC but that would be using 1966 era premium fuel. It's currently set to 5 deg BTDC, for whatever reason. I wonder will it ping using the fuels available today if I set it to 7.5?
There may be an advantage @ 5.0, but there may not be an advantage @ 5.0 Tough call, honestly. Me, I'd set it to 7.5 BTDC and see how it drives - your call.
Yeah, I'm not 100% sure about where to set the timing. The manual says to go for 7.5 deg BTDC but that would be using 1966 era premium fuel. It's currently set to 5 deg BTDC, for whatever reason. I wonder will it ping using the fuels available today if I set it to 7.5?
1. Adjust the dwell first because it can affect the timing slightly.
2, Then adjust the initial timing to 7.5 or 8 degrees at the RPM prescribed in the CSM. You may have to increase the idle speed temporarily with the idle screw, NOT the A/F screws.
3. Reset the idle speed.
4. If you have adjusted the A/F mixture before adjusting the dwell or timing, thats fine. You can go back after setting the dwell and timing and check the A/F settings. You actually want the A/F mixture adjusted fairly close before you start dwell and timing tasks.
Your Toronado will run fine on today's fuel. You will probably want to use premium and without ethanol if you can find it.
Ask me how I know........
Maybe I missed it, but did you change the PCV and hose? Was that the cause? If the vacuum is now good, stop!!!
Completely solve the vacuum problem first. Don't go changing other things (timing, dwell etc...) until you figure out the cause of the low vacuum. If you change something that causes another problem (because of a defective part, or something done incorrectly) you'll never figure out what was wrong because you will have two unrelated problems.
Maybe I missed it, but did you change the PCV and hose? Was that the cause? If the vacuum is now good, stop!!!
Completely solve the vacuum problem first. Don't go changing other things (timing, dwell etc...) until you figure out the cause of the low vacuum. If you change something that causes another problem (because of a defective part, or something done incorrectly) you'll never figure out what was wrong because you will have two unrelated problems.
Vacuum leak is solved......unsure of what was causing it as I didn't change any parts. I'm just moving on now to dialing in the dwell and timing, then AF mixture.
Right, back to running like trash. Yesterday, I had it up and running and warmed up then I adjusted the mixture screws to max vacuum. Seemed to be running great, the vacuum was up around 19" and it seemed ok.
Started it up today, and it seemed to be running pretty good when it started up but when I backed it out into my driveway I could feel an off-idle hesitation but it was still running ok. I let it warm up in the driveway for a bit and it just seemed to get worse and worse. Sure enough, it started to behave exactly as it had before with low vacuum (13-14")and a real bad hesitation when you gave it gas. I'm at a loss.
I adjusted the mixture screws back in and then ran them out to 3 turns out and tried again but it is doing the same thing. Made no difference.
Note that my vacuum gauge is hooked up to the vacuum port that runs the head lights, so I think I can rule out headlights system.
Last edited by ourkid2000; April 11th, 2023 at 08:08 AM.
Right, back to running like trash. Yesterday, I had it up and running and warmed up then I adjusted the mixture screws to max vacuum. Seemed to be running great, the vacuum was up around 19" and it seemed ok.
Started it up today, and it seemed to be running pretty good when it started up but when I backed it out into my driveway I could feel an off-idle hesitation but it was still running ok. I let it warm up in the driveway for a bit and it just seemed to get worse and worse. Sure enough, it started to behave exactly as it had before with low vacuum (13-14")and a real bad hesitation when you gave it gas. I'm at a loss.
I adjusted the mixture screws back in and then ran them out to 3 turns out and tried again but it is doing the same thing. Made no difference.
Note that my vacuum gauge is hooked up to the vacuum port that runs the head lights, so I think I can rule out headlights system.
If it starts fine then runs progressively worse as it warms up, that sounds like the choke is not opening properly. Did you verify that the choke was fully open when it was running poorly?
Yeah, the butterfly is wide open. I had the air cleaner off when I was testing the vacuum and it was completely pulled off. Actually, it still warm so I'll snap a picture here:
Last edited by ourkid2000; April 11th, 2023 at 08:31 AM.
So I just did a cold start on the car today and it was acting up immediately. It started but I could barely get it going. Putting my hand over the choke area or closing off the choke almost fully seemed to bring the RPMs up and the engine would run slightly smooth,
This is unlike the last time I started it when it ran pretty good at first and then it slowly got worse and worse.
I had a look down through where the secondary rods are and I could see the fuel level was just a little below the gasket. I have no idea if this is too high or not. It's not overflowing or anything like that.
Seems weird that it would have a fuel level problem that is somewhat intermittant? Or is that something that can happen? Just for good measure, I put the old points and condenser back in but it made no difference. Was easy enough to try just for troubleshooting.
March 25th, 2023, 05:18 AM
