I'm about to give up diagnosing this 65 Valiant I got. I'm desparately trying to get it roadworthy. But I know right now it would be unsafe to drive it on the road. It's got either an ignition issue or fuel issue but I can't figure out for sure how to diagnose where the problem lies. The engine is a 1966 170 with I'm guessing 50,000-60,000 miles going by how it looks under the valve cover. It had been sitting it a shop parking lot for 2 years until I got it about 3 years ago. Since then I've redone the brakes, a few gaskets, distributor point-type, new voltage regulator, ballast, coil, wires, plugs, engine/dash harnesses, rebuilt gauges, starter, alternator, water, thermostat, fuel tank, lines, sending unit, and about 3 remanufactured Holley 1920's. Currently have a correct for 65 3054 List on it. I also had it off last week adding a correct original fuel bowl baffle. Checked float level and it was correct. Once it gets up to operating temperature and even before in Park it idles perfect, no smoke. Steady 550 RPM which is factory specs. It has 17 in-hg vacuum at idles drops to 14-15 in drive. I can't drive it on the road but just around the yard when you give a half throttle or full throttle it will buck and spit, and sometimes even stall. Well after it warms up it still does it. The heat riser is stiff but can be moved freely by hand, I've flushed it with solvent many times but it never get's totally loose. My fuel pump puts out 5-6 PSI and when you shut it off it doesn't drop down right away. I checked dwell today it's a steady 41.5 degrees. Could the pump still be bad eventhough the pressure is right at idle? It's definitely something that happens after it's put into drive.
Can fuel pump be bad with a constant 5-6psi reading?
- Thread starter wh23g3g
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kesteb
Well-Known Member
Most parts store carb rebuilds are junk. The symptons seems to indicate not enough accelerator pump shot, or not enough initial advance.
The 550 rpms at idle should be with the transmission in drive.
The 550 rpms at idle should be with the transmission in drive.
OUTLAW
Master of All Mopars
There are 2 properties when checking a fuel pump. 1 is pressure and it sounds like you are ok there. the next is volume a pump can have proper pressure and insuffient volume. I don't know what the volume is for your car but I would venture a guess that if it pumps a cup of fuel in 15 to 20 seconds that is ok too. I would look for trash in the line or as stated above no accell pump action.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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If the fuel bowl is full, you will be able to idle that 170 for at least a minute or two, or drive it around the parking lot for nearly as long, or have at least one good half throttle burst to 15/20 mph.
It sounds like you have a power valve issue,an accelerator pump issue, or the vacuum advance can is pulling the plate off to one side, destroying the ig. dwell.
Or a freaky thing such as a cracked insulator on one plug.
-Its hard to imagine 3 carbs all having the same symptoms, so for the moment lets assume the carb is possibly ok. As a quick test, I would disconnect the vacuum advance unit,plug the line to the carb, and roadtest it one more time.
-Your vacuum sounds a little low in drive.A 3 to 4 inch drop at550, going from N to D sounds a bit much. That 6banger convertor shouldnt be that tight. So I would suspect a timing issue,or a mechanical issue, before a carb issue. I think the pump is fine.
-Have you done a compression test.One or more non-sealing intakes could contribute to your symptoms.
-When a 4 cycle engine is shut off there is always one or two valves that remain partially open. If it sits for a long period of time this way, condensation gets inside the engine and rust can form on the valve stems and even the sealing surfaces.Perhaps enough rust forms,to prevent the valve(s) from sealing. Now, the engine may idle, because very little combustion pressure exists at idle;but the vacuum will be low. As combustion pressure goes up, some of it may leak back up into the intake manifold, upsetting the mixture there. As the combustion pressure rises to maximum, under WOT full load low to mid rpms, a lot more combustion pressure can get back into the intake, and then you have crap happening.Then at higher rpms there may not be enough time for the pressure to escape back into the intake, or other cylinders may pick it up. The end result of that would be that the engine begins to run better, at least somewhat.
-Now, Im not saying thats whats going on with your slanty, only that its a possibility.And there are other simpler possibilities.Such as a tight valve adjustment, a bad coil or cap, or secondary voltage leakage.
-A compression test may not prove this valv thing either. But it will provide the basis for justifying the next test; the cylinder leakage test.
-So on that note, I would recommend a valve adjustment to the loose side of the spec. Then the compression test. If this test shows one or more low cylinders, then the leakdown test is called for.
Good luck
It sounds like you have a power valve issue,an accelerator pump issue, or the vacuum advance can is pulling the plate off to one side, destroying the ig. dwell.
Or a freaky thing such as a cracked insulator on one plug.
-Its hard to imagine 3 carbs all having the same symptoms, so for the moment lets assume the carb is possibly ok. As a quick test, I would disconnect the vacuum advance unit,plug the line to the carb, and roadtest it one more time.
-Your vacuum sounds a little low in drive.A 3 to 4 inch drop at550, going from N to D sounds a bit much. That 6banger convertor shouldnt be that tight. So I would suspect a timing issue,or a mechanical issue, before a carb issue. I think the pump is fine.
-Have you done a compression test.One or more non-sealing intakes could contribute to your symptoms.
-When a 4 cycle engine is shut off there is always one or two valves that remain partially open. If it sits for a long period of time this way, condensation gets inside the engine and rust can form on the valve stems and even the sealing surfaces.Perhaps enough rust forms,to prevent the valve(s) from sealing. Now, the engine may idle, because very little combustion pressure exists at idle;but the vacuum will be low. As combustion pressure goes up, some of it may leak back up into the intake manifold, upsetting the mixture there. As the combustion pressure rises to maximum, under WOT full load low to mid rpms, a lot more combustion pressure can get back into the intake, and then you have crap happening.Then at higher rpms there may not be enough time for the pressure to escape back into the intake, or other cylinders may pick it up. The end result of that would be that the engine begins to run better, at least somewhat.
-Now, Im not saying thats whats going on with your slanty, only that its a possibility.And there are other simpler possibilities.Such as a tight valve adjustment, a bad coil or cap, or secondary voltage leakage.
-A compression test may not prove this valv thing either. But it will provide the basis for justifying the next test; the cylinder leakage test.
-So on that note, I would recommend a valve adjustment to the loose side of the spec. Then the compression test. If this test shows one or more low cylinders, then the leakdown test is called for.
Good luck
I thought about trying the test of disconnecting the vacuum advance and plugging it and then test driving. I don't think I've done it before. Someone earlier had suggested valves too tight, so I checked them the proper Chrysler way but there was none out of specs. I actually have another remanufactured Holley 1920 sitting in a box that I haven't put on because going through 3 remanufactured carbs and still the same symptoms I'm thinking that maybe the carb isn't the problem. I have not done a compression test on this one but I know I need to so I can see where the engine is at as far as being gone. I know when I had the timing cover off to change the gasket and front seal the timing chain didn't have any slack in it. I know they want the engine to be at operating temperature before you do the compression test but can you still do it without that so I can avoid getting burned. I've only done a test one time on another engine, don't you do one cylinder at a time? Or do I remove all the plugs at once? I recently had the intake and exhaust manifold off because of a small intake leak. Now the same place where the intake leak was before is no longer there. I cannot find any vacuum leaks around the intake or carb. I know the fuel pump isn't but about $20 but again it appears to be changed recently before I got the car and I don't really think it's the problem so I haven't changed it either. I wouldn't be surprised if the distributor vacuum advance is bad. So if I disconnect it and plug the ports on the advance and that is indeed the problem will the car be performing better or what is it going to do?
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Hi there.
-I take it you are new to this fixing thing. Thats ok. we all had to start the same way.
-First off, theres several good responses in this thread which pertain to the accelerator pump. Make sure yours is adjusted correctly and working.With the engine off, and the filter house removed,lean over the top of the carb and shine a flashlite down the throttle bore. Then operate the throttle to open the butterfly(s). If its working correctly, you will see a stream of gas squirting into there. It will begin immediately as you operate the throttle and should continue un-interupted for almost as long as you continue to rotate that arm. It HAS to begin immediately. It HAS to continue un-interupted.
-The idea with the vacuum advance is just to disable it for the short roadtest, and if theres no change in the way it performs,then to reconnect it.
-Next is timing. Most of the guys here running sixers,me included on my beater, have discovered that our slantys like way more idle and low speed timing than the factory ever gave them. Unfortunately if you change the initial timing you will have to modify your distributor to not over advance it under WOT/full-load conditions.In your case I would crank the initial up to ten or even fifteen degrees, BEFORE TDC to see how it responds.If the problems disappear, the dizzy will need to be modded. When/if you do crank in more timing, you will need to be aware of the sound of detonation occuring, in which case, back out of the throttle immediately.Or just stay out of WOT/full load.At the completion of the test, you will need to put the timing back, until such time as you have modded the dizzy, if it turns out to solve the problem.
-As to the V-can.The stem of the can locates the point-plate in the dizzy.( I think I read that you have a new point-type dizzy, but Ill include this description, because I think its still relative).When the parts in there get old,and the can gets to yanking on the plate, part of that motion may get used to close up the point gap or push the drive shaft over to the side. This ends up destroying the dwell time, and the timing. The end result is crappy running when the can gets vacuum. Which is any time except idle and somewhere near or after half-throttle to wot(wide open throttle). The rest of the time the can is seeing varying amounts of vacuum and transferring varying amounts of motion to the point-plate. So thats why we disconnect the hose for the retest.The engine wont respond properly and will feel sluggish, as compared to a properly working system, but if the problem you are experiencing stems from the worn dizzy, this will alleviate or eliminate the issue. If it gets better but not eliminated I would open the point gap another .006 or so(doesnt have to be exact) and retest.If problem disappears,its time for a new dizzy.
-While youre in there you might as well test the can. With engine running, just suck on the carb end of the hose that goes down to the vacuum advance can. The engine should pick up rpm, and should remain at that new rpm for as long as you keep suction on the hose.
-Wait I just reviewed your new parts list and noticed you have a dwell meter. In that case, just put the dwell meter on the running engine, and suck on that hose as described above. If the dizzy is in good shape the dwell wont change much, if at all. No roadtest required.
-I know you said the valve adjustment was good. But From your earlier posts Im under the impression that youre new to this activity, so if you dont mind could you elaborate a bit on how you performed it, and the specs you used, and if the engine was hot or cold, please.
-So, the compression test. Yes its best to do it with the engine warmed up. All the plugs come out before starting. Dont use a cheap gauge or a push-on-the-hole type.The results are only as good as the equipment used.The plugs are on the "cold" side of the engine.You may have to loosen the alternator and rotate it out of the way, to test no 1. Be careful not to short out that big fat wire thats hanging off the back of it.
Crank the engine til the gauge peaks. Count the number of compression cycles that it takes to peak. Record all the numbers. Yes its ok to stop in the middle of the test(not recommended), so long as the gauge holds the last reading.
-I take it you are new to this fixing thing. Thats ok. we all had to start the same way.
-First off, theres several good responses in this thread which pertain to the accelerator pump. Make sure yours is adjusted correctly and working.With the engine off, and the filter house removed,lean over the top of the carb and shine a flashlite down the throttle bore. Then operate the throttle to open the butterfly(s). If its working correctly, you will see a stream of gas squirting into there. It will begin immediately as you operate the throttle and should continue un-interupted for almost as long as you continue to rotate that arm. It HAS to begin immediately. It HAS to continue un-interupted.
-The idea with the vacuum advance is just to disable it for the short roadtest, and if theres no change in the way it performs,then to reconnect it.
-Next is timing. Most of the guys here running sixers,me included on my beater, have discovered that our slantys like way more idle and low speed timing than the factory ever gave them. Unfortunately if you change the initial timing you will have to modify your distributor to not over advance it under WOT/full-load conditions.In your case I would crank the initial up to ten or even fifteen degrees, BEFORE TDC to see how it responds.If the problems disappear, the dizzy will need to be modded. When/if you do crank in more timing, you will need to be aware of the sound of detonation occuring, in which case, back out of the throttle immediately.Or just stay out of WOT/full load.At the completion of the test, you will need to put the timing back, until such time as you have modded the dizzy, if it turns out to solve the problem.
-As to the V-can.The stem of the can locates the point-plate in the dizzy.( I think I read that you have a new point-type dizzy, but Ill include this description, because I think its still relative).When the parts in there get old,and the can gets to yanking on the plate, part of that motion may get used to close up the point gap or push the drive shaft over to the side. This ends up destroying the dwell time, and the timing. The end result is crappy running when the can gets vacuum. Which is any time except idle and somewhere near or after half-throttle to wot(wide open throttle). The rest of the time the can is seeing varying amounts of vacuum and transferring varying amounts of motion to the point-plate. So thats why we disconnect the hose for the retest.The engine wont respond properly and will feel sluggish, as compared to a properly working system, but if the problem you are experiencing stems from the worn dizzy, this will alleviate or eliminate the issue. If it gets better but not eliminated I would open the point gap another .006 or so(doesnt have to be exact) and retest.If problem disappears,its time for a new dizzy.
-While youre in there you might as well test the can. With engine running, just suck on the carb end of the hose that goes down to the vacuum advance can. The engine should pick up rpm, and should remain at that new rpm for as long as you keep suction on the hose.
-Wait I just reviewed your new parts list and noticed you have a dwell meter. In that case, just put the dwell meter on the running engine, and suck on that hose as described above. If the dizzy is in good shape the dwell wont change much, if at all. No roadtest required.
-I know you said the valve adjustment was good. But From your earlier posts Im under the impression that youre new to this activity, so if you dont mind could you elaborate a bit on how you performed it, and the specs you used, and if the engine was hot or cold, please.
-So, the compression test. Yes its best to do it with the engine warmed up. All the plugs come out before starting. Dont use a cheap gauge or a push-on-the-hole type.The results are only as good as the equipment used.The plugs are on the "cold" side of the engine.You may have to loosen the alternator and rotate it out of the way, to test no 1. Be careful not to short out that big fat wire thats hanging off the back of it.
Crank the engine til the gauge peaks. Count the number of compression cycles that it takes to peak. Record all the numbers. Yes its ok to stop in the middle of the test(not recommended), so long as the gauge holds the last reading.
I'm going to try unplugging the distributor vacuum advance first. I suspected it could be a problem because I thought it happened on my Charger too. I don't have a good vacuum pump or one that's affordable. I did the valve adjustment according to the Chrysler service manual, I think the specs were .010 and .012 but don't remember which side is which unless I look it up. But they were all within specs. I did it precise too, I divided the damper pulley evenly into whatever degrees it was and turned to each mark and checked the appropriate valves. The only valve clearance check I've done before that was on a 76 Datsun 210 and I don't remember it being as complicated. If it's a bad distributor that would be easy, because I can just warranty it out. I know it's something simple and annoying causing this. I know there's bad accelerator pumps but when I've gotten 3 remanufactured carbs within the last year from the same company I'm putting that last on the list. I do see a good constant stream of fuel come out when I snap the throttle. It also starts up fairly quick and stays running even after a few days of sitting without starting. Like it starts up and stays running on the second try.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I think those valve specs are too tight. I seem to remember them being looser. Like .010intake and .020exhaust. I set mine hot and a tad looser.(12/23)
The accelerator pump should start immediately when you begin to GENTLY rotate the throttle arm. Not snapping.
Setting the valves with the piston at TDC(each one in turn) the way you did is the most accurate way. There are other simpler and quicker ways. But the TDC way is the most accurate.
You dont need a vacuum pump. Human power is sufficient to operate that Vcan.
I doubt your problem is simple.Putting air in a low tire is simple. Trouble-shooting and Tuning is/are probably the most complicated procedures to do with cars. And its only getting worse as time marches on.
Try more timing. 10*BTDC, to as much as 15*BTDC. Reread post#6.
The accelerator pump should start immediately when you begin to GENTLY rotate the throttle arm. Not snapping.
Setting the valves with the piston at TDC(each one in turn) the way you did is the most accurate way. There are other simpler and quicker ways. But the TDC way is the most accurate.
You dont need a vacuum pump. Human power is sufficient to operate that Vcan.
I doubt your problem is simple.Putting air in a low tire is simple. Trouble-shooting and Tuning is/are probably the most complicated procedures to do with cars. And its only getting worse as time marches on.
Try more timing. 10*BTDC, to as much as 15*BTDC. Reread post#6.
I tried warming up the engine to normal temp then plugged vacuum advance and carb fitting. Nothing changed at all in the way it runs. After that I stopped and checked to make sure my choke wasn't stuck but it was fully open. I stopped and looked at the fuel stream when I rotated the throttle. I don't know how much is suppose to come out but it was clear and strong. I think I played with the timing but bumping it up didn't change anything. And there is only so far you can go because the way the hoedown is slotted. I think highest I had was 10 btc.
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