Author Topic: I cant freaking win. Sound like fuel pump? (Read 3582 times)

torredcuda · « **Reply #15 on:** July 25, 2009 - 09:11:17 AM »

If it only dies after a long ride when it`s hot I would suspect vapor lock.I also had a car that would die after driving 20 minutes and it was old rubber fuel line collapsing on the inside but looked fine.Replaced the couple short sections or rubber line and no more dying out.Another idea is to route a remote line and temporarily mount the fuel pressure gage to the cowl or somwhere you can read it while driving and see what pressures you have.

wally426ci · « **Reply #16 on:** July 25, 2009 - 09:18:45 AM »

Is this motor pretty stock? Id lose the regulator and try an OEM fuel pump for kicks.....

burnt orange · « **Reply #17 on:** July 25, 2009 - 10:27:59 AM »

I had a 77 GMC pickup with the same problem. I replaced EVERYTHING except the carb and the pickups in the tanks. It would run great most of the time, but at some awkward point in time it would crap out just like you describe (hauling trailer in mountains, rush hour traffic in the city....) I worked on that problem for hours and hours and never did resolve it.

I finally sold the truck to a friend. He knew all about my problems with it.

Now, here is the weird part - the problem never happened again! He did the same sort of driving as me, never did a tick of work on the fuel system. The only work he ever did was to repair rust asnd repaint the body!

I am totally convinced cars are alive. That truck was just dicking me around and liked the new owner more. My Cuda responds to me talking to it, and certainly has a personality.....am I crazy?

This probably doesn't help you very much, but maybe you should talk nicely to your car, or paint it again or sell it. Good luck in any case.

shadango · « **Reply #18 on:** July 25, 2009 - 11:36:07 AM »

Quote from: torredcuda on July 25, 2009 - 09:11:17 AM

If it only dies after a long ride when it`s hot I would suspect vapor lock.I also had a car that would die after driving 20 minutes and it was old rubber fuel line collapsing on the inside but looked fine.Replaced the couple short sections or rubber line and no more dying out.Another idea is to route a remote line and temporarily mount the fuel pressure gage to the cowl or somwhere you can read it while driving and see what pressures you have.

I've replaced the rubber fuel lines......back by the tank, just a short piece, and then at the front, to the fuel pump.

I just got back a while ago from a ride....drove around just fine for a good 20 miles or so.....them as I got closer to home, it wanted to die when stopped, in drive..........as I got closer to home, same as yesterday, it got uglier.

Have been messing with it in the garage now for a good couple hours.....tried different variables:

Swapped in a new ignition module
Swapped in a new ballast
Checked coil readings....16k or so between either terminal and the center, low ohms across the two terminals
Voltage at the coil is around 6.8 or so when not running.....higher , like 8.9 , while running
Tried different rod springs
Tried different settings of the IMS screws, a half turn at a time, either way
Tried bumping up the throttle screw a bit, by 1/4 turn...idled faster but still no good.
Tried adjusting fuel pressure from 5 to 6, then to 4

In all cases, the engine idles, starts running poorly at some point and then dies out on its own unless I gas it.

Fuel filter still looks like it doesnt have much gas in it, but the carb is getting fuel, cause when I work the throttle I get gas there.....

Watched the venturi nozzles a idle and I cant see any gas dripping....

I am at wits end.

shadango · « **Reply #19 on:** July 25, 2009 - 12:20:04 PM »

Ok, now I just went back out after it cooled down again.....then as it warmed up, it started running a bit rougher as predicted.....faint smoke from the exhaust, and very heavy fumes....

Looked again at the carb and noticed that every so often a drop of fuel would come out of the booster nozzle on the driver side....sometimes a bigger drop than others....where the gas shoots out for the accelerator pump...in the center of the venturi, facing down.....seemed to affect the idle poorly for a split second......

What causes that? I know it shouldn't do that so that will be my first thing to consider......

*********
update

Well, I tried lowering the idle a bit by screwing out the throttle screw 1/2 turn and richening the IMS screws by 1 turn.

WHile I can no longer see the dripping from the booster venturi, it still dies out.

71chally416 · « **Reply #20 on:** July 25, 2009 - 01:37:06 PM »

Sounds to me like you're just shooting in the dark and trying process of elimination to fix your problem. I suspect you have some kind of carb issue but I don't recommend that you try to fix it yourself if you have no expertise with carbs. You're probably not ever gonna get it right with internet directions.

Before you go spend more $$$ for parts get somebody that knows carbs to go over your carb and adjust it for you. Especially the floats and the mixture when the motor is warmed up. There really is no "one turn" or "two turns" rule to setting the mixture. It takes experience to know where to set the mixture screws and they could be different from side to side, especially with a dual plane intake.

shadango · « **Reply #21 on:** July 25, 2009 - 01:53:32 PM »

I hear what you are saying.......

The float level is pretty simple to set.......and shouldnt matter if the car is warm or cold, rght? I followed the edelbrock directions...actually have done it a few times now, between two carbs.....and had similar issues with both eddy carbs. I could be set a little low right now, since running them at the 7/16" measurement seemed to make matters worse....

As far as idle mix, yeah, I hear ya as far as needing to have a trained ear....but again I followed the eddy directions....start at 1.5 turns out, adjusting each side til the idle increases...then lower throttle screw, do other side.

Folks here suggested that my low idle vacuum could be due to a leaky intake gasket.....had been putting that off to try this other stuff....again, not sure if I have a cam or not, but sure idles like it does. The cam could explain the low vaccuum at idle to a degree....(4-5 " hg)

I am also still wondering if it is vapor lock inside the carb maybe.....like the fuel in the bowls perculating....the body of the carb does feel pretty hot.....I am already running the special heat-isolatiing gasket eddy recommended.

I do feel like I am running in circles though. I swapped out the ignition box and ballast cause they are cheap and easy and I need to carry spares anyways I am told....the fuel pump, again, cheap try and now I have a spare.....so nothing lost here but my time and frustration

But yeah I am feeling frustrated. It runs well enough until its hot and then all heck breaks loose.......thats the frustrating part.

quagmire · « **Reply #22 on:** July 25, 2009 - 05:48:24 PM »

Coils also have a nasty habit of failing when hot too, may be worth checking if everything else checked out okay. Have you done a compression test yet? That may give you some indication as to whether you have a mechanical problem or if you do have a huge cam. If the compression is high, then you probably do have an intake sealing problem with vacuum that low.

wally426ci · « **Reply #23 on:** July 25, 2009 - 07:03:22 PM »

What about the pick-up coil in the distributor? Ive heard that could cause a similar problem...... anyone?

quagmire · « **Reply #24 on:** July 25, 2009 - 07:08:49 PM »

Sure could. Even on older cars like this there are multiple things that can partially fail with temperature changes.

71chally416 · « **Reply #25 on:** July 25, 2009 - 07:27:54 PM »

Sometimes Intake gaskets can leak from the inside too when the motor warms up. You could be losing vacume and sucking oil in from the lifter valley. That would explain the smoke and rough running when it's warmed up, but that you can't detect any leak on the outside. I think you said you have a stripped out Intake bolt? You should re-gasket the Intake and Helicoil the stripped bolt. Something is obviously changing when the motor gets warm and that's the most likely culprit to me.

6packCuda · « **Reply #26 on:** July 25, 2009 - 10:04:16 PM »

Did your troubles start after filling the fuel tank? It's possible that you got a tank of crappy low octane gas that is boiling way too easy and causing it to vapor lock. A fresh tank of gas just may help.

shadango · « **Reply #27 on:** July 26, 2009 - 08:56:49 AM »

Quote from: quagmire on July 25, 2009 - 05:48:24 PM

Coils also have a nasty habit of failing when hot too, may be worth checking if everything else checked out okay. Have you done a compression test yet? That may give you some indication as to whether you have a mechanical problem or if you do have a huge cam. If the compression is high, then you probably do have an intake sealing problem with vacuum that low.

Yes, I did a compression check and all cylinders were ok...in the 150 psi area as I recall....pretty consistent across all.....

I just took a ohms reading on my coil.........while cold it is reading about 10,800 ohms or so from one terminal to the center. When its hot, it is reading around 13,600 to 13,800......

The coil is an Accel super stock coil....according to their website it should read

Primary 1.2 OHMS
Secondary- 8.9 K OHMS.

Cold, mine is reading
Primary 1.5 to 1.6 ohms
Secondary - 10,900 ohms

Hot, mine is reading
Primary - in the 2.0 range as I recall, didint write that down.
Secondary - 13,600 or so, as high as 16,000 at one point if memory serves.

Wonder if that is enough of a jump to be causing my issues? Maybe the spark is weakening due to the increasing resistance when it gets hot and there isnt a strong enough spark to keep her running?

The first Accel super stock coil I had started leaking so I replaced it with another.....

These readings though have me wondering....

I am thinking about just getting a oem coil and trying that......

71Chally.....When I had my carb off I did notice a thin film of what appears to be oil on the floor of the manifold......the smoke at the exhaust is very very difficult to see but its there...cant tell if its black or blue smoke though.....how would the intake gasket be leaking "internally" ? I did the tests that some folks suggested......taped up the breather hole, put my thumb over the pcv valve hole and got a slight buildup of pressure (not vacuum).....that seems to indicate no internal leak, doesnt it? Not sure if I did that test though when the engine was hot and having issues or if it had cooled down by then......maybe thats the next thing?

Get a stock coil and try it, which means warming her up.....and if it still dies, check the pressure test again?

Or do you think the test I did isnt accurate?

shadango · « **Reply #28 on:** July 26, 2009 - 09:05:18 AM »

Quote from: 6packCuda on July 25, 2009 - 10:04:16 PM

Did your troubles start after filling the fuel tank? It's possible that you got a tank of crappy low octane gas that is boiling way too easy and causing it to vapor lock. A fresh tank of gas just may help.

The question I have is: if its vapor lock, would there still be fuel at the carb? I thought vapor lock caused the line/carb to run dry? I have pulled the fuel line at the carb when it acts up and there is (cool) fuel there...actually the fuel comes out of the carb at the fitting at a good rate too..so carb has fuel....unless its boiling in the bowls.....but I am running the heat isolating gasket already....how can I check to see if the fuel is boiling in the bowls?

71chally416 · « **Reply #29 on:** July 26, 2009 - 09:50:34 AM »

Quote from: shadango on July 26, 2009 - 08:56:49 AM

71Chally.....When I had my carb off I did notice a thin film of what appears to be oil on the floor of the manifold......the smoke at the exhaust is very very difficult to see but its there...cant tell if its black or blue smoke though.....how would the intake gasket be leaking "internally" ? I did the tests that some folks suggested......taped up the breather hole, put my thumb over the pcv valve hole and got a slight buildup of pressure (not vacuum).....that seems to indicate no internal leak, doesnt it? Not sure if I did that test though when the engine was hot and having issues or if it had cooled down by then......maybe thats the next thing?

The soot inside your intake could just be from reversion because of the cam. I've had multiple gaskets leak internally on both big and small blocks. Sometimes the SB gaskets break down from getting oil soaked if they are the wrong type. The internal cylinder leakage from blow-by will overcome any internal vacume caused by an Intake leak. It'll be easy to see if you pull the Intake and one or two adjacent head ports are oil soaked.

Author Topic: I cant freaking win. Sound like fuel pump? (Read 3582 times)

torredcuda

Re: I cant freaking win. Sound like fuel pump?

wally426ci

Re: I cant freaking win. Sound like fuel pump?

burnt orange

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shadango

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shadango

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71chally416

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shadango

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quagmire

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wally426ci

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quagmire

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71chally416

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6packCuda

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shadango

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shadango

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71chally416

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