Car refusing to speed up and lack of power - Impala Tech
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post #1 of 32 (permalink) Old 06-05-2015, 10:37 PM Thread Starter
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Car refusing to speed up and lack of power

Some reason I remember there being a troubleshooting forum but I guess I was imaging things ??

Well anyways I just recently noticed something weird while driving and this has never happened before.

This only happens when I'm attempting to accelerate after a stoplight, going up a slight incline, or going up a small hill. When at a stoplight, I push down on the pedal quite a bit and it refuses to speed up like normal, sticks around 20 mph, then I hear the engine get quieter for a second, and it feels and sounds like it's about to die. In fact, it freaked me out to the point where I thought it was about to die. I was afraid to push on the pedal more because I was worried it would break down with cars behind me. Overall, it's really slow when just generally accelerating which is abnormal. It's pretty much the same situation when going up a hill. I was actually forced to shift into low really fast....which I don't normally do because it does fine in drive going up a hill.

So while making a stop some where, I just decided to put more lead/octane in the gas tank to be safe because I think a lack of that stuff causes engine failure in cars that require it.

Does anybody have the slightest idea what's going on? I have been driving it for a couple weeks now, 3 times a week with no problem.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #2 of 32 (permalink) Old 06-06-2015, 07:09 AM
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It sounds like a carb or choke issue. Black smoke is usually choke related. Bad fuel filter? Water in gas?
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post #3 of 32 (permalink) Old 06-06-2015, 08:45 AM
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Could be ignition or carb related. Sounds to be running overly rich.

There is no power to be gained by changing to a more expensive gas. 110 octane race gas won't make one horse more power in your engine than the cheapest gas you can find will. Raising the octane lowers the chance of detonation. If your car will run on 87 octane gas with out a death rattle then you don't need to run high test. In fact running rich lowers your chance of detonation which is why all carbs out of the box are jetted on the fat side.

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post #4 of 32 (permalink) Old 06-06-2015, 02:25 PM Thread Starter
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Hmmm...the first thing I actually did was check the choke and made sure there was nothing obstructing it but everything looked fine.

It's actually possible that there is water in there. I remember my brother was having some issues with his Buell motorcycle. It was sitting outside in the rain for a day or two while he was at my house. He tried driving away and it just kept breaking down while he was accelerating. We diagnosed it to something around the carburetor since it sounded like it was having trouble breathing. He ended up taking out the whole carburetor and sending it to a guy that specializes in them to get it rebuilt and scrubbed clean. He got it back, put it back on, tried testing it, and it just broke down. We came to the conclusion that there was water in the gas tank so we put some denatured alcohol in the tank and everything was fine afterward. On the upside, that rebuilt carburetor made everything run smoother for him and it sounded a whole lot better.

However, I'm not going to try putting denatured alcohol in it till I know exactly what's wrong and figure out the correct solutions. I'll also check the fuel filter when I get a chance. The thing is, I just don't know how water would get in there. It has sat out in the rain while covered numerous times and there isn't really a location (that I know of anyway) it would enter in. I also have a locking gas cap to prevent tampering.

Dave, I actually use unleaded/regular gas but still put lead substitute (not necessarily octane) in it since it requires it. It's been a long time since I got a tank of gas for it since it's been sitting around during bad weather. I always put lead substitute in whenever I refill the tank. I just figured it could use some more since it's really been that long.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350

Last edited by Classiccarman; 06-06-2015 at 03:07 PM.
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post #5 of 32 (permalink) Old 06-06-2015, 04:48 PM
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Too Late!

It already has 10 to 15% by volume denatured alcohol in the fuel already. If any rain water gets into the under ground tanks like they did back in the old days the gas doesn't float on top of the water: The water gets sucked up into the fuel bonding one to one molecule for molecule with the alcohol which is also bonded to the gas molecules.

Big Dave

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post #6 of 32 (permalink) Old 06-06-2015, 05:16 PM Thread Starter
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Hmmm...okay. So it doesn't really matter if water did get in because the denatured alcohol in the gas probably absorbed it anyway? I guess I'll check the fuel filter first then.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #7 of 32 (permalink) Old 06-07-2015, 10:37 PM
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Sounds to me to be a fuel pressure problem. Car is running out of fuel under a load. #1 check float level. #2 Check fuel pressure at pump. #3 check fuel filter, may be plugged. #4 Do you have the right fuel cap. Vented or non vented? #5 Check fuel lines for cracks or kinks. Alcohol dries out rubber parts in the fuel system causing them to fail.
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post #8 of 32 (permalink) Old 06-08-2015, 08:56 AM
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I'm with Dadstoy on this and have experienced a similar problem long ago that was fuel pressure/flow related. I think I had a kink in a rubber hose, but all of Dadstoys suggestions sound good to me.

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post #9 of 32 (permalink) Old 06-08-2015, 01:29 PM Thread Starter
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Thanks for the suggestions! I'll look at everything dadstoy has mentioned. I haven't had a chance to look at anything yet but I will towards the end of the week and post updates.

It's been sitting in one place since Friday. So if there is any kind of leak I may be able to spot something on the ground. If not, I'll check the lines anyway.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #10 of 32 (permalink) Old 06-08-2015, 08:43 PM
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Ive had this happen to me a couple times. Fuel pump both times. But a rusty tank will plug a fuel filter.
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post #11 of 32 (permalink) Old 06-09-2015, 04:10 PM Thread Starter
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So by simply looking and observing, I think I narrowed down on some of the suggested issues.

My fuel cap is non-vented, at least I'm pretty sure (I don't remember when I bought it, it is a aftermarket cap though). Whenever I go to the pump, I have to remove the cap slowly because you hear and feel the pressure being released, along with some fumes.

Most of my fuel line is metal and I don't see any leaks on the ground from where it has been sitting since Friday. The only rubber that I can see is on both ends of the fuel filter that only extends about 2 inches on both ends. One side connecting to the metal line and the other connecting to the fuel pump under the hood. The rubber looks and feels perfectly fine.

So I guess it's narrowed down to the fuel filter and/or fuel pump.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #12 of 32 (permalink) Old 06-11-2015, 09:52 PM Thread Starter
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So today I put in a new fuel filter with new rubber fuel injection lines for good measure. It's still acting the same way during a test drive around the neighborhood.

So I guess it's the fuel pump. I always buy parts from Summit and I found this one: http://www.summitracing.com/parts/cr...make/chevrolet

For my car and engine, that looks like the best result that pops up. Four of the results just say "stock" gph, which I guess is original and what I probably have. One had 50 gph but all it's attachments were female. This one is 30 gph with the right attachments.

What does everybody think of that one? Is that enough gph? What else factors in to getting a new fuel pump?

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #13 of 32 (permalink) Old 06-12-2015, 07:52 AM
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I have spent tens of thousands of dollars at Summit and Jeg's over the years. Never got so much as a Christmas card in recocognition (thgough Jeg's includes a ball cap with their name on it on many orders over $500 I don't consider my advertising for them to be a benifit). Point is though they do sell performance parts below suggested list price, they are not the place o be buying rubber hose or spark plugs. Shipping alone will kill you.

I can recommend if you are buying mail order; try Rock Auto dot com. I do so not because I am gettingh a discount, or any money in endorsing from them. Why is because they list American made parts first. They always list, if available a part from the GM OEM vendor that sold the parts back when your car was new and of course the inevitable off shore cheap priced part for the bottom feeders. Price is competitive even with shipping. Not going to beat WalMart on price but they have a much better selection.

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post #14 of 32 (permalink) Old 06-12-2015, 12:04 PM
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I buy what I can Local. Do not like to pay shipping. Check your fuel line size. That pump has a 3/8 inlet. Yours might be 5/16.
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post #15 of 32 (permalink) Old 06-12-2015, 01:18 PM Thread Starter
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I really don't mind shipping costs. Plus, the warehouse Summit ships in my area is in Nevada, I'm in Washington State. I end up paying a basic shipping cost (4-5 business days) and end up getting the parts in about 2 business days. Same idea with Amazon in California. Also whenever I get basic things like hoses, wiring, spark plugs, oil, lead, etc. I always go to O'Reilly's Auto if I know it's not worth buying it online.

I'll check the fuel line size today. But does everybody think that pump looks good? I'm not exactly sure what to get in regards to gph. I figure the one I have right now is less then 30 gph since it looks like the original/stock and it doesn't specify the flow rate. I'm pretty sure the flow rate needs to be just right. O'Reilly's offers expensive ones at 100+ gph for a small block which doesn't sound necessary.

Edit: Oh wait! O'Reilly's has one for 40 gph. http://www.oreillyauto.com/site/c/de...0401&ppt=C0025. I was looking at their performance section and saw the 100+ gph.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #16 of 32 (permalink) Old 06-17-2015, 03:39 PM Thread Starter
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Well I bought a fuel pump from Summit yesterday. I ended up getting one that supplies 80 gph since those can run on engines anything up to 400 horsepower and has 5-8 psi. I was going to go for this one: http://www.summitracing.com/parts/su...make/chevrolet. But I had to settle for their substitute because the first one is out of stock till next month: http://www.summitracing.com/parts/su...make/chevrolet.

Now I didn't do it for the price, I did it based off the reviews. The only other option was a "Holley Avenger" and I didn't like the mixed reviews it was getting due to problems.

But now I'm a bit paranoid because of stuff on the internet I was reading about how mechanical fuel pumps are made cheaply these days and out of the country. So I contacted Summit about where both of their Summit branded fuel pumps are made and who makes them. They said they aren't aloud to tell me who makes them but they're "big name" companies (plural). They're made in Korea, which wasn't surprising to me seeing how a lot of parts I've seen are made in Taiwan and Japan. From the reviews, I would guess one of the companies is Holley. So I guess I'm glad that I didn't spend the $80 on the Holley brand name pump which are made in Korea as well.

However, I do fear that it might crap out on me but I'll have to take the risk. If I find something else before I install the new one, like Edelbrock, then I might return the Summit one. After checking Summit I checked O'Reilly's and for 80 gph, they have pretty much the same stuff such as Holley and other high powered 100+ gph stuff but also Mr. Gasket which I hear is cheap as well. JEGS is loaded with Holley and has a lot of 110+ gph Edelbrock pumps. They also have this Carter one which looks interesting: http://www.jegs.com/i/Carter/180/M4891/10002/-1. I'll have to check to see where they're made though.

Thoughts? Advice?

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #17 of 32 (permalink) Old 06-17-2015, 04:01 PM
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My first thought is "you're over-thinking this". I understand your quality fears but since you can't control which country or poor kid made your fuel pump at least you can pick a company that will support you if you run into issues. (Holly, Edelbrock, Summit)

My 2nd thought is that I think you might also be over-thinking the GPH rating. I say this mostly because you're not currently experiencing an issue related to max-flow and I don't think you'll notice any difference between an 80GPH or a 110GPH. It doesn't force that much fuel to the carb, it just has the capability to flow that much under ideal conditions when needed.

In the end, the necessary GPH to support 400hp is much lower anyway.
According to Holley, around 30GPH.
http://holley.com/data/TechService/T...ech%20Info.pdf

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post #18 of 32 (permalink) Old 06-17-2015, 04:32 PM Thread Starter
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Thanks for the response! Yeah you're right, I'm over thinking it. But understandably, I don't want to end up stranded. These are the risks I have to take though.

That link doesn't work by the way. 40 GPH was my original estimate but I changed it to 80 GPH after reading the product descriptions and car part articles.

Regardless, I'll have to try out the one I bought in the interest of time and the fact it'll be here tomorrow with all the fittings. I'm pretty happy with the price as well.

80 GPH shouldn't hurt anything though, right?

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #19 of 32 (permalink) Old 06-17-2015, 09:53 PM
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Yep, you're right. Link bad. Damn web-site developers.

I poked around and found it here: http://documents.holley.com/techlibr..._tech_info.pdf

That one worked for me.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #20 of 32 (permalink) Old 06-22-2015, 05:50 PM Thread Starter
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For me that was the most disappointing moment of 2015. Well that most disappointing moment so far. I put it in the new 80 gph fuel pump and did a test run and I started having the same exact issues again.

It could be fuel in the gasoline. But I took a sample in a jar by unhooking the fuel filter, and let it sit for a few minutes but I don't see any water bubble at the bottom of the jar.

I'm not really sure what else to do. Any suggestions? Could be the timing?

Edit: I'm going to check the spark plugs next. Bad spark plugs have pretty much the same symptoms.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350

Last edited by Classiccarman; 06-22-2015 at 11:30 PM.
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post #21 of 32 (permalink) Old 07-15-2015, 12:35 PM
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All good advise from fellow members. Here is another simple one that will exhibit symptoms you mentioned. If your exhaust system is really old or sits around for years you could have a clogged muffler which inhibits air flow. If air gets into the engine it has to get out. If it doesn't your performance could lag to the point of almost zero acceleration. I had this experience many years ago and I couldn't even merge onto the highway but the car would cruise ok.

That's why if car is left to set for a very long time it's NOT a good idea to start it up for a few minutes to warm it up. You will be creating condensation in the exhaust system which rusts the insides of the pipes and muffler and all accumulates eventually in the muffler. This practice also allows moisture, gas and acids to mix with the oil. Not good. Drive the car. It's fun and helps with good promote good seals, engine, trans and rear end lubrication and assures fresh gas.
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post #22 of 32 (permalink) Old 07-15-2015, 01:35 PM
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The old potato up the tail pipe trick doesn't have to get that far back in the exhaust system to cause issues.

There is a by-pass valve in the exhaust that is spring loaded to open as the engine revs. But if it corroded shut in the closed position (the at rest or power off position) it could force all of the exhaust from the passenger side of the engine through a half inch by three quarters inch tunnel that passes through both heads and runs under the carb through the intake manifold. It was put there for cold weather operation, but in Florida is useless, so you rarely see one intact for long. You can find on line a hollow spacer to replace that heat riser flapper valve.

Not saying it is the issue . It is just one more part that can cause performance problems for those unaware it was put there.

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post #23 of 32 (permalink) Old 07-15-2015, 05:39 PM Thread Starter
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Quote:
Originally Posted by Big Dave View Post
The old potato up the tail pipe trick doesn't have to get that far back in the exhaust system to cause issues.

There is a by-pass valve in the exhaust that is spring loaded to open as the engine revs. But if it corroded shut in the closed position (the at rest or power off position) it could force all of the exhaust from the passenger side of the engine through a half inch by three quarters inch tunnel that passes through both heads and runs under the carb through the intake manifold. It was put there for cold weather operation, but in Florida is useless, so you rarely see one intact for long. You can find on line a hollow spacer to replace that heat riser flapper valve.

Not saying it is the issue . It is just one more part that can cause performance problems for those unaware it was put there.

Big Dave
It could literally be anything so any ideas will help. I looked up the heat riser flapper valve and some pictures show it directly below the intake manifold where the collector is. Where exactly is it located?

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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post #24 of 32 (permalink) Old 07-15-2015, 05:52 PM
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Here is a picture of the spacer that replaces the flapper valve:



A picture of the flapper valve:



The exhaust manifolds with the valve installed and spacer installed and with nothing installed excpt brass nuts that won't seize up solid with rust:



Picture of the heat riser valve attched to the manifold, and with a piece of straight pipe coming out the bottom



Big Dave
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post #25 of 32 (permalink) Old 07-15-2015, 06:11 PM Thread Starter
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Quote:
Originally Posted by wannaSS View Post
All good advise from fellow members. Here is another simple one that will exhibit symptoms you mentioned. If your exhaust system is really old or sits around for years you could have a clogged muffler which inhibits air flow. If air gets into the engine it has to get out. If it doesn't your performance could lag to the point of almost zero acceleration. I had this experience many years ago and I couldn't even merge onto the highway but the car would cruise ok.

That's why if car is left to set for a very long time it's NOT a good idea to start it up for a few minutes to warm it up. You will be creating condensation in the exhaust system which rusts the insides of the pipes and muffler and all accumulates eventually in the muffler. This practice also allows moisture, gas and acids to mix with the oil. Not good. Drive the car. It's fun and helps with good promote good seals, engine, trans and rear end lubrication and assures fresh gas.
Yes I've thought of this. I have angled glasspacks coming in today and I'll be cutting off my stock mufflers and replacing them. The idea here is to get a really good flow going instead of having a clogged muffler flow. I also desire more sound. While I'm under the car, I'll be inspecting all the pipes as well.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
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