Can a leaking fuel pump gasket cause vacuum leak?

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wh23g3g

wh23g3g

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So I've got my 65 Valiant driveable now. Even got it tagged and insured now. Drove it around the neighborhood a few times and it does good. It's the 170 with the Holley 1920 the correct oem number too, less than a year old. I believe I can pretty much drive it wherever and however long I feel ok with. I know the front end is shot though. It starts good, idles good, and drives good. Unless you do full throttle to the floor from a dead stop. I had a mechanic come over and now everything's been gone through, charging system now working properly, timing has been reset, carb adjusted, ignition firing good, points set, fuel pressure is 5psi, new fuel system throughout. That's the only driveability problem now is just full throttle from a dead stop to the floor it will cut off, but it's easy to start up right away so it's not getting flooded. No vacuum leaks apparent at the intake. It's got good 17-18in-hg vacuum at idle. I noticed over by the fuel pump some oil spray but not leaking down from the head gasket or valve cover. So I'm assuming it's from the fuel pump. Could that gasket cause a vacuum leak too causing performance problems but still produce the required 5psi at idle? I can't think of anything else we've not gone through. It's pretty sparse under this hood, no power steering, no a/c. I know it's not a powerhouse but it should not cut out just because you stomp it to the floor from a stop.
 
No. Will leak oil. A bad pump can leak oil into the pan, which is a serious problem.
 
1920's don't hold a lot fuel, so in my opinion it could be the fuel pump (even though it shows 5 pounds) what is the volume it puts out at 5 lbs?
Not expecting you to know the answer to that right now, but I am expecting you to find out. :D
Like you said, everything else you could think of has been done.

Pumps are cheap, but I also realize we cant always just run out and buy something either.
 
SGBARRACUDA said:
Oh no a bad pump can leak OIL in the pan! Sorry I had to throw a jab at you. You mean, can leak gas into the pan? right?
Click to expand...

Well LOL I guess it depends on what you put in the "fuel" tank

In my life I've been privy to THREE explosions due to fuel

First was early seventies. I was stuck on shore patrol in San Diego. They had me typing booking forms, I hated it, but that's another story

We had a third class was 'always late' One day he called, came in late, and said "you won't believe this."

I said "probably not, it better be good"

He said he had "the kid" go out and start his 57 Chev, and they heard a loud noise. Went out and the hood was dented FROM UNDERNEATH. It had blown the oil breather / filler cap off and hit the hood, and had ruptured and blown one valve cover right off the engine!!!

===============================================

The other notable one one night in my home town we were leaving a local cafe / bar late. A late seventies Ferd was parked, someone getting in and fired it up. All sorts of noise, flame, sparks, and flame come from underneath. It ruptured the oil pan!!!!

================================================

Last one I was not close to. Friend of mine showed photos of the damage.
 
I don't smell any fuel in the oil so hopefully it hasn't started to get into the pan. I'll have it changed within a week. So it won't be driven all week. I was told it could be an accelerator pump issue but I swapped out the carb two different times with another and the problem always remained. I may as well swap out the fuel pump regardless for reliability. I can't trust the fuel gauge either so never know how much gas is actually in the tank, I've had all kinds of problems out of these gauges that I've had redone. I get one working and then another goes out. Now the fuel gauge works seemingly correct sometimes and sometimes it will go all the way to full and I just had it redone, it took forever to get it back too. Luckily I had a spare one redone while having the temp gauge redone. Can you run any seafoam through this engine since it doesn't have a brake booster hose to use, what can I use to inject it? I'm sure the valves could use some cleaning since it's not been in service for over 10 years. It doesn't smoke. It definitely isn't a powerhouse stock. It sounds like a v8 but sure doesn't match it in power. Little 170 with 101hp and 155lbs-ft. No idea why whoever swapped the 225 for this 170, according to fender tag should be a 225. Block number comes up as a 1966 170. Still it's cool to cruise around in eventhough it's just a junk car that was on it's way to the crusher when I was able to save it.
 
I know you said you swapped out the carb a couple of times, but let me ad those 1920 carbs were prone to bad accelerator pump issues. I'll bet if you look down the carb and work the throttle slowly you will notice a lack of pump shot. Speed the motion up until you see the squirt. Do this with the engine OFF for heavy sake. I've had to work on pump linkage and travel on these carbs in years past. I was turning wrenches when these were new.
 
17-18 at idle doesn't sound all that good, could be as high as 21-22. have you adjusted your valves yet? if it sputters on a WOT from a stop, your accelerator pump is not up to par, check the linkage and also your timing. make sure your pot holds a vacuum and the plate is moving. pop cap and suck on advance hose: observe breaker plate rotating, now use your tongue to plug vacuum hose and see if plate holds. easier done than said. My 1920 had a strange hole in the side that spit fuel when the accelerator pump went bad. strange design.
 
Well I've installed a vacuum gauge on it to see where the vacuum is sitting at idle and it's 17-18 which according to the gauge is in the low side of the good zone. I would like it if it were higher. I don't know what the mileage or the age of the rebuild on this engine is if at all it was ever rebuilt. It's a swap previous owner swapped 225 for a 170. I tried rebuilding the 1962 Holley 1920 that came on the car with a new accelerator pump and all that was in the kit. It still had the same symptom. I tried to check the clearance on the valves the Chrysler way and none were off specs. But I could've still done that wrong because I wasn't totally familiar with the procedure. My mechanic took out the distributor and moved it a notch over and got it to the good running condition it is now. I can't remember what the total timing was but I want to say it was around 30 degrees total timing. I know specs on this year engine is initial 2.5 btc but he said he does by highest vacuum. Which I'll admit the engine runs better than when only I was fooling with it because I can actually drive it now. But eventhough I can still drive it and eventhough it's not a big block high horsepower motor it should still take off when you mash the gas to the floor. What if you were driving it and for some reason had to pass someone or you had to turn in somewhere before a car hits you? It should be able to take off without cutting off, that's almost a safety issue. Does the Carter BBS for this year perform any better than the Holley 1920? I haven't tried it.
 
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