fuel delivery issues

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jctucker

fuel delivery issues

Post by jctucker »

I was pulling out of my wife's work thursday, getting on it pretty good when I suddenly lost power. it was still idling a little bit so i limped into a parking lot and turned it off. There wasn't (that I noticed) any unusual noises. Carb linkage is ok. Cranks, no start. It sputtered a little bit once in awhile and once or twice would even kinda idle for a second. I pulled the fuel feed hose off the carb, nothing coming out at all.

I expected this and had ordered a pump from IAP that Monday. Pump was there the next day. Got the pump installed last night, same issue. Tank is 3/4 full. Lines are clear, filters are clear. I removed and re-installed the pump 3 or 4 times (and this isn't my first rodeo), same issue.

I found a thread where some had a broken auxillary shaft. Is this common? I'm assuming I can watch the shaft thru the fuel pump hole and see. Oh, the timing belt is in good shape. If I spray carb clean down the carb it'll idle. Thoughts? Thanks everyone, this has really got me bummed out.

Edit: I had ordered the fuel pump before this happened because of long cranking issues after the car sat for more than a few hours, long cranking when below 1/2 tank and, frankly, not wanting to start at all when parking nose up on a hill.
grittracing

Re: fuel delivery issues

Post by grittracing »

had you been driving for a while before getting to the wife's work? and or did you sit in the parking lot for a bit till she came out.

couple thoughts to check

1 make sure your fuel line is routed far enough away the engine to keep from it vaporating before carb.
2 carb rebuilt kit , in the pump (i think its called a pump)on the carb there is a diafram that goes bad that can cause
someething about the same.
3 check the high end jet to make sure it isnt plugged with something
jctucker

Re: fuel delivery issues

Post by jctucker »

My wife's work is about 20 minutes from the shop, but it was about 90 out. Ran awesome all the way there. Pulled into the parking spot, shut it off and came back out about 5 minutes later. Started right up and drove off. As soon as I hit Speer (the main drag) I punched it and a second later it fell on its face.

1) Vapor lock was my first thought. No dice, it's still doing it even when cold and cracking all the lines.

2) I replaced the accelerator pump a couple months ago (is that what you're talking about?). There's another pump looking thing near it that's leaking a little. Again, I'm not even getting fuel up out of the main fuel pump now.

3) I can pull jets, but the thing won't even start.

Also, the last couple weeks before this happened it would idle like crap after a hot start. After a mile or so it would clear up.
Last edited by jctucker on Tue Jun 28, 2011 10:10 am, edited 1 time in total.
grittracing

Re: fuel delivery issues

Post by grittracing »

ok have you tried pouring a little fuel down the carb? how does it run. and double check your work on the pump to make sure nothing came loose. you may also have a intake gasket issue. you can spray starting fluid around it to check for leaks. or check for leaks on the vacume hoses. start with the one from the dissy and the one from the brake boaster.dont think it is but it may also be a plugged cat.concerter
jctucker

Re: fuel delivery issues

Post by jctucker »

Yeah, if I spray carb clean down the carb it starts and idles until that's burnt up. It'll actually runs kinda nice like that for a couple seconds.

I looked at the vacuum lines, they're ok. In my experience the engine would run (like dog ****), but not really idle even with a huge vacuum leak.

I haven't checked the cat, but usually after those have been sitting overnight the engine will start and run until plugged again. However, I'll unbolt the pipe and take a peak.
grittracing

Re: fuel delivery issues

Post by grittracing »

sounds like the diaphram in the carb loosing prime. Needs to be replcaed. I know you said you replaced it. But i would have another look at it. It might have not been lined up and got pinched.
jctucker

Re: fuel delivery issues

Post by jctucker »

Awesome, I'll pull it off and take a look. Would that affect the fuel pump pushing fuel up to the carb with the hose disconnected though? Or will these not do that?
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: fuel delivery issues

Post by bradartigue »

If you apply suction to the fuel line do you get any fuel out?

Did you clean and inspect the fuel pickup assembly/in-tank filter? I'd be inclined to think the culprit is back there given this problem has gotten steadily worse over time.
jctucker

Re: fuel delivery issues

Post by jctucker »

Yeah, that was one of the first things I did. Pulled the pick-up assy and made sure it was all clear. I can blow thru that and then the hose all the way to the fuel filter before the mechanical pump.

The vacuum idea is a good one. I'll bust out the Mityvac and see if I can pull fuel forward. Again, the feed line at least is completely clear, from what I can tell.
bulldog4444

Re: fuel delivery issues

Post by bulldog4444 »

I had a reoccuring issue with where the vapor canister fitting went into the carb. It would loosen and let in enough air in to mimic a failing fuel pump. I would jam it back in and be good for a couple more years until it loosened again. Also, check the carb to intake bolts and of course the idle shut-off solenoid.
jctucker

Re: fuel delivery issues

Post by jctucker »

Thanks, bulldog! I'll take a look at the canister. I checked the intake nuts. They were really loose when I bought it and have loosened up once since then.

If the idle solenoid goes will the car not start at all? I checked it about a month ago but will look it over again.
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: fuel delivery issues

Post by bradartigue »

jctucker wrote:If the idle solenoid goes will the car not start at all? I checked it about a month ago but will look it over again.
If the solenoid goes the car will not idle; it will start if you have your foot on the gas. It disables the primary idle jet, so when you hit ~1400 RPM it starts to stumble and around 1000 RPM it flat out fails.

But this is moot if you're not getting any fuel from the line.

Hey you don't have one of those ancient one-way fuel valves on that car do you? They failed constantly, and were the subject of a service letter saying to replace them. If it is still in the line I'd chunk it. I'm only thinking of it because a car I've been working on still had one (and the original fuel lines, go figure). It would be in the "in" line between the pump and carb or between the firewall and pump. It looks like a lawnmower fuel filter, like a UFO with two stems.
jctucker

Re: fuel delivery issues

Post by jctucker »

I haven't seen any check valves in the fuel line. There are two fuel filters. One pre-pump, the other post pump.

Last night I quickly tried to pull fuel forward using the Mityvac but couldn't. I don't know whether I wasn't getting a good connection or if there's a hose in the pickup or something. I'll try again this morning. I'm also going to pull the pump and make sure the aux shaft still spins.

Thanks so much for everyone's help so far. Also, if it is the shaft I'll need to buy one. So, if you got one laying around...
baltobernie
Patron 2020
Patron 2020
Posts: 3466
Joined: Sun Nov 25, 2007 6:00 pm
Your car is a: 1973 Spider [sold]
Location: Baltimore, MD

Re: fuel delivery issues

Post by baltobernie »

Try driving the car with a half-tank of gas and the fuel filler cap loose enough to let air in.
jctucker

Re: fuel delivery issues

Post by jctucker »

It's got 3/4 of a tank and won't even start, to say nothing of driving. I've pulled the cap (checking for vapor lock). The car will not fire off unless I spray carb clean down the venturis (venturii?).
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