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| Is THIS fuel pump going bad? Now WHat? https://slantsix.org/forum/viewtopic.php?t=42370 |
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| Author: | Sam Powell [ Sun Oct 24, 2010 5:26 am ] |
| Post subject: | Is THIS fuel pump going bad? Now WHat? |
Hi Guys, sorry to be absent for a spell. I have been too busy to post lately. I left the Dart in my store parking lot last night afraid to drive it home, and very unsure of what to do now. On the way to work, the fuel pump was making a very loud whine, and the engine started missing as if it were running out of gas. Prayer power kept it from dying on the rather major road leading there, but it being Saturday, both the dealer who sold me the tank/pump combo, and my street rod builder mechanic were unavailable for consultation. The previous time I drove it, I tried a WOT blast the last block from my house, and it promptly went into detonation hysteria, so I quickly shut down, and when I did so the fuel pump was making a louder noise. I did not put the two events together. Fuel pump noise......detonation. Bad fuel pump=not enough fuel=lean mixture=detonation. But, this was a new fuel map. It just needed tuning right? So, I drove into the garage, and proceeded to richen up the boost end of the fuel map. After that I took the car off the road for a week while I removed the seats to get at the wide band controller to send it back, and while the seats were out, did some long delayed interior trim work. I was feeling great about being able to drive it again, and had forgotten the fuel pump noise until I headed out. I dismissed it as just one of those annoying things you put up with on modified cars. After all it is only 4 miles to work. What could fail in that short period of time. Here are the possible culprits as I see it. 1. It is out of gas. Not likely. When I went out tuning 10 days ago I filled it, and have put only about 50 miles on the car since. Unless it got only 3 MPG it should be nearly full. The gas gauge has not worked in ages, but I guess I could push a dowel down into the tank to check it. It is not parked where someone could steal fuel, unless they sneaked into the garage at night and took nothing but gas. 2. The fuel pump is failing. It has very few miles on it, relatively speaking. But, this seems very possible. It is a GM design, produced by an aftermarket supplier of unknown origin. But, it is in the tank, and dropping the tank is a chore. This is not something I want to do in a parking lot. 3. There is a pickup in the tank that is plugged. This seems very possible. It is whining as if it is running dry. But, I do not know the design of this pump, and cannot picture what might be wrong here. I don't know if it has a filter sock on it, or what. Again, dropping the tank is awkward. If I try to drive it either home, or to Tommy's place it might die in a very dangerous place, or continue to destroy the fuel pump, if it is OK but running dry for some reason. The roads on the way home or to Tommy's are very, very busy, rather high speed, multy lane affairs with no shoulder. I do have AAA coverage, and I can call to have it towed to either destination. Any ideas? What do you suspect is wrong, and what is the next step...... or two. Sometimes I really long for the old mechanical fuel pump and 2 bbl carb. |
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| Author: | Dart270 [ Sun Oct 24, 2010 5:41 am ] |
| Post subject: | |
FPs make loud noises when you run out of gas (aeration). Any possibility of fuel leak? Pickup clog I suppose is possible, but all that stuff is new. Sorry to hear about the problems. So far, I have not lost an elec FP, but I've been scared a few times by loud noises. Possible the regulator got stuck open or closed? That could cause high load on the pump. Lou |
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| Author: | Sam Powell [ Sun Oct 24, 2010 6:04 am ] |
| Post subject: | |
A fuel leak of that magnitude would have been seen. Theft is actually more likely, since the gas cap is not locked. I guess there are thieves out there who would steal gas before taking tools or a color TV. The regulator is a possible culprit, but when I was chasing down the fuel pressure problem before, the dealer that sold me this regulator told me he had never, had one fail. I suppose he could be guilty of selective memory here, but the tone indicated that would not be high on his list of things to check. I will start it up today, and watch the fuel pressure gauge. I guess I could take a couple of gallons of gas and put them in. If it quiets down, then the mystery shifts. I guess they still sell locking gas caps. Sam |
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| Author: | GunPilot [ Sun Oct 24, 2010 3:16 pm ] |
| Post subject: | |
Loud fuel pump is consistent with fuel starvation, in my experience. Not necessarily an empty tank, but easy to test by pouring a few gallons in. Bad fuel pumps have been silent, for me. |
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| Author: | Sam Powell [ Sun Oct 24, 2010 4:32 pm ] |
| Post subject: | |
Boy do I feel SILLY. It was out of gas. You guys were right. But silly and happy can go together. I don't have to take anything apart. I don't have to spend money now on a fuel pump. I can continue on with "the plan". Part of which includes fixing the fuel gauge. I took five gallons over in a can and it took all five of it. Then I drove to a gas station and it took 10.5 more. I had to re-start the fuel delivery about five times, as it continually cut off early. It is very hard to get this tank and filler to take the fuel. It readily cuts off prematurely. My guess is I have been driving around on a nearly empty tank much of the time. I have a habit of filling up after 100 miles. But with the filler nozzle cutting off early, it must have been getting lower and lower with time. Last time I got gas it only took 2 gallons. It may have only had a few more than that when I "filled" it up. So there you go. This follows Lou's back to basics rule. Rule out the most basic things first. Edit: I wrote fuel pump above instead of fuel gauge. I am glad I went back and read it. Sam |
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| Author: | GunPilot [ Sun Oct 24, 2010 6:45 pm ] |
| Post subject: | |
Glad it was an easy fix. Just another page in the book of EFI knowledge. Maybe not a whole page, just a post-it note in the margin. |
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| Author: | Dart270 [ Mon Oct 25, 2010 5:35 am ] |
| Post subject: | |
Yay! Do not assume the worst, just the simplest! Lou |
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