Thank you for your experience. I wish I knew what to change on the top of the fuel tank. I have taken that all apart to change the pump, so I'm confident I could do it if I knew what piece it was. I will have to review my pictures and other on-line resources to see if I can find it. You don't, by any chance, know specifically what item to replace on the top of the tank?

About the ASD, see http://www.increa.com/reverse/dodge-van-repair about 1/5 down the page, there is a pinout of the relay. I remove the relay and put a jumper between pin 30 and pin 87 on the car connector. This powers several items including the fuel pump whether there is a key in the car or not. See the diagram on the web page just above the relay pinout. Down toward the bottom of the page, look for the picture with the green alligator jumper.

When you replace the ASD relay output with a jumper, it will eventually drain the battery pumping fuel and putting power through your ignition relay. The bigger issue is a safety issue. Fuel is pumped even if the engine is not turning - even if you remove the key from the car. And the ignition circuits are live. That's a bad combination in the engine compartment unless you're really paying attention. Maybe put a hold-down switch on the dashboard to parallel the relay output. Activate the switch for about 15 seconds before starting and then turn the switch off for normal ops while you use the car.

I initially emptied my fuel tank by shorting across the ASD relay output pins. I just jumpered the relay and disconnected the fuel line at the fuel filter and let it all run into a gas can (see picture on the left toward the bottom of the above page). In retrospect, use the drain line that comes out of the gas tank and is capped off with a rubber cover just as it pokes out of the body frame. Start a siphon on this line and it will drain from the very bottom of the tank.

 

 

Airtex......... I was afraid of that. I absolutely will NOT install their pumps. They suck. They have an incredibly high failure rate. I have had bad ones right out of the box. Of the three that I installed, before I learned my less, the longest lasting one made it about 1 year. Almost to the day. The other two failed within a month. (and one of 'em, didn't even make it out the driveway before it died.)

Also, TBI only wants like 12 to 15 PSI....... So, 70-95 is WAY over the top.

 

I know a lot of people have a lot of opinions about good and bad companies, car manufacturers, etc. I'm trying to not get hung up in those conversations. Rather I'm just trying to work with what I have. Yes, anytime someone asks what part, it's almost always a reply about how terrible the choice was. Okay. Got it. Chicken Little. Water under the bridge. (An alternative critique would be to recommend what you know is a good choice.)

For now, the pump works. I'll deal with failure later -- if it fails. For now, with a working pump, I'm interested in getting the van starting reliably! I think now, because nothing has changed, it wasn't a pump problem anyhow, so I think the old and the new pump were both okay.

About fuel pressure, all the pumps run in the high double-digit pressure. Don't confuse the PUMP output max pressure with the pressure that is regulated at the TBI carburetor. When the pressure goes above the target, the regulator spring opens and the excess fuel (and therefore pressure) is blown "overboard" back to the gas tank.

Yes, at the injectors, the spec'd pressure is 14.5 psi and I'm very close to that. Actually, the injectors work when the pressure is above about 11 psi.

 

Arty444,

I checked more books. One "check valve" is on the vent line to prevent back flow into the tank and to provide "rollover protection" - I would imagine if the tank gets dumped upside or sideways it somehow cuts off fuel. The tank is venting fine, so I think that's okay.

A second check valve is "near the output of the pump". Uggh... I think that means back inside the pump assembly inside the tank. I'd rather not go there, so I think I'll buy an $8 check valve and put it externally in the supply line before the fuel filter - as you proposed.

But.. maybe not necessary anyhow, because I inserted a length of clear 5/16" fuel line before the carb and ran the van a bit and then stopped it and repeated several times. The fuel *pressure* immediately drops to zero when the ignition is turned of (intentional for safety or is this wrong?) while the liquid fuel clearly stays in the line up by the carburetor. I think I need to chase another cause even though more fuel is a solution. I know that extra fuel upon cranking DOES make this engine immediately start, but maybe there is some emission control or other goofy thing that is really "causing" my problem.

Right now, I'm lost. Everything has tested good in the fuel system.

 

I put short .m4v video clips of the fuel injection with the ASD relay harness shorted and with the relay installed normally. I think they will play on your iPhone or your desktop computer. I also posted a video of the fuel pressure Tee-d off the fuel line just before the carburetor. Look toward the bottom of the page http://www.increa.com/reverse/dodge-van-repair/ Any thoughts appreciated!

 

Wow. Those were short...

Spray pattern leaves a bit to be desired, but, at least they are both spraying, and from what I can tell, look pretty equal?

Fuel pressure seems to drop right back down to zero after you shut down the engine though..... It really shouldn't do that. (check valve in pump?)

Does it run OK now?

 

Yea, sorry about the video quality. That was me holding a light in my mouth, operating the camera with one hand, and turning the ignition with the other! I tried to make them short (just the key turn and what the injectors did) so it would be a quicker download for people. I'm thinking because fuel is fluid (not air), the drop in pressure is okay. There is no "elasticity" in the system - like a brake line with no air - so as soon as the ignition drops the ASD relay, the pump immediately quits pumping. I'm not sure pressure should stay up, but I think the fuel *should* stay in the line and not drain back at all.

However, did you see the big squirt of fuel when the ASD relay was shorted? With it normally hooked up, there is an even and misty spray that slowly increases as the pressure comes up 8.. 9... 10 psi.

I picked up some clear fuel tubing and connectors and I'll test with that installed by the carb and then I'll be able to watch for sure if fuel drains down after the engine run.

 

Hey man, ya gotta do what ya gotta do. A video of you making the video would likely bring some smiles though.

I saw that...... Was there pressure on the system when you jumped the relay?