1987 ford econoline e350 rv will start and run for about 30 seconds sometimes more sometimes less and then stalls. Recently replaced fuel pump and fuel filter. Also replaced today a couple vaccum lines that were leaking.

I was leaning towards vacuum leak but not sure. It doesn't matter if the engine is cold or warm and doesn't matter if I give it gas or not. It looks like it is leaking a small amount of gas under the carb from a part that has fuel lines attached to it. My dad replaced the part its leaking from recently. I think it was stalling before he did that too not sure

Any ideas?

 

When it stalls, spray carb cleaner into the throttle body intake. If it wants to keep going, then you've got a fuel delivery problem.

 

When I spray carb cleaner when it's about to die it keeps it running sorry forgot to mention that in the post. I'm still finding vacuum leaks and will probably just pull the carb and replace all associated vacuum lines as well as the gasket where the carb meets it.

 

It's pretty easy to make a low-cost smoke tester:


Makes it easy to find vacuum leaks.

 

does your RV have a carb or is it fuel injection?
I'm guessing a carburetor and if so then check the fuel flow anyway. has the RV sat for a long time or did the problem just start?

 

It is carbureted I thought I added that in original post as well. But definitely carb

 

ah yes, you did. " It looks like it is leaking a small amount of gas under the carb from a part that has fuel lines attached to it." I know you just replaced the pump and filter but the reason I recommend checking the pressure and flow rate is because there can be problems behind the pump.
My 85 quit on me driving down the road. It would start and run for a few moments and quit again... Turned out to be a pin hole in the pick up tube on the sending unit. It would enough gas to fire thew engine but not enough to keep it running. A friend helped me change the fuel pump in the parking lot we coasted into but that wasn't the problem.



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Actually it has an electronic fuel pump surprisingly. I checked engine bay even though my dad said he replaced the pump and it was forsure in the fuel tank but I always like to verify the stuff that has been done by someone else as unless I did it or saw it with my own eyes I can't forsure say something was done and or done properly lol.

But it is in tank electric fuel pump. The part leaking below the carb is a ore carb filter I believe. Will need to replace that I'm sure my dad tightened it too much and ****ed the threads.

I guess he had a mechanic friend come take a look a while back too and they checked the oil pressure switch as I was directed to check that and jumping the terminals made no difference.

Progress I've made so far is replacing two vacuum hoses at the carb that were ruptured and my dad said it is running longer than it has before so hopefully making progress.

I honestly think it is probably a large vacuum leak at the carb or intake manifold. Not 100% though.

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The smoke can is a cinch to make - just buy a grommet kit from Harbor Freight and some nichrome wire from Amazon.

Steve

 

I have the ford service manuals for a 1985 and a 1988 Econoline but the 85 shows a mechanical pump and carb while the 88 shows the 460 would be EFI

I am not sure on a 87 460 but isn't there a spacer plate under the carb and the EGR is mounted to that spacer? My 85 is but it is a 5.0 engine with a carb. Have you checked the EGR?

 

I need to correct my last post... After digging a bit deeper my 85 manual shows the 7.5 having an electric pump and carb. I do not know how much difference there is between the 85 and 87

 

we have an 85 econoline and are having some issues. We are having a no start problem with our 460 7.5 automatic trans. She fired right up with the old motor in it even tho it had a throw rod and a hole in the cylinder!!! After purchasing another block and rebuilding it from parts off the old motor that only had 65,000 miles on it btw. No it’s never rolled over! We’ve done a lot and still a slow crank no start This is what we’ve done so far. 1st checked for spark & fuel have both, have brand new battery deep cycle, TDC turned it over by hand and the timing chain is fine it is keeping timing! Replaced the starter relay and the ground cable we have went through fuses and replaced the bad ones. We have ground cable from Battery to block, one from block to frame, one for battery to chassis, and the motor to chassis ground. We have also been using a voltmeter and have tested throughout the wiring and we seem to have a voltage drop at the battery when cranking it over it drops from 12.5v to 8v. Checked the wire to the starter and it reads 12.5v all the way unhooked could be bad going to replace it. Have checked the fuel filter as well and it is fine. The ignition wire to the solenoid is now not reading anything was reading last night when testing.

 

I am not that familiar with the big block 460's. You might want to post a new thread of your own over in the big block section of FTE where that is the engines they deal with.
https://www.ford-trucks.com/forums/forum53/

Is the engine able to turn over fast enough to start the engine?
Deep cycle are not made for cranking though they should start an engine that is known to start easy. They do not have the cranking power of a starting battery. I have ran a deep cycle battery in one of my cars for a short time but it was a 5.0 engine that started right up. Deep cycle batteries are made for long slow discharge where a starting battery is made for short bursts of high am draws. If you are dropping down to 8 volts then you may not have enough power to some of the electrical components to run the engine.
You said that you are going to change the positive cable. That might help as the crimped ends can look good but have corrosion inside them. A week connection will raise the amp draw and can cause a voltage drop. So can a bad starter so you might want to have it checked! If you have an auto electric shop that specializes in rebuilding starters and alternators, that would be a much better place to have it tested then a local auto parts store.

Has the engine ever ran since you installed it?

 

Did you replace the relay switch for the electric fuel pump ?
Each time i have had a relay go bad, i've circumsized the plastic cover off with Dremel and a diamond blade.
Once carefully cleaning the points contacts and re-installed the relay, the engines have fired right up.
You might try this as a check, because your engine runs if fed fuel through a vacuum port.
_ _ _ a possible culprit !