351 Ford van (Engine Acceleration Problem)

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  #1  
Old 05-29-05, 07:03 PM
Guvner
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351 Ford van (Engine Acceleration Problem)

It seems to not have any ability to accellerate or even rev up in idle. I'm thinking either one of the two fuel pumps are failing or the catylitic converter is clogged. Any advice to check them both. My brown shop manuel doesn't even have fuel pump in the table of contents. Jeeeezzz..

1991 E-350.

Thanks... Gary
 
  #2  
Old 05-30-05, 11:38 AM
E
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Start with the basics, are you getting spark, are you getting fuel, what year, when's the last time you did a complete tune up including a fuel filter?
 
  #3  
Old 05-30-05, 06:03 PM
Guvner
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Should have told you where I am so far...

It did this same kind of thing before when I changed the electronic module on the distributor. Figured it had come loose. Wasn't the case. I thought fuel, change the filter and even found a bad connection on the front pump. (It was working until I touched it to check it and the connector kind of came apart.) Anyway. It starts fine, idles fine too. Just when you try to wind it up even in neutral now the engine just bogs down. I will say this about the front fuel pump. When it had the broken connection from me playing with it the engine stopped starting quick. Once I remembered the spongy feeling of the connector I took it off and found the sulphated connector just hanging there. Being an HVAC guy I quickly put a new connector on and it started fine in a second making me thing it was less of a fuel pump problem then something else. Not finding any specs on where and what I should have read in my shop manual I headed for a search engine and a repair forum.

Another issue that I didn't mention was the fact that one of the check valves gave out and melted the valve on the top of the engine. It got loud just as I noticed a bit more power coming from the engine leading to my suspicion that a clogged catalytic filter might be at work. I sealed up what I had to and made sure I had no vacuum leaks. (Done this before) Blowing the valves made me think I might have a pressure problem on the exhaust as this is the second one in about 5 months. Any ideas on how to check these items without complete disassembly of the exhaust system? (The 4 bolts holding the exhaust to my catalytic converter were less than impressed with my acetylene torch so I'm left with only a sawzall most likely to take the bolts off. (Just turning them cherry red didn't make them want to be allowed to unskrew..)

Any help would be appreciated. I am an AC guy so there are some things I can help on at least from the common sense side as I am not an automotive AC guy but know my way around the industry a bit.

Going out to clean garage and look for my cheaper Chilton manual.

garyk@findmall.com

1991 E350, 145,000 miles, not overheating, 351 V8 engine.

Guvner..
 
  #4  
Old 05-30-05, 09:52 PM
Guvner
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Signed up with Chiltons yearly service... But..

I can't seem to get the answer if I have more than one fuel pump. I know my 1990 had one in the fuel tank but this one has at least one on the rail outside the tank. Chiltons doesn't say it doesn't have two, just tells you where to find them. Also says something kind of contradictory. Says while system is running at idle you should get one pint in 20 seconds for amount of output. I guess there's enough fuel to let it run once disconnected for the 29 seconds.????

Also mentioned but didn't say where port for testing pressure of fuel pump is.

It says: "Connect a fuel gauge to the pressure test point (shrader valve) on the fuel rail. "

Don't see any shrader valve anywhere assuming the fuel rail is the rail the fuel lines are run on. Where would this shrader be? What guage do you guys recommend to do the testing with if it exists? Says it needs 35 to 45 psi. Are we on the right track here?

Thanks... Guvner..
 
  #5  
Old 05-31-05, 06:06 PM
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From what I gather from your post you have an idea what it is.

Another issue that I didn't mention was the fact that one of the check valves gave out and melted the valve on the top of the engine. It got loud just as I noticed a bit more power coming from the engine leading to my suspicion that a clogged catalytic filter might be at work.
Keeps buring up that check valve cause the exhaust has no where to go, it takes the path of least resistance.

The test port is on the rail that holds the injectors or the line feeding the rail. A fuel pressure test would be in order recorded when the power fails.
 
  #6  
Old 05-31-05, 06:53 PM
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Fuel Pressure Check (shrader) valve

If memory serves correctly, on my 1987 Mustang, the valve was located behind the Alternator, on the right, while standing in front of the car. God, I miss that car...

cuedude
 
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Old 06-02-05, 02:45 PM
K
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These engines are notorious for having the timing chain jump. After 100K (or if the oil was neglected) the nylon teeth on the sprocket would wear to a point that the timing chain would jump a tooth (or more). When it does that, you'd be lucky to keep the engine idling - and even if it runs, you'd be lucky to get over 30 mph. Gary, your complaint sounds very much like this problem.
 
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Old 06-03-05, 08:12 PM
Guvner
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Hmmm.. I tested the slop in the chain today.. 6 degrees...

I was told 10 was even acceptable. I checked the pressure on the fuel pump at idle. (What little idle I could get..) 40 psi. Checked the vacuum switch at inlet of fuel lines. No fuel leakage.

I wanted to check the timing but cannot figure out where the plug is you need to disconnect to check timing. Any ideas? Wasn't anywhere near the distributor plug. That bunch of wires quickly disappeared into the main trunk of wrapped wires.

I was sort of thinking MAPP sensor but you're making me think I need to find that plug and check the timing with a light. I was told that if the catalyitic converter was clogged it would still start and idle for a short time just fine. It barely runs for 15 seconds.

Any more thoughts? Guvner..
 
  #9  
Old 06-04-05, 12:35 AM
Guvner
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Found the gray spout connector... Disconnected it and checked timing..

Based on the last known position of my distributor it showed 10 degrees BTC.

I think that is in the range of being OK... There was 0 - 10 - 20 - 30 degrees all marked on the harmonic balancer and this was coming in at 10 degrees.

Well.. On to the Mapp sensor unless you guys tell me 10 degrees is awful...

Guvner..
 
  #10  
Old 06-04-05, 06:54 AM
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It seems to not have any ability to accellerate or even rev up in idle
and now you said
I was told that if the catalyitic converter was clogged it would still start and idle for a short time just fine. It barely runs for 15 seconds.

I'm a little confused which is it
 
  #11  
Old 06-04-05, 08:45 AM
Guvner
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I've always said it would start... It still won't rev up..

And now it doesn't stay running worth beans... I reread what I posted. I see no contradiction there. I suspect the converter is at work blowing my valves but I'm told that it will still run at idle at first. It doesn't. It's not completely clogged on the exhaust if it has problems as I still get some pressure out when it runs. Is it enough? No idea.. Just strange I've blown my second valve in 6 months.

Getting a look at it with a timing light was an adventure getting it to run long enough. Did it at night at least so was able to get a good look at what little I could get it to run.

The only difference between 3 days ago and today is idle has almost quit working entirely.

Any thoughts?

Thanks... Guvner..
 
  #12  
Old 06-04-05, 09:23 AM
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The reason Iím confused is you omitted the fact that your conditions changed over the past couple of days. Things have progressed and now it wonít stay idling.

Your cat has to be clogged. The reason the valves burn out is they are check valves to prevent exhaust getting into the air injection. The exhaust will take the path of least resistance out the maybe 2Ē or better exhaust pipe when the cat is clear instead of ĹĒ or ĺĒ air injection tube. But in your case it canít get thru the cat, itís trying to get out the check valve, thatís what burns the valve out. Also you said it ran better when the valve was burnt out. That backs up what Iím telling you.

It will get to the point where you no longer will be able to start it less alone idle.
 
  #13  
Old 06-04-05, 10:07 AM
Guvner
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Thanks for the fast reply Larry..

I can see you are one of the more respected folks here. I will add that since then I've opened up that hose that blew out its valve to see if it improves its ability to start and nothing happens. Same old. Another mechanic tells me that I should still be able to start with this condition even if it wasn't for very long. You seem to dispute this.

That's my quandry right now. He's going to call me back today to give me some voltages to check on the sensor. He says I really need a scope on this sensor but the voltages will give me a bit of a way around it.

I don't doubt the valves went out for a reason at all. My problem is conflicting information from a proven source (He always knows exactly what's wrong with my Tahoe over the phone from Florida) and your input here. I'm trying to glean as much information as I can from here and balance it against what I'm being told. I have the original brown shop manuals from Ford to my old 90 Ford Econoline and this is just one year newer. Plus I signed up at Chiltons. It's amazing how they don't tell you things you want to know.

Anyway... bear with me if you don't mind as I'm just plodding along here.

By the way. If I had any success getting my converter off I would have done it a long time ago... I torched the bolts cherry red and they didn't even get phazed. Got all the clamps loose but the metal is already squezzed on a new exhaust sytem so I'm not as excited about ruining it yet as you might imagine. It looks like I'll have to cut the 4 bolts where the two manifolds join the converter and drill them out and make a gasket to put it all back together. Is that the normal way of operation if you end up keeping your converter? (Flat flange, 4 bolts with their heads welded into the converter)

Thanks... Guvner..
 
  #14  
Old 06-04-05, 11:07 AM
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Has it gotten to the point where it will no longer start? If so the plugs will foul because the fuel is still being injected but there is no air. If the exhaust is clogged there will be no flow so therefore it can't draw air from the intake.
 
  #15  
Old 06-04-05, 01:51 PM
Guvner
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15 to 35 seconds is all I really get any more...

Almost seems like it has a huge vaccuum leak but with all the stuff off it's kind of hard to tell... Have looked and looked for a break in the vacuum. Nada... Guvner..
 
  #16  
Old 06-04-05, 03:00 PM
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You could drop the engine pipe on each side where it bolts to the manifold.
 
  #17  
Old 06-04-05, 11:40 PM
Guvner
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Quit throwing common sense at me would you?? :eek:

That would be too easy to do... Darn...

Ok... If I get back from lake in time tomorrow or if it rains out the plans I'll try it tomorrow... Looks like I have a new problem or maybe even a related one... I was just under there to see how accessible the exhaust manifolds were and there was oil and antifreeze coming from the passenger side of the engine...

Yech... The most unaccessible side too... Can't hardly change a spark plug on the front of that side... Checked the oil right away for antifreeze and checked the coolant too.. Didn't see any missing so it must be a slow one...

Thanks for the suggestion anyway... Guvner..
 
  #18  
Old 06-06-05, 10:16 AM
Guvner
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All hail Larry... You were dead right... fired up right now..

Thanks a bunch bud... Your home AC ever stops you give me a call and I'll walk you through it and tell you where you're heading...

Thanks again... Email me if you'd like and I'll give you a contact number. Like to return the favor sometime..

All the best... Gary
 
 

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