7.3 Ford Pump/Fuel Problems (no fuel to injectors)

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bridge's picture
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Joined: 07/19/2006

I just purchased a School Bus built onto an 89 Ford E-Chasis (7.3L iDI) that was converted to veggie oil and ran fine on it for a couple of years, taking my friends band on tour all over the country.

I purchased it REALLY cheap under the guise if it wasn't worth fixin i would just scrap it. BUT, I REALLY want to fix it and use it for my band and other social projects, and friends projects, to tour in.

HERES THE PROBLEM:
There is almost NO FUEL getting to the injectors.

now, i'm no professional mechanic but i know a few things...

it seems its either the MECHANICAL PUMP, a clogged FILTER, or the IP is clogged or just shot...

so my question is, HOW DO I FIGURE OUT WHERE THE PROBLEM IS and FIX IT on a small budget? or if it is something completely different...

thank you so much

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barkerp's picture
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Joined: 07/20/2006

This site her good info on troubleshooting diesel engines;

http://www.intellidog.com/dieselmann/idi.htm

If you are mechanically oriented it will walk you through diagnosis.

bridge's picture
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Joined: 07/19/2006

thank you i've actually gone through a lot of those procedures, but most of the fuel pressure diagnosis that he lists requires !. that he engine idles (mine won't start) and 2. expensive testing equipment that i don't have access to... all the electircal diagnosis was very helpful tho...

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bridge's picture
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Joined: 07/19/2006

has anyone heard of using KEROSENE to dissolve coagulated svo that can clog up the pump??? does it work? how do you get it in there and how long does it take? thanks again

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rdbigfarmboy's picture
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Joined: 09/04/2005

It sounds like a supply pressure issue. That would be my first guess. So replace the filter and put on an electric pump to help the mechanical pump. I have a 10 -15 # electric supplying the 5# or so mechanical. This took care of my poor performance problems, and makes purging after filter changes easier. On the chevrolet I have 2 electric pumps one on each side of the filter. They cost me $70 each from carquest.

-------------------------
Randy Daniel
near Collinwood TN.
Part time farmer runs 2 tractors and a Ford F350, Chevy 2500 on dewatered filtered (salt and soda) used grease.
http://cesqg.bravehost.com/

rkpatt's picture
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Joined: 11/05/2004

It doesn't take much fuel at the injector , just a lot of pressure ..Let some one who is familiar with diesels take a look . Your problem may be very simple like too slow cranking RPM .

It is better to bypass the mechanical pump completely . If you use an electrical pump to supply the mechanical pump you the diapragm could break on the mechaincal pump and you would not know until it is too late that your engine was flooded with fuel and bearings trashed . There are threads on this at the IDI discussions and www.dieselstop.com . I bypassed the my pump on my 1994 F250 7.3 IDI completely . I even removed the mechanical pump and installed a big block chevy fuel pump ( will also fit this engine ) block-off plate from Autozone. I have been using the Master E8012 pump from Autozone --$35 .

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bridge's picture
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Joined: 07/19/2006

so the electrical pump sounds like the best advice yet, and thats what i'm working on right now (ah the fumes, j/k) so we'll see if that will do it. i'm also using a gas fumes to try to get it started which i was told should get the fuel pulling through and i'm running a kerosene tank into it to try to clean up years of filtered wvo... so if anyone else has anymore advice i would appriciate and i'll keep y'all informed of my progress... thanks

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pray for peace? you might as well be praying for death!!
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rkpatt's picture
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Joined: 11/05/2004

Have you tried spraying some WD40 into the into while trying to start it ? You can use starting fluid (ether) but only very small burst with the glowplugs disabled . If the glowplugs aren't disabled, the ether can be a big problem ( ie fatal for your engine ) . WD40 should be OK in warm weather. Make sure your cranking speed ( starter and batteries must be good ) is fast enough to get enough compression to start .

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Rabbit Man's picture
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Joined: 08/20/2004

Last week while towing a 5th wheel through Salem, Oregon, my '92 F250 7.3 IDI just stopped....dead. After getting towed off the highway in 105 degree heat I suspected the lift pump had failed. I have a clear section of fuel line from the diesel filter to the IP as a diagnostic aid when I was having trouble with air in the lines (after an SVO conversion). I noticed that no fuel was passing through the clear line when my wife cranked the engine so I picked up a lift pump from the local NAPA and wrestled it in with my $10 socket set. As it turned out the new lift pump didn't cure the problem. With the key on, I wiggled the wires going into the top of the IP. There must be some sort of solenoid in there because it started clicking and then the engine started and the fuel flowed. If this was the case, then fuel will not flow from the lift pump while cranking if this valve in the IP doesn't open....does that make sense? I just returned from my trip and haven't investigated it yet.

-------------------------
Grease is still the word!
1978 Mercedes 300CD
1992 F-250 7.3 IDI
1960 Morris Minor 1000 Convertible (Datsun Power)
John Deere 410 Backhoe

604TD's picture
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Joined: 03/16/2005

Rabbit Man, sounds like you had a loose connection at the fuel shutoff solenoid on the IP, which needs power to open and let fuel in.

604TD's picture
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Joined: 03/16/2005

Quote:
Originally posted by: bridge
I just purchased a School Bus built onto an 89 Ford E-Chasis (7.3L iDI) that was converted to veggie oil and ran fine on it for a couple of years, taking my friends band on tour all over the country.

I purchased it REALLY cheap under the guise if it wasn't worth fixin i would just scrap it. BUT, I REALLY want to fix it and use it for my band and other social projects, and friends projects, to tour in.

HERES THE PROBLEM:
There is almost NO FUEL getting to the injectors.

now, i'm no professional mechanic but i know a few things...

it seems its either the MECHANICAL PUMP, a clogged FILTER, or the IP is clogged or just shot...

so my question is, HOW DO I FIGURE OUT WHERE THE PROBLEM IS and FIX IT on a small budget? or if it is something completely different...

thank you so much

-------------------------
pray for peace? you might as well be praying for death!!
http://iprayfordeath.tripod.com

-------------------------
pray for peace? you might as well be praying for death!!
http://iprayfordeath.tripod.com
trace the fuel out of the lift pump, disconnect hose and crank engine, if no fuel replace the pump. Also check for power at the IP fuel shutoff solenoid when key is in the run position.

One of the best fuel diagnostic aid is a return line sight tube. Take the doghouse off. Locate the metal fuel return line which goes to a hose and splice in a sight tube. Easiest way is get a 3" long 3/8 od Lexan tubing, cut the hose and insert lexan tubing. It should be full, without bubbles if everything is right.

Rabbit Man's picture
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Joined: 08/20/2004

Thanks 604TD....The connection was tight at the IJ solenoid. Could this valve be sticking or failing internally?
Could the 105 degree weather have anything to do with it?
If it happens again, can I use a "jumper wire" to supply 12v to it just to get to a safe place. It was a real drag to break down in 5 o'clock traffic, pulling a 5th wheel RV in blistering heat in a strange town!

-------------------------
Grease is still the word!
1978 Mercedes 300CD
1992 F-250 7.3 IDI
1960 Morris Minor 1000 Convertible (Datsun Power)
John Deere 410 Backhoe

bridge's picture
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Joined: 07/19/2006

so i got a $40 electrical lift pump and that succesfully got fuel to the injectors. i've been running the return line into a jar to see what i get. i'm using kerosene right now in hopes that i can dissolve some of the old wvo that was in there.

>>> is it okay to run kerosene back into the diesel tank????

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pray for peace? you might as well be praying for death!!
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rkpatt's picture
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Joined: 11/05/2004

Have you tried the WD40 or ether yet ?

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bridge's picture
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Joined: 07/19/2006

yes no luck with wd40 or ether but it turns over and starts with gas fumes but dies after about 10 sec.

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pray for peace? you might as well be praying for death!!
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niko's picture
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Joined: 01/23/2006

not sure if this is on the right track...
could you have let a lot of air into the injectors?
if so then just crack all of them and try to turn it over until all the air is outta there.

niko.

bridge's picture
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Joined: 07/19/2006

tryin it. i definitely got some air out (bubbles --> no bubbles) but one of the batteries fried.. so i'm gonna work on on it more today and i'll be back on here to let y'all know if it works and possible get more advice... by the way thank you all so much for helpin out i really apprieciate and can't wait to teach others what i'm learning.

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pray for peace? you might as well be praying for death!!
http://iprayfordeath.tripod.com

niko's picture
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Joined: 01/23/2006

yeah the same thing happened to me when trying to get all the air out. had to borrow a friends charger and then wait all night.man those things take a long time. but once they were full again it only took another half hour to get it started.
the process went like this:
unscrew all the fuel line going into injectors. turn it over until you see solid fuel resting on top of the holes. then tighten back down (make sure you mark them when loosening cuz you can mess things up if you tighten too much).
then crank it a few more times.hopefully it starts.
then never let your tank get low enough to pick up air.
.niko.

bridge's picture
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Joined: 07/19/2006

it was the IP! fer about $500 got it running. thanks.

-------------------------
pray for peace? you might as well be praying for death!!
http://iprayfordeath.tripod.com