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78fordwayne
Top Member
USA
2868 Posts |
 Posted - 04/05/2007 : 5:52:28 PM
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I was reading Doug's topic on injection pump time and it got me thinking...
I have a 92 3700 with the 7.3lt. 185,000 miles. The bus starts ok most of the time. Once it warms up a little it idles fine.
The problem I have, lets say im going 55MPH , if I push the gas pedal to the floor the engine gets louder but the bus slows down to about 40MPH. No smoke or anything no missing. I get the most power at half throutle anything more than that and it just looses power.
Now I know from working on buses in the past that when the pump is going bad it will do the same but it will smoke and miss like crazy. My bus has no smoke and no miss.
Could it be out of time or does this sound like a pump issue?
Thank you 
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Doug
Active Member
USA
45 Posts |
Posted - 04/05/2007 : 9:51:58 PM
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| Hello , I was reading your post and had the same issue with a 7.3 . Sounds like the filter is plugged or the lift pump is bad . When that happens it means it is not getting enough fuel to the injector pump |
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IBTMech
Top Member
USA
973 Posts |
Posted - 04/06/2007 : 3:11:57 PM
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Sounds like lack of fuel to me.
Full throttle will advance the timing but if the fuel isn't there......... |
If it doesn't fit, FORCE it.
If it breaks, well, it needed replacing anyway.
Pullin' wrenches for 45 years. |
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78fordwayne
Top Member
USA
2868 Posts |
Posted - 04/06/2007 : 3:30:46 PM
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I have changed both fuel filters. I will order a lifter pump and see if that helps.
Thanks
Any more ideas? |
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jeepcjron
Advanced Member
USA
262 Posts |
Posted - 04/06/2007 : 5:33:59 PM
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| lift pump drive cam wear was an issue on these also. i would check fuel psi before throwing parts at it |
its like a slinky! useless but fun to watch. |
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78fordwayne
Top Member
USA
2868 Posts |
Posted - 04/06/2007 : 6:33:56 PM
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Now that I think about it, The way it starts it acts like it isnt getting fuel right away. When its cranking its only fireing on 1 cylinder for about 5 seconds. Than it starts and dies right away. The second try it always starts right up.
I ordered the lift pump from my work. Its only $18 so no big deal. Ill just keep my fingers crossed. LOL |
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78fordwayne
Top Member
USA
2868 Posts |
Posted - 04/17/2007 : 8:02:30 PM
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Ok I put a new transfer pump in. I have more power at half throttle then I did before.
However I still have the problem if I push the pedal to the floor I start slowing down .
Any more ideas? Thanks |
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IBTMech
Top Member
USA
973 Posts |
Posted - 04/18/2007 : 5:21:57 PM
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As long as there's no black or white smoke, you need to monitor the fuel pressure during a test drive. Even though you have new filters, it appears you have a fuel supply problem........ a collapsed hose..... a restricted tank suction tube...... a defective check valve....... for some reason, you do not have an adequate fuel supply.
I had a similar problem years ago with a bulldozer and finally pulled a shirt out of the fuel tank.
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If it doesn't fit, FORCE it.
If it breaks, well, it needed replacing anyway.
Pullin' wrenches for 45 years. |
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78fordwayne
Top Member
USA
2868 Posts |
Posted - 04/19/2007 : 5:34:09 PM
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quote:
Originally posted by IBTMech
As long as there's no black or white smoke, you need to monitor the fuel pressure during a test drive. Even though you have new filters, it appears you have a fuel supply problem........ a collapsed hose..... a restricted tank suction tube...... a defective check valve....... for some reason, you do not have an adequate fuel supply.
I had a similar problem years ago with a bulldozer and finally pulled a shirt out of the fuel tank.
No shirt ! I checked last night .LOL
I took the little bleeder set screw out of the top of the fuel filter housing on the top of the engine right before the line goes into the injection pump. Cranked the engine over and the fuel sprayed out about 4 feet i would say.
Does anyone know what the fuel presure should be at that point?
Ill try to hook up a guage to it.
Thanks! |
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92' 7.3 issue
