Idi cutting out
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Idi cutting out
Alright guys posting again didn't get a whole lot of responses on last let's see if I can word this better this time around. I have a 1984 f250 6.9 that was rebuilt to a 7.3 with new injection pump, new lift pump,oring kit, return line, rear tank,filter, rubber from lift pump to filter.
so now it's cutting out and dying going down the road. Idles just fine. But I stay revved up it starts to cut out and die. When I going down the road the truck with surge/cut out then die. Only two hoses I haven't replaced are two from tank to selector valve. Any ideas it runs way to good to be timing. Injectors...
so now it's cutting out and dying going down the road. Idles just fine. But I stay revved up it starts to cut out and die. When I going down the road the truck with surge/cut out then die. Only two hoses I haven't replaced are two from tank to selector valve. Any ideas it runs way to good to be timing. Injectors...
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Joined: Aug 2010
Posts: 2,554
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From: Northern Arizona
When you say cutting out... how do you mean? Running rough, surging and stalling is air intrusion. You just have to trace it down.
If the engine continues to run smooth but looses power and dies (and you notice a softening of the diesel clatter before the stall) it is probably return line back pressure. I had this problem because of crud building up at one of my FSV couplings. You also mentioned that it was a 6.9 replaced with a 7.3. The 7.3 uses larger diameter return rail hoses. If you are running a 7.3 IP with 6.9 return rail olives and hoses, that right there will cause issues. If you are sure you have the right return rails, you can test the back pressure thing by running the return into a catch jug by your brake booster and see if your problem goes away.
Also, replacement lift pumps are crap (Chinese Replacement Auto Part). I have heard of rapid failures and parts that are bad right out of the box. If you have access to a fuel pressure gauge, check to see that you have 5-7 psi after the filter head.
If the engine continues to run smooth but looses power and dies (and you notice a softening of the diesel clatter before the stall) it is probably return line back pressure. I had this problem because of crud building up at one of my FSV couplings. You also mentioned that it was a 6.9 replaced with a 7.3. The 7.3 uses larger diameter return rail hoses. If you are running a 7.3 IP with 6.9 return rail olives and hoses, that right there will cause issues. If you are sure you have the right return rails, you can test the back pressure thing by running the return into a catch jug by your brake booster and see if your problem goes away.
Also, replacement lift pumps are crap (Chinese Replacement Auto Part). I have heard of rapid failures and parts that are bad right out of the box. If you have access to a fuel pressure gauge, check to see that you have 5-7 psi after the filter head.
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