93 F700 intermittent problems
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93 F700 intermittent problems
Long story but several years ago i bought a pair of identical 93 F700 lo-pro trucks that had been sitting a long time. They both have 7.0 motors and Allison 545s. They are back burner projects that im fiddling with again. The tanks were full of gunk and fuel pumps on both were garbage. I opted to use aftermarket universal external pumps on both trucks. I replaced the filters and regulators also. Neither truck would run correctly at rated fuel pressure. I bought aftermarket adjustable regulators and when i tightened the pressure down to about 55 psi, both start and run like they should. Now, 2 new problems:
Truck 1 would shift and drive right if I just barely gently moved the accelerator. I discovered it has several capacitors rotted off in the ecm. Where is the best place to send it off to?
Truck 2 runs and shifts perfect until you go about 3 miles. After that, it starts acting like a fuel issue. If you drop it neutral, turn off the switch for a second, it will start back up immediately and run perfect for another mile or so, then repeat the same symptoms. Sometimes the check engine light comes on, sometimes not. What is my next step there?
Sorry for the long post and multiple questions. With the matched pair I can do some parts swapping if necessary.
Thanks in advance
Truck 1 would shift and drive right if I just barely gently moved the accelerator. I discovered it has several capacitors rotted off in the ecm. Where is the best place to send it off to?
Truck 2 runs and shifts perfect until you go about 3 miles. After that, it starts acting like a fuel issue. If you drop it neutral, turn off the switch for a second, it will start back up immediately and run perfect for another mile or so, then repeat the same symptoms. Sometimes the check engine light comes on, sometimes not. What is my next step there?
Sorry for the long post and multiple questions. With the matched pair I can do some parts swapping if necessary.
Thanks in advance
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"Truck 2 runs and shifts perfect until you go about 3 miles. After that, it starts acting like a fuel issue. If you drop it neutral, turn off the switch for a second, it will start back up immediately and run perfect for another mile or so, then repeat the same symptoms. Sometimes the check engine light comes on, sometimes not. What is my next step there?"
Sounds like more gunk building up on the fuel pickup. Pull it apart again and check for more contamination.
On the ECU, have you looked for a replacement?
Sounds like more gunk building up on the fuel pickup. Pull it apart again and check for more contamination.
On the ECU, have you looked for a replacement?
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I will check the fuel pickup to make sure, but I dont think thats my issue the way i plumbed it when put the aftermarket pump on it but I will check.
The ecm is not available at Advance auto parts, but a Cardone number cross reference is at another auto parts store and at Amazon. They are $250-$300. There are several places that advertise rebuilding for $150 or so, but when I had dime size rusty corroded spots on mine I wasnt sure I could expect to get mine rebuilt without additional charges anyway. I am not having any luck finding good used.
Thank you for the reply
The ecm is not available at Advance auto parts, but a Cardone number cross reference is at another auto parts store and at Amazon. They are $250-$300. There are several places that advertise rebuilding for $150 or so, but when I had dime size rusty corroded spots on mine I wasnt sure I could expect to get mine rebuilt without additional charges anyway. I am not having any luck finding good used.
Thank you for the reply
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parcher440
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