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rubystargoats

93 F150 5.8 with no power

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My daughter bought the 93 F150 super cab long bed 2WD with a rebuilt engine. Runs good with no load but no power. does anyone at least somewhat close to Covington, have scanner that can do diagnostics on this thing?  5.8 V8 auto trans. nice looking truck and  she was able to get it for $1,000.00. Exhaust does not seem restricted check engine light is on so need to read codes and any other info with a scanner. Will be checking compression first.

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Stop by Autozone or Orielly you have to know where plug is for diagnostics I had a 93 Dakota they would scan with help 

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I would read codes first.

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 I am hoping to scan it as well as other diagnostics and it runs so poor it may be multiple things. I don't have time to drive it around and it has so little power it is a road hazard on the hills of which we have many..

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The previous owner gave up on it after replacing a bunch of stuff. I am beginning to think it may be a bad cam or cam timing issue but??? I want to eliminate the easy stuff first. pulling the plugs might show something as well as compression reading so going to start there since I don't have a scanner.

Edited by rubystargoats

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Being a 1993 does it have an OBD2 port?  They weren't required until 1996. 

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I have no Idea, she just got it home and it is in the shop drying out and then I have surgery on Wed. She said she had someone coming to help her so hopefully I can just point and laugh...

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OBD 1.  That's what I was thinking.  The first think that jumped in my head was a distributor or spark advance problem. 

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Do you have a timing light Dan?  It would be easy during a rebuild to offset the distributor by one tooth the truck would still start, but be absolutely gutless.  

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   T have a good timing light but i need to clean up the pulley and find the marks. I would think it has already been done but???   Fuel pressure looks ok so checking plugs and compression next then timing. not sure this engine has ever run right since the "rebuild" I wonder about cam timing as well as cam break in issue and flat cam.

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As with any rebuild there are so meny things it COULD be, sometimes you just need to eliminate one thing at a time.

 One thing to consider, the crank pulley/ vibration dampener might not be installed correctly, or even the right one.

 You might have yo verify that TDC is the mark on the pulley.

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8 hours ago, Bob V said:

As with any rebuild there are so meny things it COULD be, sometimes you just need to eliminate one thing at a time.

 One thing to consider, the crank pulley/ vibration dampener might not be installed correctly, or even the right one.

 You might have yo verify that TDC is the mark on the pulley.

   that is the plan, one thing at a time. Going to check TDC mark when we have the plugs out.

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    Some one came over to help with the truck. pulled 6 plugs and then had to go.  All 6 were black and damp. Still need to pull the last 2 and then check compression. I may also try to use a jumper again to try to get it to blink the codes for me as well. It gave no blinks last time I tried even though the check engine light is on. It is really frustrating to not be able to do any real work on this thing....it could be as simple as a sensor or connection is bad but??????   I will know more when they run compression test.

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Are the valves adjustable on that motor? I’ve seen low compression from improper adjustment on rebuild just an idea if comp is low

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I will have to double check but the other Fords I have played with, it is just the installed valve stem height that is set and no adjustment with the hydraulic lifters. They could still be off if the installed height was off. hopefully run compression test tomorrow. I can't do much for another couple weeks or so, so waiting for the daughter to help. Especially since it is her truck........

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On 1/14/2020 at 12:07 PM, Frankenstien said:

Let me know if you need a hand I might be able to swing out this weekend 

 

    Until this shoulder heals, I can always use an extra hand. I did finally run compression on one cylinder (without te daughters help, i got tired of waiting for her) and got 140 psi, not bad for a cold engine. I really need to get the other 2 plugs out of impossible places and check all 8. Then clean and install plugs. The plugs are almost new and I do not want to soot up another set of new ones, then clean and highlight timing marks on the damper pulley for a timing check and engine warmup. Then try to gets blinking codes again, the check engine light is on. I wish I knew more of the rest of the story behind the truck and "rebuild"

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I think you can get by with just doing a relative compression test at this point. 

 Disable the ignition, easiest way is to disconnect the primary side of the coil. Crank the engine over and listen for any change in engine speed as it cranks over.

If you have low compression on one of the cylinders the rpm  will change when that cyl is on compression stroke.

 If it cranks over nice and steady you PROBABLY don't have a problem with compression. 

 I still would take #1 spark plug out and get it to TDC and check how close the timing marks are.

 Another way is to loosen the distributor hold down and start the engine. move the distributor till you get the highest RPM, then retard the timing back so you loose about 100 RPMs, check the timing with a timing light as see where you are at, you probably be around 15 to 20 BTDC. 

 Do you have access to a vacuum gage?

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    Finished compression test today all 8 at 140 or 135, ok for a cold motor that has not run for a week or so. Next is to check timing elements and then run again to warm up and try to get codes again..  One thing still bothering me is the check engine light is on but no codes will read with the dash light blinking or the code reader, often this means that the ECM is  bad and the engine is in limp mode. That would explain all the current symptoms.  Just not ready to accept it yet, going to eliminate as  mush other stuff before going there. Unless someone has a spare 93 ford 5.8 auto ECM laying around....

Edited by rubystargoats

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