Was all set to sell my 92 4.9 today, buyer fired her up, test drove and was happy. When he went to leave, she cranked slowly and wouldnt start again. He gave title back, went his way til we can sort it out (hes still interested thankfully). The batteries good, alt was working and a replacement starter was swapped on. Got her fired with jumping after buyer left. What would cause this slow crank issue? I thought possibly plugged cats/exhaust since little flow comes from the tailpipe.

ideas?

 

Corroded batt terminals, internal corrosion in 12v feed from batt to starter.
A jumper cable from battery + to starter lug will show if its the cable.
On my E350 the starter terminals were easy to get at underneath without jacking anything up. Ended up replacing the cable and starter both.

 

will definitely test that, also bought a brand new battery for it (80 with moms employee pricing). Just sucks since I had the cash lol

 

well threw in the brand new battery and she starts better. Still cranks kinda slow though, weird. Heres a short vid of how she starts, not sure why it turns slowly...
<iframe width="853" height="480" src="//www.youtube.com/embed/BI4i0wLYXjo?rel=0" frameborder="0" allowfullscreen></iframe>

 

I'd pull the starter, have it tested by a shop specializing in rebuilding those and/or alternators, not AutoZone et al.

Have you tested the alternator for its output etc? That's not related to the somewhat slow starting but it could affect how much reserve is left after a drive for the next start.

A test can also be done with the starter in-chassis to determine the starting amps which could point to the starter needing serviced.

Sucks to have something act up when the buyer shows up---hope this gets resolved and the sale goes through.

 

Buyer was nice though, he actually pulled the old starter and put the replacement I had on himself, made no difference to starting though. Really wanna cut off ahead of the cats to test run for plugged exhaust, would be loud though lol

 

With a known good battery and known good starter...
For my money its the power cable.
Its a simple fix, just pull the engine ...

 

There is a tester for that, it's called a "Back Pressure Tester"

I just did the test on my '92 5.8 about a month ago, "borrowed" it from a mechanic I know and deal with, it took all of 5 minutes to do the test.

Pulled the O2 sensor, screw in the adapter, guage has about a 6 foot line on it, to get back to the steering wheel, to start the truck, and rev it up a couple of time, if needle stays in the green, no problem with plugged cat or exhaust.

Take the (hot) adapter out, and screw the O2 sensor back in and your done.

And........I'll go with jonesg money, that the 22 year old positive lead from the starter relay to the starter is toast, pull some insulation off the wire to see how black the copper is. Fords copper wiring is not the most longest lasting.

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