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Hi everyone I am new here and recently acquired a 1991 XLT Lariat 7.3 idi club cab 4x4 f250. It has a E4OD and 146,350 miles on it. When I first got it I put new Motorcraft Glowplugs in and two new Motorcraft 850cca batteries and a electric fuel pump in. I have noticed that the tach sometimes will work perfectly and other times it reads 0 at idle and will move only when given throttle. Should I be concerned about this and my second question is what are the common issues with the 7.3 idi? I am attaching a picture of my truck and would appreciate some advice.
The intermittent tach issue is probably the sending unit on the engine. I've never heard that the cluster goes bad.
Common problem areas for our trucks are #1 AIR INTRUSION followed by failing starters, leaking fuel select valves, broken glow plug tips etc. in no particular order. If your truck is running good then just keep driving it and make sure you use Motorcraft or Beru GPs. You're more dedicated than I am, I wouldn't fork over the cash for Motorcraft batteries.
Nice truck. XLT is a keeper. On my last 2 idi's, the tach was wonky too. On my 91 w/e4od the tach would not work until the truck warmed up'. It's not cable driven so over time the electronics get a bit lazy. If your trans doesn't go into limp mode you're ok. You have any maintenance info? That is a D60 swap candidate for sure. Nice score . If you feel it's too much for you to take on, just let me know! I'll take it off your hands.
Your question: ... what are the common issues with the 7.3 idi?...
The most common issue is failure to do the routine maintenance. The second issue is when there is a mechanical issue the owner wants to "throw parts at it".....
So, perform those mundane, routine maintenance chores. When that truck "talks to you".... Listen well and follow up.
The intermittent tach issue is probably the sending unit on the engine. I've never heard that the cluster goes bad.
Common problem areas for our trucks are #1 AIR INTRUSION followed by failing starters, leaking fuel select valves, broken glow plug tips etc. in no particular order. If your truck is running good then just keep driving it and make sure you use Motorcraft or Beru GPs. You're more dedicated than I am, I wouldn't fork over the cash for Motorcraft batteries.
I work for a ford dealer in ohio and the truck saw air force servic then farm service before I got it. I cant get the tach sensor at work anymore and I already put glowplugs in Motorcraft to be exact. I am about to service the trans this weekend. My other question is is it common for the voltage regulator to go out and for the AC compressor to lock up? Also what can I do to convert it from V belt to serpentine?
My AC went out on my 91 also. Don't know if it's common. Don't think you can do a serpentine setup. The vac pump sets up top right iirc. But you never know. Throw enough money at it and you can do practically anything. Look up 3G swap for the alternator. Look for a trans pan with a drain plug. My 91 didn't have one and it sucked to service.
lone wolf did a write up on here about cleaning the contact on the tach which i think fixed the issue he was having, mine does the same thing but i dont want to take the dash apart unless i absolutely have to do it
Nice truck. XLT is a keeper. On my last 2 idi's, the tach was wonky too. On my 91 w/e4od the tach would not work until the truck warmed up'. It's not cable driven so over time the electronics get a bit lazy. If your trans doesn't go into limp mode you're ok. You have any maintenance info? That is a D60 swap candidate for sure. Nice score . If you feel it's too much for you to take on, just let me know! I'll take it off your hands.
it was owned originally by the United States Air Forc and until around 2005 was on Wright Patterson Airforce base in ohio it was sold at auction and lived on a farm in Springfield Ohio till I bought it and I had to replace all the return lines and reseal all the injectors and put in all the glowplugs and a radiator. The fluid that came out of the transmission cooler when i did the radiator was red and did not smell burnt.. I refilled the trans with Motorcraft MercronV and that was that. Now I have noticed that when the tach is not working right it has a funky1st and 2nd shift that you barely feel and 2nd to 3rd feels normal but 3rd to 4th is a repeat of the 1st to 2nd shift and reverse comes on pretty quick. But when the tach is working normally it shifts like a normal truck. So I don't know. I really have not dove deeply into automatic transmissions.
the Tach signal from the sender runs thru the PCM then to Drive the Tach itself....IF the tranny is shifting badly then you may have a bad sender, generally when it looses Tach signal to the PCM it will set the OD cancel light to Flashing indicating the system is in LIMP Mode.
Check to make sure that OD Cancel Lamp works.....if not most likely broken wires where the harness comes out of the shift lever going to the small connector.
if the tach sensor is bad, it will put the trans in limp mode which you are seeing with the funky shifts. do not continue to drive it this way, it will ruin the trans.
as far as the serpentine belt goes, i would never change my 88 to run one.
if it fails you are down.
if a v belt fails, you still have others on the truck to get you where you are going.
the good thing about V belts is that there are always at least 2 belts on the crank and water pump incase one breaks.
if the tach sensor is bad, it will put the trans in limp mode which you are seeing with the funky shifts. do not continue to drive it this way, it will ruin the trans.
as far as the serpentine belt goes, i would never change my 88 to run one.
if it fails you are down.
if a v belt fails, you still have others on the truck to get you where you are going.
the good thing about V belts is that there are always at least 2 belts on the crank and water pump incase one breaks.
well its the only vehicle I own and it never has set the od to flashing and the light does work so I am wondering if it could be the cluster and not the sender. I noticed the oil pressure gage is lazy as crap and that the speedo is off atleast 5mph. So 25 is actually 20 ect. Also the volt gage is wonky it shows just above 8v on fully charged batteries and then once everything is warmed up if you fiddle with the head light *** it suddenly will be at the upper end of the A in NORMAL. I do not know everything about these I am coming from a 90 5.0 LX mustang to this truck. I do know I saw a harness plug that concerned me. Could this be my whole problem?
if i remember correctly that plug is in part at least glow plug power feed. i would repair it, as the condition it is in is just asking for a fire to start.
speedometer on your 91 is cable driven off a gear in the tailshaft of the transfer case.
5 mph off at 25 mph is 2 teeth on the drive gear.
if i remember correctly that plug is in part at least glow plug power feed. i would repair it, as the condition it is in is just asking for a fire to start.
how can I fix it? I can't get that harness anymore and its situated almost directly under the fuel filter. Also what harness should I look at to solve the gauge cluster issue I mentioned? The irony is both my fuel tanks work perfectly and switch perfectly. I am trying to solve it as inexpensively as possible. Its again my only vehicle and I want it to be reliable.
for the burned plug, i just eliminated it. i used inline crimp connectors, but instead of crimping them i soldered them and used heat shrink tube after to protect the connections..
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