hi there,
im new to this forum i just bought an 88 f-250 ex cab long bed today. 7.3idi 4x4 5spd. no idea how many miles is on it im guessing over 200k. this is the first ford and first diesel i have owned. that being said there are a few problems with it and i dont want to turn my wife off to it already because things aren't functioning correctly. i have searched around the forums for the issues but i haven't found any that are quite like mine. shall we begin:
first off, my speedometer does not work so well. the first 10 min or so of driving it does not work or deflect at all. then it bounces around. but not near where it should be. bounces between 35 and 45 when actual speed was 65-75 does not seem accurate or reliable. i guess that sums that one up
second, i cant trust the fuel gauges. after 170 miles on the forward tank there is no meter deflection and it is a good half inch past the full mark. the aft tank which is full now indicates completely empty. i understand that the senders may go bad. i have never worked on these before or the truck as a whole. is there a step by step with pictures? and a place to buy replacements or a test to confirm that the senders or meter is faulty? and also the truck runs fine on both tanks.
finally my wife noticed when i get really into it i puff some smoke. my wife says its sort of a white smoke (not the best description i know but i haven't seen it myself is it just a diesel thing or should i be slightly concerned?)
there a few random things i would like to replace around the truck does anyone have a good place to buy parts like a turn signal stock.
thank you all for your time
happy motoring
nick reno

 

Nick, You should pull the vehicle speed sensor on the rear axle. Is in the front of the pumpkin, only thing with wires on it. You can try to clean it, an see if it functions properly. If it doesn't, just replace it. Go OEM for sensors.

The Fuel Gauge senders are a notorious sore spot on OBS trucks. Just replace them. The front one is easy, no need to drop the tank. The rear requires that You either drop the tank, or lift the bed.

The smoke is fairly normal. With that kind of mileage on the truck there is going to be a little blowby past the rings. I've cleaned My 93 with AutoRX treatment and can tell that the gray smoke has been reduced, but not eliminated.

Another nice thing about these trucks is that the salvage yards are full of them. Stuff like turn signals, and such are readily available, and fairly cheap. Heck, You might try to get a speed sensor off a 90+ truck from the salvage yard. The gassers use the same sensor. The speed sensor was improved over the years, and superceded at the dealerships. So If You go to the dealer, You'll get the latest, and greatest from Ford.

 

Did the 88' has a speed sensor in the axle? If it's cable driven the cable should be on the transfer case, driver side. Likely the cable is starting to come apart causing the jumping needle.

Fuel gauges could be sending units. If the other gauges are acting up it could also be the voltage regulator in the dash/gauge unit.

 

nreno88,
Welcome to FTE and the IDI diesel forum.

88 4x4 should be cable driven off the transfer case.
My guess there is either the driven gear or the drive gear is worn out, they are plastic.

Fuel gauge issue is most likely the sending units.
But we did have a user here change the fuel tank selector valve a while back, when he did the tank selected was reversed from the tank the fuel was drawn out of.

Possibly someone has already changed the tank selector valve on your truck and the same thing is happening.

If I remember it right, rear tank selected, rear tank fuel level indicated, but fuel was being drawn out of the front tank.
Likewise, front tank selected, front tank fuel level indicated, fuel drawn out of the rear tank.

 

thanks for the welcome. do i need a tech manual for the repairs or is there how to's available? im assuming the speedometer part that goes into the transfer case is a cable that is concealed by the skid plate. there are a few electrical connections as well. as for the blow by the only real cure is to rebuild but there is a few products on the market to minimize the problem. luck for me i dont have to pass emissions. any links would be appreciated
thanks again.
i also missed that it seems to be leaking a bit of oil after the long drive. its coming from pretty high up. i think that some of the gaskets may just be craptastic after a 3 year sit
reno

the fwd fuel tank indicated over full at the gas station and after 200 mi the rear tank after being filled up indicated empty

 

well after driving the truck pretty regularly for a week, it has stopped smoking entirely. when it is colder out well say about 50ish or less in the morning and the block heater has not been plugged in. it really dose not want to start. even with cycling the glow plugs two or three times. when it finally does catch it will blow a bit of smoke (i know im contradicting my self with the previous statement but this is the only time and if it dose not start after 10-15sec with no fire and retried) iv heard that the smoke being emitted right when the engine starts is due to glow plug issues. can anyone confirm or deny this? also i was wondering what temperature the truck should be able to start up on a cold morning if it has sat all by its lonesome without the block heater and what can be done to improve where my truck is right now. thank you all for your time. oh and i ordered the spedo gears so hopefully getting those soon.

 

With the rotation of the engine remember the inj. pump is firing the injectors off, so if it does not light off immediately it loads the cylinders with raw fuel until it finally builds enough heat to take off.
As far as cold starts, I don't use a block heater at all. Even in our Jersey winters, 20*-30's* mostly, it starts first time and quickly on the first cycle of the plugs.

 

If the battery system, fuel system and glow plug system are all functioning correctly, below zero should not be a problem.

 

the glow plugs may be my issue. the batteries are holding a steady 14.6 while the truck is running and greater than 12volts when the truck is not running. i think that the fuel system is function correctly with no leak down because no matter how cold it is, it will fire very quickly as long as it has been plugged in. my truck has been retrofitted with a start button but i believe that the glow plug relay and key lock still function as they would minus the start feature. i get a quiet clicking from under the dash when i havent started the truck and the wait to start light is out. would you recommend replacing the glow plugs and controller or wheres the best place to start with a problem such as this. also if the truck has been driven that day it seems like the truck will start pretty quickly on a single cycle of the plugs, im guessing that it is because of residual heat in the block. any advice and comments is greatly appreciated. thank you all for making the transition to the idi as smooth as possible.
nick reno

 

One the 88 you have the new style glow plug controller.

It should light the wait to start light for 10 seconds or more on the first start of the day.

The new system uses resistance feedback to time the glow cycle, so glow plug resistance is critical for proper operation.
.5 to 1 ohm is the desired resistance range for each plug, measured between the connector and the threads/nut.

At .5 ohms, the glow plug will draw 24 amps when heating.
At 1 ohm, the power consumption drops to 12 amps, producing 1/2 the heat in the same amount of time.

Start by checking the glow plugs, they are usually where the problem lies.
Use Motorcraft/Beru ZD 9 glow plugs for replacements.

.5 ohms is very close to a dead short, and some cheap multimeters will not show resistance that low.
Digital seems to be the best choice.

 

Easiest way to quickly test them is with a test light. Simply attach the wire lead of the tester to the positive + side of the battery. With the pointed end of your light, touch the glow plug end where the wire attaches. This will only work to test for an open circuit in the plug. If you have a meter they should be ohm tested for resistence.