Tanker3278

I just picked up a 92 F250HD with a naturally aspirated 7.3L IDI. Doesn't seem to be much out there for those engines. Anyone know of some good power mods or fuel efficiency mods I can do? I'll be going to a turbo later on, but I want to know what's out there for NA IDI diesels.

Tanker3278

Was wondering if the glow plugs stay lit all the time or are they timed to light up on the compression stroke?

Will be replacing my plugs and injectors soon and realized I didn't know. I know they just glow hot to help the diesel ignition but don't know what they do when they are not needed (intake stroke and exhaust stroke).

chelios

i think that glow plugs just kinda warm up your engine, they are not timed to light up. if you have more questions about diesels, i would look to a diesel-oriented forum. i'm pretty sure 99% of the guys on here have f150s with gassers.

Old_Skl_Raptr

x2. i think the glow plugs just warm it up and then shut off and the diesel bein compressed so much explodes

conman365

Glow Plugs are only used to intially start the motor. Some diesels don't even have them. The cummins inline series are glow-plug free. I wouldn't replace the plugs unless they are faulty. There really isn't a whole lot you can do with these IDI trucks. They'll pull anything and last forever, but the only real substantial upgrade I've seen done to these trucks is a turbo and a cold air intake.

Robertb6963

Correct, the Cummins engines use a heater to heat the air instead of the block.

You can hear your glow plugs ticking when you turn the key to run before you start the truck.

We have a 93 N/A and a 94. Our 93 has 504,xxx miles and runs like a champ, however they are terribly slow. I would look into a turbo/pyrometer/(intercooler possibly too?) like you said. Exhaust would help, also.

bobkyle2

straight pipe it... and you can make your own cold air intake cheap and works great.... you can turn your injector pump up really easy too... and that helps alot... but you really need your exhoust opend up and a CAI..... i have a 93 7.3 idi..(greatest truck ive ever owned)... if you buy glow plugs you need to get ford glow plugs... the cheap ones never last... another thing on performance of these trucks is a electric fan set up... and get rid of the stock clutch fan...

1987f-150

i know it would be a big project but i really want to put a 6.9 idi in my 1987 f-150, what kind of things do i have to replace other than the motor and tranny? please give me some good info cause yahoo awnsers is stupid and is filled with idiots lol thanks.

Tanker3278

For a project like that I would suggest starting out with the manufacturer's electrical info because going from a gasser to a diesel requires replacing a lot of the vehicle's wiring harness.

When working on my '94 F150/4.9L my Dad sent me an EVTM that was produced by Ford and used in Ford dealerships. EVTM = Electrical & Vacuum Trouble Shooting Manual. An EVTM is a great tool to have, even for regular maintenance. It has complete wiring diagrams and images of the connectors that will tell you which pin in the each plug is which & what it does. I was not able to find one for my '92 F250 so I ended up getting the Ford shop manuals instead - not nearly as good. I don't know if Ford made EVTM's before '94 but it would be worth the effort looking for it if you could find one for an '87. The EVTM I have is for F-series & Bronco so it will have both the F150 & F250 data in it.

Outside of the engine and tranny there is a lot under the hood (and dash) that is different. I've been reading through my EVTM (slowly, due to limited understand of electrical stuff) learning the differences between the too vehicles.

Here's just a few things I can think of off the top of my head...
1. The starter solenoid on a gasser is not a starter solenoid on a diesel - its two parts, a glow plug relay and a glow plug controller. The relay sends current to the starter and the glow plug controller rather than the starter and the coil.
2. Its a dual battery setup on a diesel because of the huge draw on the batteries at startup: 8 glow plugs draw 192 amps total at full draw plus the juice for the starter - and the starter requires more because you're pushing a bigger, compression driven engine. Spark plugs don't require anywhere near that much current because you're only making a spark to detonate the fuel and the coil ups the volts to do that, and there aren't that many gassers out there that have 15:1+ compression ratios like the 17.5 & 21:1 in IDI diesels.
3. Parts clerk at O'Reilly's Auto told me diesels make very little vacuum. If so, your whole vacuum system is different.
4. Diesel radiators are huge compared to gassers.
5. You'll need a stiffer suspension to handle the extra weight in the front end. Diesel engines are much heavier than gas.
6. You'll be sending a lot more torque to your axle, if you don't already have an 8.8 (you should) I'd go no smaller than that and I'd make sure it has a gear that can take the power going through it. A 9" or a 10.25" would be much better. Your drive shaft is also going to be a different length because of the tranny (probably)
7. Your fuel sending units should be just fine, will probably love sending diesel instead of gasoline, but you'll have to change your filter in the line.

All that means ALL the electrical under the hood and a bunch of stuff in the dash has to get replaced to be able to run a diesel. You'd want to take all the accessories off the donor vehicle so they would be correct for the wiring harness.

Fortunately, the cabs and front clips on F150s and F250s on those years might be (not familiar with the older series) completely interchangeable. Meaning aside from the engine/tranny the majority of your fabricating would be suspension stuff to handle the extra weight, unless the F250 parts are interchangeable too.

That's a lot of work if that's what you like to do. I'm lazy, I'd go buy a F250 and stick F150 labels on it. If you're gonna do it, I'd do the surgery with an F250 of the same year.

Hope that didn't rain on your parade...

bobkyle2

the wiring is simple to convert it... you can wire a 6.9 or a 7.3 idi up very easy... you would have to have a diesel tank... the f150s have elec fuel pumps... the 6.9,7.3 has a mech pump on the engine... and it has a injector pump on the engine... (if i was going to put it in a f150 i would cut the tanks off and put a diesel tank in the bed)... you could get online and find someone that can tell you how to wire up your glow plugs to a switch....( thats what im going to do to mine to get rid of that damn glow plug controllor)..the 6.9,7.3 have a vaccumme pump mounted on the engine...hardest part about that job would be getting the f150 to hold the engine(very heavy).. after you get it to hold it... you would have to have axles to hold the torque...... (im not positive but i think the transmissions are the same but you would definatly need a diesel torque converter .... if you are really wanting to do this i know a few good web site that show you how to do this stuff... ive helped build one of these before... but the guy didnt replace the axles and suspention... he just beefed up the front end... he uses it to haul wood in his yard... never sees over 1000rpm... so he didnt worry about the axles