questions

[rip van sparky]

Hi,
I just bought a 1991 F350 ext. cab dually. I have been able to answer most of my questions by reading around but a few remain. I believe somebody turned up the IP on my truck (without a turbo) because it belches smoke like a 650hp CAT pulling a 45 ton excavator anytime I give it more than just a little throttle. It has good power (other than 5th) for pulling, but I would like to turn it down so that it isn't quite so obnoxious. Can anyone point me in the right direction? Also, it's a pain to start when cold. When I turn the key to warm up the GPs I hear clicks that are about a second apart from what I believe is the GP relay (behind intake). I was wondering what the cycle time should be. I think that I could have a miss, can I locate it by cracking the injector lines? I have a CAT 3208 in my big Ford that I have done this with, but as simple as the 7.3IDI is it is much simpler still. One more thing, when the truck is in neutral with the clutch out there is a disconcerting rumbling/thudding sound emanating from the bell housing. It stops if I push in the clutch. I haven't been able to hear it when moving. I was wondering if this has something to do with the DMF. I discovered the headlight switch that was trying to catch my truck on fire right away. Frightened. Will probably wire it up like my Mack (seperate circuits for headlights and running lights). Well, this has gone on longer than I had anticipated so thanks for any help you may have.

 

[towcat]

Welcome to the site! You got the right idea for most of the truck's issues. Will post a link on how to turn down the pump(just do it in reverse of the instructions). will add more thoughts in a little bit.......
here's the linky (POKE HERE) It's written by ziggster40 from over at STD(thedieselstop). He knows his **** and writes it down in a way that everyone can understand it. haven't got him to come over here yet tho. As far as your headlight switch, when you take the switch out and replace it, make sure the plastic block that holds the wire connectors is in good shape too, otherwise the switch's life will be short lived. replacement blocks with pigtails was availible at the Furd stealership at last check. Do use care in the headlight section, many a F-series trucks died an untimely death due to headlight switch fires. Oh yea, you're on the right track on cracking loose the injection lines to find the bad cyl. One more thing, isolate the bad cyl first and fix it before stressing out over the DMF.

 

[Agnem]

Hi,
I just bought a 1991 F350 ext. cab dually. I have been able to answer most of my questions by reading around but a few remain. I believe somebody turned up the IP on my truck (without a turbo) because it belches smoke like a 650hp CAT pulling a 45 ton excavator anytime I give it more than just a little throttle. It has good power (other than 5th) for pulling, but I would like to turn it down so that it isn't quite so obnoxious. Can anyone point me in the right direction? Also, it's a pain to start when cold. When I turn the key to warm up the GPs I hear clicks that are about a second apart from what I believe is the GP relay (behind intake). I was wondering what the cycle time should be. I think that I could have a miss, can I locate it by cracking the injector lines? I have a CAT 3208 in my big Ford that I have done this with, but as simple as the 7.3IDI is it is much simpler still. One more thing, when the truck is in neutral with the clutch out there is a disconcerting rumbling/thudding sound emanating from the bell housing. It stops if I push in the clutch. I haven't been able to hear it when moving. I was wondering if this has something to do with the DMF. I discovered the headlight switch that was trying to catch my truck on fire right away. Frightened. Will probably wire it up like my Mack (seperate circuits for headlights and running lights). Well, this has gone on longer than I had anticipated so thanks for any help you may have.

Welcome! Thanks for doing your best to read up before asking too many questions. We don't get enough people doing that. HERE is where we keep a lot of links to guys with their own web sites and good information. The headlight switch is a known issue. If you read our FAQ (Frequently Asked Questions) post, you will find your answer there.