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View Full Version : 7.3 diesel excursion runs weird



htmchris
06-24-2007, 10:21 AM
I got a 2000 ford 7.3 diesel excursion 4x4 on 6inch lift and 35 tires 16.5x9.75x35 Iam sure its got stock gears but install all of banks kit exhaust big hoss turbo spring and air filter power chip and trans comander my problem is that when you just take off it will fall off boast and lug unless you stay in it then boast is great about 25 pounds at 1000 on exhaust has any one had this problem or would know how too fix it you dont have too haul ass but it runs exclent etherwise just seems that its wrong too preform that way also when I tow my boat you have too have overdrive off and sometimes with out the boat with ac on it wont lug with over drive off is it a gear thing!

ToMorrow44
06-24-2007, 01:55 PM
I have the same set-up in my 02 F250. I don't think I've ever had the problem you're having though. I think you said you have the Big Hoss module is that correct? I know I don't have that so there may be a difference. I know in my truck, the only time I've seen 25lbs of boost is hauling ass towing the boat (7000lbs) up the 5 (grapevine). Otherwise the boost is not supposed to be that high and neither is the exhaust temp especially if you're not towing. Again, maybe the Big Hoss module allows this. As far as the power falling off, I would say that it would have to be a turbo problem and possibly the wastegate keeps getting stuck open..? I think your best bet would be to call banks and I bet they could tell you what's wrong. Good luck and keep us posted.
-Tom

STV_Keith
06-24-2007, 02:06 PM
What do you mean it falls off boost? It starts to make some boost then goes back down?

htmchris
06-24-2007, 05:54 PM
ya it makes good boost and banks said that the boost and exhaust is at correct temps if you just drive it will start too bog not too much you could feel the rpm come down at normal driving wre is way I been driving round with over drive off she the reason is Ive never owned a 7.3 and thought that this is the set up for all this stuff thats been put on the excursion diesel but it dont feel right to me she tows like a monster with minal black smoke I did pull the chip out and drove it around and the problem is still there ? HELP GUYS IAM LOST ON THIS,

STV_Keith
06-24-2007, 07:03 PM
You're going to have to reword that for me. I can't make sense of it?

htmchris
06-24-2007, 08:12 PM
the vehicle when driving will start luging after you take off it makes boost then shifts then drops down to were you have to push more pedal down to bring up rpms shouldent still have a little rpm i think its do too the gearing where it takes off then shifts then rpm just drops off on the fwy she runs perfect do to the rpms are there for normal driving ?

ToMorrow44
06-24-2007, 10:03 PM
You're going to have to reword that for me. I can't make sense of it?
I'm with you there. From what I get, you hit the gas to take off then the boost falls off after it shifts? Do you have to apply more throttle to bring the boost back up? Is the boost proportional to RPM (higher RPM higher boost)? If its a yes to all of the above, I think its operating normally. When the diesels get up to driving speed and the motor is no longer working very hard, there's less exhaust flowing through the turbo= less boost. Turbo's aren't like superchargers where they make boost only with RPM, turbos make boost when the motor is loaded hard. Does that clarify anything?
-Tom

AZJD
06-25-2007, 07:09 AM
Re-gear it. It's a clunky Ford. It sounds like you are getting into 2nd gear and it is dragging the motor down due to tall gears.

STV_Keith
06-25-2007, 10:52 AM
What RPM is it shifting at? 1st and 2nd gear it shouldn't engage the converter lockup clutch, so it shouldn't drop that many RPM's. 3rd or 4th it might.

htmchris
06-25-2007, 10:58 AM
replying to tomorrow 44 yes that is what is happening it seams weird that when it shifts to second gear it drops so low and banks says that is great I think ill regear the axles and I should be fine. thank you guys for all the help this web site is GREAT HELP, SEE YA ON THE WATER.

2ndIINoneMotorsports.com
07-15-2007, 09:12 PM
Still having the problem? I can take you for a test drive in our X...She's slightly modified on STOCK gears pushing 37's :D

BadKachina
07-16-2007, 09:38 PM
You've got another issue. I had 39's on my 2000 Ex with stock gears and a Bullydog, it never did what you described.