3800Pro Forums banner

Rebuild after 13 years. Help?

326 Views 9 Replies 3 Participants Last post by  dezldave961
I have a 98 GTP. Lots of mods. From what I remember it was high 12s 1/4 mile back in the day. Pulled it apart 13+ years, for a coolant leak. Was still running fair when I pulled it apart. While apart I decided to do a Gen V swap as well as upgrade my intercooler. Today I started her up over 13 years later. It has sat in the garage the entire time. It fired up and the second try. Idles rough for a short amount of time then smooth out. No leaks. Everything seemed better than expected to be honest. I was worried it wouldn’t start. Shortly after the garage started to smell like I was at a bonfire. And I saw white exhaust coming out the tail pipes. And I pulled down the exhaust from the resonator and downpipe. I can see all the crap in the resonator from what looks to be an old mouse home. I got that taken care of refastened up. And all seems well. I took it for a drive around the block just now. it seems to have very little power. It smells rich that I can tell. No codes yet. Any ideas on anything I could have overlooked? I know it’s a very vague question, but it’s been so long since I’ve drove this car.


See less See more
1 - 10 of 10 Posts
Did you change the oil or any of the fluids? That would be the first thing I'd do after it sat that long. If you just took it around the block & didn't put any mileage on it the pcm might need more time to relearn the fuel trims. Could also be an issues with the boost bypass valve or one of the vacuum lines to the supercharger. Thats the only things that initially pop into my head. Very nice engine bay btw!

Yes, all fluids, except trans, were drained and filled. Currently running Distilled water to flush coolant system. Will drain and fill with proper ratio,
New Mobile one 5w-30 Synthetic. Will drain again in 500-1000 miles. Next step is to finish water lines for the intercooler. My PRJ full size cooler has both lines on the same side now.
So need to reroute everything. Boost Bypass valve seems to funtction fine. When I give it throttle, I can see it close. I can also see boost when I give it some throttle. I have not gotten on it yet and do not plan to until next oil change. I am working on finding software for my DHP tuner as well as Tiny tuner.
I plan to swith to E85 or E50.
I run E50 on my tuned f150 Ecoboost, so easy calculation for me.
Smart move. I always baby mine coming out of winter storage. Sounds to me like you are doing everything right. I was thinking maybe your issue is a dragging caliper or parking brake. These cars have small drum setups in the center of the rear rotor, its possible something ceased up in there.
I think I was used to my Ecoboost. I have the tune set up to have a pretty touchy throttle response. On the 98 GTP, they are cable driven, so not much throttle until you bury the pedal.
I suppose there is not changing that...It feels pretty good. I have 2 more IM Monitors to ready up. Then I can go do emissions. Still waiting on CAT and EVAP.
Just need one to ready up.

Then need to work on the suspension. I currently have Koni adjustable struts with lowering springs.
I imagine I will need new ball joints. Can anyone list the other bushings to replace while i'm in there?
The 3800 TB mechanism is exponential (notice the dual pivot), probably meant to limit some spinning with the SC. A simple swap to a Northstar TB gets you a direct single-pivot cable pull, and you will notice it immediately.
If that setup isn't giving you an aggressive pedal when you hit it, you've got some more upkeep to do before beating on it... Or you're doing an apples to oranges comparison in your head (I mean that in a purely scientific sense of comparing two different configurations with different feasible upgrades and traction capabilities).
It has been a long time since I drove it, 13 years. I guess I just got used to the truck. I am guessing we can not tune for throttle tip in on these, being they are mechanical throttle bodies?
You can adjust the Acceleration Enrichment (transition) and Performance Enrichment (boost/open loop) fueling areas. The rest is just mechanical, which calibrating your brain-foot connection to different vehicles will be the solution.

After driving my F-150 a ton in the last 5yrs, getting in my cars now feels totally different, and almost uncomfortable until I routinely drive them for a bit.
1 - 10 of 10 Posts