Please help me narrow this down (Long)

[VadersV6]

After about 100 man hours, Im almost to the point of giving up and selling this car. I got 16mpg with 4.56's, and now with the right rear and gears, Im getting 14. (I havent misread the odometer. I always calculated with the wrong gears.)
What Ive done:
Got 3.42's back in it. ($1300 later)
Replaced my crappy 28# injectors with new 50's.
Autolite 24's
Replaced a bad plug wire. All wires Ohm well.
Coil packs Ohm well.
Set the cam sensor.
Set the IAC
Adjusted TPS and sweeped the whole signal. its good.
The PCV valve is good. I also set up a catch can for it. The volume is about 1/2 pint. After only 300 miles, the can is more than half full.
I replaced the O2 sensor. This one shows far more active o2 crosscounts than my old one.
Tightened up my crossover.
Tuned it to good BLM's.
Checked everywhere for vacuum leaks. (Im getting about 18" at idle.
Tried a different MAF.
Bellmouthed the IC inlet.
All hose clamps are tight and everything is sealed as far as i can tell.
EGR valve and solenoid are good.
I have no misfiring anymore ( I had major misfiring when I was getting 16mpg)
Set FP to 38 line off.
Compression is 150psi all around.
All the brakes dont drag, and the bearings seem ok. The Ebrake cable is set loose as well.
I even have my tire pressure up to 38 on all tires.
I always stay on the vacuum side when cruising and never get on it (cant afford to.
Only MAF code I have is from when I disconnected it while running (24) I havent cleared it cause Ill have to re-program everything)
The engine idles smooth in open loop idle, but a bit rougher in closed loop.

I know Ive done alot more. I just cant remember everything right now.
Ive thought of a clogged cat, but usually when that happens, the car makes no power and you have to give it alot of gas to keep speed up. I dont have to do this. I barely have to give it any gas to cruise. I also checked for balooning and this hasnt happened.

I have no TCC lockup. Im still tracing this problem down, but I think I dont have a lockup convertor cause I can bring the rpms up to 3000 rpm before boost even starts building. The purple wire has been disconnected by the prior owner for some reason. Only reason I can think of would be if he had a non lockup in here. If the solenoid was bad, I dont see why he would pull that wire out. At 70mph, Im at about 2200rpm going downhill and about 2800 going uphill. I dont believe the tranny is slipping. It shifts very firm.
Lou Czarnota said that he has run many turbo regals with non lockup convertors, and none of them got less than 19mpg. How much of a mileage difference have you guys seen with the lockup?

I havent had the plenum off to look inside yet, but I was told that the heads had been ported and it had a small cam. The engine doesnt really idle like it has a cam though. Regardless, it obviously doesnt have enough overlap to affect vacuum (18"), or cause a lopey idle. Perhaps whoever ported the heads ****ed them up to the point they flow much worse than stock. Ive seen this happen. But, like I said, I barely have to give it any gas to get the car moving and keep it moving.
It runs really strong under boost.
The prior owner hosed the wastegate up in a weird way, but it does work.
There is no water in the oil or vice versa. The oil is kind of old though. Like 5000 miles old. This never killed my mileage on any prior cars.
I know you guys are sick of hearing this, but please help.

 

[crownvic96]

if you have a non lockup high stall converter and you do a lot of city driving your miles per gallon will be atrocious, about what you are describing.

i remember in another post about how you checked your mpg. maybe you just typed it out weird and i misunderstood or something. anyway, how i check my mpg is go to the gas station. top off the tank, reset the odo. drive until its close to empty, refill the tank, check the odo, divide miles driven on odo/gallons put back into the car. and i do that for maybe 2 or 3 tanks than average those 3.

 

[VadersV6]

Almost all my driving is done on the highway, and I do check my gas useage as you described. I do climb alot of mountains going back and forth through the 241 every day, but theyre not so steep that Im ever in boost trying to climb them.
I have a new gas cap. No one is stealing my gas since my car is locked up in the garage.
I cant find any gas leaks.
After shutdown, my fuel pressure bleeds down about 10 psi within the first few minutes, and then maintains that pressure for a good while.
I have the stock exhaust system, with the exception of some no name cat that they welded in (they went and cut the 4 bolt flange off).
I dont know if i mentioned that Im getting this mileage with lean cruise! I thought that maybe my ignition wasnt up to the task of burning a 16.5:1 A/F, and that maybe I was getting alot of misfiring, hence the bad mileage, but I turned it off for a few days and the mileage was even worse.
I also have a new fuel filter...well it was new. I put a can of fuel system cleaner it when i first got it. After that, i replaced the filter. After that, I ran 3 more bottles of fuel system cleaner though it. I doubt this is an issue.

 

[crownvic96]

this cat is of concern to me as well. sucks they welded it on. if it is indeed too small after some hard driving it will probably be glowing red hot.

its either got to be in your torque converter or that cat.

 

[VadersV6]

The cat is smaller than a stock one. I tapped on it and it almost sounds hollow. Ive read that the TCC lockup is worth like 4mpg. While that would be great, my mileage issues are bigger than that.

 

[crownvic96]

do you know if the stock torqe coverter is indeed in the car?

if the TCC is good for 4mpg that will put you at 18mpg and if the cat is too small that could get you your other 2-4mpg you are looking for.

 

[VadersV6]

It doesnt have the stock convertor as I mentioned above. I have no idea what convertor is in it. All I know is that I can bring it up to 3000rpm before it starts building boost. I have no idea if its a lockup or non lockup convertor. The prior owner had pulled the purple power wire to the TCC lockup solenoid out and zip tied it up and out of the way. I dont know if they did this because the tranny is set up for non lock or if the solenoid is just bad. Im left to guess with everything on this car cause I cant get ahold of the old owner that hacked the car up to hell.

 

[crownvic96]

get a new lockup converter. problem solved

 

[VadersV6]

Fixing the other billion things that were wrong with this car drained all my money, so Im probably going to have to settle for a used D5 or work out a trade. Thing is, I dont know whats involved in switching a setup from non lockup to lockup. Ive read its more involved than a simple convertor swap...I just dont know whats entailed. I just hate being left to guess with everything, since I tracked the original owner down, but I cant get a call back from him.. ( I didnt buy this car from the original owner).

 

[crownvic96]

my transmission experience is limited, best i can offer you is to search the trans forum here and maybe call around to a couple of the transmission shops linked on the homepage of this site

and keep checking the parts for sale. you may luck up

 

[salvageV6]

I highly doubt you will get 19mpg avg. without the lockup.

Maybe you should try one of Lou's recommended chips.

Do you drive mostly city or highway?

 

[VadersV6]

An easy 90% of my driving is highway. Hey salvage- I threw up another question for you in the tranny forum.

 

[TurboTnZ06]

I have a used D5 laying in my garage from a donor Turbo T which had 115,000 miles on it. Worked fine for me until I got a PTS 9/11 converter.

The D5 totally sux on any modded car w/ a bigger turbo, even a TE44 is too much for the D5, IMO.

BTW-Make sure your chip is burnt for those injectors.

Email me at
jim at wispertel dot net
if you are interested in a stock unopened D5. What do they go for? I see advertised $35-75. Make me an offer. Shipping is from zip 80439, so that may be more expensive than anything.

 

[VadersV6]

Ill send that email..
My injectors are MSD 50's, and the part number on the extender chip correlates to the part number they specify for MSD 50's. Since I pulled the LS1 Maf and translator, and replaced the o2 sensor, my blms seemed to balance out quite a bit, not to mention the car runs so much better. the throttle response has improved dramatically. after feeling how it was running and watching my o2 crosscounts being so active, I thought I had nailed the problem. I spoke too soon though. Its hard to believe a torque converter can wreak so much havoc.
While I do keep on the vacuum side of things while cruising, and I dont have to give it much gas at all, the vacuum drops FAST when I touch the throttle. That tells me the motor wouldnt be running all that strong in N/A form. Given I have an intercooler that sees a 5psi pressure drop at moderate boost, and have a complete stock exhaust system, I can see the motor not being very efficient. But, this was the way the regal came from the factory, running 25+mpg, so I cant point the finger at that. I read somewhere recently about some raced out turbo buick that pulled off 42mpg. Thats unfreaking believable. I know they're pushing a ton of timing, but still....my god!

 

[salvageV6]

My window sticker says 17 mpg city and 25 mpg highway.

With lockup you will be doing good to get a 20mpg avg.

I like the idea of finding a stock D5 and getting your lockup fixed.

A better flowing exhaust might help you, but then again your foot will probably be in it more.



Both my cars get about 17-18 mpg. reasonably well tuned in MHO, but mostly around town driving, they aren't lightweights however, and I don't baby them off the line when ricers or SUV's or beemers line up next to me.

Don't believe everything you hear on the internet either, just read one of the MPG threads.

 

[VadersV6]

Salvage- I made a post in the tranny forum. I got some good data last night. I appreciate your help more than you know! I owe you a beer
My city driving mileage is atrocious. Good thing I drive mostly all highway. But 14mpg on lean cruise isnt all that peachy either.