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Kidd-7

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96 Cougar 4.6L
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The smurf is back and overall I'm ecstatic, I need come clarification though. I'll start with the work done.
- Rebuilt 4R70; junkyard listed it as from a 2001 Grand Marquis ~120k miles. When Rob opened it he realized the fluid has never been changed. It also had an 11" TC.
- Because of the smaller TC he replaced my fly wheel.
- Replaced rear main seal; Fuel pump; filter; fuel line.
- Installed the Mark Driveshaft & limited slip rear carrier.

On the drive home going about 55-60 when I let off the gas the RPMs would dip to ~1k bounce up to ~1.5k do this 2 -3 times then settle near 1k.
On the highway I did not have this issue, nor the following day driving to work, very different driving scenarios though. Rob suggesting driving and keeping an eye on it, stated it could be the TC locking up and it has a higher stall so it will drive differently.

Any input here would be appreciated.

Also, on my way to work Friday it threw a lean code on bank 2. Looking at the fuel trims they are ~10% low (short + long).
If the fuel pump is higher flow than stock this would cause the injector duty cycle to be shorter, explaining the above, correct?
 
The thought came to my mind that the PCM was adjusting to the changes, but if the battery was unplugged for any lenght of time... Hmmm... keep us abreast if the issue continues.
 
Kidd-7 said:
On the drive home going about 55-60 when I let off the gas the RPMs would dip to ~1k bounce up to ~1.5k do this 2 -3 times then settle near 1k.
On the highway I did not have this issue, nor the following day driving to work, very different driving scenarios though. Rob suggesting driving and keeping an eye on it, stated it could be the TC locking up and it has a higher stall so it will drive differently.
Click to expand...

I would think the rpm difference between TCC locked and unlocked is 200-300 rpm at most (?).

Or is that difference greater due to a higher stall TC?

Also, why would a Grand Marquis have a higher stall speed to begin with? Doesn't seem to fit the personality of that car.

I understand the stall speed is the rpm at which forward movement must occur (?).
 
I've bought a bunch of gm trans' and all had the same tc as ours. Sounds like you got either aftermarket, or a marauder trans.
 
CFSO and TCC schedules in the factory tune with an aftermarket TC may behave oddly, I'm guessing that's what you're running into.

The smaller the diameter of the converter, the higher the RPM it can be spun to without causing damage and also the less area there is inside for the fluid coupling and, generally the higher the stall.

Stall is actually a result of what the factory calls K factor and is a function of input torque. You can read more in Jerry's Thesis.
 
When the PCM is reset, it uses CFSO more aggressively during the initial drive cycle to relearn the engine's misfire signature. Once this completes CFSO is less noticeable.
 
theterminator93 said:
When the PCM is reset, it uses CFSO more aggressively during the initial drive cycle to relearn the engine's misfire signature. Once this completes CFSO is less noticeable.
Click to expand...
Maybe that's what I experienced. Driving her on Friday I didn't notice that RPM bounce at all, but it was a very different driving scenario also being I didn't spend much time in the 55 - 60 mph range.
 
A marauder is a gran marquis, with dual exhaust and a 4v 4.6 engine, Whoever grabbed the trans might not have noticed the subtle differences.

Wikipedia is wrong, the marauder is not supercharged.
 
Last edited:
True, I would hope the JY would’ve been smart enough to know the difference, but…
 
1997ThunderbirdLXV6 said:
I would think the rpm difference between TCC locked and unlocked is 200-300 rpm at most (?).

Or is that difference greater due to a higher stall TC?

Also, why would a Grand Marquis have a higher stall speed to begin with? Doesn't seem to fit the personality of that car.

I understand the stall speed is the rpm at which forward movement must occur (?).
Click to expand...

Stall speed is when the RPM difference between impeller ( engine rpm ) and turbine ( transmission input ) reach 90% .. so the wheels may start moving at engine speed 1700 rpm ( as an example ); the transmission is getting about 1530 RPM .. or roughly a 170 RPM difference. Higher stall TC would have a larger RPM difference with the 90% rule of thumb between locked / unlocked.
 
Grog6 said:
A marauder is a gran marquis, with dual exhaust and a blown 2v 4.6 engine, Whoever grabbed the trans might not have noticed the subtle differences.

I just noticed, there's a jy an hour away with two of them; I think I'll call them tomorrow, and see what they want for a blower,er a motor. :)
Click to expand...
No blower on the Marauder, they got a C-head 4.6 4v, same as the automatic Mach1s, only with the intake facing the other way.
 
I fixed the post; wikipedia is wrong, lol. The jy only wanted 600 for the motor, so I was going to go look. :)
 
I have never seen a Marauder in any junkyard. Would be very rare indeed.

Grand Marquis also offered a performance package in most years, which featured dual exhaust, rear air suspension, different wheels, and I'm wondering if that also included the different torque converter (?).
 
This is the Marauder I wanted when I was 16...

1747095425538.png

I saw this car on the way to school everday and man, did I want one of these! Same red with black rear hood.

THough, I probably couldn't see over the steering wheel at the time... :P

(oops, didn't mean to highjack the thread)
 
Update: on the drive in today I was able to sit at ~ 55 - 60 mph and let off the gas a few times. RPMs were stable, so I suspect that was mainly the ECU, PCM whatever doing it’s learning thing.
 
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