400i feels sluggish

I have a 5 speed and very limited experience with the autos, but it does sound as though something might be wrong. I believe that the 0-60 time for an auto should be less than 8 seconds, not a rocket ship by today's standards but you should still feel a real good rush if you put the pedal to the metal.

The plug analysis should be very instructive. I would also check the ignition timing.

Good luck,

John

 

I'm with John here, keep looking.
The autobox will be a bit "doggy" right off the line but once the revs get up she ought to move right along.

 

The last time I drove a 400A I was not inspired. That said, there are ways to set up a GM 3 speed to improve performance.

Regards,

Art S.

 

Aaron, didn't you just "tweak" your firing order? Did you reset and recheck timing afterwards? An engine can appear to run well at an idle with timing too advanced but then be way of the curve on the high rpms and under load. Also need to check the timing and advance at both idle and high (3000 or greater) rpms to see if the spark advance is occuring correctly. Not sure on the Ferrarri if this is controlled solely by the ECU or if like some of the American cars a set of weights in the distributor affect this.

 

The 400i doesn't have an ECU. An advantage for us shade tree mechanics.

Al

 

Aaron

You didn't put diesel in it, did you?

Aidan

 

chevron with Techron is a great over the counter fuel system cleaner, if your injectors are being fussy.

my .02

 

AAron..As you know I've had my 1980 400i for about 10 years, and...I had my tranny rebuilt with shift kit..don't remeber which one..try a tranny service first..change the filter..then put the tranny on the heart-lung machine that flushes out the entire system that replaces ALL 12 quarts including the torque converter..amazing..a normal service only drains about 4 qts. ..then check all vacuum lines and the vacuum valve on the side of the tranny..or replace it for $10 at NAPA take your car to the BEST tranny shop in town..probably the old guy that's grown up with T400s..no additives period......also T400s hate them...for about a$100 you'll be amazed at the measurable improvement in overall perforfance as trannys are the most neglected and over-looked system on almost all of our cars....also..a complete rebuild including a new or rebuilt torque converter should cost no more than $850-$1000 in and out of the car..if they want more..use the same defense that you would use with the FCar dealership.....run... don't walk away...all this being said, good luck...and by the way would you just happen to have the wiring schematic for our car..thanks..Jacques..over

 

AAron..As you know I've had my 1980 400i for about 10 years, and...I had my tranny rebuilt with shift kit..don't remeber which one..try a tranny service first..change the filter..then put the tranny on the heart-lung machine that flushes out the entire system that replaces ALL 12 quarts including the torque converter..amazing..a normal service only drains about 4 qts. ..then check all vacuum lines and the vacuum valve on the side of the tranny..or replace it for $10 at NAPA take your car to the BEST tranny shop in town..probably the old guy that's grown up with T400s..no additives period......also T400s hate them...for about a$100 you'll be amazed at the measurable improvement in overall perforfance as trannys are the most neglected and over-looked system on almost all of our cars....also..a complete rebuild including a new or rebuilt torque converter should cost no more than $850-$1000 in and out of the car..if they want more..use the same defense that you would use with the FCar dealership.....run... don't walk away...all this being said, good luck...and by the way would you just happen to have the wiring schematic for our car..thanks..Jacques..over

 

AAron..As you know I've had my 1980 400i for about 10 years, and...I had my tranny rebuilt with shift kit..don't remeber which one..try a tranny service first..change the filter..then put the tranny on the heart-lung machine that flushes out the entire system that replaces ALL 12 quarts including the torque converter..amazing..a normal service only drains about 4 qts. ..then check all vacuum lines and the vacuum valve on the side of the tranny..or replace it for $10 at NAPA take your car to the BEST tranny shop in town..probably the old guy that's grown up with T400s..no additives period......also T400s hate them...for about a$100 you'll be amazed at the measurable improvement in overall perforfance as trannys are the most neglected and over-looked system on almost all of our cars....also..a complete rebuild including a new or rebuilt torque converter should cost no more than $850-$1000 in and out of the car..if they want more..use the same defense that you would use with the FCar dealership.....run... don't walk away...all this being said, good luck...and by the way would you just happen to have the wiring schematic for our car..thanks..Jacques..over

 

so going back a few months in time, was the car running properly? If so, I'd start by "undoing" whatever distributor / firing order changes you made. Make one change at a time and evaluate results before going to the next.

 

Look at the fuses for the fuel pumps. If they are not well connected, you may be running too rich.

400 gts

 

You don't suppose he has a blown accumulator allowing the fuel pump to free flow into the injection system do you?

 

Don't know. However, I had a problem when suddenly the left bank was running rich, with black smoke from the pipes. The right bank was hardly running, getting some fuel from somewhere. When I touched fuse # 3 on the left fuse box in the glove compartment, the engine fired up as normal. It had a poor connection.

400 gts

 

Aaron, let's think about this in a logical manner yea I know logic and Italian design doesn't go together but lets try anyway.
I doubt your chain jumped time.

You only need 3 things; air, fuel, and fire. You already know a lot since the 400i has 1 fuel system for each bank. Its something small.

So lets do the easy stuff first then progress to the tougher stuff.
1) check the air cleaner on the left back (hey isn't that French?) and make sure there isn't some clog behind it
2) double, then triple check the installation of the spark plug wires for being in the proper order. It seems you've caught yourself making a mistake once here already.
3) swap the left and right fuel pump fuses and relays
4) (one of the other Fchatters, help me here) check the deal that moves next to the fuel distributor, can't remember the name its under the black boot, and make sure it is clean and functions.
5) Get a fuel pressure gauge on that side and see if it is in spec

I'm thinking it can't be the distributor settings because you have one bank not dripping fuel.

 

crap! should have typed "bank"...would have been funnier if I'd typed right.

 

My 400i's not too speedy off the line, either, but once it gets going, boy can it cruise!
I'm sure lots of factors contribute to this, not only the "sluggish" TH400, but the heaviness of the car, the gearing, and the lack of torque.

Don't forget: Some of the fastest cars Detroit ever made back in the day were brutal off the line, and came with TH400s.

 

I think the reason for the poor 'off the line' performance your talking about is the lack of throttle response. Its due to the K-Jetronic injection system. When you punch the throttle, the butterfly valves open but the metering plate acts like another throttle until the draw of the engine forces it open. The control back pressure pushing it closed fights its opening until the vacuum of the the intake forces it open.

I wounder if a bypass valve on the lines going too the warm up regulator that opened on WOT would help. Hmm...