Hi my name is Luke, and have only just joined this forum , I have recently purchased a 1981 Cadillac Seville 6.0 , the owner had very little info on vehicle . Im seeking the following , I've notice there's a very delayed shift from 2to3gear is this normal? , it won't shift into 3 until doing50 mph? , And drops into2 once below 50 mph . Is the auto controlled manually , electronically ? , and can adjustments be made . Any advice would be appreciated , Luke , all the way from down under , Perth australia

 

Nice to see someone from down under here. The tranny problem you are having is most likely the T.V. cable (throttle valve) This cable must operate freely with no kinks or binding. You can find the adjusting lock tab that is part of the carburetor lever and unlock it by pushing down on the spring loaded tab. Check to see if it runs any better before by taking it for a spin. You may need a new t.v cable if it has been damaged by work done in the past.

 

Forgot to mention...when you unlock the t.v. tab hold the throttle wide open and then release the lock tab then release the throttle lever. Take it for a run.

 

Thanks for that , I understand , same set up as a trans am . Can u tell me what size this motor is , is it an olds block , distributor at front , I understand it has this so called 468 setup , But I believe it to be disconnected , is it preferable to be in this state? , What is the correct ignition timing on said vehicle ? Over the years , how have these motors stood up , And finally , I gather these arn!t throw u back in the seat v8s , more cruisers , Are there slight improvements that can be made , as in r u better staying with original carbies etc , intake manifolds, or should I just enjoy the vehicle as is , Thanks , Luke from down under ,

 

These engines are 368 c.i. and 6.0l.....They are very reliable engines and if maintained well will last a long time. I have the same engine in my 81 Brougham. You can't really do too much as far as hop them up, but they do share the same block as the 500 and 472 so if you want lots of go power get the 500 and play with that. The timing is 10 BTC if you have the DFI and 18BTC if you have the carb. This motor has the TPS on the intake and should be set precisely to get the best throttle response. They are not speed demons but make up for it in comfort and ride. It is best to have the full 8 cyl. firing at all times and don't worry about the 4-6-8 feature. You will have the TH400 transmission with the 368 engine and they are like a truck tranny. Hope you enjoy your ride and come back any time for help.

 

Thanks for all your info , much appreciated, have determined its a 6.0 dfi , Can u advise voltage reading for tps . The motor seems to ping a little under acceleration , . Is it best to stay with the dfi setup , Is swapping ,to a carby advantageous . ? On top of the rocker covers are plug in electrical connectors , what are then purpose of these ? , Thanks Luke , down under

 

The electrical connections are for the modulated displacement solenoids. This is the heart of the 4-6-8 function. I leave mine disconnected but I don't think it matters either way. The DFI-368 was rated at 140 hp and the 4bbl carb. was rated at 150 hp........so I don't think it is worth the expense to switch. The voltage reading for the TPS is .5v...+or- .05v. The setting is critical and a bit tricky to do. I replaced mine and still have the spec. sheet if you would like it I could send it to you. I also have all the Cadillac Factory Service Manuals if you would like any info from those. I also have a few spare parts for the 81...like fan belts, wiper switch, baro/map sensor combo, temp. sensor,tail lite lens, wheel center crests, ISC motor and bracket,A/C ac***ulator and pipes(new),soem chrome stuff. You could do away with the CAT converter for a few more horsepower,if you are allowed there. Do you have many of these cars there that are good for parts or are things very hard to find??

 

thanks for that, there not to bad for emissions in this state, its not a yearly thing. im fairly good mechanically , i have a trns am , fuel injected, which i do all my work on for the last 10 years . i understand how to set the tps adjustmnt . when u say do away with the cat convertor , is that to bypas or simply remove the ceramic inside convertor ? ,, the air injection is also disconnected , will be removing the air pump shortly and pretty much doing a really good tidy up of the engine bay . with some cable tying and removing what i can , so at least its neat and tidy , when the bonnets lifted , adjusted the tv cable but auto still holding gears to long , road speed has to be high before it shifts , gather its a govenor problem , unless these autos have a va***n modulator ? . r the oil filters standard gm / chev type ? theres not many , but there is still a few caddys over here , but getting less by the year , there more used for sunday drives , dont forget a lot and this one have been converted to right hand drive , a job and a half as you can imagine, cheers , have run the full page , luke

 

also i gather the tps setting is .5 throttle closed , is there any areas in the front wheel drive setup , that need special attention , as in , do they have c/v drives that are to greased or checked in any way , this vehicle has been converted to run both fuels , that is gasoline , and lpg , liquid petroleum gas . the reason being its cheap , lpg is in ur currency around $2.40 gal , where fuel is nearly $5.0 gal , so lpg is popular here . the caddy is a elegant model , brown sides and a champange top , ai basically saved it , a young guy had it and it was going downhill slowly , so being a glutton for punishment ive taken it on to bring it back to its glory , back to the caddys there r quite a few of the later sts models here , some of them find there way thru from hong kong and japan , like the states the v8s were very popular in the 70s and 80s , but its all economy driven , and probably there as well very bland looking vechicles , with no character , in todays market , , one consolation here in this state its fairly dry country , so rust is not amajor problem , thanks , luke

 

After looking in the manual I found out that the front drive does have cv joints,, one inner and one outer but don't require maintenance, just keep the oil topped up. The cat. can come right off and put in a piece of the pipe, I believe it's 2 1/2" On the tranny issue then it must be the shift modulator which I had to change also due to odd shifting. This is the first time I have heard of a Cad. on propane but I see the point because of the price.