500, 472, 425, 368 Discussion, 79 CDV 425ci - TPS in Cadillac Engine Discussion; I havent done all my research yet, (TIME) and I find the Haynes manual for these cars particularly CRAPPY. Is ...
- 07-30-05 07:56 PM #1Cadillac Owners Member
- Join Date
- Jul 2005
79 CDV 425ci - TPS
I havent done all my research yet, (TIME) and I find the Haynes manual for these cars particularly CRAPPY. Is there a TPS on these motors? I ask because i get hi idle with ac on and at about 85% throttle (NOT WOT) i feel a 'flat spot' so to speak, but wot will pull on thru.
- 07-31-05 11:31 AM #2
Re: 79 CDV 425ci - TPS
That car came with either a carbonator or port fuel injection which is not common. Assuming that you have the Rottenchestor carbonator, there is a solenoid which increases throttle angle whenever the AC compressor is receiving power. You probably need to adjust this. IIRC it has an 8 mm nut built into the plunger. The solenoid will not increase throttle by itself when power is applied. You have to manually increase the throttle and then it will not return against the idle screw which is built into the side of the Carbonator until solenoid power is removed.
As far as secondary throttle flat spot goes, make sure that your primary choke pull off holds vacuum and is connected to a good manifold vacuum source.
If that is OK then there are a few other carbonator related things to check. Before going any further than that with the carbonator, make absolutely sure that the distributor mechanical advance and vacuum advance are both working correctly and not binding. Also check vacuum line routing against the underhood emissions sticker. Check timing according to the proceedure on the sticker. Look for any vac lines that could be leakers and replace the little buggers.
If your car still bogs then it's time to find one of those online
"carbonators are the greatest thing on the planet and here are the 999 steps to adjust one properly" blurbs. Your secondary air door might be flapping in the breeze and that adjustment takes a few lines of text and a few pictures to properly explain.
BTW, you will find no TPS on any carbonated Cadillac before 1981.
- 07-31-05 12:42 PM #3
Re: 79 CDV 425ci - TPS
TY for that clarification Ape Man, i'll check into what i'm working with with your info in mind. thx
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