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anyone want to guess whats wrong with my engine?

FlatBlackBurb

FlatBlackBurb

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okay so i just finished putting my brand new 1975 cadillac 500 in my 1969 coupe deville. here's what happened:

i started it up and it idled really high probably at about 1500. but pulling the gas pedal back a little bit calmed down the idle to a more reasonable speed. (im gonna say about 900). when i press on the gas the engine accelerates but when i let off the gas the engine speed does not decrease. i have to reach behind the gas pedal and manually pull it for the speed to decrease. so i drove the car for about 40 feet when i heard a sound like when you try and start a car thats already running, coming from my engine. the engine speed sounded like it increased too along with this terrible sound. so i quickly turned it off. my buddy who was standing right next to it at the time said he saw a ton of sparks fly out of the drivers side of the engine bay. he didnt know exactly where.

after i investigated it i went to move it again and nothing happened. then a little later i tried to move it again and it did the same thing with the noise and the engine speed increasing. i immediately killed it but it was in the middle of the road. i said f*** it and towed it up the hill with my truck to my house.

also every time i started my car and ran it for about 20 seconds, white smoke would appear to come from where the exhaust manifolds bolt up to the exhaust pipe. is this because i dont have a gasket and there's a little bit of a leak coming from that area? or is it because a little bit of rain did get under the hood the other day and it could still be wet down there. or is it possibly another problem?

i have the proper levels of oil and atf in there. is there something i'm missing? the car starts easily and runs and idles perfectly. anyone want to take a stab at whats causing this problem? i'd like to get some input because im going to be working all week and wont have that much time to crawl under there and look around. thanks
 
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I have no idea without looking at it. I suppose at some point we need to meet since we don't live too far from each other. I've seemed to have met and worked on everyone else's rig that is local to me so why not yours.
 
Starter on the drivers side of a Cadillac? About the only thing I can think of that would spark on that side, if that is indeed where it is. Melted battery cable perhaps...
 
Sounds like a huge vacuum leak. Does it have power brakes? Is there a port on the back side of the carb or manifold? I helped a friend one time with similar symptoms and found that his son put washers above the carb gasket then the carb. Funny sound that was.
 
4X4HIGH said:
I have no idea without looking at it. I suppose at some point we need to meet since we don't live too far from each other. I've seemed to have met and worked on everyone else's rig that is local to me so why not yours.
Click to expand...

haha yeah totally let me know if you need help on anything and i'll do the same. we've got some more builds going on down here and your always welcome to come check things out anytime.


no the starter is on the passenger side. my friend probably saw things wrong. i've never heard of a starter sparking when engaged with the engine running though. it sounds like faulty wiring. hey i might have solved my own problem!
 
I'll take a guess on the sparks/noise...

Loose/exposed wiring grounded out, causing sparks, and engaging the starter...

:dunno:
 
Having to pull the throttle back really sounds like a bad/sticky throttle cable.

The noise and sparks can easily be something contacting the flexplate (i.e. wires, dust cover, etc.).
 
yeah im gonna guess faulty wiring. im gonna look into the flex plate though as well. im pretty sure thats not it since the transmission and engine were pulled from a perfectly running car that the owner had driven for 10k+ miles.
 
stupid question on your throttle, but are return springs in place? I could be mistaken, but I'm pretty sure it's linkage all the way to the carb, no cables.

As for the starter, its wiring somewhere. Best thing to do is jack it up and look for the melted wires. For it to melt that quick it after startup it would almost have to be on your exhaust...
 
yeah i messed with the springs today. there was barely any tension on them so i definately need new ones. i took about half the spring length and attatched it to where it would normally go (if that makes any sense) and it works a lot better.

as for the wiring im pretty sure i know whats going on now that i think of it. i just re used my old battery cable from the old 472 and attatched it to the 500. the 472 starter had the main hot wire and then the two posts. the new 500 starter has the main and only one post because i looked at a wiring diagram and the new starter has no ground, it grounds itself. and im pretty sure that the old ground is just hanging out there very close to the starter. maybe its contacting and making something happen? i'll take a look tomorrow morning before work if the weather permits. damn this rain!!!! :mad:
 
The two small post on the starter are (S) for start and (R) for relay. The relay terminal was used with early vehicles with points distributors to give a full 12 volts to the coil only when cranking to help it start easier. The start terminal is what hooks to the ignition switch and makes the starter crank. In later years some starters only had one small terminal (S).
 
okay. that wasnt the problem. on second thought it didnt really sound like the starter engauged. it just did it twice more like within seconds. and i noticed something about it. its always when i start off from a stop going about 2-5mph and its always uphill. and this time i noticed the gas pedal slightly "accellerated" as soon as the noise started. how did i get back up the hill to my house? i backed down the whole thing and started from a dead stop at the bottom. any other advice or information you think might be helpful?
 
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