yet another rochester question...this is getting old...

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cutlassguy

Master Mechanic
Dec 15, 2011
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my 87 olds cutlass supreme is still running like sh*t. so far ive replaced the distributor, wires, plugs, fuel filter, air filter, and the pcv is clean. whats happening is it idles half *ss ok but as soon as its in gear it boggs right out. i triied adjusting mixture screws and from what i know you snug them up then back it off until the rpm or vac raises then lowers, then return them to where the rpm or vac is the highest. i used a vac gauge and listened to the rpm but to be honest after i backed them out about 2 turns i never noticed any change, even after continuing to back them out about 8-10 turns...im surprised they didnt fall out. i remember triing to adjust these before on another 305 i had and the same thing happened. as is i have about 20 inches of vac and its steady. (got a vid if you wanna see it) another thing i noticed was when i was spraying brake cleaner everywhere to try and locate a vac leak (which i didnt) when i sprayed the little valve thing that sits inside the air breather and has the 2 vac lines underniegth it, the motor would run smooth until i stopped. i triied disconnecting it and plugging the vac line from the carb but no difference. i also timed it to 8 degrees. im at a complete lose as to what else it could be...i also removed the fuel line and had someone crank it over and it has good pressure, also my accel. pump is spraying 2 strong jets into the carb. carbs not lose. this is something that seemed to just happen all of a sudden too so there wasnt anything i could kinda blame it on. if theres ANYTHING else anyone can think of i appreciate it immensly!!! another thing i did was dis-connected the battery to reset the computer. could it have anything to do with my egr? i also dis-connected that and plugged the line but it never made any difference and the diaphram still moves. PLEASE HELP before i go an buy a Mustang!!!
 

cutlassguy

Master Mechanic
Dec 15, 2011
350
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oops my question was does it sound like i need to do a re-build on my carb. also i ran sea-foam thro the tank, crank case, intake and sprayed a sh*t load of carb cleaner thro the carb. do they just go to complete sh*t all of a sudden? it was pretty clean looking to begin with.
 

DoubleV

Royal Smart Person
Feb 25, 2011
2,156
406
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Medina Ohio
Correct me if I'm wrong but didn't you state before you weren't running on the computer and now you're saying you are? Which is it man? You need to tell us once and for all EXACTLY what the heck you're running or you're never going to get the info you need to fix this right.

IMO, a carb rebuild would be a good idea at this point.

And stop making long posts with no spaces/paragraphs. It makes them harder to read, so most people don't bother and then you get no help.
 

cutlassguy

Master Mechanic
Dec 15, 2011
350
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0
DoubleV said:
Correct me if I'm wrong but didn't you state before you weren't running on the computer and now you're saying you are? Which is it man? You need to tell us once and for all EXACTLY what the heck you're running or you're never going to get the info you need to fix this right.

my bad. from what ive read its a partially controlled carb. it has a vacuum advance distributor connected to the carb. but also has this MCS that apperently runs off the ECM...

the numbers on the carb are 17087124 - 2376 JRM

i want to do a rebuild but i also want to know if its something else aside from what a rebuild would correct.

anyhow i checked the MCS with a multi-meter and there was 25.3 Ohms of resistance so apperently thats still good.
 

cutlassguy

Master Mechanic
Dec 15, 2011
350
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this is what ive got.
 

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cutlassguy

Master Mechanic
Dec 15, 2011
350
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actually dont most if not all cars made in 87 run off of some sort or computer? i definately have the OBM-II attachment under my steering wheel if that makes any difference.
 

DoubleV

Royal Smart Person
Feb 25, 2011
2,156
406
83
Medina Ohio
cutlassguy said:
from what ive read its a partially controlled carb. it has a vacuum advance distributor connected to the carb. but also has this MCS that apperently runs off the ECM...

the numbers on the carb are 17087124 - 2376 JRM

No such thing as a CCC carb that used a vacuum advance distributor from the factory. It's obvious you have a vacuum advance distributor since you've stated you have a vacuum cannister with a vac line, but you need to determine if you really have a CCC carb or not as I don't know that carb number.

So do you have a CCC carb or not, or did your car originally come with it or not? This question NEEDS to be answered. There's plenty of ways to tell;

1) Got an O2 sensor on one of your exhaust manifolds?

2) Got a computer behind the passenger side kick panel?

3) Do you have a big black plug ( ALDL ) hanging under the dash in the area where the radio/ashtray is?

4) Yes your carb appears to have a MC solenoid plug but some Chubby carbs still had this plug but it wasn't a CCC carb. Does your carb have a 3 wire plug sticking out from the front of it? This is the TPS and I can't tell from your pics if you have one.

If you answered yes to any of the above, then your car has the CCC system, or at least parts of a CCC system as a vacuum advance distributor is NOT standard in a CCC equiped car and who knows what other butchery has been performed.

My guess is you don't have the CCC system, but you have a) a CCC carb swapped on or b) one of those funky carbs with the electronic 'dual volume' accel pump solenoid which I personally don't know much about. Where do the wires from your supposed MC solenoid go?

The idle passages could be gunked up which could be causing your shitty idle and a proper rebuild would fix that.
 

cutlassguy

Master Mechanic
Dec 15, 2011
350
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ill have to check on the O2 sensor cause the last owner put duel exhaust and took the cat off so im not sure whats going on down there aside from i know the heat riser in the exhause manifold isnt hooked up to anything.

i DO have the big black plug under my dash tho, but i do not have any other clips on the carb. for the MCS, one wire comes from the wiring harness (which from my understanding has a key switched 12v to it) and then the second wire coming off the clip goes to a clip on top of my thermostat housing (which should be some sort of variable ground) for the MC.

i dont think anythings ever been changed as far as the carb goes cause everything looks like it should from factory, also if someone changed this carb and put something in that wasnt there before, they would have had to find another thermostat housing with this clip on top..wire in the other wire to the harness....from what ive read this IS the carb for this motor.

i just entered (17087124 4 barrel rochester carburetor) into google and it found the exact carb i have. im pretty sure it is that duel pump one if i remember correctly.

im going to pick up a carb rebuild kit today and see what happens. ill keep ya informed.
 

DoubleV

Royal Smart Person
Feb 25, 2011
2,156
406
83
Medina Ohio
Sounds to me as if you have that silly dual volume accel pump carb because I know one of the wires going to it comes from a temp sensor as you say yours does and a MC solenoid would have both wires going to the CCC wiring harness. I thought those weird carbs only came in some 80's trucks though. Oh well, either way, that's what it appears you have which means NO CCC stuff.

The 80's GM cars sold in Canada had Chubby engines and no CCC system until later on when they finally adopted it.

And kudos on your paragraphs! MUCH esier to read your posts.
 

cutlassguy

Master Mechanic
Dec 15, 2011
350
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0
yah im pretty sure it that lol :( anyhow i started the rebuild today so we'll see how everything turns out. im gonna post another question just because i need the answer ASAP but if you know, feel free to answer.

im doing the carb dip now and on the top air horn the cam that lifts the secondarie jets up is plastic. can i still dip it or will it dissolve it?

also is there anything on the choke housing that will get damaged if i dip it? i dont see any plastic.
 
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