ok so first my car wouldn't run at all with the computer connected to the distributor. and fine when it wasn't. so i chenged the distributor to a summit vacuum HEI and got new plug wires. i dont have the vacuum advance hooked up cus i dont know were to connect it. but neways it seems to backfire at low rpms like when im merging to the freeway from a stop, but runs fine after 1700 rpms but seems to stop accelerating at 4000 rpms. but it accelerates fine when the car is to 160 degrees. any ideas on how to fix this befor i kill the motor.

o ya and it only has 400 miles since the rebuild. and its got a 288/298 at 120 crower cam. u guys think i need a non computer carb to go with the dizzy?

so much its my only running car now. yup i sold my DD Toyota 4x4

 

Why did you change to that dizzy anyway, why not just a stock replacement? I think that's a problem right there. Is your computer connected and working with the computer now? I suppose if you change the carb you would be ok but then smog of course. But that's all up to you.

Good luck, hopefully someone else will chime in here with better/more advice. Carbs are not my area of expertise.

 

lol
if it aint gm, its broke

 

i changed to this distributor cus when i put a different CC one it would not run with the computer connected and with a vacuum advance set up i can tune the advance curve easily if i ever need to. it runs fine now just not when the motor is cold. and i live close to work so it warms up half way there.

 

Seek professional help. Very few problems have been solved thru forums.
DATED 7-16-10
dated because i've seen nothing happen to dead cars for weeks, because the subscriber checks every REPLY to see if that fixes it.

 

If it ran fine with the computer not connected why did you change the dis??. To get your car running right your gonna have to play with it.

Your only running Mechanical timing, which is based off engine speed only. Vacuum advanve basically over advances the timing under low to mid engine loads for fuel economy and driveability. Thats why it runs like crap under port throttle. You need to connect the vacuum advance to manifold vacuum. Before you do that you need to set your timing, both inital and fully advance. You may need to swap out springs to get it running right. Then you can play with the Adjustable Vacuum Advance if you have it.

have fun and goodluck


and dont listen to 3rdBird he just wants your $$$

 

actually it runs like crap at WOT and fine at part. but something one of u said got my brain working so i took a look at my carb and i think i narrowed it down.

when the engine is cold i think the carb is actually running the car rich cus i cut the CC distributor out of the mix. so its not getting the right readings cus the distributor was giving it information on something. hence the backfire and the fact that it dosent rev past 4000 when cold and under load that can be because its taking too long to burn the rich mixture. so when i get a chance ill try to get my hands on a non cc carb and put it on and see if it runs the way it should with all mechanical readings.

and 3rdbird i actually stumped every mechanic that looked at the motor thats y i gave up and pulled it for the rebuild. and then i found 3 rolled cam lobes. this time every mechanic is sayin something different so i gave up and asked u guys. but still i get were ur coming from.

thanks guys tomorrow ill see how it runs cold. i have the timing set to 8 advanced now and ill try to lean it out to c if that helps when cold then ill return it before it warms up so i dont hurt it.

 

http://www.fuelairspark.com/ezefi/default.asp

 

8* initial but what is your total timing?

You should be wanting ~34* total, I used to lock out my vac advance and have all mechanical in by 2000 RPM on my HEI's. If you run vac advance you should check how much you are getting as some are adjustable, and vac advance should go to direct manifold vac.

Have you checked all plugs and wires as to their condition?

Run like crap at WOT sounds to me like too much advance / lean and I sure would not ad more timing and less fuel to a lean situation.

Best way to check rich / lean is to READ YOUR PLUGS.

 

well my distributor adds a total of 11* by 1700. and vac another 10. and ill pull the plugs to see what they look like. i have a chart so ill just cross check it.

and how do u lock out a vac advance?

and i said it wrong it dosent run like crap at WOT, just WOT under 2000 rpms cold. and it feels like a lot of lag and a few times its backfired.

lastly how would i check total timing? cus i only got timing marks untill 14*

 

Well if you already have the #'s you already have total timing.

8* initial + 11* mechanical + 10* vac = 29* total but I'm no mathmagician

You lock out vac advance by removing it and staking the pin that moves, some dist. have different ways.

I realize you have timing marks until 14*, you need an advance timing light like this to check total timing http://www.sears.com/shc/s/p_10153_1...0070921x00003a You turn the dial to adjust for advance.

I think if the car runs good warm and the plugs look good after you check them, then you are suffering from a bad case of "I have a carb car and they are cranky"

If you want to lose the cold start / running bad when cold / running bad at differnt altitudes etc. etc. , go FI

 

what I said above.
700 bucks isnt bad considering the cost of a good carb now a days

 

TraviZ, Vin, totally disagree! Nothing wrong with Carb. Had a 84 L69 and I swear it ran and started regardless of temp outside just as good as my TBI. You just need to keep them CC. Sorry, I still think you went down the wrong road with HEI, stick with a stock type setup and CC Carb and ECM and I think you will be ok.

And jerk off TraviZ, I wasn't saying he had to go GM, just stock setup to figure things out at first, wasn't trying to say he couldn't go aftermarket parts a**hole!

I also second Terrell's ideas, you need to figure out those vaccuum leaks! Good luck bro

 

update i hooked up the vacuum advance and set the idle on the carb and now its a lot better i just need to fine tune the carb. but now it has a lot more power then when it did. my dad took a look at the carb and used a screw driver and bam its cherpin second and third shifts now not to mention WOT actually feels like its a V8 now.

 

KEEP THEM CC? you mean Computer controlled?
(hint: all thirdgens were HEI )
oh.. except the TTA, it was distributorless..


and thirdly, to the post above, gratz on getting that timing figured out, and i hope you learned something about ignition from this thread vin had lots of great info for you!

 

TraviZ, yes CC means computer controlled. And thanks for correcting me on all having HEI

Glad you got the problem fixed See, carb is not bad at all Screw these FI guys lol, j/k

 

thanks guys for all the help u guys really helped me nail the problem

ya i would agree with u if i didn't have a cheep FI motor knocking on my door.
My uncle called me today and said he might change his mind on the motor for his chevelle to a big block 396. he wants the one in my boat but hes looking for a already rebuilt one. so i might get a cheep LT1 with the computer and wiring. next thread i post might be asking what wires do i need to pull for the conversion.

 

right, a cc carb is no more then a low pressure fuel management with extra doo hickeys to go wrong and wear out

 

VS

 

OMG, give it up already TraviZ! I still maintain my love for my carbs, wish I still had my 84 L69 3rdgen.

JazzT/A, sorry for kinda highjacking your thread and arguing with TraviZ about carbs. In any case I hope it all works out for you either way you go.