69stang390

Few things with the 69 coupe that are just REALLY pissing me off and i need help guys.

I think my holley 770 carb is just too much for the 390bb. The thing is, if i were to just punch it, she would hesitate like she died and then just take off like a bat out of hell. Does that sound like too much carb?

Another thing is theSHIFT KITin the c6 autotrans which makes it a PAIN and i mean PAIN in the *** to drive through town.She will just "rev" constantlyand doesnt shift when you think she should. I have to keep the rpms high or she wont act right and its hard to do this in traffic. What can i do?

Another thing thats just making me want to crawl into a hole, is the fact that when i "kill it" the engine acts like it wants to stay on and makes a hard "knocking noise." Igiveit time afterputting it into park before i shut it down, but one time i wasnt thinking right and killed it right after parking it. Ever since, it has been knocking hard and making a terrible noise when shuting down.

Anybody know how to adjust the timing on a Mallory Distributor? I started her up after about 3 hours, gave her about 30 seconds to warm up, backed out of my brothers house, and as soon as i through her into drive, she died. Can you believe it? This car has been running like a champ, but all of a sudden, out of no where, she is acting up. Ever since i left my hood up around a couple of my brother's buddys, she has been acting up. I found my "regulator" plug that charges my battery was pulled out and there is no way it just fell out.

Sorry for writing so much, but it just isnt right and i need help.

ldollar

i feel your pain. i am sorry i cant offer you any help on these issues cause i am a rook in all these things myself. but i know there are lots of guys here who will come to your rescue. Just be patient because a lot of people are not online on Saturday night. But come tomorrow, you should get some good answers.
Just know that you are not alone. I have had several of these problems myself and am still working through the carb issues and what sounds like "dieseling" to me....when you shut off the engine. I am gonna take my baby in to get dyno tuned on Tuesday and hope to get her running better than new by the end of my session. Sounds like your should keep your brothers buddies away from your car! I know my brothers friends will never touch anything under my hood, they are all new model German car drivers. Sometimes I wish I was too! But stick with it, the car is a labor of love.

dcohen

calm down, we here at mustangforums.com are gonna help you through this, we can do this toghether

try adjusting the carb, 770 probably isnt extremely to big, it just needs some fine tuning

check your tranny fluid, not just for how much, but what color it is and texture

to adjust the timing, get a timing light and mark the ballancer with some white paint, loosen the bolt at the base of the distributor and turn in clockwise or counter clockwise until the 2 white marks line up when the light flashes

you can do it bud, were here for ya [8D]

Colorado_Mustang

The carb is not tuned properly. I have a 750dp on my 390 and it's just right. Stab the throttle and the 285/75-16's howl in protest.

Overall, it just sounds like you need some overall tuning help. The timing doesn't sound too far off, but FE's need more than 30 seconds before they're happy. There's a lot of metal to get warmed up in there. I generally take about 2 minutes with mine, and that's in the summer time. I'm just glad I don't have an auto (no choke either....).

remicks

The knocking, rattling and dieseling part I had this experience with on my old truck with a 400M after the engine was modified. What is maybe happening is that you changed your compression ratio by some modification you did and now you require a different grade of gas because your current grade is detonating when it shouldn't. Another tell tale sign of fuel combusting when it shouldn't is pinging or knocking. If you are running the low grade for your area 87 or 89 whatever it may be a simple test will be go to an autoparts store and get one of those octane boosters and pour it in and see if that fixes your issue.

69stang390

Thanks for the quick responses, im starting to lose sleep at night. I plan on tinkering around on her tommorrow and just need to know where to start. Its just weird how all of this came out of nowhere. The engine was rebuilt four months ago, has holley intake/carb, mallory igition system, super comp headers, bigger cast heads; this thing is CLEAN, performanced out, and ran like a pearl until today. I dont know anything when it comes to carbuerated cars or bb engines, so im just going to see if one of my buddys can help me out or find a mechanic. Its just hard to let someone else get under the hood. I can promise you I wont be a noob for long. Any help GREATLY appreciated....that knocking is just terrible. Sounds like shes throwing up.

69stang390

I run the highest grade fuel around here, I think its 93. She runs good, its just the starting up and shutting down part. AND the shift kit in it, i love it on the highway but its hell following someone. Can i take it out?

valley firearms

You may try and adjust the modulator to get it to shift sooner. At the back of the trans there is a diaphram looking device with a vacuum line connected. This is the modulator. Get a small slotted screw driver and stick it in the hole that the vacuum line is connected to. I forget if you have to go clockwise or counterclockwise to make it shift sooner. I'm sure someone here can expand. It's been 20+ years since I have adjusted one on a C4. You may have to experiment. Hope this helps.

Sounds like your carb is out of tune. You may not be getting enough fuel in the primary stages. You may need to adjust the primary accellorator pump. When the car is off, look down the carb and push the linkage all the way back as if you were flooring it. See if you can see the fuel squirting into the venturis. You may have a bad diaphram, a stuck check ball, or debrey in the port if it is weak or you cannot see the fuel. It may also be time for a rebuild. And of course you know the timing needs to be retarded a hair. Is your car running hot?
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67mustang302

Sounds like you do need some tuning. Is the carb vacuum secondary? If it is you could try a heavier secondary spring. Or give it more accelerator pump shot. What squirters/cam do you have? 770cfm is a tad on the large size for a stock 390, but not enough for it to not run well(maybe just get worse mileage, like that matters with a BB), 700-800cfm range is good for a built 390. Get the tuning worked out and you'll find yourself having to roll into the throttle to keep traction

69stang390

I dont know if the Holley 770 is vaccuum secondary or not. I park itacross town in my dadsgarage or i would just run out and take the shaker/filter off. How do i adjust the primary fuel pumper?

Im assumingthe shiftingon a c6could be adjustedthe same way as the c4? My dad keeps telling me its a shift kit/hard shift.
Does the timing being retarded a hair meana 1/8 turn counterclock wise of "normal" with the Mallory Distributor?....Car is NOT running hot.