Author Topic: Pls help new mustang owner...... (Read 6736 times)

Blk66289 · « **on:** April 28, 2011, 06:40:40 pm »

......... New Carb and engine work coughing, backfiring and stalling

Hey Everyone,

My name is Marty, and I'm new to this forum. Before xmas I bought a 66 Black Stang(i'll get a pic up soon, photobucket is down) , fresh from USA.

It had been great the first 2 months, running like a dream, and fun! Me getting excited booked it in for the full "treatment". Extractors, mild cam, intake manifold, roller rockers, holley card dominator. I'm no mechanic so I went with a recommendation.

Problem is, she coughs, plutters, backfires and stalls at low revs.

She runs like a dream at decent revs with heaps more grunt, heaps better sound.

I've had it back twice to the mechanic but he can't seem to get it running smooth at low revs.

Seriously, the way it just runs like a dog at low revs and stalls has really killed the fun, and the kids keep asking me "whats wrong Dad, "whats wrong with it".

It's so frustrasting. Especially with my 12 year old son, who is Autistic. He absolutely loved going cruising in it (when it was reliable) but he gets upset easily, and I can't take him in it at the moment while it's stalling and carrying on like this.

Some of you may have had the same experience, or could have some tips or recommend a good mechanic around bayside Melbourne who could look at it.

Thank you if you can help in any way.

red066 · « **Reply #1 on:** April 28, 2011, 06:54:06 pm »

Hi Marty welcome
Im no mechanic but have heard of things like that if the cam is to big
Im around Seaford , will have to get you to a Lets go cruising night at Mornington
Cheers Peter

ozford · « **Reply #2 on:** April 28, 2011, 07:18:13 pm »

if its only a mild cam then yur problem is with the carb. the dominater series is for big hp apps. get a smaller cfm carby. if you want to stick to holley then i suggest a 650 vac secondarie

stormin · « **Reply #3 on:** April 28, 2011, 08:18:42 pm »

If its a 289 with a mild cam a 600 vac secondary should do the trick A 600 vac secondary I've found is plenty big enough for a mild cam 302.
Its possible the cam is too big . Make sure the accelerator pump is giving a full supply when needed.
Stormin

ozford · « **Reply #4 on:** April 28, 2011, 08:24:43 pm »

oops my bad, yes i meant a 600 like storming suggested

HEVEN67 · « **Reply #5 on:** April 28, 2011, 08:42:36 pm »

A Rotchester is a much better choice Marty.
luvhev

stormin · « **Reply #6 on:** April 28, 2011, 08:47:17 pm »

When you say mild cam what lift/duration /lobe centres is it supposed to have? What rev range is it good for?I put a mild cam in my 65 vert with a 302 with a rev range from memory 2000 to 5500.Runs and idles smooth with a kick when you tickle her.
This is the range where you will drive nearly all the time unless you are heading for the drag strip in which case the rest of the car will need some work.
Stormin

stormin · « **Reply #7 on:** April 28, 2011, 08:50:07 pm »

Haven't got a vacumn leak have you?
Stormin

JimNiki · « **Reply #8 on:** April 28, 2011, 09:13:28 pm »

Matey, too many variables to work with...
It's usually fairly easy to diagnose with the right process of elimination.

Start by knowing the engine vac at idle...
That may be the root of your problems?
If your brake booster works well and the car brakes well, then it's probably not a low vac issue.
Set your timing to 8dbtdc, adjust the carb idle to 850 rpm as a test and go for a drive...

Let's take it one step at a time...

65muzzy · « **Reply #9 on:** April 28, 2011, 09:38:55 pm »

Take it back to the mechanic. That's who installed everything and the car was working fine before going there. Were you the one who suggested the cam, carb etc. If so you might have to sort it out.

jcmc · « **Reply #10 on:** April 28, 2011, 09:51:00 pm »

Dominator sounds like a lot of carb for a 289.

Blk66289 · « **Reply #11 on:** April 28, 2011, 10:25:54 pm »

Hi everyone, thanks for all you comments. really, thank you.

Originally the mechanic said it is a very mild cam. I'll try to get some more info on the cam. He also mentioned that a vacuum hose had popped off, that explained the first round of problems.

After refitting the vacuum hose, and rejetting/retuning the carb, it is running better but still carrying on a lot. Stalling, backfiring, etc. like I mentioned in my first post.

Please excuse me, I'm new to the mechanics of it all, but keen to learn. I dont' want to get it on the drag strip, just cruise sat morning, give it a sqirt, show off a bit, nothing to serious.

I'm not keen to take it back to the original mechanic. He's a nice bloke but he's a had a few goes at it and he really can't get it right. He charges like a wounded bull too, and I'm just over it. I think he 90% knows his stuff, but the other 10%, which is the 10% I'm struggling with he's a bit lost on I think.

I originally got Griffs to quote the work and wish I'd taken it to them. They said to go with a Holley 750 I think it was, it was my mechanic who suggested the dominator, which like some of you have mentioned might be too much carb for the 289.

The brake booster works pretty well, and there is quite a difference from not having a booster before to having one now. Thanks fro the advice with the timing and carb idle. I might have to get a mechanic to look at that though, I don't know how to do that. The Holley dominator has 4 idle adjustments as well?? Maybe overkill and too much adjustment?/ I'm not sure.

jaythefordman · « **Reply #12 on:** April 28, 2011, 10:54:56 pm »

750 way too big, as suggested a 600 is a much better fit. start with that and go from there.

Dominator way too much carb, and they are mechanical secondaries, so you may also be over fueling as you hit the accelerator. Stalling from too big a carb.

caretaker65 · « **Reply #13 on:** April 28, 2011, 11:46:47 pm »

Marty,

Welcome to the forum, as you have found out so far..quite a few helpers when in need of advice.
One of the guy's here - BLKPNY (Steph) is brother is a mechanic maybe Carrum Downs area.

You could look up Steph and ask for this brothers details if you wish. At least you will know you have a mustang nut working on your pride & joy.

Maybe if you get it sorted & not doing anything on Sunday morning, cruise over to Keilor Hotel for the Keilor Rotary Club carshow. Kicks off at 7.30 thru to 1.30pm Craftmarket as well in case the other half wishes to tag along.

Cheers, Geoff

Roegs · « **Reply #14 on:** April 29, 2011, 06:14:07 am »

Hi Marty, Welcome,

My car used to be a little hesitant at low revs as well.

I redid my idle mixture screws and that fixed the problem. May be something to look at, pretty easy to do, here's an instructional video:

http://www.youtube.com/watch?v=UPGLUsW5ZeE

Cheers

Roegs

caretaker65 · « **Reply #15 on:** April 29, 2011, 09:41:26 am »

Roegs,

Some good info there, thanks..

Trans-Am · « **Reply #16 on:** April 29, 2011, 09:42:56 am »

Hi Blk66289,

:welcome:aboard...

As other member's have stated, if it's a 750 Dominator (annual discharge boosters), it's way (way...) too large for your application (unless you're revving your engine to 8,000rpm!!!).

Did you purchase this from your mechanic (sounds like he may wanted to off load it?).

Start with a 600-650 Vacuum secondary and make sure the power valve is adjusted to your manifold vacuum (where it won't just dump additional fuel in when you come off your idle circuit). Timing and fuel mixture's will proceed after this...

When checking the timing (without knowing your cam specs), try hooking up an extrenal vaccum gauge and go for the highest vaccum reading, then take the car for a run to see if it starts to detontate (ping) underload or at WOT (wide open throttle) and then retard the distributor a little to eliminate the detonation.

Again, if BLKPNY's brother is close by, I'd recommend that you get in contcat with him and book the car in to see if he can fix the problem?

Cheers,

Trans-Am:cool:

moe · « **Reply #17 on:** April 29, 2011, 09:49:47 am »

Take it to a place that can put it on the Dyno to tune it properly and advise the correct carb size/jet size for your application.

They can the regraph the distributor to suit as well.

MustangMedic · « **Reply #18 on:** April 29, 2011, 10:51:51 am »

I agree with Moe, if your not the mechanical type and you don't have the gear, then get a Mustang specialist with a dyno to do the tweaks. You get peace of mind and a a place to take it back to if you have any issues, as they tune lots of cars and are usually well experienced in solving these types of issues. My 2 cents worth

ozford · « **Reply #19 on:** April 29, 2011, 11:13:02 am »

just alittle ot. pleeze be xtra careful when yur hotdogging around with kids as passengers. with the mods you have its easily over 300hp and with a car thats pushing 50yo not a very safe combo. i have mates with xy's and xw's with big hp and little safty features and the mums arnt very happy when they take the kids for a spin:nono:

Ash · « **Reply #20 on:** April 29, 2011, 11:26:44 am »

Quote from: ozford link=topic=14306.msg145891#msg145891

i have mates with xy's and xw's with big hp and little safty features and the mums arnt very happy when they take the kids for a spin:nono:

I have a feeling my wife is going to be in a similar frame of mind with my 428CJ.

Blk66289 · « **Reply #21 on:** April 29, 2011, 12:07:00 pm »

Hey thanks again for the tips/advice, really good advice from everyone. I'm really inspired that it looks to me from the response that Mustang owners really stick together and help each other out.

I've taken the car up to Pete's garage in Moorabin. He's going to change the carb to match the car, put in electronic ignition and tune it up for me. He agreed it has a lot of good gear from the previous mechanic but carb totally wrong for the motor and it's running very, very badly.

I'll be safe too, thanks for the reminder. Sure i'll give it a sqirt if it's safe with a mate, but with kids and passengers normally I'm just into cruising very locally.

I'll post when I get the car back and let you all know how it's running.

Thanks agian:smile02:

JC074 · « **Reply #22 on:** April 29, 2011, 04:50:32 pm »

Blk...love those 17" dude - what tyres they running, and do they rub much?

TheDarkStang · « **Reply #23 on:** April 29, 2011, 05:06:58 pm »

My kid sleeps through burnouts now...........that takes me off the Father of the Year nomination list , doesn't it.

67FBGT · « **Reply #24 on:** April 29, 2011, 05:32:52 pm »

Yes your carb is way too big, as the others say a 600 should be plenty; I have a warmed up 302 & a 650 is just perfect for it for cruising or giving it a squirt if I feel like it. There's no way I'd try for bigger. 750? Who's he kidding?
And yes go for a Pertonix electronic ignition kit to eliminate the points in the distributor.
Get the timing spot on with the above installed & all should be well.
Yes, safety is an issue with our old cars, few concessions to safety, no airbags etc; make sure you have good seatbelts & kiddy seats installed, & seriously the very best brakes & steering control. Lots of braindead d**kheads out there that give no quarter & can carve you up in seconds, they just assume 40yr old cars can respond the same as their modern ones. The car can easily be replaced, but your kids welfare can't.

Pls help new mustang owner......

News:

Author Topic: Pls help new mustang owner...... (Read 6736 times)