I'm starting to give up....

MY 85 GT · Mar 17, 2008

Ok i install my new fuel pump...also install my new carb 1806 650 cfm thunder series carb did plug,cap,rotor,coil wires....and checked timing i was wrong it is at about 15 degress BTDC....and the car still surges..stumbles,when driving normal..when getting on it half pedal it doesn do any surging.....and it has a weird smell to it not from the convertor but like burning plastic almost....the plugs were pure white.....i have no idea what else to check...any ideas??? Thanks

85_SS_302_Coupe · Mar 17, 2008

White plugs is a lean condition. What fuel pump and what kind of pressure is it running at? Are you sure you don't have any vacuum leaks? What brand carb is that? By converter do you mean torque converter or catalytic converter?

MY 85 GT · Mar 17, 2008

sorry i wasnt more clear...The car is an 85 GT i installed an edelbrock 1806 650 cfm thunder series...the fuel pump is a carter 6-6.5 psi with a rate of 120 gallon per hr...i meant cat convertor its a 5 spd.....the car seems to run ok if floored or driven hard normal driving it sucks...it surges...bucks almost like its running out of fuel.....plugs are white...and smells funny...i did a comlpete tune up and checked timing its set at 15 degress BTDC.....i might have a vac leak but i dont think so...how can i tell...thanks....

EMW150 · Mar 17, 2008

MY 85 GT said:
sorry i wasnt more clear...The car is an 85 GT i installed an edelbrock 1806 650 cfm thunder series...the fuel pump is a carter 6-6.5 psi with a rate of 120 gallon per hr...i meant cat convertor its a 5 spd.....the car seems to run ok if floored or driven hard normal driving it sucks...it surges...bucks almost like its running out of fuel.....plugs are white...and smells funny...i did a comlpete tune up and checked timing its set at 15 degress BTDC.....i might have a vac leak but i dont think so...how can i tell...thanks....

Start with timing. Confirm the timing is advancing properly. It sounds like you may have it retarded. Don't tune for initial advance, tune for total. You want about 34 to 36 degrees total and you want it early in the rpm range. About 2400 rpms if you can. Wherever the base timing falls,it falls.

MY 85 GT · Mar 17, 2008

Ok so bascilly get it back to top dead center make sure the rotor is facing number 1 for starters? I know my intaila timing is at about 15 degrees..dont know my total....I dont think its retarded cars starts fine...even when its warmed up....how would i know if the vac advance wasnt working....

EMW150 · Mar 17, 2008

Starting has nothing to do with the max timing.

Try this: Unhook the vacuum advance and plug off the vacuum line. Start the engine and rev it while checking it with the timing light. Loosen the distributor hold down slightly so you can turn the dizzy. Now slowly start raising the rpms and watch the advance. Keep raising the rpm till it won't advance anymore. Hold the throttle steady at that rpm and turn the distributor to 34 degrees. Tighten the dizzy holddown and take it for a ride. Don't plug the vac advance back in.

Fast63 · Mar 17, 2008

For 85_SS_302_Coupe, the carb is an edelbrock.

Like said, the white plugs are a lean condition. Did you just install the carb and not do any adjustments to it? You may have to move the accelerator pump linkage bar up to give you more fuel.

For your timing, it sounds like your initial is fine, but keep the timing light on it and rev it and see how much the timing increases. Most of your timing should be in by 3000rpm.

Use this link of the edelbrock carburetor owners manual, if you don't already have this, to do some basic tuning. http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf

I hate to say this to, but I also have an 85GT, and as you know there are vacuum lines EVERYWHERE and I can almost guarentee something somewhere is leaking, but chasing the leaks is difficult. You can look for obvious signs of cracked or disconnected vacuum lines, and you can go through one by one taking off lines and plugging them to see if the car runs differently. To see if your vacuum advance is working, put a vacuum hose on the port of the vacuum advance and suck on it. If you suck constant air, it's bad, if you can't, it's good.

MY 85 GT · Mar 17, 2008

Thanks guys for the respnese..the carb is new but it was doing this before i installed it...and i adjusted it by the book...I also checked my Vac with a gauge at idle its 15 pounds i though it should be a little more then that? i will try checking timing again..and look for vac leaks i hope i find it soon i cant even drive it like this....

EMW150 · Mar 17, 2008

MY 85 GT said:
Thanks guys for the respnese..the carb is new but it was doing this before i installed it...and i adjusted it by the book...I also checked my Vac with a gauge at idle its 15 pounds i though it should be a little more then that? i will try checking timing again..and look for vac leaks i hope i find it soon i cant even drive it like this....

Try what I told you with the timing. It will rule out any problems there. If it's still no good try spraying carb cleaner around your intake ports and carb base and see if the idle picks up. It will find a vacuum leak real fast.

EDIT: What are your cam specs?

MY 85 GT · Mar 17, 2008

EMW150 said:
Try what I told you with the timing. It will rule out any problems there. If it's still no good try spraying carb cleaner around your intake ports and carb base and see if the idle picks up. It will find a vacuum leak real fast.

EDIT: What are your cam specs?

My cam spec are stock i guess...i bought the car a few weeks ago....i doubt it was changed doesnt have to much of a lope car looks pretty orginal it might have been changed...i know the vac seems a little low...but there could be a leak maybe i dont think so tho....

Fast63 · Mar 17, 2008

15 is normal vacuum. Once you know everything else is squared away, you probably need to chase some vacuum leaks. My car still stumbles and runs like poop when cold, im convinced there are vacuum leaks associated with switches that run the vacuum differently when the car is not warmed up.

MY 85 GT · Mar 18, 2008

Thanks Guys for your advice yesterday i took the car by a shop that only works on mustangs i had him take a look at it he drove it and said its timing he thinks withou even putting a timing light on it that its to advanced...I checked with a timing light at it was at 15 degressi didnt think that was too advanced...he told me to back it down a little and i should be fine...Do you think that is the problem...i sure hope so....its annoying that way it surgers now.....

85_SS_302_Coupe · Mar 18, 2008

15 vacuum with a stock cam...i dunno. I don't know a damn thing about Edel carbs, but i just rebuilt my Holley and went through all the vacuum adjustments yesterday and my vacuum at idle is something like 23 with stock heads and cam. I would definitely check the timing like EMW150 suggested. If it's not that then it could be something like a blown intake gasket.

What's it idling at?

Once you get the timing taken care of, take the car for a drive down a road where there's no traffic that you can shut the car down and not have to worry about getting in anyone's way. Drive it at 35mph for about a 1/4 mile, and shut the engine off at that speed...just kill it right while you're driving. Pull over (remember that you don't have power steering or brakes so be careful) and pull out a plug from each side and see what they look like. You might just be lean at idle, in which case it could be carb related.

EMW150 · Mar 18, 2008

I agree. 15 seems a little low for a stock cam.

MY 85 GT · Mar 18, 2008

yeah i thought so too....i kinda remember something like 20 inches of vac at idle was good....maybe its a combo of things to much timing...maybe it does have a vac leak...My car idles at about 850-900 rpms....and doesnt seem to have a miss at all it does kinda have a nice lope at idle.....i mean for a stock 85 it seems to have a hot sound to it for a stock car...and crappy exhaust it still have the factory y-pipe to a single cat back to a Y into 2 mufflers and going thru a 2-1/4 piping....Maybe the carb needs to be adjusted more.....Ill post back after i re-time the car

Fast63 · Mar 18, 2008

I had 11-12 vacuum with the E-cam, and 15 with the stocker. You guys think my vacuum gauge maybe does not read accurately?

EMW150 · Mar 18, 2008

MY 85 GT said:
yeah i thought so too....i kinda remember something like 20 inches of vac at idle was good....maybe its a combo of things to much timing...maybe it does have a vac leak...My car idles at about 850-900 rpms....and doesnt seem to have a miss at all it does kinda have a nice lope at idle.....i mean for a stock 85 it seems to have a hot sound to it for a stock car...and crappy exhaust it still have the factory y-pipe to a single cat back to a Y into 2 mufflers and going thru a 2-1/4 piping....Maybe the carb needs to be adjusted more.....Ill post back after i re-time the car

And make sure you set it for total timing, not initial. When you get it running properly it'll probably lose the lopey idle but should run much better.

MY 85 GT · Mar 18, 2008

Yes i will set it for total when i get my Dist loose...lol I have a really nice timing light that does regular and total timing it has the dial in the rear to adjust for total .....i just need to get the Dist loose so i can adjust it...i sprayed it last nite with PB blaster hopefully that will losen it up some....

EMW150 · Mar 18, 2008

Fast63 said:
I had 11-12 vacuum with the E-cam, and 15 with the stocker. You guys think my vacuum gauge maybe does not read accurately?

Probably accurate. Lower vacuum readings at idle can come from alot of different things. Ignition timing, valve timing, worn rings, leaky valves, vacuum leaks.......

85_SS_302_Coupe · Mar 18, 2008

As for the total timing, i'm running a Mallory Comp 9000, which is mechanical advanced. If i go out and set my total timing to about 34, how do i know base timing won't be all crazy?

I'm starting to give up....

MY 85 GT

85_SS_302_Coupe

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MY 85 GT

EMW150

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Fast63

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MY 85 GT

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85_SS_302_Coupe

it sucks (I know) to be on the receiving end

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