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04-07-2004, 12:41 AM | #1 |
Garage Queen Material
Join Date: Oct 2002
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problems accelerating???
drove the truck for the first time tonight. it sounded really like it was running good in idle, and we got it to run good at idle in gear too. when i went to drive it, it would barely accelorate unless i gave it more than enough gas. i didnt want to step on it to much cause the time late at night and the open headers.
how should i adjust my carb for a baseline? the timing seems to be off a little cause my dad and i can hear a miss, but for the most part, its good. i didnt have a chance to borrow a timing light, so i had to do it by ear. oh, and my tach doesnt work either, i need either a tach adapter for my msd box, or a new tach |
04-07-2004, 01:13 AM | #2 |
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Do remember that you're running a pretty radical cam -- It isn't gonna respond as quick in the lowend as it did before...
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1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) |
04-07-2004, 01:14 AM | #3 |
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i also, have a 2500 stall, that would matter too. maybe its just i thought i had to give it lots of gas cause it was late and it was so loud???
but, it kept wanting to die on me whenever i tried to come to a stop. |
04-07-2004, 01:18 AM | #4 |
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Thats unusual wanting to die...
I really dunno enough about this kind of stuff yet -- But I would guess something is up with your timing, or your valve lash...
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1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) |
04-07-2004, 01:20 AM | #5 |
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the timing is a lot better than it was, but still not perfect
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04-07-2004, 01:26 AM | #6 |
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Gotta get that timing tape on man Also check your vac and mech avances to make sure either is stuck...
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1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) |
04-07-2004, 01:28 AM | #7 | |
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04-07-2004, 02:00 AM | #8 | |
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04-07-2004, 02:25 AM | #9 |
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i was having trouble deciding on a 2500 or 3000 stall and i went for the 2500 cause of how much i want to be driving int on the street.
but 1 thing at a time, lets get it running good first |
04-07-2004, 02:32 AM | #10 |
driving is in my blood
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Stall is good for this combo, while the cam is bigger the ports in the heads aren't too big so hes good. Aren't you running a Qjet? Thats probably the problem right there, they are very hard to tune right. Does the TC flash up to 2500 before you start moving or will it move before it gets to 2500rpm? My 2200 [actually stalls around 2400] convertor takes a lot more gas to move then my 1800 did, feels like its lacking power because of the slippage. Once you floor it you know the TC is working just like its supposed to though And thats behind a mostly stock, low RPM motor. So that might be your problem also.
EDIT: more ideas. Timing should be set to 10* without the vaccum hooked up and it should be hooked into MANIFOLD vaccum. Also a vaccum advance can would be helpfull but not needed. Some combos, like my 79, like ported vaccum because of 87octane, a tiny cam and 9.4:1 compression. With manifold I get a little pinging at low rpm's. Start with my above baseline and work it until its good. Are you getting a good a/f ratio? If the idle mixture is too different then the normal mixture then you'll get a stumble coming off idea while its transitioning in the carb.
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. Last edited by Tom; 04-07-2004 at 02:36 AM. |
04-07-2004, 02:34 AM | #11 |
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my tach doesnt work because of my 6al box
i'm looking around to see if i can borrow a good one from a friend tommorow |
04-07-2004, 04:22 AM | #12 |
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mine acted like yours at first, but I think it was just from being tight ??
but after about 100 miles it's seems to have more power & I can get a tire bark @35-40 mph now when it hits second gear. |
04-07-2004, 07:17 AM | #13 |
yeller
Join Date: Oct 2001
Location: Twin Cities
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what kind of tach do you have?
Unless you have an Autometer, Ford Motorsports, Mallory, Moroso, or SW...you need a MSD tach adapter # 8910 or 8920, depending on what type of dizzy you are using. See page 7 of your 6AL instructions...nice big chart on there. What kind of plug wires are you running? What kind of dizzy? There is a bunch of important stuff in the MSD instructions...if you goofed on the tach it is a good possibility you goofed on something else. Might want to read or re-read them to be sure everything is hooked up right.
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Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale Last edited by bigblock73; 04-07-2004 at 07:47 AM. |
04-07-2004, 09:00 AM | #14 |
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i have a sunpro supertach II. really old but it worked fine with a stock hei. i'm gonna try and borrow an autometer tach from a friend today and get a timing light too.
the plug wires are 8mm taylor wires. msd probillet hei dizzy w/ vac. advance. the plugs are gapped at .050 because in the 6al instructions they recommend gapping your plugs between 50 and 60. it doesnt help either that the only gas in the truck is half year old 87 octane the carb needs major adjustments i can tell, how should i tune the idle mixture screws? with a tach and vacuum gauge right? hmm... where can i find a cheap vacuum gauge for sale? also, the engine has a lot of run on when i turn the ignition off. as in, i turn the key off, and still runs fine for about 3 seconds and then quits normally. but i'm sure thats from the carb, timing, and the old low octane gas. |
04-07-2004, 09:12 AM | #15 | |
yeller
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Quote:
I don't have the manual here (I am at work), but I do remember it saying you couldn't run solid core wires (or something along those lines)...are your solid core? The manual also has a section on run-on...did you read it as well? Also, the MSD manual has about 10 different ways to hook up the MSD based on the ignition system you are using...make sure you have it wred right. The diagrams are in the back of the book. Eric, you have to go back and check EVERYTHING you have done, and this includes the simple stuff such as this. Reading manuals does pay off.
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04-07-2004, 01:45 PM | #16 |
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yeah, i flipped through the manual. the way i have it hooked up looks like its the simplest way to do it. since its only 1 connector going from the box to the dizzy.
my wires are spiral core wires also. only thing it said about run on, which is what my truck is doing, is something about hooking up a diode to a wire on either a external voltage regulator or internal voltage regulator on the delcotron alternators, like i had stock. but i'm running a 1 wire alternator now. |
04-07-2004, 11:52 PM | #17 |
driving is in my blood
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There seems to be alot you've missed. Might be time to go back and check EVERYTHING again.
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. |
04-08-2004, 12:23 AM | #18 | |
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04-08-2004, 12:34 AM | #19 |
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hmmm... lacking power down low, dieseling, and timing set by ear. i'd say a timing light would cure alot of your problems.
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04-08-2004, 12:44 AM | #20 | |
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04-08-2004, 12:55 AM | #21 | |
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1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle. |
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04-08-2004, 12:57 AM | #22 |
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the run on is mot likely one of two things....
1. your timing is too far advanced 2. your electric fans are producing a current after you shut the truck off. an electric motor is basically the same as a genorator but works backwards. if you have the fans wired a certain way, when you shut the truck off the fans keep spinning and produce a current in the opposite direction of what you have wired through them. so this gives your ignition some additional power after you shut it off. you can either install a diode so current cannot flow back in the opposite direction after you shut it off or you can turn the fan off before you shut the truck off.
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'51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's |
04-08-2004, 12:59 AM | #23 |
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we hit it at the same time destructo
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'51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's |
04-08-2004, 01:08 AM | #24 |
5-7 dropped 87 CC Dually
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OPEN HEADERS! Shorty open headers no less, You can't do that. Hope you didn't burn a exhust valve. No wonder you can't get that thing to run right. Thats why you have your lean exhust. You have to have some back pressure on that little motor. That converter will stall at 3000 in big heavy truck. Set the base timing at 14 with 36 total at 3000. That will get you running. You can fine tune it after that your motor may like more or less. Get some pipes on that thing before you go any farther.
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04-08-2004, 01:19 AM | #25 |
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i gotta get it running good enough before i can go the the exhaust shop and get the pipes welded up.
so, the run on is probably from my fans, because they are hooked up to the ignition on the fuse box |
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