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#1 |
Mustang Maniac
Join Date: Sep 2000
Location: GA, U.S.A
Posts: 2,266
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![]() Alright, I've almost exhausted all my options. For the last week and a half, the stang's been sick. First it started off as the battery wasn't getting charged. After much troubleshooting and a new alternator
(a bit hasty on my part, but hey, it only costed $36), I found it to be the wires going to the back of the alt were rotting and broke off. I've fixed those since. But now that the charging problem seems to be totally taken care of, there is something else weird that is going on: At cruise speeds, there is a very slight stumbling. It's really apparent when I really get down on it (WOT). At the end of each rev for 1rst and 2nd gear at near WOT, it stumbles. It's the kind of thing that makes you sure it's either a clogged air filter or fuel line, but I've run it with filter removed and also changed fuel filter and same thing happens (but seems to be a little less apparent). I've checked all the plugs and all look fine also, they're under 10,000 miles old-- should not be plugs. I have a relatively new rotor and cap. The things next on my list to check are plug wires, and coil. Anyone think this could be a coil issue or perhaps distributer. An external visual inspection on the plug wires says they're A okay, but could be some internal issues, don't know (they've been on there since motor was built ~ 2 years ago, but shouldn't have to change them so soon. Also, voltage regulator is relatively new (whole charging system is fine). I run usually run 89 octane, but put in 93 every once in a while. I was thinking about gasoline, but I'm pretty sure it's not an octane issue and the quality of gas I'm pretty sure is just fine also (Amoco or Chevron). Last thing on my list is to go over the carb to see if that is the culprit. This should've been a simple fix, but I'm not finding what the problem is. I've gone through many other different things and still no solution. So I am coming here (after over a week of troubleshooting). I need some advice guys. Any suggestion? The car will drive, but she's still a little sick and won't win any races until this thing is cleared up. ----------------------------------------- 351W-powered 1979 Ford Mustang notchback Stock 5.8L under custom made 4" cowl, C4 w/ shift kit Holley 750 cfm, Edelbrock Performer RPM intake 1 5/8" MAC shorty headers, Al driveshaft 2.5" Off road H-pipe, 2-chamber Flowmasters Front: 225/60/15, Rear: 255/60/15 Eagle GT II Weld wheels (15x6;15x8), 8.8" Rear w/ 3.55s 14 x 4” K&N air filter. Only a couple of weeks b4 Project FOX begins!!! ![]() "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body |
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#2 |
Git jiggy
Join Date: Oct 1999
Location: MO USA
Posts: 865
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![]() I'm thinking either the coil, plug wires, or how about the PIP module inside the distributor. A friend of mine had a really bad stumling problem at cruise or accleration and it turned out to be the little module thing inside the distributor. I believe it's called a PIP but, of course, I can't remember what the heck it stands for. You can pull the cap and rotor off and see it down inside the distributor. What's your fuel pressure? Could it possibly be the fuel pump?
------------------ 1994 Red SVT Lightning #2019 |
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#3 |
Registered Member
Join Date: May 2001
Location: Harrisburg, Pennsylvania
Posts: 379
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![]() my suggestion would be to check out the carb......take a flashlight and look down in carb while it's running,check and see if the thottle pump is working,also look to see if it's spraying right......this might not help if it's only messing up under hard throttle(can't put it under hard throttle while it's sitting in park).....but it might tell you somthing.......it sounds like it could be a carberation problem....check fuel psi too
i'm thinking that the pip is only in the computer cars,yours should have a halls effect pick up in the distributer(pretty dependable).......but a weak spark could cause the problem so it might be good to replace the ignition wires,cap and roter just to illiminate that as the cause........my theory on trouble shooting is procces off ilimination....illiminate the things that could cause the problem, starting with the cheapest thing first good luck ------------------ i'm really a not so old guy with 87 gt.......87gt,T top -169,000 on odometer-14.7 qt.m/80 capri(future project) |
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#4 |
Junior Member
Join Date: Mar 1999
Location: Ventura, California
Posts: 8,981
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![]() Ignition System:
I would replace the plug wires because I'm that kind of guy. The best ignition system in the world isn't worth much if the energy can't get to the plugs. I would try and borrow a coil, and see if there's any difference. If there is, replace it. If not, keep yours. Fuel System: Which fuel filter did you replace? Most Holleys have a bronze filter in the bowl where the fuel line fitting attaches. Make sure this is replaced or removed (if you have an inline filter). Check your line pressure at idle and at 4000 rpm. Make sure it's no lower than 6psi. Check the float level in your secondary bowl. Make sure your power valve isn't stuck shut. Is your carb Vacuum Secondaries or Mechanical Secondaries? If Vac, which secondary spring are you using? If Mech, what are your secondary jets? Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!! |
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#5 |
Moderator
Join Date: Mar 2001
Location: Myrtle Beach SC
Posts: 1,643
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![]() Ok last ditch option after you have tried all the stuuf before mentioned because its all alot easier, Pull the gas tank and remove the pump. I believe there is a little "sock" of filter bag type thing on the bottom. If it is cloged up theres your problem. All the junk that collects in the tank settles in the tank until you hammer down on it and create negative pressure. The stuff naturally tries to find a way out and the only way is through the pump. If thats the problem. Clean the screen and flush the tank. Put it all back together and it should be fine for another hundred thousand.
------------------ '93 lx notch 4 banger (drive it to work currently), Using the 306, 8.8 posi, 4.10's, summit rear cover, elec. fan, cowl hood, wieand stealth intake, holley 650 d.p.carb., built c-4, e-303, full autometer guages, msd box, mallory unilite dist, and coil, roll cage, summit seat, subs, 15x10's in the back with slicks, skinnies up front, all in use for 1988 Hatch Drag Car. Hope to start running next year. Hoping for 7.20's after all is done with small motor. |
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#6 |
Mustang Maniac
Join Date: Sep 2000
Location: GA, U.S.A
Posts: 2,266
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![]() Man. Forgive me for taking so long to respond. Thanks everyone for replying.
96GTS, Inside my distributor is the pickup coil and reluctor, no PIP. My fuel pressure SHOULD be at 7-7.5 psi, that's what it was when I first built the car, but I don't have a fuel pressure gauge now to check it. old guy, I haven't yet checked the carb, but will do tomorrow. No, I can't visually check it at high rpm, but you're right, it is at least something to look at at idle and revving. Cap and rotor are fine after inspection + they're relatively new. I was gonna change the plug wires, but when I removed one of the old ones to replace them (one at a time), something just didn't feel right so I rolled the new plug wires up, stuck them back in the box and decided to wait on that (maybe I was just lazy). I will check fuel psi. I have the same method as you on starting with cheapest, easiest to get to parts first, then move on by process of elimination. ![]() PKRWUD, I'll borrow a coil from a friend and try it out. I would replace the plug wires b/c I'm just that kind of a guy too, but this time I decided to wait on that (seems to be pointing more to a fuel problem). I bought the wires, but put them back in the box for now. I'll probably end up putting them on anyway. I replaced the inline filter (b/t fuel pump and carb). I'm not sure if there is an actual filter in the bowl, but there just may be one. I'll check on that. I think some come with a screen (not actually a "filter" I guess) at that fuel inlet. I haven't yet checked the float level in sec. bowl, but will do it. I was concerned about the power valve, but usually if it's broke, it's usually broke open and allows fuel to just keep going through. Thus, I'm thinking this wouldn't affect it like it feeks at high rpm, but I'll check it anyway. I have vacuum secondaries and the secondary spring is the stock spring. pony_power_90, My fuel pump is outside of the tank, but I think there is a filter back there also. Can't remember. I'll have to check. I hope it isn't that little screen/filter bag on the float inside the tank b/c I'll have to beat myself over the head for not changing it as I should've when I removed the tank a year ago. It shouldn't be b/c when I did remove the tank, I totally cleaned it out. ---------------------------- Some other notes: 1) My fuel light on my console hasn't gone off (not normal) even though I have about 6 gallons of gas in the tank. SOmetimes it'll come on a little prematurely, but never with this much gas and it'd never stay on so long, but it won't go off. I haven't been driving the car hardly at all for the pass week or 2 so maybe I just need to drive a little more and it'll go off. Don't want to read too much into this. 2)Coincidentally, changing my ignition module (something I at first forgot to consider)--$15.00!-- seemed to help significantly. I don't want to jump to any wrong conclusions too fast, but I got down on the motor hard and it only stumbled (a diff kind of stumbling now, but much less) at very high rpm (~5000-5500). Seems much stronger. It even is much smoother cruising. As far as I can tell, everything now seems to be pointing to fuel/carb problems. Thanks again for your previous replies and future ones. ![]() More suggestions are welcomed. ----------------------------------------- 351W-powered 1979 Ford Mustang notchback Stock 5.8L under custom made 4" cowl, C4 w/ shift kit Holley 750 cfm, Edelbrock Performer RPM intake 1 5/8" MAC shorty headers, Al driveshaft 2.5" Off road H-pipe, 2-chamber Flowmasters Front: 225/60/15, Rear: 255/60/15 Eagle GT II Weld wheels (15x6;15x8), 8.8" Rear w/ 3.55s 14 x 4” K&N air filter. Only a couple of weeks b4 Project FOX begins!!! ![]() "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body |
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#7 |
Junior Member
Join Date: Mar 1999
Location: Ventura, California
Posts: 8,981
|
![]() Can you duplicate these symptoms in the garage, or does it only happen while driving? If you can duplicate it, get a fuel pressure gauge and see what it reads when the problem occurs. Again, for me, get out a 1" and a 5/8" open end wrench, and check the fuel inlet on the carb for a filter of some sort. The secondary float level is easy to check too.
Don't forget to swap coils, though, either. When a coil gets older, it starts to cut out at higher rpms. Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!! |
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#8 |
Mustang Maniac
Join Date: Sep 2000
Location: GA, U.S.A
Posts: 2,266
|
![]() Okay, I feel like I wasted you guys' time.
Let me be quick and to the point. The culprit was the plug wires. I made myself just go ahead and put the new ones on and it totally solved my problem. Thanks to all who replied. Forgive me for how long I take to reply, but I have recently been carpooling to work and don't have to drive my car during the week. When I get home, I don't usually have much time to mess around with it. Thanks again. ----------------------------------------- 351W-powered 1979 Ford Mustang notchback Stock 5.8L under custom made 4" cowl, C4 w/ shift kit Holley 750 cfm, Edelbrock Performer RPM intake 1 5/8" MAC shorty headers, Al driveshaft 2.5" Off road H-pipe, 2-chamber Flowmasters Front: 225/60/15, Rear: 255/60/15 Eagle GT II Weld wheels (15x6;15x8), 8.8" Rear w/ 3.55s 14 x 4” K&N air filter. Only a couple of weeks b4 Project FOX begins!!! ![]() "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body |
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#9 |
Junior Member
Join Date: Mar 1999
Location: Ventura, California
Posts: 8,981
|
![]() Told ya so.
Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!! |
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#10 |
Mustang Maniac
Join Date: Sep 2000
Location: GA, U.S.A
Posts: 2,266
|
![]() ![]() ----------------------------------------- 351W-powered 1979 Ford Mustang notchback Stock 5.8L under custom made 4" cowl, C4 w/ shift kit Holley 750 cfm, Edelbrock Performer RPM intake 1 5/8" MAC shorty headers, Al driveshaft 2.5" Off road H-pipe, 2-chamber Flowmasters Front: 225/60/15, Rear: 255/60/15 Eagle GT II Weld wheels (15x6;15x8), 8.8" Rear w/ 3.55s 14 x 4” K&N air filter. Only a couple of weeks b4 Project FOX begins!!! ![]() "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body |
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