5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

5.0 ignition problems?

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Old Apr 11, 2011 | 10:44 PM
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Default 5.0 ignition problems?

So when I bought my 5.0 it chugged and bucked a little bit, only under about 2k RPM, the PO said that the headers toasted plug wires so whenever it started he would just change the wires. So I took it to the shop today to have them give the whole car a once over. The first thing the mechanic noticed were the battery clamps were extremely corroded and loose. It made sense that this could be the issue. The alternator can't power all the electronics at such a low RPM, so when the battery loses connection from the crappy clamps it wouldn't have enough power to run everything including the ignition. So it would chug. Would also explain the backfiring that would come from a "rich condition" produced by the plugs not igniting the fuel in the cylinders. So he soldered some new clamps onto the wires and I was on my way. It seemed to help a bit but it still chugged and bucked. So I bought some plug wires and installed them tonight. Took it around and still got the same results. Doesn't seem to backfire anymore now though. Could I just need a tune? Its got a mild cam, injectors, Wally 255, GT40 heads, Trick Flow intake, 75MM TB, BBK long tubes and Flow Master mufflers. I'm still finding out mods as the days pass.

Thanks,
Sawyer
Old Apr 12, 2011 | 08:33 PM
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Anyone? I'm at wits end with this freaking chugging under 2k. The main speed limit in my town is 25 MPH and in 2nd gear that's just below 2k. And in a car as obnoxious as mine I don't want to attract any unwanted attention by speeding.
Old Apr 13, 2011 | 02:15 PM
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Originally Posted by 318
Anyone? I'm at wits end with this freaking chugging under 2k. The main speed limit in my town is 25 MPH and in 2nd gear that's just below 2k. And in a car as obnoxious as mine I don't want to attract any unwanted attention by speeding.
Possibly mass air meter not matched to injectors? How does it run other than <2000? Smell rich? Timing? It does sound like plug wires though.
Old Apr 13, 2011 | 02:56 PM
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I just put a new set from Napa on. The Mustang guys on my local forum are telling me that Orangeish yellow injectors are stock 19lb. They are saying it sounds like it might be off time. I'm checking the time this weekend.
Old Apr 13, 2011 | 03:54 PM
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the timing could be off but you would most likly have starting troubles and problems through out the entire rpm band, check the mass air to see if it is actually calibrated for the stock injectors.
Old Apr 13, 2011 | 06:15 PM
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How would I know if its calibrated to the stock injectors? I'm taking it to the local Mustang guru next Friday hopefully. So if I don't get it figured out I'm sure he'll tell me what needs fixed.
Old Apr 13, 2011 | 07:04 PM
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if it's an aftermarket mass air meter (C&L, Pro-M, etc), it should have an ID tag with the calibration on it.
Old Apr 15, 2011 | 04:47 PM
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So I've gotta buddy comin over to check my timing today, and was wondering what the base timing should be set at? Is there a tag somewhere or something that would tell me what it needs to be?
Old Apr 15, 2011 | 04:59 PM
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My LX was doing somewhat of the same thing. Replaced the dizzy and no more problems. Look inside of your dizzy if it's dirty and rusty like my old one was that might be a problem also, just sayin...
Old Apr 15, 2011 | 05:52 PM
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Thanks. That was something that was kinda rollin around in the back of my head, but wasn't gonna just tear into it without someone mentioning it.



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