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General Tech => Aftermarket Tuners - Generally => Topic started by: 90 stang vert on October 16, 2012, 08:36:18 am



Title: surging while driving
Post by: 90 stang vert on October 16, 2012, 08:36:18 am
i have a 90 mustang gt not running well, it has a surge while driving its a pretty big one. any ideas would be greatly appreciated.


Title: Re: surging while driving
Post by: Joel5.0 on October 16, 2012, 09:05:38 am
 :welcomesbf.... don't forget to add your location to your member profile..... :thanx:

Suggest to start with the basics:

1. Run a set of DIY KOEO/KOER self tests and post the results = http://sbftech.com/index.php/topic,2471.0.html

2. Verify overall intake tract sealing for vacuum leaks form the MAF to the lower intake and attached vacuum lines/hoses.

3. Measure and report back engine idle speed level and manifold vacuum reading.

4. Check what the spark plugs are "saying" = http://sbftech.com/index.php/topic,2735.0.html

5. Is this a stock setup or does it have any upgrades or bolt-on's installed? (intake, exhaust, heads, camshaft)

LUK


Title: Re: surging while driving
Post by: 90 stang vert on October 16, 2012, 09:28:26 am
the car has some mods 306 with heads upper and lower intake, 520 cam, and exhaust.


Title: Re: surging while driving
Post by: Joel5.0 on October 16, 2012, 09:45:50 am
520 cam ?


Title: Re: surging while driving
Post by: 90 stang vert on October 16, 2012, 09:51:56 am
thats the size of the camshaft (lift).


Title: Re: surging while driving
Post by: 90 stang vert on October 19, 2012, 11:04:59 am
Hi Joel,

i checked my spark plugs, pulled number 1 spark plug and it looked fine. i pulled one on back end and it was fouled up all black. i will change all plugs and see if there's a change. what should i gap the plugs to .35 or higher?


Title: Re: surging while driving
Post by: BirdMan on October 30, 2012, 01:20:08 pm
I don't know if this applies to injected engines but on a carbed one I had too much timing.  Dropped 2 degrees and it was okay.


Title: Re: surging while driving
Post by: turbo2256 on October 30, 2012, 04:31:20 pm
Does it still have EGR hooked up? If not you may have too much timing at low load conditions.


Title: Re: surging while driving
Post by: 85_GT on October 30, 2012, 04:50:29 pm
EGR spark is an adder based on EGR flow.


Title: Re: surging while driving
Post by: turbo2256 on October 31, 2012, 09:57:35 am
One thing I remember is changing all the timing charts to resemble that of a mechanical distributor and data logging for info to change light load conditions.
So happy I went back to carbs on my build dont think about EFI any more all my tuning info is in 3 notebooks I will pass on to my son.
MY SBF builds take me past factory ECM RPM limits. Might go EFI again if I were to go with indivual TB aftermarket system.