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351w EFI performance upgrades?

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  #181  
Old 10-08-2016, 11:55 AM
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Originally Posted by 351miller
Was using scanner to read what timing was then adjusting distributor. I think it is maf but not sure either . Truck is 97 5.8
Did you remove the SPOUT connector? 97' is likely SD, assuming it's in an f250 or f350. Is there a MAF sensor in the intake tube? Is it OBDI (EEC-IV) or OBDII (EEC-V)?
 
  #182  
Old 10-08-2016, 12:22 PM
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Assuming what the scanner was showing was volts for o2. Where do I start checking to find out why it's running rich. I would have thought with the amount airflow I added it would be lean
 
  #183  
Old 10-08-2016, 12:45 PM
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ok what can gather from Internet and looking at truck. Obd 1 and sd no sensor in intake tubes and eec plugs is under hood drivers side inner fender.
 
  #184  
Old 10-08-2016, 01:51 PM
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Truck is obd1 with sd
 
  #185  
Old 10-08-2016, 04:12 PM
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Which cam did you use. Sorry if I missed it. SD is sensitive to LSA.

I don't have a ton of experience I've just read a lot recently, and have been asking questions that might help one of the experts help you.

It's possible the sensor isn't working correctly. Does the exhaust smell rich? What do the plugs look like?
 
  #186  
Old 10-08-2016, 05:53 PM
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Motor is a stock 97 5.8. Mods are pro comp gt40 heads,5.8 lower intake ported to match 5.0 upper intake, 1.7 roller rockers with longer pushrods to center on valve stems, hotter ignition from coil to plugs, shorty headers and new exhaust. Cam is factory roller.
 
  #187  
Old 10-08-2016, 07:08 PM
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What kind of scanner were you using? Can it give any other information, like fuel trim?
 
  #188  
Old 10-08-2016, 07:33 PM
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Snap on is all I can say it's the neighbor whose helping me. I'll see if he can check fuel trim
 
  #189  
Old 10-08-2016, 07:43 PM
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Have you located the spout?
The little grey plug.
 
  #190  
Old 10-08-2016, 08:03 PM
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Yes played with timing today. Pulled spout out reved motor by hand and turned distributor , set it by ear but got more power and motor revs better. Feels like I'm just now back to the power I had before doing any upgrades.
 
  #191  
Old 10-08-2016, 09:06 PM
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So no timing light? Hmm. Did you check timing on the scanner with spout out?
 
  #192  
Old 10-08-2016, 09:47 PM
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Tried bounced from 10 to 30
 
  #193  
Old 10-09-2016, 01:16 AM
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You need a timing light to set the timing, period.

The computer has only one way to control the timing of the engine, and that is through the SPOUT wire. The computer also has no way to verify the timing - all of its timing information comes from assuming the distributor is perfectly set to 10* BTDC.

If you unplug the SPOUT connector, the computer has absolutely no control of the timing. The read out on the scanner is just what the computer is trying to command the timing to be.
 
  #194  
Old 10-09-2016, 05:30 AM
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I'll get timing light, but do I still set to 10 Btdc with the six little tune. Also what should my plugs be gapped at. .043-.046 is stock. Running the hotter ignition should I open them up some.
 
  #195  
Old 10-09-2016, 11:10 AM
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I would start with 10 degrees and go drive it. Six liter tune up just calls for advancing the base timing as much as you can get away with, without pinging under load. I tried it with plugs at 0.055" and found 11 degrees was all my truck (96' F150) would tolerate.
 


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