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Discussion Starter · #1 ·
I bought a 95 mustang 3.8 already split port swapped now I keep getting told I have to tune it but I’ve seen that people haven’t had too, I’ve replaced the TB, TPS, IAC, reset the idle it’s got 15lbs injectors in it. It runs like garbage on cold start won’t idle and spits and spudders it’s got egr removed not deleted [engine light is on]
Once it warms up it’s drivable
Any ideas? And yes I’ve checked for vac leaks
video attached
 

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The Parts Guy
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What do you mean by "reset the idle" if you're not adjusting the tune file? Which EEC are you running? You mention 15 lb/hr injectors, but that wouldn't be stock for either the Singleport or Splitport EEC. What method did you employ when checking for unmetered air? What DTC(s) are present?
 

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The Parts Guy
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Just watched the video. :oops: Letting it continue to detonate away is not helping your rod bearings one bit.
 

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Discussion Starter · #4 ·
What do you mean by "reset the idle" if you're not adjusting the tune file? Which EEC are you running? You mention 15 lb/hr injectors, but that wouldn't be stock for either the Singleport or Splitport EEC. What method did you employ when checking for unmetered air? What DTC(s) are present?
No flow at egr is the only dtc, there is a way to reset the IAC and idle where you disconnect the battery, they are stock single port injectors, tried both smoke test and spraying brake clean found a few leaks and fixed them

And I’m aware just wanted to get a good video of it happening
 

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Super Moderator
97 Thunderbird 4.6, 98 Mark VIII LSC
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11,171 Posts
You didn't answer the most important questions:

1) What PCM are you using?
2) What injectors and MAF sensor are you using?
3) Who's tuning your PCM for the combo?

Nobody can help you without these answers.
 

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Discussion Starter · #6 ·
You didn't answer the most important questions:

1) What PCM are you using?
2) What injectors and MAF sensor are you using?
3) Who's tuning your PCM for the combo?

Nobody can help you without these answers.
The stock 95 pcm, they are the stock injectors off the 95 3.8, not tuned by anyone yet, and I believe the MAF is off the 01 I will double check that though
Also to note I bought the car like this I didn’t do the swap myself so it’s a part number hunt on what was used
 

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Super Moderator
97 Thunderbird 4.6, 98 Mark VIII LSC
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11,171 Posts
If you want to do your best to get it going without a tune, the MAF and injectors need to come off the same car the PCM came from otherwise your fuel and spark delivery will be off. If you're keeping the 95 PCM, you will need the MAF to go with it. Any other mixing of injector flow rates and MAF sensors will require a tune.

The reason it runs like crap when it's cold is because it's running in open loop: relying solely on that relationship between the MAF and injectors being correct. Since it's not, the actuality of fuel delivery is nothing like what the PCM is expecting (or what the engine needs). Once it gets warm the PCM switches to closed loop, which will help get fueling closer to driveable mixtures with O2 feedback. It doesn't fix the spark being out of whack, though.
 

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Discussion Starter · #8 ·
If you want to do your best to get it going without a tune, the MAF and injectors need to come off the same car the PCM came from otherwise your fuel and spark delivery will be off. If you're keeping the 95 PCM, you will need the MAF to go with it. Any other mixing of injector flow rates and MAF sensors will require a tune.

The reason it runs like crap when it's cold is because it's running in open loop: relying solely on that relationship between the MAF and injectors being correct. Since it's not, the actuality of fuel delivery is nothing like what the PCM is expecting (or what the engine needs). Once it gets warm the PCM switches to closed loop, which will help get fueling closer to driveable mixtures with O2 feedback. It doesn't fix the spark being out of whack, though.
Okay sounds good there is a 95 at a wrecker here so imma go pull the MAF off it and also go pull a egr and hook that up as I’ve heard of really bad idle problem when it’s removed entirely
 

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97 Thunderbird 4.6, 98 Mark VIII LSC
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Not having EGR shouldn't have any effect on idle characteristics. The EGR valve is only open at part throttle while cruising.
 

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Discussion Starter · #10 ·
Not having EGR shouldn't have any effect on idle characteristics. The EGR valve is only open at part throttle while cruising.
We’ll I put the new MAF IAT in I found a cold air in a 96 so I grabbed that and also grabbed the egr sensor off a 99 and plugged just the sensor in and it runs no hesitation at all
 

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SuperNewbie
1995 Thunderbird LX 4.6 red
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3,592 Posts
We’ll I put the new MAF IAT in I found a cold air in a 96 so I grabbed that and also grabbed the egr sensor off a 99 and plugged just the sensor in and it runs no hesitation at all
Sounds like positive progress.
 
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