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Hi I have a 1988 Mustang GT it has an E303 cam and ever since it was installed it seems to run very rich so much so that It'll make your eyes water. It has been converted to mass air flow and does have an off road H pipe but before the cam with the off road H it wasn't nearly this bad. Suggestions?
 

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Hi I have a 1988 Mustang GT it has an E303 cam and ever since it was installed it seems to run very rich so much so that It'll make your eyes water. It has been converted to mass air flow and does have an off road H pipe but before the cam with the off road H it wasn't nearly this bad. Suggestions?
I have and 87 with an E303 cam with 1.7 roller rockers also
converted to mass air and mine runs rich too. I also have an
adjustable fuel pressure reg and I reduced some of the
richness by lowering the fuel pressure to 30 lbs. it still runs
rich but not as much.
 

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Discussion Starter #3
I have and 87 with an E303 cam with 1.7 roller rockers also
converted to mass air and mine runs rich too. I also have an
adjustable fuel pressure reg and I reduced some of the
richness by lowering the fuel pressure to 30 lbs. it still runs
rich but not as much.
Interesting good to know that it's not just me I just wish I knew what to do to get it so it isn't so strong.
 

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When was the last time the spark plugs were changed, and were they gapped them properly when they were last changed? Could be a poor spark not burning fuel completely.
 

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sounds like you make have changed the amount of air going into the engine after switching the cam. you probably need to change the MAF Sensor and housing to get the correct air flow ratio. i would contact the manufacturer of the cam or MAF sensor and talk to them directly. its possible that you need bigger injectors with the new cam...
 

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Shouldn't need bigger injectors. Plus if the injectors were too small it would run lean. The MAF needs to be recalibrated because it cannot read proper air flow from the cam change. Need to put a chip in it and have it tuned.
 

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needs a chip and needs to be tuned with a cam swap period.

there is actually a good chance it is lean if your eyes are watering. the bigger the cam, the more fuel needed at low rpm since the extra reversion bleeds off more compression.
stock cam idles at 14.5 to 1 afr and a bigger cam needs a richer mixture due to reversion again.
also, a bigger cam needs more initial timing over stock to idle properly.

or just put a carb on it and give her hell for far less . . .
 
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Discussion Starter #8
The motor was just rebuilt as well forgot to mention that but before that it was the same thing with it making your eyes water when behind it
 

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needs a chip and needs to be tuned with a cam swap period.

there is actually a good chance it is lean if your eyes are watering. the bigger the cam, the more fuel needed at low rpm since the extra reversion bleeds off more compression.
stock cam idles at 14.5 to 1 afr and a bigger cam needs a richer mixture due to reversion again.
also, a bigger cam needs more initial timing over stock to idle properly.

or just put a carb on it and give her hell for far less . . .
What he said except get a tune, don't go carb...

The motor was just rebuilt as well forgot to mention that but before that it was the same thing with it making your eyes water when behind it
You're running lean as sht now due to the cam swap and the computer can't compensate. The before the cam swap smell was more than likely due to not having cats. When I had my motor rebuilt they put in a comp cam that's similar to the e303 and the ecu didn't like it much so I had to get a tune.
What heads to you have? If you have e7's the stock maf and 19# injectors will work just fine after a tune. Even if you were to swap to say 24#'ers and a "calibrated" maf you'd still need a tune due to the cam.
Adjustable fuel pressure regulators are an old school way to try and get the air fuel ratio correct and it still will be close but no cigar. Unless you know what you're doing and have an a/f gauge I wouldn't mess with an adjustable regulator as you might make things worse. If you get a tune no adjustable fuel pressure regulator is necessary. If it's an option I'd go the dyno route vs an oh Bama tune.

ps: "clocking" the maf will do diddly.


Looks like I picked the wrong week to quit sniffing glue.
 
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