Running rich, slight miss after motor swap

[dusten]

We have a 93 Ranger with cali emissions(cam sensor, egr)
The motor has overheated, so we were going to rebuild it. Upon inspection the head is toast. We acquired a complete 98 motor. We stuck the 93 rods and new pistons in the block with the 98 heads and cam. We used the 93 intake and We put all the emissions and sensors on the 98 block. Upon completion the truck has a slight miss and hesitation, and appears to be running rich(from reading the spark plugs). Im curious if the 93 had a different cam than the 98, and that is causing the rich condition.
My dad is a 20 year master tech for gm and has checked all the simple stuff.
I did a search and couldnt find anything about it, but he said in all data they show different part numbers.

 

[bronco_lou]

did you pull any codes?

 

[pcollins]

could be multiple different things. a 93 and a 98 are two completely different generation rangers.

 

[Twizzler09]

But they'd still both be OHV 4 liters.... which means that inherently they're very near identical as far as the motor is concerned, besides heads and emissions equipment.

As far as I'm aware, the camshaft remained the same throughout the years. If your using the 98 heads, the head design differed from 93 to 98. In the earlier 4.0's the combustion chambers were slightly larger. I *think* it was '95 when ford switched the heads to the "fastburn" design, which is the smaller chamber.

This is all very much memory based, so take it with a grain of salt, lol. I may have skewed the information around altogether

 

[twigboy3]

were they both cali emissions that could have something to do with it

 

[aspevacek]

Camshaft synchro timing is some to look at if the 93 is like the 97 I have. It takes a special tool to time it dead on and to my understanding if it is even slightly off it could be fireing the injectors at the wrong time and possibly not set an engine code. I had a bad synchronizer on m yand it was bad enough to set the code but not sure if they always set a code or not.

 

[dusten]

I was wrong, the heads are 93 heads. He picked up a set prior to the install.
As far as the motors being both cali emissions, other than cam, crank and block, the motor is all 93 parts. I will let him know about the cam synchro timing.