1998 Dodge 1500 Engine swap problem

We just replaced the 360 engine in a 98 Dodge with a 360 out of a 95
Dodge pickup. The 95 engine ran great in the junk 95. Now that it is in the 98, it runs very rich and poorly. Both trucks are automatic trans.

95 Engine was EGR, so we used intake and right exhaust manifold from the 98. Also used the 98 injectors and distributor (cam sensor, too).

Nothing that we do makes it run worse or better. I have changed engines in other similar Dodges, with no troubles.

We just found out that according to Hollander interchange, and also O'reilly auto parts that the flex plate between the 95 and 98 is a different part number....so, has anyone had a similar experience? What is different between the two flex plates? Is it possible that the 95 flex plate is causing the crank sensor to read something incorrectly?

I also looked up the interchange on a manual flywheel, and it lists them the same between a 95 and a 98 so that seemingly strikes down my theory......

Hate to have to pull it apart to compare the flex plates, but we can if we have too. Anyone with any advice? thanks!

95 would be OBDI, 98 OBD II.
Since you swapped dist and cam sensor, along with the injectors, I'd guess the same as you, crank sensor. Real easy to mess those up on a swap.

But before even going there I'd look real close at wiring to see if anything got pinched or left disconnected. Super rich at cold start indicates ECT.
Can you get any codes out of it?
Do you have access to a scan tool to check all the sensor outputs?

97 is the change over year.
the flex plate is weighted and the torque converter is neutral at that point vs weighted converter on the 95.

not positive on the harmonic.

all electrical connectors changed about the same time, so as stated above you should have reused the whole harness and sensors from the 98 if you are running it with the 98 computer.

the only other thing I can think of is timing. there is an arrow in the distributer telling where number 1 must point or the computer cannot control the timing properly.

The only thing that isn't original to the 98 is the basic engine including harmonic balancer and flex plate. We put the 98 intake, throttle body, injectors, distributor, etc. onto the 95 engine. Intake and right exhaust manifold from the 98 were installed on the 95 engine because the 95 engine had EGR and the 98 didn't.

All wiring, sensors, injectors, etc. are original to the 98.

I don't know how it ran before because the original engine had a connecting rod through the oil pan....so, no telling how it ran.

We had a guy scan it...don't remember the codes, but there were two. One was coolant temp. or something, and the other said no cam sensor signal. We installed a new cam sensor in the distributor, and it runs the same.

Rotor is pointing at the mark when #1 cyl. is at TDC.

I put a 98 Engine in a 95 before, and we just put a 2000 engine in a 94, and had NO problems...just changed intakes, etc. just like we did this time!

As far as the flex plate....that should have nothing to do with it? Basically, we have an unweighted torque converter and unweighted (95) flex plate....so, that should only just cause vibration...correct?

thanks for the help and advice!

So ECT (Engine Coolant Temp) is a code.
The quick and dirty deal is to plug in a resistor across the connector terminals so you can rule that out. The computer does monitor this so it can see how quickly it comes up to temp. There are codes for this, but at least you can plug in a 90 degree resistance and see if it's still super fat.
From THIS PAGE it looks like a 5k ohm resistor will do it. Clear the codes after checking.
If the connector is disconnected, it will be no retun and 'see' very cold and force it rich. Check those wires!

I agree, should only cause vibration.

coolant temp not reading will cause rich running.

did the other code clear when you put in the new sensor?

Coolant temp. code cleared after installing new sensor. It didn't change the way that it runs, though.

Only one code now. Depending on which scan tool we use, it says crank/cam sensor intermittant and the other scan tool says something to the effect of not reading cam sensor.

We have also tried a couple of other computers off of some of our parts trucks....we can make it run worse, but not better. However, we don't have any PCM that is an exact match for this truck. Closest we have is from a 99 1500 with a 318, automatic.

All of this for trying to help out an elderly friend. She loaned a guy $3000.00 and she took the truck as collateral (not knowing that the engine was bad). The guy is now in jail for robbing a few stores in town....he won't be much help to get any info from!

the only think I can think of is that the vibration is throwing it off.
since the fly wheel may be bouncing a little, it might throw the sensor off.

there is no cam sensor in a 98, only the crank sensor.

have you tried replacing that?

I thought the difference between the early and late Magnum flexplates was the early plate had an asymmetricical converter bolt pattern, and the late plate had a symmetrical bolt pattern

Have you checked your distibutor/ crank sensor sync? You will need a scan tool to do this properly. You can get it close by putting the engine on TDC and removing the dist. cap and aligning the rotor with the mark on the distributor.