1990 tbi 360

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MoparDaddy

MoparDaddy

Damn Right I Carry!
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On my d250, I have done a full tune up over time since i git it a few months ago. traded an acura for it to work if and make a few extra bucks. tune up includes: plugs , wires, cap, rotor, fuel /air filter, PVC valve, vacuum lines. The truck however is still running rich. I'm wondering what else I may be overlooking aside from timing? Someone once mentioned to me to tune the regulator. not sure how to do that?

I included a wiring diag of the engine for those unfamiliar with this setup. Not sure if it will do any good or not lol.
 

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Only thing that would come to mind would be the temp sensor or the pre-cat O2 sensor. Is it sending any codes?
 
There is no adjustment to the fuel pressure regulator.

Check your fuel pressure. These things are very sensitive to fuel pressure issues. In addition, pull the hose off the back of the regulator and see if there is fuel in the line which would indicate the regulator has failed (Note: this is not a vacuum line it is simply a "drain" in case the regulator fails)

I also agree you need to check the codes - however you mentioned the "assembly disintegrated", can you elaborate? I might have a part or two to help you out.

How did you set the timing? - You need to have the engine at operating temp, disconnect the coolant temp sensor, then set the timing. There are 2 sensors 1 for the gauge and one for the computer so be certain to get the correct one.
 
sls001 said:
There is no adjustment to the fuel pressure regulator.

Check your fuel pressure. These things are very sensitive to fuel pressure issues. In addition, pull the hose off the back of the regulator and see if there is fuel in the line which would indicate the regulator has failed (Note: this is not a vacuum line it is simply a "drain" in case the regulator fails)

I also agree you need to check the codes - however you mentioned the "assembly disintegrated", can you elaborate? I might have a part or two to help you out.

How did you set the timing? - You need to have the engine at operating temp, disconnect the coolant temp sensor, then set the timing. There are 2 sensors 1 for the gauge and one for the computer so be certain to get the correct one.
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I haven't set the timing yet. The light assy literally began falling apart in my hand. I was unable to it back in the truck.

I didn't think that sounded right about the regulator. I'll check the regulator itself and see if its bad
 
if the bulb holder itself is still ok and it will hold a bulb you should be able to at least flash the codes.
 
Can you send me a better resolution diagram, or post a link to where you got that?

You don't even need to get under the dash. You have the diagram, get to the computer, identify the lamp wire, and just splice into it.
 
Ok. Update: checked regulator. No leaks or dribbles and no trouble codes. Got a 55 with signals "no error codes"
 
check the vaccum hose to the map sensor, those things will run pig rich if there is an issue there.
 
Didn't work. I've replaced ALL the vacuum lines and it still runs really rich. Still no trouble codes present. I'm about to put a 4bbl on it an say F*** it...
 
Run some fuel injector cleaner through it. Also, spray the throttle body inside, let it soak in, then spray a bunch more while it's running.

Some of the fuel injected racers have some kind of sensor or something in the throttle body that needs to be cleaned periodically. I'm not into FI and forgot what it is! :(
 
Locomotion said:
Run some fuel injector cleaner through it. Also, spray the throttle body inside, let it soak in, then spray a bunch more while it's running.

Some of the fuel injected racers have some kind of sensor or something in the throttle body that needs to be cleaned periodically. I'm not into FI and forgot what it is! :(
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I run Lucas through it religiously. I thought about having a professional fi cleaning done
 
Do the early magnums have the plate on the bottom of the intake manifold if so that is prone to leak vacume.

Brian
 
If I remember correctly, the temp sensor controls mixture, you might use an ohm meter an plumb part of an old plug wire in the temp sensor circuit...
 
abody said:
If I remember correctly, the temp sensor controls mixture, you might use an ohm meter an plumb part of an old plug wire in the temp sensor circuit...
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I'll see if I can find multi meter test procedures.
 
67Dart273 said:
Can you send me a better resolution diagram, or post a link to where you got that?

You don't even need to get under the dash. You have the diagram, get to the computer, identify the lamp wire, and just splice into it.
Click to expand...

How's this
 

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.................U may need to change the engine coolant temperature sensor[should be grey color] which is what the computer reads the black 1 is what the temp gauge in the dash reads..........I;ve also seen the front 02 sensor cause this problem...........kim.........
 
oldkimmer said:
.................U may need to change the engine coolant temperature sensor[should be grey color] which is what the computer reads the black 1 is what the temp gauge in the dash reads..........I;ve also seen the front 02 sensor cause this problem...........kim.........
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That didn't work. Anyone know if my TBI dizzy will work with a 4 barrel
 
Back in the day we used to see issues with the coolant temp sensor the O2 sensor and the egr. Used to do all three and then a battery disconnect to reset the computer.
 
The EGR would hang open a little which would lower the vacum signal to the map sensor. The computer sees lower vacum and adds more fuel.
 
Tech857 said:
The EGR would hang open a little which would lower the vacum signal to the map sensor. The computer sees lower vacum and adds more fuel.
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Yea. They unhooked the egr and crimped the line going to it. I figure that's a lot of the issue. The smog pump is non existant. So I'm not even goin to worry about chasing gremlins. I picked up an Eddie 1405 that's missing the choke for $25. I'm just gonna hunt for a CHEAP 4 barrel intake
 
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