Final tune, Need help |
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Final tune, Need help |
Morph914 |
Mar 23 2022, 12:34 PM
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#1
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Member Group: Members Posts: 435 Joined: 22-August 16 From: St Augustine, FL Member No.: 20,326 Region Association: South East States |
Ok , so I have the engine running but it needs tuning. A little background, rebuilt stock 2.0 with D Jet, running a 123 dizzy. It fires right up and idles a little rough at first then smooths out. It revs fairly well and sounds good. The problem starts under load, it starts to stutter a bit.
I have not messed with the adjustment screw on the ECU or tried adjusting the throttle position sensor, or been able to check my fuel pressure. Iām hoping to rally any troops in the north Florida area to help me get these final details ironed out. Thanks in advance, John |
emerygt350 |
Mar 23 2022, 02:08 PM
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#2
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Advanced Member Group: Members Posts: 2,146 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
No kidding. Looks like new. Maybe better.
1 should be fine as long as the port on the distributor isn't going anywhere. Is there a vacuum line on the dizzy? It may not have a port, depends on the model of 123. |
Morph914 |
Mar 24 2022, 06:33 AM
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#3
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Member Group: Members Posts: 435 Joined: 22-August 16 From: St Augustine, FL Member No.: 20,326 Region Association: South East States |
No kidding. Looks like new. Maybe better. 1 should be fine as long as the port on the distributor isn't going anywhere. Is there a vacuum line on the dizzy? It may not have a port, depends on the model of 123. There is a port on the dizzy, I have been experimenting with it on and off, seems to run better with it off. The engine is an early ā73 2.0, it originally had a 1.7 |
JamesM |
Mar 24 2022, 09:20 AM
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#4
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Senior Member Group: Members Posts: 1,915 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
There is a port on the dizzy, I have been experimenting with it on and off, seems to run better with it off. The engine is an early ā73 2.0, it originally had a 1.7 Its probably running better with it off as the 123dizzy should be retarding rather than advancing the timing on vacuum. On a stock setup the vacuum retards the timing at idle and overrun. Timing should be checked with the vac line disconnected @ 3500 RPM to the 27 deg mark on the fan. Set the 123 to the A or B curve and make sure the port it is connected to is below the throttle plate, the port that is seeing vacuum at idle. This will most likely cause your idle speed to drop quite a bit which you will need to compensate for by opening the air bypass screw on the throttle body which will then also probably require a minor adjustment to your idle mixture knob as well. This may help your cold idle as well but... You mentioned your motor is an early 73, looks like your airbox isnt though so it makes me wonder if you may have other part mismatches going on. Early 73 2.0s I find are a little more temperamental when it comes to parts as they were a very unique setup (hack) from the factory and the temperature curve on the sensor is very different than all other years. Need to be sure your MPS, ECU, and Head Temp Sensor all match for the year, either 73 or 74 and that if they are 73 you also need to be sure you have the inline resistor to the head temp sensor. |
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