Final tune, Need help Options

[Morph914]

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.
I’m hoping to rally any troops in the north Florida area to help me get these final details ironed out.

Thanks in advance,
John

[JamesM]

SET RUNNING FUEL PRESSURE BEFORE ANYTHING ELSE.

The ECU knob only impacts mixture at idle (assuming your TPS is good) The way I normally set that is to get the car fully warmed up, let it idle, start with it on the rich side and then lean it out (turn knob counter clockwise) until the engine starts to hunt and then turn it back clockwise 2-3 clicks. You may want to rev it a couple times in between adjustments of the knob to see where it settles.

Rough idle when cold? is your AAR kicking up the idle speed when cold as it should? guessing it either isnt or your idle mixture isnt ideal.

Stuttering under load? That one is a little tougher to guess at without more information or seeing what the car is doing. Could be a lot of things but if your fuel pressure is adjusted properly and you dont have any restrictions in fuel flow then you may be looking at a bad/futzed with MPS, or possibly bad TPS. Other than fuel pressure there is no adjustment that is supposed to be occurring on d-jet that would affect mixture under load.



Good Luck! Looks like you have a really clean setup there.

[emerygt350]

Looks gorgeous. None of those things besides fuel pressure will help you assuming the tps was installed correctly. Hopefully someone close can pop by. If you want to do the basics yourself, go to a flaps and rent a fuel pressure gauge, make sure it is 29lbs. Make sure the timing is good. Do you know what they set the 123 to? Is it Bluetooth or pot? That alone could be your problem. I see the advance port on the throttle body is plugged.

[Morph914]

SET RUNNING FUEL PRESSURE BEFORE ANYTHING ELSE.

The ECU knob only impacts mixture at idle (assuming your TPS is good) The way I normally set that is to get the car fully warmed up, let it idle, start with it on the rich side and then lean it out (turn knob counter clockwise) until the engine starts to hunt and then turn it back clockwise 2-3 clicks. You may want to rev it a couple times in between adjustments of the knob to see where it settles.

Rough idle when cold? is your AAR kicking up the idle speed when cold as it should? guessing it either isnt or your idle mixture isnt ideal.

Stuttering under load? That one is a little tougher to guess at without more information or seeing what the car is doing. Could be a lot of things but if your fuel pressure is adjusted properly and you dont have any restrictions in fuel flow then you may be looking at a bad/futzed with MPS, or possibly bad TPS. Other than fuel pressure there is no adjustment that is supposed to be occurring on d-jet that would affect mixture under load.



Good Luck! Looks like you have a really clean setup there.

Thanks, I’ll start with the purchase of a fuel pressure tool

[Morph914]

Looks gorgeous. None of those things besides fuel pressure will help you assuming the tps was installed correctly. Hopefully someone close can pop by. If you want to do the basics yourself, go to a flaps and rent a fuel pressure gauge, make sure it is 29lbs. Make sure the timing is good. Do you know what they set the 123 to? Is it Bluetooth or pot? That alone could be your problem. I see the advance port on the throttle body is plugged.

I set the 123 to the #1 setting, it’s the non Bluetooth unit.

[Van B]

Looks gorgeous. None of those things besides fuel pressure will help you assuming the tps was installed correctly. Hopefully someone close can pop by. If you want to do the basics yourself, go to a flaps and rent a fuel pressure gauge, make sure it is 29lbs. Make sure the timing is good. Do you know what they set the 123 to? Is it Bluetooth or pot? That alone could be your problem. I see the advance port on the throttle body is plugged.

I'm not gonna lie. I stopped reading the thread and just gazed upon the beauty of that restored engine (IMG:style_emoticons/default/grouphug.gif)

[emerygt350]

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.

[BeatNavy]

There could be a number of things going on, but JamesM is always a great source on FI knowledge and troubleshooting.

Having said that, it won't run right until you get the proper tune selected for your 123 based on your specific FI setup (ECU, throttle body, etc.) AND get the timing dialed in. When I was running my 123 I was using curve "B" and retard only as my FI components were basically correct for a '74. I can't remember when curve "1" is correct, but you need to verify if that's correct for you. 123's are great once you navigate a couple of initial installation challenges.

There are a couple of good threads out there on this, including this one: http://www.914world.com/bbs2/index.php?showtopic=324473

That engine and engine bay are beautiful (IMG:style_emoticons/default/beer.gif)

[JamesM]

There could be a number of things going on, but JamesM is always a great source on FI knowledge and troubleshooting.

Having said that, it won't run right until you get the proper tune selected for your 123 based on your specific FI setup (ECU, throttle body, etc.) AND get the timing dialed in. When I was running my 123 I was using curve "B" and retard only as my FI components were basically correct for a '74. I can't remember when curve "1" is correct, but you need to verify if that's correct for you. 123's are great once you navigate a couple of initial installation challenges.

There are a couple of good threads out there on this, including this one: http://www.914world.com/bbs2/index.php?showtopic=324473

That engine and engine bay are beautiful (IMG:style_emoticons/default/beer.gif)

(IMG:style_emoticons/default/agree.gif)
and thanks!

Need the proper setting on the 123dizzy and the vac port should be retarding on manifold (not ported) vacuum. "B" is what i run on my 74 as well.

[emerygt350]

It is an interesting mix, can't wait to hear what year it is. I say early early 74.

[Morph914]

Looks gorgeous. None of those things besides fuel pressure will help you assuming the tps was installed correctly. Hopefully someone close can pop by. If you want to do the basics yourself, go to a flaps and rent a fuel pressure gauge, make sure it is 29lbs. Make sure the timing is good. Do you know what they set the 123 to? Is it Bluetooth or pot? That alone could be your problem. I see the advance port on the throttle body is plugged.

I'm not gonna lie. I stopped reading the thread and just gazed upon the beauty of that restored engine (IMG:style_emoticons/default/grouphug.gif)

Thank you, now if I can just get it dialed in.

[Morph914]

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 ‘73 2.0, it originally had a 1.7

[emerygt350]

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 ‘73 2.0, it originally had a 1.7

Ahh! That explains the advance port on the TB. My 73 has the same dizzy and it really likes the advance port attached (to the correct port on the TB) but you do need to make sure the timing is good. I do it by feel, idle, and performance, then double check with a light. Mine is on #1 with advance connected, very happy. Is it a big difference between advance and not? No, but I like it. I am running about 36-37 all in currently. Engine is running cool and AFR looks good. Idles at 900 (well, at least that is what the gauge says). No stumbles anywhere. This is a 9/72 build date GA engine. I tried running the retard setting, and it worked fine, but no real point in doing that.

29 psi on the fuel pressure gauge.

[JamesM]

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 ‘73 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.

[emerygt350]

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 ‘73 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 you 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.

Yikes, yeah, hopefully it is just the snorkel. I saw that strange plugged port and wondered about that. A quick look at the CHT for a resistor in line might help, so would a look a the ECUs number. I think I would get the number off the block, check the CHT, and check the computer. Does it have a PCV valve or is it passive? All of those things will help determine what you are working with.

James, 73 had retard and advance on the 009, it's choose your own adventure with the 123. You can go for #1 and hook it to the ported vacuum or put it on A and go for the retard port. Unless you are having issues with a high idle, there is no reason to mess with the retard side of things.

[Morph914]

Ok, a lot of investigating to be done. (IMG:style_emoticons/default/idea.gif) I can tell you that the ECU that came with the 2.0 was not working so I swapped the one that was on the original 1.7 and it worked. I’ll get the #s off of everything and report back.
The air cleaner that came with the 2.0 looks to be for a late model with smog. This will have to do until I can locate the correct unit.

[BeatNavy]

You're using the ECU off a 1.7 on a 2.0? It will run, as in fire the injectors, but it's a mismatch and will never be properly tuned. You need to make sure in particular that the ECU and MPS are matched properly for a 2.0 engine: https://members.rennlist.com/pbanders/DJetP...m#Compatibility

You also need to make sure your CHT / ballast resistor setup is matched to the ECU (assuming you get a '73 setup).

Correct matching for early '73 setup is an 037 ECU with an 037 MPS and the proper ballast resistor (IIRC).

[914_teener]

My bet is on fuel pressure or fuel delivery.

But listen to what James or Rob adds. They've BTDT.

That is quite the engine bay.


Check fuel pressure first.....and make SURE none of your fuel lines are kinked otherwise you will chase your tail.

You didn't say where the fuel pump is located.....in the front?


Good luck.

[friethmiller]

@Morph914 - Damn that's a nice engine bay! It reminds me of mine but you've got FI and it's nicer (IMO)! Great job!

[914_teener]

Oh...I just noticed...did you check your vaccum line routing? Go to Jeff Bowlsby website and check.

Maybe its an optical illusion but the vaccum hose routing to the De-cel valve doesn't look right.

What are your D-jet components matched for? A 73 2L or 74?


Edit....Ooppps Rob's already asked that.