D-Jet Fuel Injection Help, Loss of Power with Warm Engine Options

[Mblizzard]

I have a 1973 2.0 built to a 2056 running stock fuel injection. I am running points and I have verified the dwell and timing are correct. The air temperature sensor on the throttle body is disconnected due to it causing the engine to hunt excessively at idle. The valve were set less than 500 miles ago.

The car starts and runs fine on initial start. It at times has a little hesitation on acceleration due to the wear on the TPS board I think. As the engine warms up into the normal range, I experience a significant loss of power. The temp never goes past the "M" on the temp gauge. There is never any pinging. But there is just no instant response to pressing the accelerator that is present when the engine is cool. At times pushing the accelerator results in little or no engine response for a brief period and the engine almost stalls.

I have checked numerous times for vacuum leaks, lose wires, and made sure the grounds are good. Checked the plugs and it does not appear to be running rich or lean.

I tried to calibrate the TPS according to the Pelican article but never really got the readings as indicated in the article.

I am going to go back through it one more time but I need some suggestions as to what I should check next?

[r_towle]

did you recalibrate your MPS?

Do you have a knob on top of the ECU?
If you do, turn it off, all the way.

Rich

[Cap'n Krusty]

I don't think idle CO adjustment is gonna solve his problem ....................

The Cap'n

[Mblizzard]

did you recalibrate your MPS?

Do you have a knob on top of the ECU?
If you do, turn it off, all the way.

Rich

Have not redone the MPS. But while I am sure that will help overall, it does not seem like the MPS would cause this issue.

[TheCabinetmaker]

If you don't get that tps adjusted right, you'll always have that hesitation. The knob on the ecu will have no effect either. Do you have a wide band O2?

Here's a quick fix on that tps:

Use 1000 grit wetordry and sand the traces on the board where the marks are. They are thicker than they appear. Use polishing compound and alcohol to finish up. Then try again to calibrate it.

[TheCabinetmaker]

Have not redone the MPS. But while I am sure that will help overall, it does not seem like the MPS would cause this issue.

It would if it was too lean or too rich at WOT

[r_towle]

Have not redone the MPS. But while I am sure that will help overall, it does not seem like the MPS would cause this issue.

It would if it was too lean or too rich at WOT

or at transition.

[Mblizzard]

Have not redone the MPS. But while I am sure that will help overall, it does not seem like the MPS would cause this issue.

It would if it was too lean or too rich at WOT

OK just to be clear, I am asking the following question because I don't know the answer. I am not doubting your response. If I understand the MPS it essentially controls the length of the injector pulse based on manifold pressure. While there is a temp component in the overall system, the MPS does not change the pulse based on temp. Because this only occurs when the engine is warm, the MPS should be functioning correctly?

[Java2570]

Are you still running those fuel injectors with more flow? It would really, really benefit you to have a wideband AF meter in your car; it will give you an eye into what your mixture is doing when you have the loss of power happening.

[Mblizzard]

Are you still running those fuel injectors with more flow? It would really, really benefit you to have a wideband AF meter in your car; it will give you an eye into what your mixture is doing when you have the loss of power happening.

Yes on the injectors. Don't have access to a AF meter.

[JeffBowlsby]

All the engine FI sensors are used to calculate he pulse width, including temperatures (TS1 and TS2).

The TPS must be calibrated correctly, it has the idle switch and 'accelerator pump' functions that are also ECU signals.

It apparent that your MPS needs adjustment to adjust the air:fuel mix to the characteristics of your car, which can only be correctly done with an exhaust gas analyzer or wide band O2.

[TheCabinetmaker]

Mike, what cam?

[Mblizzard]

Mike, what cam?

Stock cam.

[r_towle]

To add to what Jeff said.

if your car is too hot, you would get more fuel....to keep it from melting.
This is the case with any fuel injection system.

More nowadays....you get limp home mode which is super rich.

Like jeff said...everything in the system, all the sensors are there to tell the ECU how long the pulse width needs to be.

The FI trigger points just tell it when to do it.
Everything else is for mixture.

So.....
The best way to figure it out is with an Air Fuel gauge stuffed up the tailpipe.

I use a portable one with 8 feet of cable.
Its an O2 sensor inserted in the tail pipe with a metal clip and a screw clamp to keep it in place (lost one on the road once)

I use masking tape and run the wires up to the gauge which sits on the passenger seat so I can see it...along with my tools.

I drive the car slow, fast, transition, long highway runs.
I drive and stop , tune the MPS, drive some more....

That is how I do it.

You can also ask for someone that has the more expensive equipment and knowledge to setup your MPS properly and bolt it back in place....

rich

[Mblizzard]

Ok so I took a closer look at the plugs and decided it was running lean. Made a few adjustments and now have a much nicer plug color. Runs much better but I will have to seek out someone with a AF meter to get it exact.

Ordered a TPS board and I think that will solve the hesitation as currently the injectors do not fire when the throttle is moved as they should.

And just for fun I hooked up the temp sensor on the throttle body. For some strange reason it runs fine now with it attached.

[worn]

OK just to be clear, I am asking the following question because I don't know the answer. I am not doubting your response. If I understand the MPS it essentially controls the length of the injector pulse based on manifold pressure. While there is a temp component in the overall system, the MPS does not change the pulse based on temp. Because this only occurs when the engine is warm, the MPS should be functioning correctly?

That depends on how well it really runs when it is cold. The enrichment part of the system could be masking problems that are caused by the MPS. A rich engine for example might run OK cold, or a lean one might be OK when the cold enrichment circuit is on and then not well when the engine warms up.

Did it run ok before? People are suggesting the MPS because often a 2056 needs a tweak at the MPS to go with the non-stock engine. But, if it ran fine before with the stock MPS then that isn't an issue for you.

[914_teener]

Ok so I took a closer look at the plugs and decided it was running lean. Made a few adjustments and now have a much nicer plug color. Runs much better but I will have to seek out someone with a AF meter to get it exact.

Ordered a TPS board and I think that will solve the hesitation as currently the injectors do not fire when the throttle is moved as they should.

And just for fun I hooked up the temp sensor on the throttle body. For some strange reason it runs fine now with it attached.

So what is your fuel pressure?

(IMG:style_emoticons/default/popcorn[1].gif)

[achman_73_2.0]

Watching this thread carefully, maybe it will help solve my high idle/low idle/pinging at higher rpm etc. etc issue

What is the correct advance to set timing on a 2056?

[Mblizzard]

Ok so I took a closer look at the plugs and decided it was running lean. Made a few adjustments and now have a much nicer plug color. Runs much better but I will have to seek out someone with a AF meter to get it exact.

Ordered a TPS board and I think that will solve the hesitation as currently the injectors do not fire when the throttle is moved as they should.

And just for fun I hooked up the temp sensor on the throttle body. For some strange reason it runs fine now with it attached.

So what is your fuel pressure?

(IMG:style_emoticons/default/popcorn[1].gif)

31 PSI.

[Mblizzard]

Watching this thread carefully, maybe it will help solve my high idle/low idle/pinging at higher rpm etc. etc issue

What is the correct advance to set timing on a 2056?

I have mine at the stock 27.