Injector Swap - now low load stumble

Blown88GT

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Nov 13, 1999
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#1
Changed 30lb injectors to 47's. 30's were Duty Cycle at 100%.
Updated Required Fuel, DT, & BCV to the new injectors.
Starts & idles same as before. Went for a drive & now seems like a low load miss or stumble until the rpm's rise.
Ran & updated with VEAL, no change.
I have a datalog, but don't know what to look for.
I can see the rpm's drop to 353 rpm at time stamp 69.076s.
Duty cycle drops to 1.3%.
I'm thinking I have to change Squirts per Engine Cycle from 4 to 2?
 

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a91what

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#2
OK can you get me a datalog without VEAL running? also a copy of the tune file.

This is what i see from the datalog, Assuming you are running MAF/MAP as i can see both load parameters in the log file. When the engine goes into decel the AFR goes very lean [no bit# on status 1 in the datalog so i know you are not using overrun fuel cut] [status 2 bit #128 shows cl idle takes a long time to activate as well] This lean spot does not clear up until the rpms come up even though I can see the tps% come up [this means that the transition into load is not set right]. Looks to me you may need to alter the Accel pump settings
-make sure end PW is 0
-make sure the decel Fuel % is set at 100%

Now we need to look at the MAF table to see if there is more we can do. But first check out this snip from your datalog.
Blown88GT stumble issue.PNG
 

a91what

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#3
The stumble issue you noticed at your time stamp looks like it may be the idle going below the cranking RPM threshold if you have it set that low... that one is odd.. you can see the spark: spark advance drop from 16 to 11 and the spark: base spark advace drop to -3... basically it dropped to the cranking advance setting......
I see nothing in the status blocks showing loss of anything... maybe check that the spout is in tightly, this can be tested to see if the spark advance drops to the cranking advance.
let me know what you find
 

Blown88GT

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Nov 13, 1999
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#4
It started raining, so can only do idle in the garage. Rqdar shows just one cloud stuck over me!!
Some of these issues probably have been there all along, before the injector change.
Takes me a little extra time to synchronize the tablet in the car with the desktop in the house, where I can type this and actually see the tune & datalog. My eyes are getting very bad.
Now have it running on 2 squirts & changed the AFR table from 14.7 to 14.5 on the lower rows.
BTW, had to recal TPS, it was way off.
Hope datalog is useful.
 

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Blown88GT

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Nov 13, 1999
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Palm Beach Gardens, FL
#6
...
1. OK can you get me a datalog without VEAL running? also a copy of the tune file.
2. This is what i see from the datalog, Assuming you are running MAF/MAP as i can see both load parameters in the log file.
3. When the engine goes into decel the AFR goes very lean [no bit# on status 1 in the datalog so i know you are not using overrun fuel cut]
4. [status 2 bit #128 shows cl idle takes a long time to activate as well] This lean spot does not clear up until the rpms come up even though I can see the tps% come up [this means that the transition into load is not set right].
5. Looks to me you may need to alter the Accel pump settings
6. -make sure end PW is 0
7. -make sure the decel Fuel % is set at 100%
8. Now we need to look at the MAF table to see if there is more we can do. But first check out this snip from your datalog.
Now want to address alll your questions:
1. 10" screen is hard for me to see.
2. Yes, using both.
3. Yes, always done this.
4. Yes, it does take a long time.
5. Re-cal'd TPS.
6. Where to look? Found it (Time Based Enrichment), small window has always hidden all the settings at the bottom All I ever saw was the graphs above the settings. Always been 0.5.
7. It's always been 95.
8. MAF curve is from C&L flow bench data.
 
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a91what

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#8
min inj. pulse diff
between 30s & 47s
:think:
Most injectors min pw is around 1.1-1.3

Now this is a batch fire application so there are multiple spray events per bank, by reducing the event# the pw will increase for the same fuel delivery.
 

a91what

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#9
#6 and #7 are both found in the accel enrichment settings.
I will have to be more detailed later tonight, off to trim trees.
 

Blown88GT

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#10
#6 and #7 are both found in the accel enrichment settings.
I will have to be more detailed later tonight, off to trim trees.
I found it, thanks. I edited the post above.
I did that last week, & yesterday planted a potted Christmas tree found at the curbside trash.
 

Blown88GT

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Nov 13, 1999
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Palm Beach Gardens, FL
#11
Most injectors min pw is around 1.1-1.3
Now this is a batch fire application so there are multiple spray events per bank, by reducing the event# the pw will increase for the same fuel delivery.
Nope, not either of these.
Yes, batch fire. By reducing # of squirts from 4 to 2.

BTW, here is the link to all the Ford Injector Calibration data.
Scroll down to see the links.
https://performanceparts.ford.com/part/M-9593-LU47

How to calculate instead of measure is here (Megasquirt Deadtime Calculator):
Can't link to Google Sheets??
Have to click the link in the small print at the end.
View: https://docs.google.com/spreadsheets/d/10c8Iy5SUUmVkLgrrrDhnDFFpDzghk93XajWRFWStqG4/edit?usp=sharing
 
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a91what

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#12
Nope, not either of these.
Yes, batch fire. By reducing # of squirts from 4 to 2.

BTW, here is the link to all the Ford Injector Calibration data.
Scroll down to see the links.
https://performanceparts.ford.com/part/M-9593-LU47

How to calculate instead of measure is here (Megasquirt Deadtime Calculator):
Can't link to Google Sheets??
Have to click the link in the small print at the end.
View: https://docs.google.com/spreadsheets/d/10c8Iy5SUUmVkLgrrrDhnDFFpDzghk93XajWRFWStqG4/edit?usp=sharing
Yes, I use the same spreadsheet. I also use the lu47 injectors they are what I always recommend for up to 800hp.
 

Blown88GT

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Nov 13, 1999
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Palm Beach Gardens, FL
#13
Yes, I use the same spreadsheet. I also use the lu47 injectors they are what I always recommend for up to 800hp.
I created the predecessor of the spreadsheet. He took it to a new level.
Ford no longer makes the Jetronic to USCAR (M-14464-A8) adapters.
https://performanceparts.ford.com/part/M-14464-A8
450hp is the max I will make. Doesn't seem like a lot now, was crazy a lot 25 years ago.
Air-to-air intercooler makes all the difference, even with 2 psi drop across it.
 

a91what

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#14
I usually suggest people splicing in the new pigtails, I have had connection issues personally with the adapters.
 

a91what

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#15
It started raining, so can only do idle in the garage. Rqdar shows just one cloud stuck over me!!
Some of these issues probably have been there all along, before the injector change.
Takes me a little extra time to synchronize the tablet in the car with the desktop in the house, where I can type this and actually see the tune & datalog. My eyes are getting very bad.
Now have it running on 2 squirts & changed the AFR table from 14.7 to 14.5 on the lower rows.
BTW, had to recal TPS, it was way off.
Hope datalog is useful.
Was this datalog done with the spout removed??? anything special? basically the ecu is in startup mode for timing....
 

Blown88GT

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Nov 13, 1999
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#16
Spout hasn't been removed in years.
What kind of datalog would be best: cold start to warm idle, cold start to drive away (faster warmup), warm running?
Engine died a couple times, more than it should have.
I had no problems with the 30's.
Maybe one of the adapters isn't making a good connection?
How to connect a noid light without removing upper intake?
418IQTdxyYL.jpg
 

a91what

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#17
No I believe it's another issue and not tune related.... maybe check the electrical connectors salt and pepper shakers and the TFI.
The issue is the timing is defaulting to 11 no matter the rpm it seems... in the last datalog you sent it showed base spark advance to be -3....

I will be honest this is odd. I have not checked the rev limiter settings..
 

Blown88GT

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Nov 13, 1999
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Palm Beach Gardens, FL
#18
I think you're right. Previous tune may not have been perfect, but it worked.
S&P did have to get out of the way to remove the upper, maybe something broke?
Didn't touch the distributor. Base spark advance of -3 is weird. The datalog from the hour before is fine as is the one from the day before.
Visual under hood inspection has revealed nothing, so far.
This may explain why the engine didn't want to start the last few times. Thought it was the change to 2 squirts, kept switching back & forth until it finally started.
Now have to figure out the cause. This sucks!

Going for a bike ride now, will try again later.
 

Blown88GT

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Nov 13, 1999
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Palm Beach Gardens, FL
#19
.... maybe check the electrical connectors salt and pepper shakers and the TFI.
The issue is the timing is defaulting to 11 no matter the rpm...
Nothing from ignition goes through salt and pepper shakers.
S&P pinout.gif


Distributor harness goes beneath upper intake. One of the vacuum hose was jammed up in there, maybe this one still is?
Looks like the best way is to check continuity from the TFI connector back to the 60-pin.
UPDATE: 56, 36, 16 all checkout as good back to ECU.
Ford PIP System.gif
 
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Blown88GT

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Nov 13, 1999
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Palm Beach Gardens, FL
#20
I'm running out of ideas, don't know where to go from here.

The DIYPNP has a couple unique functions.
1. a 12 volt jack that allows you to power the DIYPNP without plugging it into your wiring harness.
2. a little step-up circuit on the F60 adapter board for TFI ignition control. This takes the 5 volt IGN signal, inverts it, and steps it up to 12 volts for TFI distributors. The transistor is designated Q1A, PN2222AD26ZCT-ND

I don't like coincidences but...
It's possible that Q1A has failed. My o-scope has a 5V square wave calibration signal. I can use this to see if Q1A is functioning by using the same dual channel o-scope to watch the signal in & out.
 

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