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ECMlink 1995 GST Will not idle after FIC 1000cc install.

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Gs98Gs99

Probationary Member
12
5
Oct 13, 2016
Carthage, Tennessee
As stated my 1995 GST will not idle after I installed a set of FIC 1000cc injectors.
The car will start, run for a few seconds and then then die.

I have verified that I have got the injbatadj set correctly. I have new plugs and plug wires, verified I have 43 psi fuel pressure while cranking as well.

I am running a 97 ECU with ECMLink v3 and a 97+ CAS, plug wires are wired up in the factory config and I have swapped the injector plugs per the ECMLlink writeup to run a 97 ecu in a 95. I have attached a log of the car starting then stalling. The car ran before the injector swap but I have not tried to re-install the stock injectors due to the new pigtails being soldiered in.
 

Attachments

  • log.2022.12.05-01.elg
    18.8 KB · Views: 32
I only had a quick second to look but you have both injbatadj and deadtime in the fuel tab set, it's usually one or the other, not both.

These are hi-Z I'm assuming? You installed the resistor delete?
 
Please don't modify InjBatteryAdj and set a global deadtime adjustment. They get added together. If the InjBatteryAdj values are correct the global adjustment would be 0.

You're also adding fuel with CoolantTempFuelAdj and CrankingFuelAdj resulting in a huge 17ms Injector pulse width when your cranking. Try getting it to start with the stock settings.

Your battery also needs a charge.
 
I've got a year's worth of experience tuning these exact injectors on my 2G, they are absolute garbage and are NOT true 1000cc as stated. You can debate me all you want but I have exhausted many trials and attempts to tweak them, they simply run too lean if you set them at 1000. I have found they are fairly accurate at -48.4% or ~863cc.

The InjBattery Adjust values in ECMlink's website are also very outdated and a ROUGH starting point. The values we are mostly interested in are the 9, 12 and 14 volt ranges. 9v is important to get somewhat right because most of the time as soon as you start cranking, the voltage drops significantly sometimes as low as 9 or 10. If you have a wacky value at the 9 volt range, you will have very long cranking times. I suggest a value of 1900 at 9 volts. At 12 volts you can leave it at the sheet specified 1230. At 14 volts I have personally input 1000 however this is after very long testing and also using Global Deadtime (+280). I know Steve is right; whatever you put into global simply gets added onto those other values, but it's not so white or black, it's actually a very gray area and I have gotten enough experience with these injectors and ECMlink during the past year that I can argue this.

Basically, without going into too much detail: We modify the InjBatteryAdjust table by inputting the injector manufacturer's settings because those settings are allegedly when they will flow closest to what they are marketed as. But newsflash, every car is different, every injector itself is different no matter how well they match them and manufacturers simply lie about flowrate so you will still be a good bit off their TRUE spec on your specific setup. That is why SLIGHT modification of that table is REQUIRED on every car. The way you know how to adjust it (again, mostly the 9,12,14 volt ranges) is by doing WOT pulls and combining your air compensation (or SD) along with incremental increases or decreases to the latencies. What I mean is, you are adding or subtracting fuel at WOT by lowering or increasing those latencies. Higher injector deadtime (latency) means MORE FUEL. When you get some logging data you can start to configure it and see how the injectors will react and affect your AFRs at WOT.

Now, GLOBAL deadtime is what you use to get your idle set right as well as your cruise/closed loop tune. Example is, car is idling, you want 850 RPMs solid and a 15.0:1 AFR, however your actual wideband AFR is somewhere in the 16 range and thus your Airflowperrev is 0.30g/s or more. This is a clear indication that you are running lean due to injectors not sized right AND/OR latency is too low (not enough time for them to deliver the proper amount of fuel). In such a case, what I would do is have the car warmed up and idling, and increase the global deadtime from 0 to 100 right off the bat. That will immediately get your AFRest and Wideband AFR much closer together, and your airflowperrevs will drop substantially (target is 0.25g/s don't question why).

Now, and this is VERY IMPORTANT PLEASE READ!. This is the moment where you go BACK to your injector battery adjust table and SUBTRACT however much you just increase your global latency by from your 9, 12 and 14 volt ranges. This is because you want to keep your idle configuration separate from your WOT settings. So if your 12 volt value was at 1230 and you increased global by 100, it would have become 1330 permanently, which would have made your cruise richer, which can then spiral into a never ending adjustment of all the above settings. It took me a LONG time to figure this out on my own because everyone was suggesting different tuning methods and I was chasing my tail. So, to reiterate: However much you increase your global by, subtract it from your latency table.

If you simply used Global Deadtime to adjust your total fueling, for these 1k FICs you'd end up with something like 800+ deadtime which MAY WORK at say WOT (13.8-14.3 volt range) but might be overfueling on cranking voltages or vice versa. This is why both settings need to be tweaked simultaneously but with equalization in mind. This way you can guarantee your idle will be good and within range, while your WOT fueling remains stable and only needing Speed Density tweaks or MAFComp adjustment.

I hope this makes sense, there is way more to it but with time you will get the hang of it. Personally I wish I never spent the money on these and would have rather gotten some 650s or 750cc units for my build.

P.S Injector deadtimes start to get affected by diminishing returns at high latencies such as at WOT. At Wide Open Throttle, the injector is almost permanently open HOWEVER you can still affect its behavior and fuel delivery by tweaking the table. But it's most important to get it right for your cranking, idle and closed loop cruise operation.
 
I only had a quick second to look but you have both injbatadj and deadtime in the fuel tab set, it's usually one or the other, not both.

These are hi-Z I'm assuming? You installed the resistor delete?
Thanks for the info. I have tried starting it with the global and deadtime set to stock with the same results. It will start for a second then stumble. And then refuse to start at all.
And yes they are hi-Z I have done the delete myself by soldering the 5 leads together and removing them from the pack.

Please don't modify InjBatteryAdj and set a global deadtime adjustment. They get added together. If the InjBatteryAdj values are correct the global adjustment would be 0.

You're also adding fuel with CoolantTempFuelAdj and CrankingFuelAdj resulting in a huge 17ms Injector pulse width when your cranking. Try getting it to start with the stock settings.

Your battery also needs a charge.
Thanks for the input, I will reset the injbatteryadj to stock and try again.
The guy I had trying to remote tune the car set up the coolantTempFuelAdj and the CrankingFuelAdj I will reset those as well as top the battery off before posting another log
 
Basically, without going into too much detail: We modify the InjBatteryAdjust table by inputting the injector manufacturer's settings because those settings are allegedly when they will flow closest to what they are marketed as. But newsflash, every car is different, every injector itself is different no matter how well they match them and manufacturers simply lie about flowrate so you will still be a good bit off their TRUE spec on your specific setup. That is why SLIGHT modification of that table is REQUIRED on every car. The way you know how to adjust it (again, mostly the 9,12,14 volt ranges) is by doing WOT pulls and combining your air compensation (or SD) along with incremental increases or decreases to the latencies. What I mean is, you are adding or subtracting fuel at WOT by lowering or increasing those latencies. Higher injector deadtime (latency) means MORE FUEL. When you get some logging data you can start to configure it and see how the injectors will react and affect your AFRs at WOT.

Now, GLOBAL deadtime is what you use to get your idle set right as well as your cruise/closed loop tune. Example is, car is idling, you want 850 RPMs solid and a 15.0:1 AFR, however your actual wideband AFR is somewhere in the 16 range and thus your Airflowperrev is 0.30g/s or more. This is a clear indication that you are running lean due to injectors not sized right AND/OR latency is too low (not enough time for them to deliver the proper amount of fuel). In such a case, what I would do is have the car warmed up and idling, and increase the global deadtime from 0 to 100 right off the bat. That will immediately get your AFRest and Wideband AFR much closer together, and your airflowperrevs will drop substantially (target is 0.25g/s don't question why).

Now, and this is VERY IMPORTANT PLEASE READ!. This is the moment where you go BACK to your injector battery adjust table and SUBTRACT however much you just increase your global latency by from your 9, 12 and 14 volt ranges. This is because you want to keep your idle configuration separate from your WOT settings. So if your 12 volt value was at 1230 and you increased global by 100, it would have become 1330 permanently, which would have made your cruise richer, which can then spiral into a never ending adjustment of all the above settings. It took me a LONG time to figure this out on my own because everyone was suggesting different tuning methods and I was chasing my tail. So, to reiterate: However much you increase your global by, subtract it from your latency table.

If you simply used Global Deadtime to adjust your total fueling, for these 1k FICs you'd end up with something like 800+ deadtime which MAY WORK at say WOT (13.8-14.3 volt range) but might be overfueling on cranking voltages or vice versa. This is why both settings need to be tweaked simultaneously but with equalization in mind. This way you can guarantee your idle will be good and within range, while your WOT fueling remains stable and only needing Speed Density tweaks or MAFComp adjustment.

I hope this makes sense, there is way more to it but with time you will get the hang of it. Personally I wish I never spent the money on these and would have rather gotten some 650s or 750cc units for my build.

P.S Injector deadtimes start to get affected by diminishing returns at high latencies such as at WOT. At Wide Open Throttle, the injector is almost permanently open HOWEVER you can still affect its behavior and fuel delivery by tweaking the table. But it's most important to get it right for your cranking, idle and closed loop cruise operation.

Your last sentence is important to the discussion and a clue why I disagree with the rest.

At idle and low loads the injector pulse width is short, a couple ms, and the deadtime is a large portion (percentage) of the IPW. At WOT the IPW is large, assuming your injectors are sized to have a duty cycle no more than 85% of the available cycle time at you WOT RPM. The contribution of deadtime to those IPWs is small. We already agreed that Deadtime in DSMLink is the sum of InjBatteryAdjust(voltage) + Global Deadtime so whatever that sums to is going to be what the ECU uses when deciding the IPW for the current load, target AFR, and any enrichments. Assuming you have your airflow measurements correct (a whole nother story) you adjust AFR in closed loop with the deadtimes and adjust the AFR at WOT with the fuel injector size setting going back and forth to dial both in. More later I have a call....
 
Last edited:
So the car is still not idling, I reset the InjBatteryAdj, CoolantTempFuelAdj and the CrankingFuelAdj back to stock values as well as top charged the battery.
 

Attachments

  • log.2022.12.13-02.elg
    12.4 KB · Views: 26
In your most recent log the airflow shows as 0.0 when the engine is running at about 1300 rpm. I don't know why. It should be about 1.7 lb/m at that condition.
When you are cranking it shows 0.5 lb/m which is about right. But then as soon as the engine fires and starts running the airflow number drops to 0.0!
 
In your most recent log the airflow shows as 0.0 when the engine is running at about 1300 rpm. I don't know why. It should be about 1.7 lb/m at that condition.
When you are cranking it shows 0.5 lb/m which is about right. But then as soon as the engine fires and starts running the airflow number drops to 0.0!
Thanks for the input, I tried re-installing the stock maf and now it will idle. Weird that on SD it would barely hit then die. Now I just need to get the fuel close so I can figure the SD issue. The first log is running on stock Inj. values, second log is running on ECM Link's suggested values for FIC 1,000's
 

Attachments

  • log.2022.12.20-01.elg
    20.4 KB · Views: 18
  • log.2022.12.20-05.elg
    88.7 KB · Views: 28
The 20-05 log is much better than the 20-01. In the 20-01 it's too rich (too much InjOn time) and it's hardly running.

In the 20-05 it does go into closed loop after about 1 minute which is good but the AEMWBGauge appears to not be working, and that results in the O2 (front) to not cycle up and down, because you are simulating narrow band. So your closed loop isn't going to be really working. This is 2 minutes after the cold start and it should probably be working by then.

The AEMWBGauge "Raw volts" is kind of stuck at 4.33 most of the time during the 2nd minute. It does read closer to normal in the first minute. Stuck at 4.33 all the time would mean it's dead. Seems like yours dies after it heats up?

The other thing that goes flooey in the second minute is the ISC steps. During the first minute they start high and trend downward like they should. Then in the second minute they trend up again, all the way to 120, which is not right since it is not dead cold anymore and it is idling a few hundred rpm above target idle.

It would be better if you could put an actual narrowband in for the O2 instead of simulating it.

Is your wideband one of the older model AEM's?
 
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