engine goes from rich to lean when elecrical load is applied

s300 and SManager software questions & answers
Alessio
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engine goes from rich to lean when elecrical load is applied

Post by Alessio » Fri Sep 28, 2012 8:10 am

I am having a really bad issue with the p28 s300. I had my tuner tune my freshly built turbo integra, it was a really hot day and also the turbo sucked hot air from underneath the hood. Altough my tuner had switched on his blower, my car's cooling fan would come also ON. engine was set up really well, idling at an afr of 15 (due to emissions test).

the next day I started the car up and found out that the engine was really running rich at 10afr!!, then I noticed that when the cooling fans switched ON, AFR would suddenly go back again to 15, and again when the fans turn OFF, AFR would go back down to 10 :(. First I thought I had an electrical problem with the fan, but I turned on my headlamps and fog lamps to apply an electrical load on the engine and the same thing happened, lights ON = 19afr, lights OFF = 10afr. and also on the smanager I was able to see that only injector duty and injector pule values were changing, when running rich, injector pulse = 2ms, running lean injector pulse = 1ms (as it should be when idling).

So till now these are the things I did:

* I have changed the battery to a new one.
* I have changed all ground cables and also added a ground cable from engine directly to the battery.
* I have set the dead times according Injector dynamics. (I am running 1000cc)

car starts and run rich at 10afr, idle is impressively stable, but when an electrical load is applied, car runs instantly lean at about 17-19afr

please help me out as I have no idea whats going on.

Alessio

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Hondata
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Re: engine goes from rich to lean when elecrical load is app

Post by Hondata » Fri Sep 28, 2012 8:40 am

It is hard to tell without a datalog, but using the ID supplied dead times are not correct and don't work very well. You need values much higher than what they supply - ballpark should be 1.25 ms @ 14V and 1.55 ms @ 12V.

However, you need to measure the voltage at the injectors and see how much is changes when the fans/headlights come on. If it is more than about 0.3V, then something is wrong (alternator, fuse, poor connection etc).
Hondata

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Fri Sep 28, 2012 10:38 am

dead times are there to compensate changes inthe injector when there are changes in electrical load. am I right?

I start my car it runs 10afr, battery voltage is 14.1v and the dead time value is 0.99. When the fan starts, battery voltage remains 14.1v, so its still using same dead time

i tried increasing dead times in the 14v section to 1.25, and afr changed from 10 to 12.7 and was very happy but when the fan kicked in, this time afr went all the way up to LEAN instead of the usual17-18.

i don't think my problem is in the dead times


surfingsk8r
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Re: engine goes from rich to lean when elecrical load is app

Post by surfingsk8r » Fri Sep 28, 2012 12:18 pm

this is a long shot but might have something to do with you tables for ect correction. Might just be a coincidence that when you have the fan set to kick on it hits a specific cell in that table that is off. Set the fan to come on at like 120 degrees just to test it and see if it still does it, if it does I would say that even if the ecu's battery reference is showing no change its possible that the fan circuit is pulling voltage from the injector circuit, try wiring in a meter at the voltage signal for the injectors and see if you have a voltage change there. Just a few suggestions might not be worth dick but its all I could really think of at the moment without seeing a copy of your calibration or knowing your setup directly.

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Fri Sep 28, 2012 12:37 pm

my car is a 1996 jdm honda integra with a turbo b18c engine.

engine specs:

ported cylinder head
ID 1000cc injectors
fuel pressure regulator set at 45psi
omnipower 2.5bar MAP
omnipower TPS
bkr8eix spark plugs
mishimoto thermostat and fan switch


also find calibration attached, will try to get a datalog tomorrow.
Attachments
map with id dead times 2.skl
(39.28 KiB) Downloaded 84 times

surfingsk8r
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Re: engine goes from rich to lean when elecrical load is app

Post by surfingsk8r » Tue Oct 02, 2012 7:11 am

I havent forgot you bud, I have just been swamped at work Ill try and take a look at the file tonight.

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Wed Oct 03, 2012 8:31 pm

Thanks, I will try to upload a datalog also. Is there any kind of test that I can perform to see if the ecu is bad??

surfingsk8r
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Re: engine goes from rich to lean when elecrical load is app

Post by surfingsk8r » Mon Oct 08, 2012 6:03 am

Alright bud i finally got a chance to take a look at your calibration file and what I found is that you need to do some more work on your tables they have a lot of peaks in them and you have load columns that have values that overlap each other. This will cause your erratic fueling issue. To explain it you have lets say a cell for 3500 rpm at load points for 8 psi and 11 psi if the map reads anywhere between those two points (9psi or 10psi) it has to interpolate what that value is. If there is a large difference between the two numbers it has a hard time deciding what fuel value to use and will cause unstable conditions. Basically you want to make all of the computers decisions as smooth and simple as possible If you have one value for example that is much higher than the one before it and then the next one is also lower maybe you need to raise the 2 lower values a bit and decrease the higher value can you picture how that would be a smoother transition? Also with the load values overlapping, I know you car is on a 2.5 bar map sensor but lets say your only running 15psi, to properly set up the map you need to have those load points above 15psi mapped as if the car would be hitting them (this should be easy to model as you can basically take the general shape of the slope of the VE plot and just increase each additional load column by 10 to 15 % to follow the trend. Start by cleaning up the tables and then get back to me.

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Sun Nov 11, 2012 3:41 am

So, I'm still going through this problem guys. I've tried changing different calibrations to see if the problem was from the actual calibration but all the calibrations acted the same. I start the engine, everything smooth afr is 14, and then switch on the headlamp and afr goes 19 :(.

I pluged in my previous ecu, an apexi power fc, through the commander I tried to set the engine as good as possible to idle. started engine, perfect idle, afr at 16 (this was the lowest value i could achieve), switched on the headlamps and afr remained 16, so I applied more load and turned on the fog lamps, afr remained 16 :).

so the problem must be either the ecu or the obd1 to obd2a conversion harness. I got hold of obd1 and obd2a pinouts and confronted them to my jumper harness, all were correct, so now I'm sure the problem is from the P28 ecu or maybe s300.

One thing I didn't mention, before I've rebuilt the engine, the engine was using a toyota map sensor and had the oem harness male plug cut off so it could mate with the map. I installed the original plug so that i could use an omnipower map with the engine. But I accidentally swapped two wires on the map :( and the engine went in limp mode revving at just 3500 before the problem was solved. Could this mistake maybe have damaged the ecu???

I was going to order another p28 ecu and put my s300 in it to see if the problem solves itself but I decided to give another shot in here.

Thankyou again for all your help

Alessio.

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Re: engine goes from rich to lean when elecrical load is app

Post by Spunkster » Mon Nov 12, 2012 10:28 am

It sounds like you just don't have the dead time set correctly for the injectors you are using.

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Mon Nov 12, 2012 10:35 am

With all the calibrations I`ve used, including the one I posted above I changed the dead times as per injector dynamics. O

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Mon Nov 12, 2012 11:04 am

at 43psi fuel pressure:

VOLTS --------- DEAD TIMES
0 --------- 2.60
8.09 --------- 2.60
10.11 --------- 1.67
12.13 --------- 1.24
14.16 --------- 0.98
16.08 --------- 0.80
24.55 --------- 0.35

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Re: engine goes from rich to lean when elecrical load is app

Post by Spunkster » Mon Nov 12, 2012 11:08 am

The dead times supplied by Injector Dynamics are incorrect.

Please read: http://www.hondata.com/forum/viewtopic. ... mes#p63754

Alessio
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Re: engine goes from rich to lean when elecrical load is app

Post by Alessio » Mon Nov 12, 2012 11:29 am

so as per the thread you posted I should up the values 0.02 at a time. But should I up only a particular dead time (the one being used at the moment) or do I increase all the dead times evenly together?

I'll try it tomorrow for sure and report back.

Thanks again for your help.

I really appreciate it.

Alessio

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