rx72c

iTrader: (8)

Hi Guys

wanted to hear some different ideas on how you guys compensate for heavy electrical loads such as high speed thermo fans, high beams etc.
If you have a nice lean idle/cruise tune these heavy electrical loads send the tune south as soon as they come on.

Looking for ideas how to add some fuel to the map to compensate for these conditions.

Slides

Do you have injector latency tables filled in?

At cruise at least you should not see a difference in AFR with electrical load if latency compensation is correct, nor really at idle (although drop in rpm or throttle bypass compensation will take you to a slightly different map point which may be fuelled differently), obviously you will need extra idle air via throttle bypass/kicker or some sort of idle ignition timing compensation to maintain idle speed with the additional load.

You really shouldn't need an additional compensation beyond correct injector latency vs system voltage but if you are still having issues you could set an electrical load input on the ecu to add a fuel trim. I wouldn't consider this a clean or elegant solution and it won't result in perfect AFRs across the rev/load scale but if may help you if nothing else does.

It has been a long time since I have played around with the haltech software i will have to have a play. What version ecu are you using?

C. Ludwig

iTrader: (27)

What he said. The base fuel map already accounts for load. If the extra load puts you between load sites and the interpolation is a little off, add more load points. You really should not need anything more than the base fuel map and voltage compensation.

rx72c

iTrader: (8)

I am sorry if i am jumping the gun here but i did not say anything in my post about a voltage drop?

Ill try this again.

Voltage does not drop on idle, the alternator places a fair bit of load on the engine to produce more power. Please note I am using a zero throttle fuel map. I can only adjust fuel VS RPM and nothing else.

So any ideas?

Slides

So it is not AFR change you are worried about but maintaining idle speed or a bit of both, you think you will get a bit more torque with more idle fuel?

Can you use a throttle bypass (does it have one fitted) or an external input to add ignition timing? (assuming you are running soft idle timing).

If it is IDA style or stripped OEM throttle and you don't want to run a bypass/idle valve (or running TPS vs engine speed tune rather than MAP) your only real option to maintain idle speed is ignition timing change (or both fuel enrichment % if very lean on idle and added ignition timing) with load by activating a digital input.

To be fair, you did say

C. Ludwig

iTrader: (27)

No, he has a mixture issue.

You disable the means by which the ecu compensates for load and then ask for a way to make the ecu compensate for load. Makes sense...

rx72c

iTrader: (8)

C.Ludwig

When you say "disable the means by which the ecu compensates for load and then ask for a way to make the ecu compensate for load"

you mean by enabling the zero throttle map?

Just so you know, to get the engine to idle at all it needs alot more fuel than would be required while cruising at the same rpm/load points. So if i dont have that zero throttle map i end up with a very jerky car at low speeds and lots of fume at low speed or a car that stalls all the time

I take it by all the negative responses there is no easy way to do this?

Slides it is not an idle speed issue, as C.Ludwig mentioned it is a fuel mixture issue.

Any suggestions.

C. Ludwig

iTrader: (27)

Yes. I meant it the way you described.

You idle in the same rev range that you cruise?

I've done multiple bridge port engines and have never run into a situation where I had to use the zero throttle map. Even with a weak and erratic vacuum signal using the base fuel map works better than the zero throttle map. In my experience, there's just no reason to use the zero throttle map.

C. Ludwig

iTrader: (27)

That said, you may be able to use the boost compensation map. Not sure if that is ignored when the zero throttle map is engaged, like the base fuel map.

rx72c

iTrader: (8)

You have got me curious that I am doing something wrong so I am going to disable it and have another crack it.

I just figured if such a basic ecu like the microtech came with an enrichment feature for outputs such as thermofan it would be something basic on the haltech but I guess not.

FalconSeven

Any progress with this, rx72c?

I have a streetported FD running Platinum Sprint RE with a similar problem. If I start it while coolant temp is still close to or above the fan switchover point, it bogs down and barely wants to idle. The idle also fluctuates ~400-500 rpm. At the normal (high point of) idle speed, AFR is good. When it dips down those 500 rpm, it leans out to 16-17, then dumps in a bunch of fuel to correct the mixture. With the fans on, I do get a voltage drop. Sometimes it will go down as low as 11.8V. The above issues only occur with the fans on, seeming to indicate that it is related to electrical load.

I've mechanically adjusted the idle with the fans running (using the bleed screw under the UIM elbow), but the Haltech seems to be compensating for this, so it only lasts a day before I'm back to idling problems. Any help would be appreciated! Thanks.

rx72c

iTrader: (8)

After getting some advice in this thread i have simply band aided the solution with a rich idle.
I tried without the zero throttle map and she still stalls.

Please note with small thermo fans 2400CFM or less this is not an issue. I am only dealing with this on car's with high current fans 3000CFM+

40AMP+ fans.
I really dont understand why it would be so hard to have a small correction or 8X8 table in the thermofan switches.

Everytime I have spoken to haltech about the issue they tell me to take it to a haltech dealer so .....

C. Ludwig

iTrader: (27)

Care to send me your map and a log of it happening. You have me curious. chris@lms-efi.com

rx72c

iTrader: (8)

Ill have access to the car in a few days. Ill email you some stuff then.

t-von

iTrader: (8)

I was having similar issues with my 20b as well with idle electrical load tuning with just side ports. I try to run my idle as lean as possible but it would stall out when I started adding a lot of electrical load. Turns out my problem was a slow internal coolant leak that was effecting my A/F ratio as the engine got up to temp. Everytime I kept adjusting my end of injection table, the tune would always seem to change. To make matters worst, if I shut the car off, it never wanted to restart till after a few minuets of sitting. This made tuning very frustrating because odviously my engine wasnt mechanically sound at the time. That was years ago.