Starting problems after injector scaling

xmaciek82x · Mar 9, 2010, 07:14 PM

I recently put on pte 780cc injectors. I scaled down the Cranking Enrichment IPW by .737 (513/696). But still the car doesn't always want to start right away. It just cranks and I stop, cranks again and maybe starts after 6-10 cranks if not more.

Is there anything else I should change?

Thanks

JohnBradley · Mar 9, 2010, 08:25 PM

Sounds lean. Shouldnt need to adjust any of the cranking enrichment stuff.

Latency and Scaling...60% of the time it works 100% of the time.

xmaciek82x · Mar 9, 2010, 08:39 PM

Latency and scaling looks good. Everything is within -+5%.

I will put the enrichment back and see if it helps. With regular ipw values the car did the same thing accept maybe a little less.

Drill_Sergeant · Mar 10, 2010, 04:55 AM

interesting, ive never had to mess with any of the Cranking Enrichment with 880 cc's and 1200 cc's.

l2r99gst · Mar 10, 2010, 06:49 AM

Is your problem cold starts, warm starts, or hot starts? Are you getting too much fuel or too little? An easy way to check is to hold the throttle half way open and crank again. If the car starts easier, then you're getting too much fuel.

It sounds like you are using the right tables, and if so, keep adjusting the temp range in which you are having the issue and add or take away fuel depending on what your issue is.

Seeing that 780s are pretty close to stock, it may simply need a latency adjustment. But you should be adjusting the other injector tables that do not scale with bigger injectors as you are doing. Many don't because they don't experience problems and/or cover it with latency and scaling, but the other injector tables do in fact need to be scaled based on the new injector size...otherwise you will be injecting that much more fuel.

Appauldd · Mar 10, 2010, 07:09 AM

The Start IPW Latency mcsec table is not entered with a " . " Just enter the value you have in your 14.06v latency.

Example.....
My 14.06 value is 0.792. So for the Start IPW table I put = 792. Notice there isn't a need for the decimal point.

95630706 · Mar 10, 2010, 07:43 AM

I scaled them both to milliseconds so they are the same... Is that OK?

Appauldd · Mar 10, 2010, 07:44 AM

Quote:

Originally Posted by 95630706

I scaled them both to milliseconds so they are the same... Is that OK?

It should be fine, but i wouldn't recommend it.

xmaciek82x · Mar 10, 2010, 07:56 AM

Quote:

Originally Posted by l2r99gst

Is your problem cold starts, warm starts, or hot starts? Are you getting too much fuel or too little? An easy way to check is to hold the throttle half way open and crank again. If the car starts easier, then you're getting too much fuel.

It sounds like you are using the right tables, and if so, keep adjusting the temp range in which you are having the issue and add or take away fuel depending on what your issue is.

Seeing that 780s are pretty close to stock, it may simply need a latency adjustment. But you should be adjusting the other injector tables that do not scale with bigger injectors as you are doing. Many don't because they don't experience problems and/or cover it with latency and scaling, but the other injector tables do in fact need to be scaled based on the new injector size...otherwise you will be injecting that much more fuel.

Problem is with Cold Starts. I will see about the lean/rich issue and get back to you. Last night I went back to my stock setting in the cranking IPW, and this morning the car started "better" still not like stock. I forgot what my coolant temp is like in the mornings, I will need to log it next time.

Appauldd · Mar 10, 2010, 07:58 AM

See post #7 above.....he did what I am talking about. But he changed the scalings so they match. Currently all you need to do is was I said....make the value at the 14.06v level be input into the Start IPW table but without a decimal point.

xmaciek82x · Mar 10, 2010, 08:14 AM

Quote:

Originally Posted by Appauldd

See post #7 above.....he did what I am talking about. But he changed the scalings so they match. Currently all you need to do is was I said....make the value at the 14.06v level be input into the Start IPW table but without a decimal point.

I was about to reply to you post. Sorry got side tracked. Why the heck I can't find Start IPW table? Is is under Fuel? All I see is Cranking IPW with has values in temperature.

Appauldd · Mar 10, 2010, 08:22 AM

HMMMM I don't seem to have it in my 8859 xml either. I havn't tuned any 9s with bigger injectors yet so I never desired to look at this.

Maybe it is time for the Gurus to step in and fine this little gem for the IX guys.

travman · Mar 10, 2010, 08:36 AM

Quote:

Originally Posted by xmaciek82x

I was about to reply to you post. Sorry got side tracked. Why the heck I can't find Start IPW table? Is is under Fuel? All I see is Cranking IPW with has values in temperature.

that cranking ipw vs. coolant temps is the table you adjust......its actually a first pulse table, its what most adjust to get the starting right.

There are a few additional start-up tables as well - you need to see the advanced fuel thread by mrfred.

IMO - u probably can fix it by adjust that 1st pulse table u already have.

new IPW start values = stock scaling/new scaling * stock IPW value (from that table)

Appauldd · Mar 10, 2010, 08:37 AM

^....The MAN !

l2r99gst · Mar 10, 2010, 09:08 AM

Also, just as an fyi, that 'start IPW msec' table that a few people are mentioning...mrfred has stated in the past that table isn't even called in the Evo8 and Evo9 roms.

I think sticking with the table that you are using will ultimately resolve the issue. I would recommend reading through and using all the defs for the tables that mrfred posted in the 'advanced fuel control' thread.