Fuel Injected ’03 went from perfect start any weather to hard to start. Will start but if you just touch throttle it dies. If it dies it is difficult to start again unless I shut ignition off 20 seconds then back on to restart. When started, if I try to pull away it dies before I get 2nd gear. It seems to need to be fully warmed up with high idle drop off before pulling out. Once under way everything runs as normal. If I shut it off for more than 30 minutes, I need to repeat the cold start process.



2003 Twin Cam FLHTCI, 103 Stroker, 10.5:1 Forged Pistons, CNC Ported Heads, True Duals, Thundermax

 

When was the last time you replaced fuel filter?

 

check out the tps and then the engine temp sensor. engine has to run on the rich side on cold startup but once warm enriched fuel not needed.
however, the ignition reset leans me to look at the ignition. have not fooled around with your ignition but some if they see an over current, will shut down until a recycle. been down that road with an aftermarket ultima system.
as was mentioned, fuel pressure but it maybe the relief on the pump sticking open but to reoccur every start cycle is odd.

 

When this started, Riding home from work it died on me a couple times and thought I was running out of gas. leaned over to left to hopefully move gas from right side to left, cycled ignition and she started..... Rode maybe less than a mile before she died. Low fuel light was not on 1st stop but was on by time I got home, Added fuel and rode to work next morning and she died during lunch....replaced the fuel pump filter and pressure regulator asm and with a full tank the problem seems to be getting worse every start.

 

I have 65,000 mile and the filter had never been replaced. I am sure I am not having a fuel issue. I believe it is a cold start enrichment issue. Most times it dies it just dies, a few times it sneezed in air cleaner like needing fuel or too lean. My I believe I am resetting the Thundermax with ignition off for 20 seconds.... I ordered a head temp sending unit and air temp sending unit last night. Thinking now maybe I should have ordered a TPS too. Maybe the TPS is temp sensitive and only functioning above a certain temperature....

If I ride to lunch and she runs good all the way there, when I go back out after lunch on a hot summer day it has died like the cold start issue....

 

It seems I have an interaction between 2 issues.

1 - The fuel filter & pressure regulator issue which was resolved with a new filter and regulator ASM.

2 - With that issue I had forgotten I had plugged in and changed idle RPM from 1050 down to 990 the night before. I have not received nor changed the TPS or head temp sensor or throttle body air temp sensor The only thing I have done is bump Idle RPM in ThunderMax back up to 1050 and it seems all is normal again???? Almost or maybe I know more now..... Anyway it will die if I touch throttle immediately after starting but if I let it settle down RPM after startup or if I just put in gear and pull off all is good. I don't understand why 60 RPM created the cold start problem but I'm back where I was.

 

Sounds like a t-max setting issue to me
Did you try re-initialize, on-off cycle routine the t-max? Also, powering on at part throttle throws a t-max off. They can be finicky that way

 

Yes I re initialized TMax finding the same. I misspoke above because later I experienced the same cold/warm start issue with the idle at original RPM. Yesterday I contacted Thundermax who asked for a run plot

Last Night I created a run plot starting at 100 degrees to 220 degrees with throttle operation as requested after warm. That plot was sent to TMax

This am I created a new run plot with 45 degree ambient demonstrating the cold start issues and engine dying. 2nd Plot was sent to TMax

Isaac the TMax Master is reviewing my problem.

 

did you test your fuel pressure, to KNOW that it is in spec?
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Yes, dealer installed the filter and regulator and tested confirming no need to change pump.

All - Isaac came back to say my base program is for 9.1:1 while I am at 10.5:1 and suggested restarting with a new base map. Tonight I plan to load the new map #788 and change max offsetts from 5 to 10% then try a few riding sessions and accept changes to see where that gets me......