Hey guys i recently started having this issue and could use some help. The car is a 2003 Evo 8 with 90,000 miles and has exhaust, cams, intake, 255 pump. It's running e85 and is tuned by an experienced tuner.

Issue started a few weeks ago where the car struggles to start only when not driven in several hours. Outside temperature seems to have nothing to do with the issue. It usually takes 2-5 times to get the car started. If the car was recently driven it has no issues starting and seems to run fine.

I bought a wideband to monitor AFR and car seems fine under WOT and idle. Today i sat the car for a few hours and without trying to start the car i turned the ignition to "ON" and my wideband gauge was reading 18. I thought my fuel pump was going bad so i tried a new one and it did not solve my issue.

Can anyone suggest another route in troubleshooting? Any help is much appreciated!

 

I'd suggest pressure testing the induction. I had one hose off and experienced the same problem.

 

Thanks, ill try pressure testing and update.

 

Had the same issue.

Had to bump up the cranking enrichment tables, issue went away.

If you aren't familiar with tuning, check all the obvious mechanical issues you can (like barneyb stated), and contact your tuner if nothing seems out of place.

 

Update: I did a pressure test and found a small leak. Fixed the leak and car idles a small amount better but still struggles to start. Next i went to check on my Idle Air Control Valve and noticed that the valve was very loose. I screwed the valve back on to where i thought it should be and also cleaned the valve with some throttle cleaner. After putting the valve back my car idles WAY better. I will need to wait till tomorrow to see if my startup issue is also solved. I will update this when i have more. Thank you to those who chimed in.

 

Update:
Car started having bad startup and idle again so i pulled the idle valve back out and it was very loose again. I put in a new OE valve and car is now fixed. No startup issues and idle is very good. If anyone else is having issues similar to mine check your idle air control valve. It is very easy to remove and test.