I am having some issues starting on my Evo IX. I have ~42k on the clock and my mod list includes:

- Apex'i Intake
- 3" Turboback Exhaust (Megan DP, Perrin hi-flow cat, Tanabe catback)
- Hallman MBC set at 24 psi
- Muse LICP
- Walbro fp
- Blox front motor mount
- JDM 3bar MAP sensor
- Tune

Recently, my car has been having difficulty starting after sitting for a while and/or if its very hot out. The car is turning over and I have had the battery tested twice so I have pretty much ruled out anything electrical. Two friends of mine have also listened to it and said that it is a fueling problem. The car so far has always started, it is just taking several attempts after sitting for a while or if its really hot out.

I have ruled out the tune since I tried loading back on the stock tune (with 3bar changes) and still experienced the issue. I ran with that tune for a very long time with no issues. Tuning has been done with ecuflash.

I have pretty much come down to thinking that it is the Walboro right now. Has anyone else had this issue with the Walboro? I plan to try swapping in the stock fp and see if the problem goes away. When I do this I will be turning down the boost. The odd thing tho is that I have had the Walboro in for quite a while now with no issues. Possibly 4-6 months. The first couple months were on the stock tune.

Has anyone else had any other issues like this or have any other ideas? Is it possible it could be my injectors or some other part of the fueling system.

Also, the car - once on - is running fine. It pulls fine and my AFRs are looking fine (I have an AEM wideband). I haven't actually logged the AFRs, but by visual inspection of my gauge I am hitting the values that my tuner set me up for.

Thanks for any help.

UPDATED - Issue found!

Finally got around to taking the fuel pump out and the grommet which seals the outlet of the pump had torn and was not holding a full seal. I had reused the stock grommet with the Walbro as shown in the HOW-TO below on step 12.

http://evomoto.com/tech_info.php?tPa...19dc05e3099239

 

id change the pump/ make sure everything is tight and filter is not clogged .. Do you have a gauge for fuel in or out of the engine bay?.... when you turn the key to the on position with out turning the car over does the pump come on?

 

No fuel pressure gauge. Its hard to say if I hear it or not. I think sometimes I can hear it and other times I can't. I have tried leaving the key in the on position for a few before trying to turn over. That *seems* to help - but not all the time.

If the car has trouble starting on the first attempt - it almost always starts on the second. I think there was only 1 or 2 times where it still stumbled on the second attempt.

 

bump. hoping to get to swapping the fp this weekend and see if that fixes it...

 

bad pump causing fuel probs, electrical, plugs, coils ect.

fuel system dirty, try a flush to your fuel system, we have 3 sage fuel system cleaner kits for 65 shipped, it will clean injectors, throttle body, intake manifold and combustion chambers,intake valves

 

I'm experiencing an almost identical problem. Literally overnight my car went from starting perfectly to not being able to idle on it's own on a cold start. If I rev it, it'll stumble at first and then it'll be ok. Once I drive for a few minutes it's able to idle on it's own.

I'm basically thinking it's either the ISC or the fuel pump. I did notice the pump seems to be whining a bit more than usual too. The AFRs during cruise and WOT are still perfectly fine though. Up until now the car has been fine once warmed up but today I noticed it started stalling and was difficult to restart even warmed up. Keep us updated with your findings and I'll do the same.

 

OP, i know someone who seems to be having the same exact problem as you described. Hopefully after you change the fp, it will make a difference. I will be checking back for some hopefully positive results.

 

I don't seem to have any idle issues at all, even when cold. It really is a matter of just having trouble starting. This morning I left the key in the on position for a good minute or two. It sounded to me like the fuel pump came on, stopped and then came on again. Then the car started fine first try. It could have been something else that I heard which started stopped and started again. It did sound like it was coming from under the dash... but it sounded an awful lot like a fuel pump whine to me.

Yesterday she was having major issues starting due to the heat. Hopefully I will get to swapping it over the long weekend and report back what I find.

 

make sure that when you installed the walboro, you included a yellow spacer. It is a very small but important part. It basically regulates the pump when there is an increase in pressure. My car had problems starting as well, but when i looked at the walboro assembly, I realized that I forgot to put that spacer in.

 

The fuel pump may be getting weak. You should hear the pump run for at least 2 seconds when you turn the key on. Its a 2 second prime. Thats probably why your car started after that. It gave the system a chance to build fuel pressure.
If changing the pump doesnt help, check the values of your temp sensors. If it starts worse when its warm outside or when the car is warm, it seems like it would run really bad when the car warmed up. At least start with checking fuel pressure and spark.

 

thanks for the advice guys.

i still haven't gotten to pulling out the walbro and inspecting it or swapping in the stocker.

the issue hasn't been as bad recently. it appears to be strongly linked to ambient temp. on really hot days it doesn't like to start even after having just run recently. on cold days though it pretty much is starting right up even after sitting all night.

 

OK I finally root caused this - description in first post