Can't tune...running to lean HELP!!!
 

Ok, so I stopped into AMS yesterday to get a custom flash. After a few minutes they informed me that my car couldn't take the tune because it was running to lean. They did me a huge favor "which I'm super grateful for" in finding out that the fuel pump doesn't change voltage when the car is at full throttle, hence running too lean. The AFR is at 14 and that was pulsing the injectors 100% at the stock map again. They didn't have a full service manual to tell them what exactly controls the voltage on the fuel pump. Has anyone had this problem besides me!? :helpme: I am really at a loss.

My mods so far are AMS FMIC, UICP and base flash. I also have a UR full turbo back with test pipe and cone filter. I really need to find out how to get more fuel to the engine..I don't want to blow it..On another not I did notice that since I'm back on the stock map the car isn't pulling timing like it was before I brought it in..This is going to make it hard to convince the dealer that there is something wrong with the fuel system..I really need to know what controls that..or what tells the fuel pump to dump more fuel..

I'm so confused. Why isn't AMS taking care of your problem? You brought your car to them, they should be able to resolve your issues....

They did all they could really to discover what the problem was. But there is no definite answer on what has to be replaced. Hence why I must go to the dealer. It's not there fault, I just need to get my hands on the full service manual for that car or at least someone who know how exactly that fuel system works.

Did they check the fuel pressure regulator, sounds like the hose came off.

Yeah, they checked all those hoses. That's not the cases..I wonder though..could it be the fuel pressure regulator..the voltage on the pump doesn't change...so I don't know..

You can check the full online manual here.

I tried it...doesn't seem to be working..know anywhere else I can get that.
Thanks in advance

Normally I'd check dc current in a suspect fuel circuit vs. a known good car if possible. One that is weak will draw less.

I didn't realize that these cars had variable elec. output to the fuel pump. try changing the tune back to stock - maybe the "base tune" got screwed up.

well before you change anything .. check the voltage from the pump .. I'd say you're running low voltage 7-8v ..

Check the fuel pump relay circuit (in the fusebox in the enginebay) or swap it out ..
Evo's run 2 stage voltage .. low and high ..

Could be just a simple relay failure ..

I had the same problem when I changed my fuel pump and hence what i did was to bypass the fuel pump relay. As this will force the fuel pump to run high voltage all the time therefore cruising and idling will be more fuel consuming.

Try and see if the fuel pump relay in engine bay is working properly. It's probably malfunctioning

The problem with this car is the fuel pump relay. The fuel pump never switches from low to high voltage, as mentioned a couple of times in this post already.

Since we do not have any of those parts in stock, we recommended that he stop at his local dealer since the part should be replaced under his warranty anyways.

I know you were very tired when you came in Steve, but I thought we had this all figured out for your already... Let me know if you need any other help with this ;)

Could this be the reason member andy5notarobot's engine may have blown up?

https://www.evolutionm.net/forums/ev...r-blew-up.html

He was running untuned with basic mods that would cause a leaner condition. This plus a bad relay?

It might be a good idea to check your relay before modding.

No, that was a combination of mods+no tune+90 octane gas+tipping the throttle in 5th gear.

Anyone have a how to on checking the relay voltage, location, expected voltage, how to check for jump from low to high, etc. I think this would be a good thing to check every now and again if it isnt super time consuming.