gary gray

Looking for some help. I'll try make this as short as I can, but I'll give you the run down. I have a 540ci mpi blower motor. This is a fresh rebuild due to it running lean from previous owner not installing a 2 bar map sensor. Before motor was rebuilt it ran great with the exception of it running lean and burning up a piston. So after rebuild I sent the mefi 3 ecm to Tyler crockett to do the mapping on it to make sure we were good on that end. Once the motor was installed I fired it up, set it to 8 degrees timing as specified by tyler and set the fuel pressure to 50 psi. Motor started, ran great on the trailer, great throttle response and thought I was good to go. I let it run on the trailer for about 10-15 minutes while checking over everything. Shut it off and was going to go for a ride. After about 15 more minutes I went to start it back up just to double check everything and it would not start unless I held throttle 3/4 of the way open and could not get it to idle unless I unplugged map sensor. I replaced map sensor with a new one and I am now able to get it started and idle but has no power under load and bad throttle response. Almost feels like it is a fuel or timing problem but fuel pressure is still at 50 psi running and timing is still at 8 degress. Injectors are 56lb injectors and we're flow tested and cleaned during rebuild. Any suggestions or things I should double check. I do have a code reader and there were no codes flashing. Any help would be great. Thanks

F-2 Speedy

iTrader: (6)

This sounds like another injector cleaning issue, but 56 lb injectors on a 540 blower application ??, Im sure the blower guys will chime in

gary gray

I was told I only needed 50lbs. Sounds low to me to but should still at least run.

F-2 Speedy

iTrader: (6)

explain more about the motor, type of injection and blower

gary gray

It's a merc mag mpi injection system with a mefi 3 ecm. Has a vortech centrifugal with 5 -6 lbs of boost. Aeromotive ajustable fuel regulator mounted on return side. Canfield aluminum heads and cmi headers. I have also sent the ecm back to Tyler just to have him recheck it and he says it's fine out that end. Just was wondering if there's anything in per tickler I should be checking before I start replacing parts.

TooLateVTEC

iTrader: (1)

Try lowering the fuel pressure?

Since youve replaced the MAP, do you still need to open the throttle way up to get it to start?

When you do that, you're putting it in 'flood clear' mode, which means its firing the ignition but not the injectors.

GPM

What is the HP of this motor ? is it a boost referenced regulator ? what fuel pump are you running ?

gary gray

Now that I did replace the map sensor it will start without without giving it throttle, after 2 or 3 times. It usually will start then stall and about the third time it will idle. I did try to lower fuel pressure and it didn't seem to help. It is a boost reference regulator. The pump is a aeromotive a1000 pump, horsepower estimated at 800-850. What I don't get is on initial start up after rebuild it seem to run find, then after shutting it done once I looked it over it all went to crap.

stimleck

Per tickler? i resemble that comment

ezstriper

Not the issue you are having here, but I don't think that merc EFI and your setup are going to work well at all....this has been around but you are way beyond the ability of that manifold with out lots of work..hopefully you changed the rails and completly redid the fuel lines/filter/etc and are using a return setup...