the engine will start when i crank it but ill die when it gets up to around idle rpm. is this because its a new engine? it doesnt flood, i can start it up like that as many times as i want in a row.. it always does the same thing. new engine trouble or something electronic. if i disconnect the afm, itll try and stay started longer, sometimes if i hit the gas itll rev shortly. with the afm connected it dies immediately with gas pedal. cmon guys i know you got some knowledge out there. thanks in advance. i just wanna get my 7 back on the road- i know some of u know the feeling.

 

did you check to see if your battery is good? like putting out the right voltage? This could cause that problem if it doesn't keep the voltage up high enough.. Just a thaught thaugh

 

If it wont stay running long then you are probably running lean. Check to see if all of your injectors are working properly.

 

SOmething with your ECU is not hooked up or hooked up wrong. Check the AFM and the connector. Is the intake hose hooked up and does the AFM open when the engine runs? Make sure the plunger in the AFM moves...

 

well i trickled charged my batt so i got 11.5-12 volts running on it, however my amps are down to like 300... it wont get any higher than that. supposed to have around 450 i think. could this be the culprit? i just figure if it starts up like that then its getting enough power cuz when it catches after i crank it the volt meter goes str8 to 12 volts.. shouldnt the alternator produce the power needed to keep it alive and or completely start up?

 

PLEASE PLEASE LISTIN TO ME.....
Check your vacumms hose to your intake make sure everything is hook up. That is your problem. YOUR MOTOR IS FINE... Make sure you got ALL connection hook up.. let me know on your progress...

thanks

 

are you throwing any coloerful Check engine lights? It might help you trouble shoot..

what it pulling for an idle when you start it?.. new motors don't like to idle so 1500+ is it's new happy zone until it's broken in..

 

it goes up to about 750-1000 rpms before it shuts off. if i tap the gas sometimes itll hop to 1500. i just realized i never had a o2 sensor connected.. its in there but no wire. with the old engine this didnt seem to bother anything. could this be affecting the starting? to clarify, the engine wont idle.. itll just get to what seems to be the right rpm for an idle then die. once and a while itll slowly drop rpm then die others it will jsut flat out die. please any help in this matter would be of use. some1 online told me about my afm. with the afm connected it hardly does anything but putter. with it disconnected, it does what i am describing now. does this mean my afm is bad?? thanks for any imput you can give

 

all the vac lines are good. could this be something to do with my idle stop screw? im really out of ideas as to what it is. i know everythign is hooked up correctly.. its not a vac problem like i originaly thought it was.

 

Check the intake manifold for leaks in the gaskets and check vacuum lines. I have the exact same problem and have done some research. I tried taking off the AFM and it did pretty much what you said. When the AFM was on, the car would start to idle but when I opened the flap more the car died. Any info appreciated,
TIA
2A+ron

 

It sounds liek a big vac. leak or maybe a bad afm?

 

all the intake manifold gaskets are new and all the vac lines are hooked up properly. my guess is the afm sensor (it opens up) but i was wondering what else i should look out for... could this have somethign to do with calibrating the tps or timing at all?

 

check to make sure u have to vacuum leaks, where di du get a motor from, mazda rebuild or someone did it for u, if teh compression is low which it will be on newly rebuilt engien that have had moslty used parts in it it will nto want to idle below 1500. get some carb cleaner and spray it around when u strat your engien cold, if u do this on the hot engine and spray around the exhaust area u can start a fire. if the idle jumps up when u spray into a certain area on the intake manifolds or hoses check to make sure u have everythign tightened and hoses are all in place. if that check ou tok and the motor runs fine everywhere except under ~1500 then its jus because your compression is low. u can adjust the idle to above 1500 for the first 500 miles usually untill the compression becomes better and your engine breaks in.

 

check the 2 10mm vac lines on the intake between the turbo and intercooler. I left one of those off once and had similar troubles.

 

My car is doing the exact same thing. In my case what is causing it, is the AFM has a fuel cut off switch that cuts the fuel pump when the flapper door closes. When your car has a vacume leak, there isn't enough air coming through the AFM to push open the door. It's a deceint sized leak, a big one would cause the rpms to climb on their own, and a small one would make it's self known only under boost.

I have a "bare block" setup, so it made finding the leak much easier. Turns out I forgot to put in the long bolt that passes through the UIM.

Try having somone hold their finure in the AFM, and see if your car will stay running.

hope that helps, let us know when you get it figured out

 

Ok.... if air isn't being drawn in through the AFM, there is a switch in the AFM that tells the ECU it isn't opening and the ECU cuts fuel. The engine will start because the AFM isn't read until it is running.

Either the AFM isn't hooked up, or you have a big enough leak somewhere, probably between the turbo and the AFM. Make sure you don't have any leaks.

If you had low compression, the engine wouldn't fire up. My engine wouldn't when I put my rebuild in.

 

aight when my boy holds the afm open the car will stay running. i suppose this means i have a vac leak somewhere but it was impossible to detect before cuz i could never have the car running. thanks, you guys are the best.

 

break in techniques anyone?

 

Not sure what type of engine you have(New, rebuilt, j-spec). Anyway I am guessing it is a rebuilt so drive it easy for the first 1000-2000 miles. I know someone here has a good guide to breaking you engine in. The only one that comes to my mind right now is the one at Rotary Resurrection. You could take a look at that one for a general idea.

http://www.rotaryresurrection.com

 

First 1,000 miles - 4kRPM max revs, no boost
Next 500 miles - 6kRPM max revs, mild boost (up to 5psi)
Next 500 miles - progressively up to redline, progressively up to max boost

Try to keep revs fluctuating as much as possible.&nbsp Try to avoid steady state RPM driving (i.e. cruising on the highway/freeway).

This is a very conservative break-in that I follow.


-Ted