2003 Mazdaspeed wont stay running after engine swap

[jasonga30224]

Hey i have a 2003 mazdaspeed protege i just replaced the engine now it wont stay running itll start and immediatly die and sometimes backfire,but the engine ran great at the junk yard with no problems.Any help would be greatly appreciated,Thanks

 

[Ricktalife]

Any check engine lights?

 

[fatti03msp]

my car did that before, it would start up and i had to keep giving it gas to keep it running. It ended up being a bad ECU.

but y like rickta said if there is a check engine light that will tell you pretty much everything.

a few things to check.

pull your plug wires and see if each cylinder is getting spark, put the wire to something metal so you can see it arc.

check plugs and gapping

check for vac leaks too

just a few things off the top of my head.

 

[01CrznMp3]

Hey I just built a forged engine and used a 626 engine. I had a lot of problems with it starting and the time I did get it running it was buckin like crazy. It turns out we have different timing gears and crank pulleys. Our timing gears have 3 tabs on each for the cam sensor to pickup where others have just 1. The same goes for the crank pulley. The ecm cant figure out where the cam/crank are in relation to eachother. Make sure you use your original cam and crank pulleys if you didnt already. Hope this helps.

 

[StealthWyvern]

Hey I just built a forged engine and used a 626 engine. I had a lot of problems with it starting and the time I did get it running it was buckin like crazy. It turns out we have different timing gears and crank pulleys. Our timing gears have 3 tabs on each for the cam sensor to pickup where others have just 1. The same goes for the crank pulley. The ecm cant figure out where the cam/crank are in relation to eachother. Make sure you use your original cam and crank pulleys if you didnt already. Hope this helps.

Very nice suggestion! I even forgot about that and I bet the OP did as well.

 

[01CrznMp3]

Did you ever get your car up and goin yet Jasonga? I was wondering if you had the same problem as me or if you fixed it.