How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Mazda
Satisfied Customers: 3967
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles
Type Your Mazda Question Here...
Chad Farhat is online now
A new question is answered every 9 seconds

Not start after engine swap. Everything looks fine no

This answer was rated:

not start after engine swap
JA: Have you checked the battery, particularly the terminal connections? Are they corroded?
Customer: Yes everything looks fine no corroded it cranks but doesn't start
JA: What is the model/year of your Mazda?
Customer: 6i and 2007 I switch it with a 2008
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yea I tried putting a new battery in And replacing the crank sensor
JA: Anything else you want the mechanic to know before I connect you?
Customer: Engine light is on and my key won't lock or unlock the doors

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Customer: replied 29 days ago.

Hey how are you

so it will not crank over correct ?

is there power to starter solenoid (12 volts) ,with ignition switch in the start position ?

did you had to unplug ecm when you did the swap ?

did you check the ground cable at starter ?

do you have a capable scanner to read fault codes ?

what was issue prior to engine swap why was it swapped ?

is there a security light on or flashing ?

did use a scanner to clear all faults in all modules ?

what type scanner you have

lets start here & we go from there

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 29 days ago.
Right it cranks but doesn't start. I swap it with a different engine because the one before I believed the crank or something else blow It won't go more then 20 mph. its getting 12 volts no I didn't unplug the ecu before swap. I don't have a scanner . There is red key inside car flashing all the time

ok lets do this ,you might get lucky

Master reset Procedure

1- Disconnect Battery Cables ( Negative & Positive Cables )you can use any electrical wire as an extension if battery cables don't reach .

2- Hold cables Together for 60 secs ,then let go

3- Wait 30 minutes

4- Make sure all doors are closed

5- Reconnect battery Cables

6- Lock & unlock the vehicles using the key from driver door side (if you have a key fob with no blade key, just lock & unlock using the key fob buttons)

7- Enter the vehicle and attempt to start

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 29 days ago.
OK I try it

ok sounds let me know


Customer: replied 29 days ago.
I tried it and nothing
Customer: replied 29 days ago.
Also there is no spark to any of the spark plugs
Customer: replied 29 days ago.
I forgot to add that

did you have any plugs on harness between 07 and 08 on engine were different or etc ?

no spark ,on coils what are we missing power or ground ? ckp installed ,did you check ?

does it have power on it

do you hear fuel pump buzzing when you turn switch from off to on to prime fuel rail

what is vin# ***** me look the wiring circuit so we can follow it

v6 3.0or 4cyl 2.3 ?

Customer: replied 29 days ago.
Yea they was different brand sparks plugs other then that they were the same.harness its a 2.3. the fuel rail is getting gas done check that. what's the ckp?
Customer: replied 29 days ago.
I can hear the fuel pump
Customer: replied 29 days ago.
Were is the vin# ***** at?
Customer: replied 29 days ago.
Also my key buttons will not lock or unlock the car
Customer: replied 29 days ago.
Me and my dad did the swap could it be the ecu??

crank shaft position sensor



oh no , why ecu swap , they did not match

the ecu will need programing to car that is your problem now

Customer: replied 29 days ago.
Its not the ecu from the new engine so u think this could be my problem?

vin number is ***** the door frame ,on the driver side end of the dash ,look thru outside windshield in

the ecu needs to have car vin # registered and key syn to it or it will not allow start up unfortunate and you will need dealer scanner or equivalent to do

but if you only swapping engine why swapping ecu you can noit with out programing

reinstall old ecu i,it should work ,unless u saying u tried 2nd ecu and also same issue

the ecu in your car that was originally in it before engine swap is what you need to use only

if you only swapping engine then no ecu necessary and will not start

so go back to original and then see what you are missing if it did not start fuel or spark we need both to start .but off course original ecu it is synced to car

Customer: replied 29 days ago.
I never changed the ecu the guy I got the engine from said I shouldnt have to
Customer: replied 29 days ago.
But I told if I get the ecu from the car I got the engine from it will start
Customer: replied 29 days ago.
I was told**

he is correct no need if only replacing engine ,, i thought u said you and ur dad did !u lost me there .lol

not true , on the ecu from other car , unless u change the key and ignition cylinder and security module etc ..

Customer: replied 29 days ago.
Oh sorry for the confusion. My dad and me put the engine in the car. The engine had everything on it we just dropped it in and hook everything up
Customer: replied 29 days ago.
My vin# ***** *****

ok , go back with oem ecu and check the ckp sensor or replaced ,if you missing spark,as long you confirm the anti theft is not triggered ?

also next step will be having scanned to get fault codes to pull up pin point test and be accurate ,u can post them back here for me & i can help further on it

Customer: replied 29 days ago.
OK thanks I'll do that I let u know what I come up with

sounds good read below how to get back in touch

Please Remember to Rate me Before you exit Since That is how we get compensated using the Stars on Top of your screen,A 5 Star Rating is much Appreciated.

You are very welcome :)

Please Read Below How to Get Back in touch with Me

Please Take a Second and Click the Stars at the Top of Your Screen To Rate Me , So I May Receive my Credit , A 5 Stars Rating is Much Appreciatted

Follow Up Questions are Included in The Price of Your Question ,So Feel Free To Ask Me.

Please Keep in Mind that when you Rate Me , it Does Not End our Conversation.

You Can Always Come Back to this Conversation and Ask Me any Follow up Question you May have on this Issue

(You can Copy this Link Page & Paste it in your Browser when Ready and it will Open up our Conversation Again)

or there should be a Tab on your Screen to Add me As Your Favorite Expert

I'm Online Daily from 7 Am Till Late Eastern Time Zone

Thank You
Chad Farhat
ASE Certified Technician

Chad Farhat and 4 other Mazda Specialists are ready to help you
Customer: replied 29 days ago.
my key battery is dead could that cause it not to work?

yes off course

replace it

replace it then redo the master reset

Thank You For The Rating :)

IF you need my Assistance in The Future on a Different issue , Just start your Question with ( FOR CHAD FARHAT ONLY)

or Click on the link Below to Enter My Profile & Under My Picture Profile There is a Box That Says (Ask Your Question)

It will be Highlighted in Orange, Type your Question in The Box & It will be sent straight To Me to Assist you .

or there should be a Tab on your Screen to Add me As Your Favorite Expert