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I’m going to try to be extremely thorough in hopes that someone can help me, without a TON of wasted time. I’m at my wits end and the shops around here don’t want to touch the car because it’s been customized a good bit..
Please forgive the long post.
The car:
2003 Mazdaspeed Protege (2.0 Turbo, FSDET engine)
The problem: When cranking, it won’t run.. but it backfires.
The backstory:
So I bought the car unmodified back in 2015. Since then I have been enjoying it as a turbo project car. I started with the typical stuff.. Front mount intercooler, blow off valve, plugs, wires, engine mounts, DVD player, etc. Some of the mods had the car off the road for a few weeks at a time, but ultimately I’d get it back together and going no problem.
During those early years, I planned on rebuilding the motor, doing a partial wire tuck , powder coating a lot of parts, etc.
I followed through with my plans. I rebuilt a motor, made it really pretty, and did the engine swap last year. I took my time, and tried to do everything as perfectly as possible. I used a lot of other Mazda parts.. like the intake off a 626, for example.
I know my work was good, because the car RAN. I drove it around and all of that. However, I had an ABS light that wouldn’t turn off, the emergency brake light stayed on all the time, and the speedometer didn’t work at all. Everything else seemed okay.
So after hours of troubleshooting, I found out that I had the ground wire for the ABS module grounded to a powdercoated bracket (which means there was no ground as the powder coat insulated it) I removed enough coating to get a ground again, and hooked it back up and BOOM! ABS lights went away, the speedo worked, and the Parking brake light worked again.
So I was SUPER stoked, took the car for a test drive, and everything seemed great.
I took the car home, pulled into the garage, and (while the car was idling) hooked up an OBD2 scan tool to check for any faults / CELs.
The scan came back clean. I was thrilled. In my head I am already getting the car inspected the next day.
Then the car just cut off. Stop running for seemingly no reason.
Ever since then, the car cranks / no starts and backfires.
I really need some good advice. I currently have like $10,000 in a $2,600 car… (I know thats stupid to non car enthusiasts, but I’m chasing my dreams)
I’ve checked all the fuses, all the relays, changed the fuel pump, changed the plugs, wires, and coils… check timing…. At this point I just don’t know and since the engine bay looks like something from fast and the furious, shops don’t want to touch the car.
Thanks in advance everyone.
(There are a couple missing clamps and whatnot in this picture. Please disregard that stuff. I don’t have the most current picture and the car isn’t at my work where I am posting this. Picture is just to give you an idea )
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Replies
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With out knowing exactly what and how was done to the engine, I can only offer some basics to look at.
Poor or unregulated engine timing is often a cause of intake backfires, but can also be responsible for exhaust backfires.
Backfires are common when an antilag system is present and active.
Fault in the wiring in the ignition can also lead to timing issues and backfires.
Low fuel pressure could cause a severely lean air-to-fuel ratio.
Have you check the fuel pressure regulator?
A missing or damaged catalytic converter can result in backfires out the tailpipe.
Broken exhaust-system piping, especially if located immediately downstream of the exhaust manifold, can result in backfiring
Vacuum leakI do not have a 2 step installed.
I do not have a catalytic converter.
I have not checked the fuel pressure regulator. I assumed it was okay because I am getting fuel. That being said, it might be getting less than it should.
My gut instinct is that I messed up wiring (burned something up) running the car with a major ground wire disconnected.
But if I knew for sure, I wouldn’t be here. I’ll check the regulator.
Thanks for the response.
The issue is as you stated:
it’s been customized a good bit..
No one here knows what was done exactly or how it was done which is the reason shops do not want to touch the car.
Case in point:
I had the ground wire for the ABS module grounded to a powdercoated bracket (which means there was no ground as the powder coat insulated it)
No one here or at a service shop would consider that on a non modified vehicle.
Or any other issue(s) that could bring about.
At best, you will be advised to check the basics because that is the only point of reference most here can go by.
You may wish to double check the ECU though…
If you had a floating ground it may have done something to the ECU (only a guess)Why are you even responding when you have nothing to say except to criticize the question? Just shut up dude.
I understand your frustration. But this situation would challenge any tech that even had the car in front of him.
Nightflyr was trying to help as best as the description warrants. On occasion, people need to be told what they need to hear, not what they want to hear. Please bear that in mind.
It is very challenging and my best advise would be to try to find an Indy shop that would take it.
I can tell you if I was the shop that would accept your car that due to the nature of the problem it may take some time and I cannot guarantee any quick results. You could have anything from a bad ecu, to a frayed wire, to a timing issue.. etc…
Good luck,
Karl
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