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Fails to start/idle after engine replacement

Tiny
REINIERVO
  • MEMBER
  • 2002 MAZDA PROTEGE
  • 2.0L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 167,000 MILES
I just finished replacing the engine, with a new one, on my car listed above Protege5. However after checking and re-checking I am unable to get the car to stay running. What happens is that it sputters at first and then shuts off. If gas is given then I can hear it popping in the exhaust. A couple of time(s) I did get it started bypassing all the popping and when 3,000 rpm's was reaches it all came alive and ran perfect.

Here is a list of items check/changed besides engine:

1. Spark plugs (replaced).
2. Wires (replaced).
3. Coil packs (replaced w/used tested).
4. Fuel pressure regulator (replaced).
5. MAF (replaced).
6. Fuel Pump (replaced w/used tested).
7. Camshaft sensor (tested).
8. Fuel injectores (replaced with used tested).
9. EGR (cleaned and tested).


One thing I did forget to mention and that is after trying to start several time(s) the spark plugs come carbon fouled.

I hope someone can give me some more insight as to what else to try. Thanks R
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Sunday, September 20th, 2020 AT 11:03 AM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
The idea that it is backfiring through the exhaust sounds like it could be fuel pressure, a vacuum leak, or even ignition timing. However, I realize you did check pressure.

Was the engine new, rebuilt, or from a used vehicle? Also, have you checked to see if diagnostic trouble codes have been set?

Let me know.
Joe
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Sunday, September 20th, 2020 AT 5:08 PM
Tiny
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A little bit of history on the engine. This was a 2.0 crate motor, however it looked that it was setup for having a distributor, because that port was open, which my Mazda Protege5 does not have. I used all the sensors from the old engine.

I did check for codes and there are no stored and no pending codes.

I will re-check the fuel pressure again, just to make sure.
I just got more oil for my smoke test machine, so I will go ahead and do a smoke test as well to check for vacuum leaks and post the results.

Thanks,
R
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Monday, September 21st, 2020 AT 3:55 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Hi,

Do you know what year the engine was designed for? Were all the sensors from the original engine compatible with the replacement?

As far as the tests, let me know what you find.

Joe
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Monday, September 21st, 2020 AT 6:27 PM
Tiny
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  • MEMBER
  • 5 POSTS
The engine is an FS engine designed for following:

1993†2002 Mazda 626
1993†1997 Mazda MX-6
1999†2001 Mazda MPV (Japan)
1999†2003 Mazda Capella
2001†2003 Mazda Protegé
1993†1997 Ford Probe
1993†1999 Ford Telstar
1999-2006 Kia Carens

The only 2 sensors that came with the new engine was the crankshaft sensor and the camshaft sensor. All others sensors are from the old engine. I have tried swapping out the camshaft sensor with the original one and no difference.

The smoke test revealed that all injectors were leaking, so I replaced all the seals and now no leaks at all. However now it does try to start and then just shuts off, like it is deprived of gas. I will test the injectors to see if they are spraying right.

Should I check to make sure the timing was setup right?

R
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Wednesday, September 23rd, 2020 AT 6:12 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

It wouldn't hurt, but chances are timing isn't the issue. Is it possible for you to record the engine cranking and upload it for me to hear? If it is a timing issue, I should be able to recognize it.

Let me know.

Joe
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Wednesday, September 23rd, 2020 AT 6:37 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
Here is a great backfire troubleshooting guide:

https://www.2carpros.com/articles/engine-backfires-while-running

Please run down this guide and report back. Can you please shoot a quick video with your phone so we can hear the noise? that would be great. You can upload it here with your response.

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Thursday, September 24th, 2020 AT 4:48 PM
Tiny
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Hey guys, here is a quick audio clip of trying to start. If this does not suffice I can do this again. Totally forgot to mention that this is my 3rd set of plugs for this car, because it seems that all 4 come out complete black. Carbon fouled. This was before I found the injector air leak.

I pulled all the plugs after trying to start and they look pretty clean, just have fuel on them.

Ken, I will go through the checklist from your site, just to verify again and post results here. Give me couple days.

Thank you both Joe and Ken for your help.

R
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Saturday, September 26th, 2020 AT 4:34 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I want you to try something. Hold the pedal to the floor when cranking to see if it changes things. By doing that, it shuts down the injectors. I'm suggesting that simply because you indicated the plugs were wet. It may be getting too much fuel. By the way, the timing doesn't sound like an issue.

Let me know what happens.

Joe
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Saturday, September 26th, 2020 AT 6:13 PM
Tiny
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Hey Joe,

I tried the pedal to the floor and here is a video/sound for that. It really did not like that, it was popping this time. So I pulled all the plugs and they were all carbon fouled this time. I also pulled the pre and post cat o2 sensors. Pre-cat is carbon fouled, but the post-cat is just fine.
I rechecked the fuel pump and it says 42 approx.

R
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Monday, September 28th, 2020 AT 2:08 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
The pressure looks perfect. The plugs having a lot of carbon is interesting. That is usually the result of too much fuel, timing (retarded), plugged air filter, vacuum leak and so on.

At this point, I feel confident that you have checked for those things. Also, low compression can also cause the issue.

If you remove the pre cat oxygen sensor, does it make any difference?

Joe
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Monday, September 28th, 2020 AT 6:23 PM

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