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Number one and four cylinders not firing

Tiny
HONDAMIKE
  • MECHANIC
  • 1997 SATURN SC2
  • 4 CYL
  • 2WD
  • MANUAL
  • 199,000 MILES
#1 and #4 cylinders not firing. Thought it was the coil (since there are 2 of them) and it did not fix the problem. I switch the coils only to have the same results of #1 and #4 not firing. I then replaced the module hoping that it was the problem. Well. It did not fix it. I am not very familiar with Saturns ( I was a Honda Tech) so I do not even know where the PCM is located. Is the PCM the next thing to replace?

I am going to borrow an OBD to pull the codes later, but if anyone has experienced this delima, I would appreciate any help!
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Friday, April 30th, 2010 AT 2:38 PM

11 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
The PCM is the last thing I would replace they hardly ever go bad on those. It's located under the dash on the driverside if u look up under there u can see the connectors. Get a noid light check both the number 1 and 4 injector connectors for signals while it's running. Also perform a compression test on all the cyls and let me know what they were. Also let me know if there is any codes.
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Friday, April 30th, 2010 AT 4:54 PM
Tiny
HONDAMIKE
  • MECHANIC
  • 71 POSTS
Got plenty of compression. I got a code PO340 - but this does not have a cam sensor. So I believe it is the result of the misfire, not the cause.
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Tuesday, May 4th, 2010 AT 8:16 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
The most likely cause of ur p0340 its usually wires and plugs they get this black carbon on the wire ends wire they meet the plugs the plugs also the coild towers get corroded up causing the code p0340. Thats strange ur number 1 and 4 cyclinders dont fire but u dont have a p0301 or a p0304 or even a p0300 random missifire. Does ur number 1 or 4 fire at all?If u pull each wire off and put it back on one at time do u loose rpms?Also is ur 1 and 4 coil sparking at all?Did u see if u have injector pluse signal to those injectors?Let me know.
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Tuesday, May 4th, 2010 AT 9:22 PM
Tiny
HONDAMIKE
  • MECHANIC
  • 71 POSTS
Replaced all wires and plugs. I even swapped the coils only to have #1 and #4 still not fire. I pulled the plug in #1 and it smelled of gas, so I assume that it is getting fuel. The other item I am going to check is the crank sensor. I was thinking if the crank sensor was bad, it would not run at all, but.
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Tuesday, May 4th, 2010 AT 10:04 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Ur right if the crank sensor was bad it wouldn't run at all or it would run warm up then die. So if u take off ur 1 and 4 wires off ur coil and crank it over does it spark from post to post?If not let me know.
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Wednesday, May 5th, 2010 AT 12:22 PM
Tiny
HONDAMIKE
  • MECHANIC
  • 71 POSTS
No - it does not spark from post to post with the wires off.
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Wednesday, May 5th, 2010 AT 1:29 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS


https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc2_engine_performance_wire_part1_1.jpg



https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc2_engine_performance_wire_part2_1.jpg



https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc2_engine_performance_wire_part3_1.jpg



https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc2_engine_performance_wire_part4_1.jpg



https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc2_p0340_cicurit_description_1.jpg



https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc_p0340_part1_1.jpg

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Thursday, May 6th, 2010 AT 3:24 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS


https://www.2carpros.com/forum/automotive_pictures/416332_1997_sc2_p0340_part2_1.jpg


i would follow that p0340 trouble tree i posted for u that looks like the problem ur 1 and 4 signal to ignition module.i also posted wire diagrams and circuit description.let me know what u find.
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-1
Thursday, May 6th, 2010 AT 3:32 PM
Tiny
METALLICGREEN97
  • MEMBER
  • 2 POSTS
I just had this same issue on my car, check the continuity of the wire going from the b7 socket of the j2 connecter on the PCM to the E socket of the ICM connector. If the wire has continuity, then I believe that leaves only the PCM as the possible faulty part if you've already proven the ICM is good or is brand new and all the other components in the system ie. Crank sensor, ignition coils etc. If I'm wrong here please correct me. (Note the j2 connector is the shorter light blue connector with exposed wires and the b7 pin is on the bottom row seventh from the left with the clip at 12 o clock) in my case the PCM is bad.
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Wednesday, September 15th, 2021 AT 6:54 AM
Tiny
METALLICGREEN97
  • MEMBER
  • 2 POSTS
Here's to hoping my fiasco of getting stranded on the Illinois/Kentucky border 1,100 miles from home helps somebody with the same issue 11 years after the original post
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Wednesday, September 15th, 2021 AT 6:58 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Metallicgreen97:

First, thank you for that information. It is very informative and helpful. Also, I know it will help others.

Take care and please feel free to come back anytime if there is something we can help you with.

Joe
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Friday, September 17th, 2021 AT 5:04 PM

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