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View Full Version : Car runs but no spark on #4 coilpack ideas?


ask52
04-09-2008, 10:11 PM
well after all the troubles with this car I finally get it out on the road and its sounding like a Subaru. also the egt isn't picking anything up on #4. went back home, swapped plugs and coil packs from #2 & #3 still nothing. checked the grounds and they were good (2 ground wires in the coilpack). could a bad igniter or ecu cause this? I'm in a bit of a panic since I'm supposta leave town Friday.

Thanks....Josh

project_s13
04-09-2008, 10:46 PM
the ignition modules one GM coil packs do this lots. it normally a bad coil pack or bad ignitition module. on a coil pack there supposed to being the key word fire one plug neg and other positive. so one should drop 2 cylinders should drop. but they dont always go like that somehow. pull the ignition modle and coil pack and look for signs of arcing. white or black. othere than that u could have a single bad wire or plug in that cylinder. if you have a multimeter you can test the coils and wires. on average car you should have 8k ohms per foot roughly on plug wires and on primary coil side you should have 3-8 ohms if i remebr right and on secondary should be around 200-300ohms. youll have to test primary and secondary coils. if you have the spec awsome if not ull have to figure an average.... so hope you got couple extras kicking around lol.

try changing wires around and try and changing the plugs around if you can. if it changes cylinders you've found your problem.

BTW is the engine missing? or it just not showing up on EGT? egt sensor maybe bad if you dont notice a miss or atleast a hesitation at WOT or idle or cruise.



OR you could be all pro and convert ur coil packs to coil on plugs from newer nissan cars ;)

project_s13
04-09-2008, 10:54 PM
PS rember on a coil pack set up ecu only fires twice 1and 3 cyl at the same time and 2 and 4 at the same time. so if ecu was causing it ud be down 2 cylinders and ud be lucky if it would run :P (it's called waste spark system) any more questions pm me always glad to help

ask52
04-10-2008, 05:40 PM
thanks for the tips, I'll check in to it again tonight. yep the car has a bad miss, no power. will hit full boost (gt28) but its boggy. gonna try to switch the wires to #2 and see if that works..

Thanks...Josh

redtop91
04-10-2008, 05:50 PM
If you have someone else that has an SR nearby, try swapping out the harness for the coilpacks that plugs into the main harness at the back of the engine. I had this exact same problem it this fixed it right up.

ask52
04-10-2008, 11:08 PM
I just checked the plug and its good. the checked the wires from the coil packs to the igniter and everything checks out. but now I'm down to running on 2cyc. #1 and #2 which is really weird. so now I'm thinking the igniter must be bad???

ask52
04-11-2008, 12:17 AM
well i found the ecu pin out. switched #4 with #3 and now it runs on #2 and #3. changed the wires back and it still stuck runnng on 2,3. tried to swap plugs and packs again and nothing.... grrrr

ask52
04-11-2008, 09:58 AM
also checked wires from igniter to ecu and everything thing is good. I'm gonna pick up an ecu and ingnter today and see if that works.

ask52
04-11-2008, 08:20 PM
fixed it! was a bad ecu, runs perfect now! on a side note the ecu has 4 individual out puts for the coilpcks. #4 was down.

project_s13
04-12-2008, 04:25 PM
ic so that ingition module runs 4 indaviual coil packs? i dont see SR's around here to much so havnt really had a change to "scope" one out

duffman1278
04-13-2008, 10:00 PM
I had this similar issue, ended up being a bad ECU.

Edit: barely read your post, and that you fixed it lol

ask52
04-18-2008, 10:46 AM
ic so that ingition module runs 4 indaviual coil packs? i dont see SR's around here to much so havnt really had a change to "scope" one out

yep the ecu has 4 individual outputs that run to the igniter chip. then it runs to the 4 coil packs.

I had this similar issue, ended up being a bad ECU.

Edit: barely read your post, and that you fixed it lol

:) yep that fixed it, but I think something is funny with the replacement ecu because it brakes up at crusing speed (3000-4000rpm) once the car warms up, yet if you give it gas it pulls hard and runs perfect. checked the knock sensor and its good. drove it 900kms on and off the gas to get it home!!! also it didn't have that problem with the old ecu when it ran on 3cyl. + it wont idle after it warms up?