Missing when cold
19 January 2010, 03:18 PM
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Missing when cold
I had a cold starting issue here :https://www.scoobynet.com/general-te...-problems.html which seems to be ok now, however i still have a problem with the car missing when cold, it normally does it when left to get cold for a few hours, not overnight? so for instance when i leave work, or like just now when i went out to lunch.
I have replaced the CTS, the lambda is new, i have tubular headers now fitted, an uprated fuel pump and standard pressure regulator, standard injectors and a Z4 ecu, the car is a 1993 WRX.
I get no error codes on the ecu.
I have a coil pack to try, but does anyone have any opinions as to what might be causing this?
Thanks for any input, right now i could drive the car off the end of the linkspan and let it float out to sea!!!
Yours Hopefully
Dave
I have replaced the CTS, the lambda is new, i have tubular headers now fitted, an uprated fuel pump and standard pressure regulator, standard injectors and a Z4 ecu, the car is a 1993 WRX.
I get no error codes on the ecu.
I have a coil pack to try, but does anyone have any opinions as to what might be causing this?
Thanks for any input, right now i could drive the car off the end of the linkspan and let it float out to sea!!!
Yours Hopefully
Dave
19 January 2010, 03:51 PM
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Sorry forgot to mention i did the plugs recently too.
I had trouble with the plug nearest the passenger so ended up bolting the coilpack on at an angle to get it to the garage, thats why i have a coilpack ready to try incase it cracked it somehow?
Dave
I had trouble with the plug nearest the passenger so ended up bolting the coilpack on at an angle to get it to the garage, thats why i have a coilpack ready to try incase it cracked it somehow?
Dave
19 January 2010, 03:55 PM
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Could well be a coil, i would fit a new one on the suspect cylinder and cold start test it to see if the fault occurs again. If it does start trying it with each other cylinder to see if the fault is infact on another cylinder.
Matt.
Matt.
19 January 2010, 03:56 PM
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What sensors would you suggest?
I unplugged the MAF and it died stright away.
I also have a crank sensor waiting to go on if the coil pcak doesn't fix it.
I did wonder about the standard FPR would this be possible ?
Dave
I unplugged the MAF and it died stright away.
I also have a crank sensor waiting to go on if the coil pcak doesn't fix it.
I did wonder about the standard FPR would this be possible ?
Dave
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19 January 2010, 04:03 PM
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I'm sure it just flat wouldn't start if it was the crank sensor. The ecu needs crank signal for timing of spark, cam, and fueling. It would just crank over and never start if it was a crank sensor. Then again stranger things have happened at sea.
20 January 2010, 09:49 AM
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Changed the coil pack last night, it looked like it wasn't flush against the head due to the bolt being cross threaded, there was also alot of green deposits on the contact end of the coil pack i dont know if that indicates anything, perhaps arcing? I wont know if its fixed till either lunch or Home time!
20 January 2010, 01:18 PM
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Green deposits mean water has got in there and caused corrosion! Probably due to the fact the coil wasn't flush allowing a way for water to get in between the coil and spark plug contact. This is most probably the cause. Clean it up with some contact spray, sort the thread, new coil on and i'm fairly sure it will be back to it's old self my fruity!!
20 January 2010, 09:47 PM
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Sorry for posting up oxygen sensor on your other thread. I should of read it properly then i would of seen youhad changed it 
. It does sound like water has got into the coil pack as mentioned above especially with the damp weather. Hope you get it sorted. 
. It does sound like water has got into the coil pack as mentioned above especially with the damp weather. Hope you get it sorted.
21 January 2010, 11:18 AM
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First test was a sucsess! Drove home last night and no missing, dont want to count my chickens just yet, i'll see how it goes tonight when i leave too, but so far so good!!
Cheers for all the comments chaps!
Dave
Cheers for all the comments chaps!
Dave
22 January 2010, 09:21 AM
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Nope still missing / spluttering / back firing when cold, for instance after work. Dont know what else to check
To recap i have replaced the CTS, the lambda is new, i have tubular headers now fitted, an uprated fuel pump and standard pressure regulator, replaced suspected coilpack with new one, standard injectors and a Z4 ecu, the car is a 1993 WRX.
I do however believe the new headers are blowing somewhere, could it may be causing a problem if this is the case? perhaps with the lambda sensor reading?
Dave
To recap i have replaced the CTS, the lambda is new, i have tubular headers now fitted, an uprated fuel pump and standard pressure regulator, replaced suspected coilpack with new one, standard injectors and a Z4 ecu, the car is a 1993 WRX.
I do however believe the new headers are blowing somewhere, could it may be causing a problem if this is the case? perhaps with the lambda sensor reading?
Dave
22 January 2010, 10:09 AM
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Ok so we know the spark is ok, it could be the exhaust leak- where is it leaking from?? also have you got anyway of measuring fuel pressure?? i.e with a pressure gauge.
22 January 2010, 10:19 AM
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I am going to get under the car tomorrow and see if i can see anything!
a garage would have to test the fuel pressure. Do you think it could the fpr not working correctly?
a garage would have to test the fuel pressure. Do you think it could the fpr not working correctly?
22 January 2010, 06:01 PM
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have you done compression test yet had exactly the same on my94 sti turned out to be piston ring. its worth the hour it takes to do just to rule out worst case .
james
james
23 January 2010, 03:38 PM
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James is right, as you'll have to take it to a garage to get the fuel pressure checked, you might aswell have the compression tested too. To be honest its starting to seem like this may be fuel related. If you rev the engine does the misfire seem to go away???
23 January 2010, 07:08 PM
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Manifold to uppipe is leaking , i dont think there is even a gasket in there!
I'll get that sorted and see if its any better afterwards. I'll do a compression test and then get the garage to check the fuel pressure.
cheers for your comments
Dave
I'll get that sorted and see if its any better afterwards. I'll do a compression test and then get the garage to check the fuel pressure.
cheers for your comments
Dave
23 January 2010, 07:11 PM
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To answer the reving question, i dont really rev it when it happens as the engine is still cold, i did rev it a bit the other day as i was so annoyed with it and i think it still missed a little bit. It still clears when the engine is warm!
Dave
Dave
25 January 2010, 11:37 AM
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A leaking gasket could cause a misfire, if its blowing as bad as you say then i would expect it to be running like a bag of cat poo all of the time. The gasket is going to need changing anyway, so get that sorted and see how she goes.
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