#1 Cylinder Missfire Detected

ok ! what i have is a 1996 pontiac grand am 2.4L 5spd manual trans. dual overhead cam,electronic ignition. (IDI) "Intergrated Direct Ignition". System
its running very rough at idle,getting bad gas milage. when i get off the freeway and come to a stop it stumbles and then picks back up. it does it at a stop light also,lacking power.

i hooked up my "OBD2" code reader, and it gave a reading of "P301" #1 cylinder Missfire Detected

#1) Replaced Plugs & Boots and coil housing Tower

#2) put a screwdriver to #1 injector and it was clicking

#3) i placed a ohm meter between #1 & #4 on the coil tower and it read 5.0 ohms the same between 2 & 3 and no reading between coil and cover Plate

#4) switched coils around to see if it was the coils. still shows #1 Missfire

#5) i checked my ignition module by connecting a test light (at the module) between bat. pos. terminal to the coil(Terminal A) and terminal B or C . when cranking engine light blinks. according to the book that should eliminate the module from being bad. but to check for open or shorted circuit in the coil wiring harness. i didnt do that. how do i do that? and where do i do that?


#6) put a ohm meter to no.1 injector, the reading was within specs described in book.

#7) i Disconected the electrical connector to the (IAC) "idle air control valve"started engine and pulled off each injector electrical and there was a noticable difference in idle change


i didnt have a spark tester light so i couldnt test that
from what i described do you have any advise or instructions besides "take it to the shop"


someone said check fuel pressure regulator,but if it was faulty wouldnt it effect all cylinders?
only #1 cylinder is being pointed out

This is starting to frustrate me to no end!!!!!!!!!

thank you

Wally

How many miles ?

If you have replaced the ignition system components, ICM,coils,plugs/boots then that would point to the fuel system.
Have you tried swapping out #1 injector with another ?

Might also do a compression test and see if #1 reads low.

did not replace ICM or coils. only swiched coils around to see if problem would switch to another cylinder, but it didnt !
i will take a compression check this weekend and also swap injector with another cyl. to see what happens.is there a way of testing my injector wire connector with a test light or multimeter without having to buy a noid light (i think thats what they call that tester for testing the injector wiring connectors)? I'll get back to you after those tests.

thank you for your reply
Wally

ok i did a compression test. #1 cyl only read 30 lbs. the rest were at 150 lbs. i also did a wet test(oil squirted in cyl.) on no.1 cyl But made no difference,still read 30 Lbs. in wich if i remember right that indicates the valves.is that right?
now the other question i have is:the car has 200,000 mi. what would be advisable: pull the heads and have just the valves for that cyl. replaced or redo both the heads? what csares me about redoing both heads is on the older v8's i remember from long back is when you redo heads and put them on old lowerend you end up taking out the oil rings! what do you think?

thanks for your reply
Wally

It could be a bad piston or rings too.The 2.4 is very expensive to repair.If it is a valve,about a grand to do machine work on the head.Two options are to get an used engine or a reman.An used 2.4 is very hard to find,about $1,200.00 for an used 2.4 quad if you can find one with a 90 day warranty.The reman has a 3 year warranty and stay away from reman engines from auto parts store.The warranty sucks taking it to one of their places for warranty work (auto parts stores) and use very cheap parts.The pistons are made in China,bearings made in Isreal and so forth.

I would say its the valve or head thats bad.
These engines are cheap to repair if you can do the labor stuff your self, like removing/installing the head.

I've seen remanufactured heads for around $800+, if thiers no major damage to the head it might be cheapest to get the head worked your self.

Not sure where you live, but some Napa's and Car Quest part stores do machining work on heads. Shouldnt be more then $300-500 if its not cracked or damaged beyond repair.

Good Luck

One machine shop in my area closed down,it was by a Napa parts store due to prices of reman engines cheaper than rebuilding.My father and I will not order anything from Napa,no delivery and my father has no time go down and get the parts running a car repair facility.Used to have one by a Carquest parts we get parts from,someone bought it out and moved it to another place.We still take heads,cranks to them for machining since they do a great job.This is in the Muskegon,Mi area and there are two left,Varney's and Northwestern Auto Machine.My father and I do not take it to Varney's anymore,the owner and his son are %$#)($# and treated my my father like crap.We take a cylinder head or crank to Northwestern Auto Machine which treat us right.

i live in n. idaho theres machine shops but dont want to mess with it if im only going to blow out my oil rings buy putting new or redone heads. yes i can do the work myself except for the machine work. i dont want to put to much into it

Wally

It doesnt necessarily cause ring damage thats BS !
I redo heads regularly, on several 100 different models/makes and I've seen no such occurance.

If you dont want to spend much, just find a used one thats not been redone, probley $150-200 at a salvage yard. No guarentee on most used items though.
Might check here too... http://www.cherry-auto.com/

I would try adding a bit more oil, and making sure you got enough on the cylinder wall. If that cylinder was misfiring from not enough spark, and washed the cylinder wall down, you may just need more oil to get them to seal enough. I saw a honda that had 22 PSI in all cylinders, it had flooded and wouldn't start after drying out. After adding more oil, it eventually started and after running for awhile the compression came up to something still too low, but it ran afterwards. It's worth trying before pulling the head :2cents:

i dont understand what you wrote at the bottom of your post - i did reply back!
anyhow the car still runs. i took the compression tests first thing in thye morning,i put plenty of oil in it,with no change in compression reading!
and about the oil rings i replaced sets of heads on 70 nova-V-8,68 comaro v-8 and 69 chevelle malibu v-8, all hab 150,000 mi plus.after doing so all of them started burning oil and in a short time progresivly got worse. thats whats happend to me in the past and had alot of engine builders tell me thats what usually happens on an old lowerend with lots of miles on it. i didnt want to go changing heads if that might happen again. then that would be alot of wasted money

thanks
Wally

Yeah a lot of older engine w/high mileage have bad rings any way, just from the excess oil burning off from the bad valve(s) or seal.

But with that low of compression thier's definatly something wrong, you wont realy know what's wrong until it's pulled and inspected. :2cents:

oh well!
thanks for the help and advise. i'm going out this weekend and buying a geo metro for the gas milage since i comutr so far to work.ill keep the grand am around for around town arrend running for my woman. better gas milage than my trk

thanks again to everyone who replied,much appreciated
Wally