idle missfire??

gjp

another post whore
Re: idle missfire??

the last time it was missing all the plugs looked good. I dont get it. I put in fresh plugs (again) and new taylors. After 20 min of it missing all the plugs looked the same. At highway speed the rpm fluctuates and the truck jerks slightly.
 

QUICK STORM

B.A.M.F. BMW Tech
Re: idle missfire??

L35 heads worked over should put you at $800 or so, you do it yourself you will save on labor
 

gjp

another post whore
Re: idle missfire??

Thanks, Yes I have read that along with about 100 other pages on this topic.
There is no way i will try a head job myself. My wife maybe.LOL I will pay someone to do that.
 

gjp

another post whore
Re: idle missfire??

I am not going to tell. And she will kick my a$$ if she reads this. She want to take a ride in my Sy as much as me. I realy got to fix this thing.
 

gjp

another post whore
Re: idle missfire??

neighbor works at speedmerchant in san jose. He will do a leakdown and check all he can. They have some cool equiptment there so he should figure it out. He better do it fast too at 100$ an hour its not going to be cheap. He will check what he can at his house first. He did some work on my stang before and I trust him.
 

gjp

another post whore
Re: idle missfire??

new distributor going in today. So the whole ignition is new now. Whole fuel system is new. What else could it be. where should my idle fp be???? I am around 37 lbs. 45 without the vacuum conected. Next step if the shop cant figure it out would be the ECU?????
 

gjp

another post whore
Re: idle missfire??

put in new dist. The truck ran great for 45 min then the missing came back. I removed the plug to injector #1 and nothing changed. I then put it back in and removed injector 5 and the same thing. I had to remove 2 injector plugs to make the engine run differently??? I dont get how it could run good for so long then I turned it off and went into 7-11. when I came out It started rough and begin to misfire again. ??????????????????????????????????????????????????????????????????????
 

gjp

another post whore
Re: idle missfire??

when its cold and I pull a plug wire it is still not as bad as when its warm and it misses on its own. It has to be multiple misfires on random cyl. I am thinking computer. I will pull the computer and make sure its all plugged it. If not I will buy a new one. Still dont see why only when its warm it does it. With the phill chip does the o2 control the fuel still??? What else controls the fuel delivery??? Ignition is just about rulled out. Its all new. Except for the alt but its putting out 13.8volts at idle.
 

mmp142965

say it like you spell it!
Re: idle missfire??

Is there any way you can swap in a stock chip to see if that helps? Maybe change the coolant temp sensor if you havent already?
 

TheNeek

this is my serious face
Re: idle missfire??

My truck does the same idle missfire. It runs pig rich at the top end too. I left the glass open once and it pulls in the exhaust fumes. Good god I almost passed out. My collant gauge never gets to 1/4. Which I know doesn't mean much, everyone says the gauges are garbage. But I still need to look into it. My truck also idles really well until it goes into closed loop. So I'm betting one of my sensors is kaput. I did an 02, air temp, and few seals. I waiting for my house to get built before I really tear into it again.
 

gjp

another post whore
Re: idle missfire??

the stock chip did it too but not as bad. My trucks runs strong too till it warms up. The phil chip keeps it in open loop. the guy at napa had a computer. He will let me try it and return it if it does not work. This will be it for me, After this I will let a pro figure it out.
 

gjp

another post whore
Re: idle missfire??

computer did not help. I re-did all the ground and nothing. I only found grounds behind the alt and just under the coil on driver side. Any more ground locations?? Any more ideas on what it could be. The hotter the engine gets the worse it runs. I cant think of what else to try.
 

Don W.

Stab it and steer it
Re: idle missfire??

Have you tried changing the eng temp sensor on the left cyl head? If it's bad wont the eng say rich as it warms up causing the miss?

I believe (someone hammer me if I'm wrong;) ) that injectors are fired in a odd/even sequence. Pulling inj plugs should give you a solid miss on that cyl. With it hot and missing look at the engine in complete darkness and see if you can see any spark jumping. Kinda depends on where you have your wires running so you can see them but what the heck.

Just thinking out loud again...
 

gjp

another post whore
Re: idle missfire??

Thanks don. Thats what I need is more minds thinking. I am out of ideas. Is that the sensor on top? what is the sensor between 3 and 5 with the one green wire?? any other sensors that could cause a fuel misfire. I can almost rule out any spark issues. Plugs look fine and I did check the engine at night. I tried carb cleaner to look for vac leaks. I am sorry guys to beat this thig to death but after sppending $$$ and over 20 hours working on this I just cant find the problem. Its gota be something I am overlooking and being these trucks are still new to me I dont know enough yet on fixing them. THANKS....
 
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