idle missfire??

W

wantingasy

Active member
Re: idle missfire??

My truck idles really weird also. I just did a tune up on it also (kit from detroit turbo-ngkur5's, taylor wires, cap&rotor) and it still idles weird. When I first start it, it idles fine. But as soon as I give it a little gas (while still in park) the rpms will like bounce up 900-1000 then down to about 475-500 where I can watch my boost gauge go from 20HG to like 10HG to compensate for the low rpms. Or when I'm driving and come to a stop at a light, the rpms will drop to like 500 and get compensated by more air again. It has never died on me though. My oil pressure gauge hasn't worked since I bought the truck in January because it did that flip thing!!! I plan on pulling the cluster out and fixing that this month. Do you guys think I should change that switch also? The guy I bought it off of says that thing is bad and needs to be replace, but I don't see how he could tell if the needle is stuck on the other side of the pin!!
 
gjp

gjp

another post whore
Re: idle missfire??

The truck got worse. It misses very bad now. It stumbles up to 1500rpm. at idle the oil guage is all over the place. from 45-80psi. Its fine when its cold. Just when is warmed up. Makes me wish I bought the GN instead.
 
QUICK STORM

QUICK STORM

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

this is one sensor that often gets over looked and is a big problem in a s series trucks, change the switch.
 
gjp

gjp

another post whore
Re: idle missfire??

the Dm shows nothing that I can see, except the bad idle. I ordered new wires. And will pick up a switch, cap, rotor, coil and check the new plugs.
 
QUICK STORM

QUICK STORM

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

wantingasy said:
How does that switch cause this problem?
Click to expand...

the switch is supposed to cut the fuel pump in a event of no oil pressure, so if the switch is shorted or on its way out it won't let the pump supply any fuel pressure, thats my take on it. i just notice with my s-10 that my rough/bad idle is kinda mirrored by my oil pressure gauge fluctuating up and down.
 
akwilks

akwilks

Mr. Keith
Re: idle missfire??

I removed the Phil Long Chip and went back to the 2 bar chip and my problem has been solved. She is not nearly as strong up top as she was before but I can live with that for now. Stalling in the middle of an intersection I cant deal with...
 
gjp

gjp

another post whore
Re: idle missfire??

my truck was doing this on stock setup too. Thats why I spent 2k to do all the mods. And its still there. I will try the msd coil. Does it fit in the stock location? Have a part # Q.S. ?
 
W

wantingasy

Active member
Re: idle missfire??

I have the msd coil and my rpm fluctuates still. I also have the 6AL box that is going to be installed in a couple of weeks. I eventually want to get the msd distributor, but I have no need for it right now. Hmm....where can I get that switch we're speaking of? And I heard it's a pain in the @$$ to get to. What needs to be removed the distributor cap?
 
QUICK STORM

QUICK STORM

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

wantingasy said:
I have the msd coil and my rpm fluctuates still. I also have the 6AL box that is going to be installed in a couple of weeks. I eventually want to get the msd distributor, but I have no need for it right now. Hmm....where can I get that switch we're speaking of? And I heard it's a pain in the @$$ to get to. What needs to be removed the distributor cap?
Click to expand...

search earlier in the thread, i posted a link to where you can get the switch.

remove the distributer, to have EASIER access to the switch
 
syclonekid43

syclonekid43

New member
Re: idle missfire??

when i replaced my switch. i used 2 swivels in order to get the socket on it. it was a pain in the ass. you can take the distributer out to give you more room.
i just replaced the tranny in my 94 4dr. so i figured i would change the switch cause its stays pinned at 80 all the time. there was not enough room.
 
gjp

gjp

another post whore
Re: idle missfire??

Napa cariesthe socket and autozone has the switch. napa has a 3" and 3 1/4" socket?? What fits?? also auto zone has 2 switches that fits our trucks. A 1/4" and 3/8". ?? I will buy both and return the one that does not fit. I have never removed a dist. before. My dad always did that. How do you put it back the same way?
 
syclonekid43

syclonekid43

New member
Re: idle missfire??

best bet would be to set it at tdc. marke the timing to get an idea of where it is. when your ready to drop it back in make sure the rotor points to number 1 cylinder. check the timing when your all done.
 
QUICK STORM

QUICK STORM

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

set it to tdc, then pull cap off of rotor and mark alignment of the rotor to the distributer base, dist goes in 2 ways because of the cam drive and oil pump drive, 1 way will be right the other will be 180 off
 
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