idle missfire??
- Thread starter gjp
- Start date
QUICK STORM
B.A.M.F. BMW Tech
Re: idle missfire??
knock retard and too much = new motor
get datamaster and keep your foot out of it.
knock retard and too much = new motor
get datamaster and keep your foot out of it.
wantingasy
Active member
Re: idle missfire??
KR=Knock=BAD....Start by replacing alllllllll your vacuum lines. Voltage plays a huge roll too. My voltage would drop when I turned on my lights too and cause the truck to idle rough. My turbo timer has a voltmeter on it and at idle it was in the low 13's dipping into 12's. I got a new alternator and that helped my voltage/and idle a lot. I still have a rough idle too when it warms up. Main things to cause that on these trucks I think are vacuum leaks(most important) and electrical problems. Search for the "bicycle test" and check for leaks. :2cents:
KR=Knock=BAD....Start by replacing alllllllll your vacuum lines. Voltage plays a huge roll too. My voltage would drop when I turned on my lights too and cause the truck to idle rough. My turbo timer has a voltmeter on it and at idle it was in the low 13's dipping into 12's. I got a new alternator and that helped my voltage/and idle a lot. I still have a rough idle too when it warms up. Main things to cause that on these trucks I think are vacuum leaks(most important) and electrical problems. Search for the "bicycle test" and check for leaks. :2cents:
QUICK STORM
B.A.M.F. BMW Tech
Re: idle missfire??
this thread sucks for newbs to read its sooooooo long
this thread sucks for newbs to read its sooooooo long
Re: idle missfire??
+1
I just read all 18 pages of this and although I'm further ahead now in what I'll check, it was a lengthy read!
FWIW I had a hard miss that nearly stalled the truck. Got playing with things and pushed the #3 wire back onto the plug - miss almost gone!
I'm just getting into looking for the slight miss I seem to get after warmup. It has a hesitation when lightly pressing the throttle but only until warmed up...and the miss starts then. I doubt its' related but I'll find out.
If I find mine (after all the regular things like cap/rotor/wires/plugs/fuel filter etc) I'll post.
Also, my 1994 4.3 N/A did this too.
+1
I just read all 18 pages of this and although I'm further ahead now in what I'll check, it was a lengthy read!
FWIW I had a hard miss that nearly stalled the truck. Got playing with things and pushed the #3 wire back onto the plug - miss almost gone!
I'm just getting into looking for the slight miss I seem to get after warmup. It has a hesitation when lightly pressing the throttle but only until warmed up...and the miss starts then. I doubt its' related but I'll find out.
If I find mine (after all the regular things like cap/rotor/wires/plugs/fuel filter etc) I'll post.
Also, my 1994 4.3 N/A did this too.
wantingasy
Active member
Re: idle missfire??
I had that slight bog off of acceleration also, still do kind of. That also almost went away with the new alternator.
I had that slight bog off of acceleration also, still do kind of. That also almost went away with the new alternator.
Flyin Ryan
hated cuz he drives fords
Re: idle missfire??
Only thing I that comes to mind right now (7am with 4hrs of sleep) is a vacuum leak thru the butterfly of the throttlebody. I'd check that when redoing the vacuum lines because if it's leaking enough i'd have to think it could effect performance some.
Only thing I that comes to mind right now (7am with 4hrs of sleep) is a vacuum leak thru the butterfly of the throttlebody. I'd check that when redoing the vacuum lines because if it's leaking enough i'd have to think it could effect performance some.
Re: idle missfire??
Well the good thing about being a doctor is I take half days off on Tues and Thurs and no kids yet so I have time to work on it now. Looks like I'll be buying some vac line and claps today and changing the fuel filter as well.
Keep the ideas coming please.
Well the good thing about being a doctor is I take half days off on Tues and Thurs and no kids yet so I have time to work on it now. Looks like I'll be buying some vac line and claps today and changing the fuel filter as well.
Keep the ideas coming please.
wantingasy
Active member
Re: idle missfire??
Pressurize the bike tube, then get a water bottle or something and spray the vaccum lines (not electrical) and watch for it getting blown away or bubbling on lines. Or I've read that if you smoke, just blow smoke on the vacuum lines and see where it gets blown out. Spray some near the Throttle body too (carefully and strategically placed) to see if that's leaking like someone else said.
Pressurize the bike tube, then get a water bottle or something and spray the vaccum lines (not electrical) and watch for it getting blown away or bubbling on lines. Or I've read that if you smoke, just blow smoke on the vacuum lines and see where it gets blown out. Spray some near the Throttle body too (carefully and strategically placed) to see if that's leaking like someone else said.
![Quickstop [UK]](/data/avatars/m/5/5165.jpg?1570199786){kind=avatar}
Quickstop [UK]
Combating adversyty.
Re: idle missfire??
what did you mean about 80 psi? That should destroy a bike inner tube...
Maybe you have a humungous leak somewhere...?
what did you mean about 80 psi? That should destroy a bike inner tube...
Maybe you have a humungous leak somewhere...?
Re: idle missfire??
Not necessarily. The pressure is the pressure difference between the tank and atmospheric pressure. 80psi is still 80psi - and that's a lot of pressure. You must have introduced it too slowly. Let more air in to inflate that tube, then listen.
BacDoc said:
Not necessarily. The pressure is the pressure difference between the tank and atmospheric pressure. 80psi is still 80psi - and that's a lot of pressure. You must have introduced it too slowly. Let more air in to inflate that tube, then listen.
Syclone#2960
What ever it takes!!
Re: idle missfire??
Well after reading 26 pages of this I would check the valve stems on the heads. The (if) plugs apear to be getting saturated with oil. I had a similar problem in the typhoon with the plug getting fouled. It would not hurt to install a tailgate strap from the alternator bracket to the frame to help with the torque and another ground source. My syclone fuel PSI is set on 32 psi with the 50lb chip. HTH
Well after reading 26 pages of this I would check the valve stems on the heads. The (if) plugs apear to be getting saturated with oil. I had a similar problem in the typhoon with the plug getting fouled. It would not hurt to install a tailgate strap from the alternator bracket to the frame to help with the torque and another ground source. My syclone fuel PSI is set on 32 psi with the 50lb chip. HTH
Re: idle missfire??
I just read all the pages of this and it sounds like too high fuel pressure. As stated that if you turn the fuel prussure down it idles with no misfire but shows too lean. what do you call too lean? Is it too lean at idle or WOT or all of it? maybe you are trying to over correct your lean problem with just raising the fuel pressure. you could try something like a better tune or bigger injectors just thinking out loud. If this make no sense its because I just read so much and am fried. :microwav:
I just read all the pages of this and it sounds like too high fuel pressure. As stated that if you turn the fuel prussure down it idles with no misfire but shows too lean. what do you call too lean? Is it too lean at idle or WOT or all of it? maybe you are trying to over correct your lean problem with just raising the fuel pressure. you could try something like a better tune or bigger injectors just thinking out loud. If this make no sense its because I just read so much and am fried. :microwav:
gjp
another post whore
Re: idle missfire??
wow, I thought this tread had died. Well after the first build my truck ran better. I still had a miss but only about once every 2 weeks. it is a problem that will never go away.LOL
I tried everything and it would still come back. The FP set at 32lbs with vac. unpluged would cause a lean condition everywhere but at idle. Idle was fine but was lean wot and part throttle. With the wb02 on and the engine missing showed idle at 12.7-13.5. same as when not missing?
Now the engine is out and truck is all apart. The valves looked fine. Everything looked normal as far as I can see. Timming chain was tight. In fact tighter then I expected for a 95k engine with only 3/16 of play.
I hope after I am done the miss will be gone. With the volvo fan. cowl hood, coated exhaust, alky, a2a and high flow water pump should keep my engine happy. New heads should take care of any problem I had there. Only time would tell.
wow, I thought this tread had died. Well after the first build my truck ran better. I still had a miss but only about once every 2 weeks. it is a problem that will never go away.LOL
I tried everything and it would still come back. The FP set at 32lbs with vac. unpluged would cause a lean condition everywhere but at idle. Idle was fine but was lean wot and part throttle. With the wb02 on and the engine missing showed idle at 12.7-13.5. same as when not missing?
Now the engine is out and truck is all apart. The valves looked fine. Everything looked normal as far as I can see. Timming chain was tight. In fact tighter then I expected for a 95k engine with only 3/16 of play.
I hope after I am done the miss will be gone. With the volvo fan. cowl hood, coated exhaust, alky, a2a and high flow water pump should keep my engine happy. New heads should take care of any problem I had there. Only time would tell.