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Thunder

Wanna-be 10 sec'r
Joined
May 25, 2001
Messages
150
I have been hunting down a problem, my blm are at 148 (idle), and I have what seems to be a misfire. Coil pak checks ok on carpers tester, and so do wires. (also swapped in my known good w/o any change) If I put an inductive timing light on the plug wires, I can see it missing randomly, and not just off of one coil. I was thinking that the problem is ignition related, but am wondering if an overly rich condition could make it miss like that. The reason I think it may be a rich problem, is I've just taken the t/b off to clean Iac...etc. I have a very strong fuel smell, and everything seems wet. Any help would be great, as I have not passed emissions yet, and have had this prob since last fall.

Thanks
 
What do your plugs look like?Double check plug wires for connection.
 
Just pulled all the plugs. I am just a beginner at reading plugs, so hopefully I am reading them right. They appear close to black on the insulators, some have a bit of a white ring on the tip of the insulator. Although the threads are a bit oily, the deposits appear to be dry. Also, a couple have the grounding electrode turned white as well. These delco 44's, and are gapped at .035.

As for the plug wires, magnacore 8mm. They seem fine. I did the caspers tester with them, and they worked perfectly, as did both of my coil/modules.
 
Does the car seem like it's bucking at all? At a certain RPM?
This seems to be the same problem that my brother is having.
He replaced the coil pack, plugs, wires, coolant sensor, and mentioned somethin the other day about smelling gas or something.
The car bucks/misses always around 2,000rpm..it only happens then.
It only does it when the car is warm too..if you let it sit over night and start it in the morning and drive away it won't do it right away..only after it's warm..
Anyone have an Idea?
 
Black1986beast-

Well, I have not been able to drive the car since last fall. I had the state suspend my plates to give me more time to get the car to pass emissions. I did not have any bucking at that time though. I really doesn't seem to be rpm related though, I can see the timing light missing, at any rpm range.
 
Chip? Fuel Pressure? Why 44's for sparkplugs; 43's are more suited to a street performance application. Yes, it sounds rich regardless of the BLM's. Maybe unplug the orange wire for the ECM to reset it, reseat your chip, and restart with a fresh set of plugs and possibly a new O2 sensor. How do the O2's look; do they bounce around at idle (which would be good)?
 
I'd get back to the basics. If it's missing on your timing light then it's probably the ignition module, coil pack, or plug wires (plugs won't show up on a timing light as they're downstream from the light). I'd swap with known good ones in that order, if you have a friend with a TR and who's willing to help. If it appears to be random on different plugs wires when you test with the timing light I'd go for ignition module. If all that stuff works fine, have you tried the tap test on the MAF? Checked your ECM for good connections? Crank sensor? Cam Sensor? It definitely sounds like an electrical problem.
Keith
 
John, my chip is a lubrant street chip... and things read the same with my lubrant emission chip. Fuel pressure is set at 42# line off, and drops to about 38# with the line on. The ecm has been reset, and also the change from the emission chip to street chip. Plugs have probably 50 miles on them if that, and a half hour of idling trying to dignose since last fall... I have some new ones going in this week. Once the blm stabilize, the o2's do bounce as they should, before they land at their spot, the o2's are way low. O2 is new ac with the same 50 miles on it.

Keith, I wasn't sure if the timing light would show the miss if it was the spark plugs. By my thinking, if there is no spark jumping the gap, there is no current flowing, and therefore nothing for the timing light to pick up. I thought it sensed the current flow, not the difference in voltage potential... not sure though... anyone know for sure?? I thought that it might be the plug wires, but they tested flawlessly with my caspers tester, although I did not ohm them yet, but will this week. Coil & module have already been swapped for my known good ones, with no better results. Maf sensor- I also have a x-lator in addition to my stock maf, and both work the same. Spare crank sensor has also been tried with no luck. I have just begun to test some of the wiring, but feel that I am probably overlooking somthing much simpler.... I hope...

Thanks
 
Hey Thunder,I too am in your alley. I'm in IL and I have my plates currently suspended to give me extra time. Been suspended since october. And I have just got her runnin in the area. I plan on getting show car insurance when i turn 25 (this november) so until then i plan to fail emissions a couple times and then get the show car emissions exemption. This is besides the point however. I wanted to ask you, did you rev it up and are you getting vibration? My car has a slight vibration (mostly at 2000rpms flat) and it seems at 1000 rpms i cant keep her smooth, almost like misfiring. I'm just curious as im tryin to pinpoint this problem and it bothers me. I installed new plug wires and brand new plugs autolites gapped .035 I have a new 800 dollar torque converter going in and i dont want the vibration to throw it off. Is there a way to check misfires with direct scan?

Scott
 
BLM READINGS

If the BLM is at 148, isn't the engine lean? Anything above 128 is lean and the opposite is true below 128.
ECM is adding fuel above and removing below. I'd be looking for the reason all that fuel is being added.
It doesn't sound to me as tho the plugs/ign would make the ecm add fuel.
Where's the cam sensor set?? 180* out and it's gonna run like crap in the fuel dept.

Thinkin out loud....:confused: :eek: :eek:

1 more? Why the 50pph inj's w/ a stock engine? Are you SURE the chip is for those inj's?? base fuel press. appears to be high for an injector of that size in a stock engine. Have you tried to lower the Fp to 38 -40?? Is the FP ga ACCURATE? If it's an on the rail unit, it could be WAAAAYYY off. ! I have an injection bench and test every such gauge on the cars I work on and have yet to find one within 3 to 5 psi of accurate...
 
Scott- I don't think that ds can tell you if you are getting proper spark. Don't really have any vibration either...

Chuck- Yeah, you're right about 148 saying lean. I just thought that with the spark not right, that unused o2 could get through the system, and give it a false "lean" reading. I hope I am reading too much into this. I am pretty sure about where the cam sensor is, but I'll do anything again, and again, and... to get this thing right. I'll check that this week.

I went with the 50's trying to do the buy once thing, maybe I should have waited. Now that I think about it, I went almost straight to my max-effort after putting the 50's in. The little run time it had with the lubrant chip I got with my pte-50's had high blm also. I suppose the chip may not be ideal for my setup.

I will throw my other fp gauge on it as well, if for nothing else, but to verify that my two gauges read similarly. (I know its possible for them to both be off). I will also give it a shot lowering the fp, although, shouldn't that raise my blm???

Thanks

ps- Chuck do you still have balanced sets of stockers available?? Maybe I'll try that route, as I have a number of chips for stockers. (At least till I upgrade my turbo)
 
I was also able to change the oil, spark plugs, o2, and pcv today. The random miss is less frequent now, only once every 15 sec or so... if that. Is this normal?? Am I just creating a problem. Also the blm came down a touch, to 144-145. (At least its moving in the right direction.)
 
hey thunder, Personally, and from what others have told me over the few years ive been in this deal. 50lb injectors is major overkill for stock turbo etc. Basically could endin up using more fuel but not goin anyfaster. You did put a better fuel pump in there right? I cant remember if you said you did or not. If not Id jump to a walbro 340 to keep the fuel comin. as far as the 50lbers, id keep em but throw in some 30's in there with stock setup and you can run good 12's with stock turbo. Then when you upgrade, go ahead and throw the 50's in. just my personal opinion.

Scott
 
Scott, I'm starting to think that going back to a smaller inj. would be best for now. I'm pretty sure that Chuck has some balanced sets of stockers for a good price. Hopefully all my #'s would fall into line again.

As for the fuel pump, its a 340 already, so that should be good for now.... (until the need for a double pumper??)

Thanks
 
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