Popping at the Track!!

[BUICKTR]

I took my car last night to the track. After the second run my car started to pop when it was in boost. If it is not on boost it's okay, but as soon as I floor (POP POP) hestitation. Any ideas. I check IC hoses and vaccuum lines they looked good. I was running C16 fuel, 24 lbs boost, TA62, Hotwired 307 pump. 50 lbs inj.

 

[blackshoebox]

Check the..

1. Coil pack
2. Maf
3. O2 sensor

Sounds like a bad MAF or coil pack to me.

-Alex

 

[rob nolan]

Re: Check the..

Originally posted by blackshoebox
1. Coil pack
2. Maf
3. O2 sensor

Sounds like a bad MAF or coil pack to me.

-Alex

I would have to AGREE with black

Good Luck
Rob

 

[ULYCYC]

Try lower octane race gas like 112 or 114 I had that problem a few times with C16 if under 25lbs of boost.

 

[BUICKTR]

I'm going to check the spark plugs today as well. I do have a spare AC DELCO MAF. If its not that then I will then check my coil and replace fuel filter. Thanks!!

 

[.38 special]

check your fuel pressure while at wot also if you have a fp guage. Make sure it isn't backing down. But it could definately be MAF or O2--do you have a scantool? Also I see you are from Texas, what track where you at.

 

[GrndNatnl]

Could too much of a plug gap cause that as well?

 

[TheNovaMan]

Too much plug gap can cause a miss, but usually there has to be some alternative path for the electrons to take (such as a burned plug wire or something such as that). Increasing the gap will uncover your ignition system's weak point(s). What is a normal turbo Buick plug gap, anyway?

 

[TRENT THOMPSON]

.030-.035 normally

 

[1970gsx]

Definetly check the plug gap. I fixed my high boost popping by closing the gap from .035 to a tight .032. It's easy enough and best of all free.

 

[BUICKTR]

I'm using the Autolite 23 plugs and they are gapped at .032. I still have stock unported heads but they just have new seals and HD valve springs. I race my car at RCR in Marion, Tx and at Alamo Dragway in S.A.

 

[GrndNatnl]

I pulled all my plugs and checked gaps shortly after I bought it. Since under boost it felt like it might have been missing at times. The gaps were huge.. at least for what I was told to put them at. They were around .040 to .045 which scared me. I closed them all up to a tight .035 and it ran great after that. Felt solid. Didnt feel like it was missing or anything. In there now are Autolite 24's. They're still pretty fresh, except cylinder 1 plug had arc streaks across the porcelin. What does this mean? Could it have been from when the gap was too big?

I have a set of AC CR43TS plugs just ready to be gapped and tossed in. Just figured I might as well wear out the ones that are in there first.

 

[TheNovaMan]

Originally posted by GrndNatnl
...cylinder 1 plug had arc streaks across the porcelin. What does this mean? Could it have been from when the gap was too big?

Yup. The spark probably went to the base of the plug between the porcelain and the threaded part.

Originally posted by BUICKTR
I'm using the Autolite 23 plugs and they are gapped at .032.

If you don't have many modifications, then I doubt your problem is plug gap. Tell us about your setup.

 

[turbov6joe]

An overly rich or lean condition will also cause the problem you speak of. Try closing the gap some (loose .033), or trash those plugs and buy a set of NGK's (plug style UR5). I picked up an honest 16 HP on a chassis dyno by changing to these plugs alone, not to mention did a test a while back and proved that they were far more superior than the CR42's or 43's when it comes to durability on a high psi motor!
PS>>what is your static FP set at?

 

[John Larkin]

NGK UR5, what's the proper code for our cars behind the plug number? I've seen several different variations.

 

[JayLashua]

2771

 

[GrndNatnl]

Should I replace the plug(s) after they've had that arcing going on? Not sure what kind of damage that can cause, depending on how long they've been running like that.

 

[turbov6joe]

"Arc streaks", hmmm. If I were you and was running over 21-22 psi of boost, I would drop to a cooler plug (NGK UR5 or CR42TS) and see what happens. The 43's are too hot for high boost IMO.

 

[BUICKTR]

I got a 750 02 reading with 2 degrees of knock. I was using C16 fuel. I'm not sure if I got a false knock. I ran 22 lbs of boost and a 50 shot of nitrous. My boost went to 24 lbs total. I just pulled my plugs out earlier and 2 plugs on the driverside were pretty white and the rest were light color but not white like those two. I just put a set of CR42TS gapped at .032. I have not started the car because it is already to late at night. (Neighbors may get upset) but hopefully in the morning I could get it started. I may use those NGK UR5 if these don't work well. Combo: TA62, 20 row IC, adj reg, hotwired 307 pump, 218/218 cam, Power plate, 50 lb inj, stock maf, chip 20 degrees of timing, THDP, ATR exhaust, stock unported iron heads (valve spring upgrade) and NX stage1 kit.

 

[TheNovaMan]

If two of your plugs are white, then IMHO those cylinders are running too lean (for my comfort anyway). Is it possible those injectors are partially clogged or something like that? Are you sure your nitrous jets are all correct? I know the TB mantra is "lean is mean," but white plugs are pretty gosh darn lean!