Missing @ 25 psi

[TurboTerry87gn]

Well I removed the plugs to take a look at them.

Ohm'd the plug wires 558 to 633 ohms except numer 1 fluctuates 1 to 20 k ohms has a bad connection at the coil side snap connector. I also ohmed the coil towers. 1,4: 11.92 k ohms; 2,5: 11.47 k ohms; 3,6 10.70 k ohms .
open from any tower to ground and open between adjacent coil packs.

Does this 10.7 k ohms fall within spec? on 3,6 tower.

Any reccomnedations for new wires. I runnig some spiral wound old ATR wires now. I was thinking the Taylor 10.xx mm spiral wound wires on summit racing site.

Before you ask the a/f is at 11.7 with 24.5 advance. Not sure if I had any voltage drops didn't log the right dashboard.

Runs fine at idle and at medium load only at high boost. I'm running autolight 103's Not sure if that bad plug wire would cause the bad misfire but I'm going to change it anyways. Seems like the high potential voltage wouldn't be bothered by the bad connection on number 1 wire but we'll see. It seems like it would jump right over it with only a minimal loss.

Anyone been down this road before. Missing only under high boost? Plug color looks good.

 

[Dwayne]

Missing under high boost.....I had to close the gap on the plugs from .32 to .28....maybe that will help.

 

[TurboDave]

Missing under high boost.....I had to close the gap on the plugs from .32 to .28....maybe that will help.

+1

 

[mikeandjen]

Not related to the wires, but how are your valvesprings? Fairly new? At high boost applications sometimes you get minor valve float which acts like a severe miss, even if they are lets say manleys or comp cams valve springs, they can still fail under high load after a while. Just a thought.....

 

[BlackBandit]

I'd replace the plug wires and tighten the gap on your plugs. If that doesn't fix it check the ground for the coil pack. I was dealing with a miss under boost and fixed it by running a grounding strap from the back of the coil bracket to the firewall.

 

[Big_D]

I'd try MSD wires, new plugs with a tighter gap.

 

[Evans Ward]

I had the same problem as you very recently at 23 PSI WOT 1st gear at the 1/2 shift. Mine was a bad and faulty cheap plug wire set that was separating at the connector under the boot at plug insulator. Wouldn't miss until it got to high RPM/ high boost level. I did pull plugs and change them but they looked good and were still are .032 gap.

 

[TurboTerry87gn]

Valve springs

I've read about this before, the extra manifold pressure acting on the back side of the intake valves holding them open too long. This could possibly be the problem, because I have never had the boost above about 21psi. I'm running a roller cam, and I had Cal Hartline order the cam and aluminum heads way back, so hopefully thats not the issue I don't want to change the springs. Just got me wodering now because it seems like it dosen't start untill about 22 psi. I'll do a little maintenance on the ignition system and we'll see.

Any other suggestions on plug wire brands? What are the big dogs running? What gap are you guys running for high boost?

 

[waddell87]

I've read about this before, the extra manifold pressure acting on the back side of the intake valves holding them open too long. This could possibly be the problem, because I have never had the boost above about 21psi. I'm running a roller cam, and I had Cal Hartline order the cam and aluminum heads way back, so hopefully thats not the issue I don't want to change the springs. Just got me wodering now because it seems like it dosen't start untill about 22 psi. I'll do a little maintenance on the ignition system and we'll see.

Any other suggestions on plug wire brands? What are the big dogs running? What gap are you guys running for high boost?

I'm running the 10mm fr. Gbodyparts...love them. Was having same issue closed gap to .032, I run 25 lbs. I use iridium plugs UR5's IX there great to. 6's are to hot. Tried .028 gap no dif. so stuck with .032, works fine. check my sig. hth

 

[TurboTerry87gn]

New accel coil pack

I got the new Accel coil pack in.
it reads 12.7 k ohms, 12.65 k ohms, 12.56 k ohms on the secondary, and 0.9 ohms on the primary. Maby the old coil was bad also.

I have updates wednesday after I get home from the track.

 

[TurboJoe3.8]

Plug wires from Russ Merritt :biggrin:

 

[Chuck Leeper]

"and aluminum heads way back, so hopefully thats not the issue."
It was on my Champs..2 yrs, 50 passes, 200 street miles, and the springs were junk. Some were <90# on the seat.
Changed to CC Beehives, picked up 300 rpm, and didn't look back. [CC hyd roller, 218/212]

 

[TurboTerry87gn]

168 dollar fuse

Well I install the new coil pack on the ing. amplifier and I pull it apart and it's all gooey. I'm thinking well I have had this problem before when my last ignition amplifier went out. I called conleys performance when the last one was miss firing and they asked if the epoxy was gooey and it was. I bought this new amp and all was well.

So I install new MSD plug wires and new plugs and the car starts right up then dies 5 seconds later. What the hell, my car dosen't die. Then it wont restart. I think, well the load of thoes new coils made the old amp drivers fail, so I 'll just go get another one. I install it and it dosen't start. I start checking things which I should have done before buying the amplifier and find the coil supply wire, terminal "M" on the ign. module is dead. Check the CCCI fuse and it's blown. I was in a hurry to get to the track, but i should have done some troubleshooting first. Now the track is closed

Well at least i got a spare ignition module. Lesson learned.

 

[Boost231]

wow that sucks. well its a lesson learned.

 

[RUQWKNF27]

Check the CCCI fuse and it's blown."
Why is it when you change the coil and module on these cars it blows this fuse???

I have had this same thing happen to me!

 

[TurboTerry87gn]

Problem not solved

OK well this might be long.

New:
Accell coil pack
Ignition module
MSD Plug wires
Plugs gap @ 0.035
Crank sensor
Reset the cam sensor timing.
Fresh race gas

Verified:
Coil supply voltage Terminal"m" I think, 13.7 at idle.
Grounds
Cam sensor timing.

Tried:
Add fuel

The car misses real bad above 15 psi, This started al of the sudden. I have been running 19 - 20 psi all day long. By missing I mean it's like it cuts out all together and comes back on like it's hitting a rev limiter or the knock sensor is pulling alot of timing out.

Things for tomarrow:
Put old ignition module and coil pack back on.
Reduce gap.
Look at plugs again.
Disable knock retard in FAST, I have it attack at 2 degrees up a max of 15.
Check valve train, springs.
Put oscilliscope on Crank sensor
Add new ground wires.
Put oscilliscope on each primary side of coil under load.
check coil supply voltage under load.


Anyway i'm not sure why these things pop the CCCI fuse when changed out.

I'm going to go over the ignition module electronics schematic and see whats going on inside. if I can find a data sheet on the RCA chip. I assume it's just sort of ring counter with extras.

 

[TurboJoe3.8]

Check all your clamps on all your hoses- make sure they are all tight

 

[RUQWKNF27]

I agree ck. clamps and hoses to I had a problem before and it was a hose that kept my boost limited.

Also I am not sure what brand module you are ysing but if it is a Wells "autozone or a "Sorgeson" take it back. I have had them in the pact and brand new they gave problems. AC Delco is the only way to go on coils.

Also you may have a problem with you fuel reguator diaphram limiting the amount of fuel supply causing it to cut out after a certain point!

 

[TurboTerry87gn]

Getting better

I tightened up the plugs to 0.032
I monitored the crank sensor output 62 hz at idle good all the way up to red line under load.
Monitored coil suppy voltage at ign. module 13.7 vdc under high load
I noticed the new ign module is only supplying 5 vdc to the cam and crank sensor, the old AC delco supplies 7 vdc.
The new ign pack is A BWD from O'reilies.

Put old ign module with Accell coil pack same problem
Put new ign module with Accell coil pack same problem
Put new ing module with old coil pack same problem
Put old ignition module with old coil pack back on problem went away...
these are AC delco parts!!!

It only stumbled one time out of about 10 in the top of first gear.

Now I have the old ing module, with old coils
New msd wires
New crank sensor BWD brand O'relies
New plugs gapped @ 0.032"

Ran my best time tonight.

YouTube - 6.557 @ 105.76

60' is getting better 1.501, I have been fighting a traction problem for some time now.