xzvs

I have got to get this intermittant miss no top end (and now bogging) problem fixed. I got my butt kicked by a riceburner!!! He cheated as his lane was clear and I had to dodge traffic but when he went, I punched it and went "BWOOOOOOOORRR SPUTTER SPUTTER". I pretended the traffic held me back but truth be told I never woulda caught him. I have done cap rotor wires plugs air filter, tps adjustment, idle adjustment, timing chain and gears, fuel filter, tested fuel pressure (fine while problem occurs), capped off my vacuum to the fuel regulator, same with egr valve. I hooked it up to a tester (snap on) no codes and looked at all the sensors at work and they are fine. The resistance of the injectors is correct. the cat cons have less than 1k miles on them (all3 changed) It is def intermittantly dropping at least one cyl, problem is it runs like a top when im under the hood. I need to catch it in the act I guess and nail it down to which cyl is doing it. I am now kinda thinking a broken wire etc to one of the injectors. Also, on the rh side I have 2 injectors that the plugs could be switched on, but that shouldn't give me a prob as every injector fires twice per rev --right?

scorp508

Our injectors are batch fire. I believe the whole damn bank fires at once.

Any of your plug wires up against the exhaust manifolds? How about your ignition coil? Didn't see that on the list. And what do you mean you capped off the vacuum line to your FPR?

xzvs

I capped off the vaccuum line to the fuel pressure reg to bump it up 10 psi. So, no vacuum leak and no vacuum to the regulator. Yes, wires are routed perfectly. Coil and module are original. I cant afford to throw parts at this thing. Been eating ramen noodles for a month now ;) One day I will throw it on our scope --but its pretty ancient. Plus it runs great every time I am under the hood. When it is missing it will miss one beat every 10-15 seconds


[Modified by xzvs, 9:35 PM 7/31/2002]

scorp508

So you have a high RPM and high heat miss. That isn't fun. I would start looking for things that are cooked. You can get a new spark control module for about $10 at autozone if you want to try that.

xzvs

I have seen a lot of spark module failures --but they just quit. It doesn't seem to matter what the temp of the engine is tho. It does it both cold and hot. It has in the past died out on me (after punching it) and taken a few mins to restart which does indeed sound like a module problem. It does normally fire right up tho --no long cranking ever (sept the one time)

merrick

Try hooking back up the vacuum line to the FPR and reset the ECM

2001 Z06

Could someone post a pic on what the spark control module looks like?

DON M

Pulling the vacuum of the AFPR is not a good idea. It only raises the pressure at low engine speed/high vacuum conditions, and screws with the ECM mapping by making it try to correct for the higher pressure. At WFO/low vacuum conditions the pressure is lowered any way.
I would reconnect it and drive it for awhile to let the ECM relearn its fuel map.

vettmech

Just because your scope is old doesn't mean it's no good ya know..... some of these older "live" scopes are nicer than the new digital ones. The digital ones process the information and sometimes aren't fast enought to capture a problem. I have several of each here at school and the only thing I use the digital ones for are to capture a problem and print it so I can make a slide and show my students
Just my .02 cents

DVAST8R_88

I agree with Scorp...
I had a 77 Firebird that I had build up for racing, and the high heat would fry the module in the distributor. As long as I would putter around, I wouldn't have hideous problems, but I could not expect any performance out of it. I couldn't explain exactly what the problem was, but popping the distributor cap and replacing the module (making sure to add the grease!) would fix it right up. I eventually spent the extra money to get one with a lifetime warranty to save myself in the long run.

Might be worth it to spend the little bit of cash to replace it. I had heard a rumor that Autozone will test it for you for free, so at least you can check it out and possibly eliminate it from the list of maybes.

ZylaRace

The right side and the left side injectors are all wired together,...... they all fire at the same time.

Reconnect the vacuum to the FPR. It is this way to provide the power shot off idle and at WOT. It acts like an accellerator pump. The stock ECM is not programmed to pick up this slack.

If working properly, there is no performace gained by disconnecting the EGR. You will keep the EPA happy by reconnecting it.

What spark gap are you running? Have you pulled the plugs? They may tell you which cyl is giving you the prob.

As the electronics age, their performace changes. I doubt testing will show you a failure. (No hard failure to find.) I'd suggest a new distrib module (as already stated), or swap in a different coil, and see what that does. You did replace the carbon button when you did the cap, right?

xzvs

ok I guess I will try a module this weekend --the scope at the shop only works when it wants to --and tends to freak out --thats why i dont like to use it. The module is under the cap and rotor just take them off and you will see it. its is black and semi curved .

scorp508

Do not forget to put the grease on the module to keep it from burning up.

yoslambo1@cs.com

i hope when you get it fixed you go hunt down the ricer & show him some chevy muscle! :boxing :chevy