Bad miss under load!! UPDATE Fuel Pump DEAD!

[94CutlassXtreme]

Yea, so my car has developed a bad ignition miss under heavy acceleration. Not so much if I'm going like 45 and floor it, but if I get on it from a stop is putt putts. I took it for a beat run tonight and was hanging with a newer BMW when it started to miss so much it wouldnt accelerate and felt like the tranny was slipping! I let off and smelt a nice burning odor for a minute. Still sounds fine. Idles fine. AC Delco Platinums and MSD superconductor wires went in a month ago. Has Accel coils but they're like 9 years old. I thinking it's either them or the ICM. Moreso I'm leaning towards the coils. Anyone agree cuz I'm about ready to go and order some MSD coils off Summit. If that doesnt fix it them I'm going to get a new ICM, and if it still dont work then I'll go and do some regular Delcos. After that I'd do a Crank Position Sensor. The only other thing that could cause a miss like this is burned, IE not closing intake or exhaust valves. Any ideas? I'm pretty fed up at this point. I'd at least like the car to run good. It's not already bad enough that a friend of mine backed into it and my driver's side door handle busted????

[95oldsVan]

I had a real bad misfire on my van that turned out to be those damn metal spark plug boot protectors on the rear of the engine.I chased down a misfire with new parts for the longest time til one day decided to discard them and bingo,the car runs like a champ.I even saw the burn marks on the plugs were it was misifiring from them damn metal sleeves.

 

Dont really need them.If your engine has them,take them off...another factor that led me to remove them was during wet rainy,damp days the misfires got worse.I knew the plug wires or etc wasnt sealing somewhere too.

 

Just a suggestion to check or try before going over board with throwing money at the car like I did.

 

 

 

 

[Z34-5speed]

I had a problem like that when i first got my car. I changed the plugs, wires, and the coils. That didn't fix the problem at all. It wound up being my o2 sensor, it was melted in half. My car would do the same thing that you describe. It even smelt alot.

 

Kyle

[GP1138]

Platinum plugs could be your first problem. These ignition systems are waste spark ignition, three plugs fire reverse polarity, which eats platinum plugs for dinner.

 

Second, I'd bet your coils are going bad.

[19Cutlass94]

Id get some regular Delco's no matter what. Check the wires and the coils.

[95oldsVan]

Id get some regular Delco's no matter what. Check the wires and the coils.

 

I agree...I have always used Delco plugs and NEVER had trouble with them,unless an outside part was bad like a coil,module or in my other case,spark plug shields.

 

ALWAYS gap your plugs and check them again if plugs you buy say Pre gapped.

 

 

 

[slick]

The Accel and MSD stuff on these cars is a waste of money. You are not gaining one bit by spending your extra cash on those.

[terryk2003]

yeah, i'd deffinatly go back to STOCK coils and AC plugs...

[94CutlassXtreme]

I understand exactly what you mean about the spark plugs firing with reverse polarity. Even still, all that means is that the spark will jump from the side electrode to the center electrode, so I'm not seeing the whole eating platinums for lunch thing. The 97 cutlass supreme calls for platinum plugs, and aside from going from speed density to MAF, the engine code is still the same. I only put the platinums in there because the last longer. Tonight I'm going to mist the wires and coils with water to try and see if there's any arching going on. Then I'd consider popping regular Delcos in there.

[SigEpCutlass]

Um...I have another possible scenario for you that's not quite as pretty.

 

That is exactly what my car did before I lost an injector. Then it got worse and started doing it at random at any speed. I thought it was the plugs, wires, or coils. I replaced the old AC Delco plugs & wires with Taylor Spiro Pros and with NGK Iridium plugs, but the problem was just as bad. Coils checked out okay, and then it was a bad fuel injector.

 

Give this a shot. GnatGoSplat suggested I give this a try when I had my problem.

If you have an inductive timing light, you can check the plug wires going to each cylinder when it's running bad. If you see 2 bad plugs going to the same coil, it's a bad coil. If the problem is now permanent, you should be able to tell by pulling the plugs and seeing if any are moist looking. 2 moist plugs on the same coil = bad coil. One moist plug most likely = bad injector.

 

My 1st instinct when I first read your description is it's a bad coil. A single bad injector doesn't have symptoms that severe.

Start the car and let it run. If it's intermittent, you'll have to drive the car or run it till the problem shows up.

When the problem shows up, connect the timing light to each plug wire one at a time and watch the strobe. The timing light will flash rapidly for plug wires connected to good coils, and flash intermittently or not at all for bad coils.

 

I have an inductive timing light because it's a very handy tool for diagnosing bad coils without actually having to disassemble anything.

 

 

 

Here's the complete post: http://www.w-body.com/forum/index.php/topic,45751.0.html

 

Hope that maybe gives you something to go on.

[94CutlassXtreme]

Well bad injectors wouldnt be so bad. I'd only have to take off the EGR and plenum. Then I could paint the plenum too. I priced out the injectors at work. My price of a nice set of Accel injectors is only 150 bux, and it would help with the fuel delivery for the nitrous. The car bogs after about 8 seconds, only because the injectors a maxxed out. I find it odd, it only happens when I really hammer on it.

[SigEpCutlass]

Don't even really worry about that yet. Did you try the test I quoted from Shawn? That should help you isolate your problem.

[94CutlassXtreme]

I really couldnt do the test at all. It doesnt miss at idle, or even if I rev it up in park or neutral. It's only if I completely floor it from a dead stop, then it sometimes happens again, even more severely at around 80 mph at WOT.

[SigEpCutlass]

I really couldnt do the test at all. It doesnt miss at idle, or even if I rev it up in park or neutral. It's only if I completely floor it from a dead stop, then it sometimes happens again, even more severely at around 80 mph at WOT.

 

You should try testing it right after that happens. If you find nothing, then it's probably a fuel injector letting you know that its not going to last much longer.

[94CutlassXtreme]

Yea so the miss was fuel related. Leaving work tonight I tried to start my car. It fired up for a second then died out. Then it would crank and crank and not start. Fuel pump is definetely not coming on. Didn't smell any gas when cranking. So basically, the miss under load was a stuggling fuel pump. I guess I can't really complain, the pump lasted 145282 miles. Not bad, except now I need to have the car towed. What's the number of the Walboro pump for the L67 swap and can I just put that in without doing any other mods like the FPR?

[Mach 5]

How do you know that it is the fuel pump. Did you hear it come on for 2 secs when the key on, no start.

[95oldsVan]

If its the pump verify that the fuse isnt blown and check the pressure at the rail.

Since its being towed,looks like whoevers going to repair it will check that for you and suggest the fix,unless you plan to fix it yourself?I couldnt recall what you said.Either way,good luck and hope this cures your car so you can enjoy it again.