Stutters at boost
 

I changed the plugwires with Magnecore 8.5mm, changed the sparkplugs with stock replacements. Now whenever i go and hit it, boost builds, just that the car doesnt go anywhere. The car sounds like its struggling, and it stutters the whole way. The exhaust also seems to get deeper as boost comes in and sounds like its popping. The car just shakes and doesnt move. Boost builds up, but it sounds like its not firing right or something :(

Please help

ALI

Pre-Detonation?

hmmm...got an A/F gauge?? the injectors stuck open? Running too rich?? either that or u have a hose that popped off.

Re: Stutters at boost
 

Be sure you replaced the wires completely onto the plugs(snapped onto plug end) and also that you completely connected the coil end, sometimes air can be trapped inside the boot and pop off the coil when it heats up. Also and maybe most important, be sure you have the appropriate plug wire going to the appropriate coil!
aRt

did you gap the plugs accordingly??

Stock plugs.... Gap??!?! WTF?

I dont have an A/F but a EGT. I checked it and its been running rich, and when boost comes in it becomes really rich.

I "burped" the wires to remove excess air from the connections already, the problem has been doing it since the stock wires. This is why i bought the magnecores.

Also im 100% positive that the wires are where they should be.

Please help

your check engine lights isnt on??

even if you get stock plugs, check the gap. I got stock ones for my 300zx and 2 of the 6 werent gapped correctly. From shipping i guess

maybe its your wiring harness. How many miles?

LOL some of you guys need to remove one of your stock spark plugs and exmaine it..

The harness should have around 108k miles on it. The motor is rebuilt, but thats about it. No warning lights are coming on, but the EGT spikes whenever boost comes into play. The car just doesnt pulls, just sits there and pop from the exhaust. It never did this before.

P.S. ulost2my7....what part of jersey city, i lived there most of my life and just moved to FL. I lived off of kennedy and danforth

ALI

i live right off kennedy and thorne street, if you dont know where that is, you're not a true jersey city guy :p:

but nice going with the move to florida, i always wanted to live in fl..

maybe its your harness then. Due to aging, maybe it cracked and one of the plug isnt getting a spark, or something.

only other thing i can think of is a hose popping off. Is it rough at idle?? If it was a Mass air flow sensor i would think the check engine light would come on.

Iceman4357-

Okay... you need to stop giving advice. Namely:

A. There is no such thing as spark plug gap on a rotary plug. Take one out. Look at it. The concept of "gap" doesn't exist on horizontal electrode plugs.

B. There is no such thing as a mass airflow sensor. Mazda used speed-density mapping, so there's only a manifold air temperature and pressure.

C. If he truly is misfiring, then an A/F mixture gauge is useless. It will read lean no matter what... Example: the mixture is 6:1, you misfire, so there's extra oxygen in the exhaust. The oxygen sensor reads "lean" even though you are at 6:1.

I know you have the best of intentions, but if you don't know what you're talking about, then keep quiet. As a great man said, "the road to hell is paved with the best of intentions." :-)

Take care,
Shad

I just reset the ECU and took it for a drive, but its the same thing :( No difference. Please any input would be appreciated

Thanks
ALI

Troubleshooting 101:

Process of elimination:

If addition of new part causes unexplained difficulty, revert to previous part and see if difficulty still exists.

In this case: Revert to stock plug wires and see if problem still occurs.

ok, the car was running perfect as usual. So i decide to change the sparkplugs, and as i am driving away from changing them, the problem arises. The car would buck from being boosted. The car builds boost and everything just the car seems to not like it anymore. So i started to check the plugwires thinking it was broken or something. Sure enough, i find the leading plug on the second housing popping off of the sparkplug after being driven (without boosting of course). So i thought the wires were giving the problem, so i proceed to order Magnecore 8.5mm's from Rx7store.net. When they arrive, i installed them using the direction on Scudeiani's site. Took it out for a drive afterwards and the same thing. Im begining to think that its just the sparkplugs are bad. Has anyone heard of new sparkplugs being bad?

ALI

Just buy new ones and find out... thats the easiest way i can tell you to trouble spark plug issues

I have changed thousands of plugs in the 20 years I have been a drive-ability specialist and most often the plug is mis-gaped, not likely in this case or cracked ether by manufacturing or the installer. I would bet on the cracked plug myself. Remove them and run your hands around the shaft. If there is a crack the grease will check in the crack and look real real close the cracks are hair thin or less.

JSJ,

Plugs used in FDs do not have adjustable gaps.

Did you use the diaelectric grease, trini?

It sounds like you probably knocked of something else while replaceing the wires. You need to get in there and look around. You will probably find a loose connection, or a hose that has been knocked off.

See the problem occured before I even changed the wires. The problem only started when i changed the sparkplugs. I thought the problem was the wires, so i changed that, but the problem still occurs. I even cleaned all of the grounds and checked them. But has anyone heard of faulty sparkplugs from the manufacturer?

ALI

anything is possible,just because it's new doesn't mean it works. take them out and change them it sounds like it may be your problem. like was said earlier go back to what you changed and and the problem is probably there.