What part of the ignition system can make the spark weak?

[90 GSX]

I'm having a random miss problem. It's pretty much always present but it feels like it gets worse as the car warms up. The car runs like a dog and it knocks a little bit 0-5 counts whereas it didn't before. The problem is at its absolute worse when I'm crusing at low throttle at high rpm like 4000 maybe. Under those conditions it missed often and hard. Since it's gets worse with higher RPM I'm figuring it's an ignition problem, but what could it be? The problem developed out of nowhere and just kept getting worse.

I've already replaced the cas, coil, power transistor, plugs, wires, and plug well gaskets and a bunch of other stuff that had a slim chance of being the problem. What the hell else is there? Could it be a pin somewhere not making a good connection, like on the ECU or something? How do you remove an ECU pin to bend it back.

On the ECU subject, I put a working ECU from a friend's car into mine and the CEL did not come on when I turned the key to "on". Aren't all ECU's supposed to do that? I started it up and the car idled the same way it did before.

 

[Defiant]

What plugs, what gap? NGK BPR6ES at .028"

 

[90 GSX]

BR7ES at 0.028", they are the marine version of the BPR7ES. They are exactly the same but the tip does not protrude, it is recessed into the plug body. The car ran VERY well with them. I threw in some BPR6ES a week or two ago to try to solve this problem but it seemed like it made the car run worse.

 

[GTPDan]

I also am experiencing the same problem. I have changed the cas, coil, power transistor, plugs and wires, and received a motoguys ecu today and changed it and it still does the same thing. It has such a bad miss that it isn't even funny. I traced all wiring from all the connections back through the harnesses and into the vehicle. I have no findings of any bad wiring on the vehicle. And i'm still getting no spark to #4 and #1. I have checked a couple relays but I'm not sure if that is the problem or not. It's so bad I can't go over 15 mph. I too am confused and would like to know if there is anything that were missing or if anybody out there has had this happen and went about fixing this problem?

 

[Defiant]

What wires?

I'd never heard them called "marine" plugs before.

 

[90 GSX]

I used to have accel 300 wires, I think they were still good because they didn't arc but my plug well gaskets were bad and there was oil on them so I got some new stock wires.

The box of the br7es says marine I believe... but they are the same plug, with a recessed tip.

 

[fulanititoo8198]

BR7ES at 0.028", they are the marine version of the BPR7ES. They are exactly the same but the tip does not protrude, it is recessed into the plug body. The car ran VERY well with them. I threw in some BPR6ES a week or two ago to try to solve this problem but it seemed like it made the car run worse.

Maybe thats the problem iirc the ngk's I run are ngk bPr7es not br7es I think those are different. You might want to double check. If you need the cross reference # some of the parts stores use instead let me know.

Edit- I googled and the P means projected. Check that chart out.

http://i2.photobucket.com/albums/y11/dsm2nrs/ngk_sym.gif

 

[tsiawd1996]

i know my plugs were not gapped right and the motor ran like crap ?

 

[90 GSX]

My car ran awsome with the br7es... unless a seemingly well-functioning plug goes bad I don't see what could be wrong with them? For the hell of it, I'm going to try brand new autolite 62's (NGK 7 heat range) and see what happens either today if I have time or tomorrow.

But yea, the 'P' in BPR7ES means protruding tip, which is why I said that the BR7ES had a recessed tip. They are good plugs but I doubt you would notice a difference going to BR7ES on a car that runs well with BPR7ES.