can't fix this

nissan lover

Registered User
I'm having a very bad bucking/missfire prob on my car. hg's are new, resealed all intercooler pipes, new plugs and wires, no codes, no lights. when i put the gennisis tool on it bank 1 o2 sensor voltage was .02 constantly. o2 voltage should never be this low and should allways have cross counts. replaced the sensor, didn't help. i'm tired of replacing parts.
 
Without knowing much more, it sounds like your DIS is shot. Bad bucking usually equals a bad DIS module. That affects the ignition, so your O2s would be off because of raw fuel possible being exhausted...
 
Your Car

Sounds like a bad vacuum leak. Or In the Ford book i think they misprinted the plug wire spots on the coil, two were switched. i fell for that one when i did my gaskets.
Good luck
 
I second the wire order problem, since the motor sounds freshly re-assembled.

Usually a bad dis will throw a code, whereas an unplugged or misplaced wire will not.
 
Tickler said:
I second the wire order problem, since the motor sounds freshly re-assembled.

Usually a bad dis will throw a code, whereas an unplugged or misplaced wire will not.

An unplugged or misplaced wire won't cause sever bucking though...I've been through both. The dis gives a definate bucking under any acceleration or just driving...wires crossed you have a hard time keeping the engine running period, let a lone driving. And usually it's just a dog then too, but no bucking.

My DIS didn't throw any codes when it went...
 
The coil pack is set up in pairs. There are 2 cylinders per coil, 3 coils. So if the coil pack goes bad, you'd loose two cylinders at the time. Unplug a row of wires, (4&3, 6&2 or 5&1) and see if it changes the way it runs. You can also check plug wires at plugs to see if they are getting spark. And if you feel like pulling the coil pack off, I think Autozone can test them.
 
nissan lover said:
is there any way of having the coil pack tested.

Keep in mind that although coils can go bad, it is much more common for the DIS to go bad than the coil. And the DIS controls the coil...
 
I am kinda leaning towards the big vacume leak theory. Spray carb cleaner sparingly around the gasket surfaces and vacume connections on the the #1 cylinder side of the engine. when you find the leak the engine speed will increase, and the o2 reading will go up. Be sure to have a fire extinguisher there because this kind of testing is very flamable. proceed at your own risk. If you have a leaky sparkplug wire you will have a lovely bonfire. If you don't have a fire extinguisher just take hot dogs.
Danny:eek:
 
On a 94 5-speed the DIS module will be located on the front side of the passenger fender. 89-93 DIS modules are on the accessory bracket behind the compressor.

They changed in 94.
 
Dis

I have a slight shudder on hard acceleration as well.

I plan to replace the DIS soon and the rear shocks have to go. (one has a blown seal)
 
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