TBI Cap, Rotor, Wires recommendations

So my fuel consumption has gone through the roof in the past two months on the 91 OCC.  I put new plugs in and it went from 12 to 13 mpg!  I'm figuring the cap and rotor are in bad shape and ready to pull the trigger on Rock Auto.  
Many options including a tune up kit with wires....

So my first thought was delphi for a cap and rotor, then I saw the tune up kits, then I saw the premium tune up kit with brass contacts on the cap and rotor.  Which to buy?  Which wires are best?  Brands to stay away from or use?

Oh it does have Taylor wires on it now, and chris did a cap and rotor when he owned it, but I've put 38K on it since I've had it...

Thoughts, comments, etc......

I changed the 02 sensor on my '92 OCC and was amazed at how much the mileage improved. Just a thought!

-Mike

81X11 wrote:

I changed the 02 sensor on my '92 OCC and was amazed at how much the mileage improved.   Just a thought!

-Mike

+1 a new O2 also solved a rich condition I had.

Sprocket, if you do a "full" tune up, be sure to also do a new ignition control module. I've had two crap out on me after doing tuneups. Both my wagon, and my brothers old 305 sedan. And when they go bad, they'll mimic a bad fuel pump.

I did NGK 2771 plugs, so far I'm pleased. But only about 1k on them. Also went with summit SUM-868858R 8mm wires. Cap, rotor and ICM are all delco.

A good set of wires will last about 60K miles or more. I got a lifetime warranty Autozone cap and rotor.

Plugs are 20K change-out, unless you use better plugs. LO3 has limited plug selection vs. LO5. Heat ranges are different because of compression differences.

At 38K it probably needs a cap and rotor. Wires should be good for another 20K at least. My dad ran the OEM wires for over 100K on a Jaguar XKE and were still good when he sold the car. Check to make sure the wires are not touching anything.

Your gas mileage would improve if you took your foot off of the gas pedal once in a while.

I'm a big fan of brass contacts in the cap. A bit more money, but none of the corrosion issues that can come with aluminium or [shudder!] plated steel. While I'm not sure what's out there right now for the L05, I've had good luck with Standard Motor Products ignition components over the years, and Accel or Delco/Delphi are usually safe bets. .

When I got Ms. Roadie, I gave here a tune up using the UNITED IGNITION WIRE Part # 17813 kit from Rock Auto. It has worked, and continues to work great for my everyday driving purposes. No Problems have arisen at all. I'm happy with the kit.

Actually the Brass cap and rotor are a weency bit cheaper than the Delphi on Rock Auto.
I since spoke to CHris and the wires are Taylor's so I'm not touching them. Think I'll order up an O2 as well, can't hurt.

Thanks for the feed back.

Sprocket wrote:

 Think I'll order up an O2 as well, can't hurt.

Thanks for the feed back.

I have a NIB one kicking around that I never used because I went to a heated, three wire O2. You're welcome to it for the cost of shipping.

Cadet57 wrote:

Sprocket wrote:

 Think I'll order up an O2 as well, can't hurt.

Thanks for the feed back.

I have a NIB one kicking around that I never used because I went to a heated, three wire O2. You're welcome to it for the cost of shipping.

OK I'll take it.

Sprocket wrote:

Actually the Brass cap and rotor are a weency bit cheaper than the Delphi on Rock Auto.

This is for the LT1 and therefore may not apply to other caps, however, I'd swear that the SMP and Delphi caps for the opti come out of the same factory, and possibly the same mold.

On the left, an SMP brass contact version, on the right, the aluminium contact cap from a brand-new Delphi opti:

[You must be registered and logged in to see this image.]

If you replace the ignition module, make sure you use an AC Delco unit. I replaced my whole distributor a while ago with a complete aftermarket replacement, and it immediately showed signs of ignition module failure. Put in a GM module and all is well.

MalibuSSwagon wrote:

If you replace the ignition module, make sure you use an AC Delco unit. I replaced my whole distributor a while ago with a complete aftermarket replacement, and it immediately showed signs of ignition module failure. Put in a GM module and all is well.

Can't stress this enough. For the price difference between the off brand and the Delco, just spend the extra $10 and get the delco. We put an Autozone one in my brothers car at first, and the same thing happened. Went and bought the delco and the car is still going.

well I shorted A&B and it threw 2 code. 32 & 44.
EGR & lean 02.  A lean O2 would explain the shitty gas mileage.

filled up 2 today. 14.53 on the tank which was about 40% hwy!

Sorry guys, still running the original cap, rotor and wires at 166K. (runs good so why replace it?) However, the changing of the O2 sensor took me by suprise. I was told (by a mechanic) that the O2 sensor either worked or not. Strange to read that changing it makes a difference in mpg. I've got a new one in stock, so maybe i'll try it

Dutch Pete wrote:

Sorry guys, still running the original cap, rotor and wires at 166K. (runs good so why replace it?)

In a word: Wear. Over time, the conductivity of the graphite core wires diminishes, putting a greater load on the other parts of the system, including the insulation layer of the wires themselves. The contacts of the cap and rotor erode, increasing the gap which again, increases the resistance seen by the coil. A certain amount of resistance is required to suppress EMF, but too much is not good either. Secondary voltage creeps upwards, insulation fails, spark energy diminishes. Poor or missing spark means increased fuel consumption. The GM HEI ("High Energy Ignition") system is good, and can crank out lots of voltage if necessary, but after 160k (I assume that's 160,000 kms? 100,000 miles?) and 21 years, I think they are probably done.

Quote :

However, the changing of the O2 sensor took me by suprise. I was told (by a mechanic) that the O2 sensor either worked or not.

Not exactly. An O2 sensor can become "lazy" -- that is, slow to respond to change. Speed is of the essence with these narrow-band sensors because they are not particularly accurate outside a rather narrow range centering on around 0.45 volts and the system is binary: the ECU can interpret the sensor data as either rich or lean, there is no in-between value possible. When the value of the sensor rises above 0.8v (ie: low residual O2 in exhaust), the ECU considers the mixture to be rich, and starts leaning it out until the sensor output is less than 0.2v. When the value drops below 0.2v, the ECU considers the mixture to be lean, and starts fattening it up until the sensor output is more than 0.8v.

As you can see, this action is a constant flip-flop, and the faster the O2 sensor can respond to change, the closer to accurate the result will be. A good sensor can respond to change in less than 1/6 of a second from lean to rich and less than 1/10 of a second from rich to lean.  On a scan tool, the "O2 sensor cross-count" value refers to the number of times the value switches between rich and lean and is considered an indicator of O2 sensor performance. A full cycle should take less than 1 second (ie: cross counts = 2 or more). As the sensor is corroded, coated with soot or contaminated, the speed it can switch diminishes. The ECU spends more time leaning or fattening the mixture during each cycle so the swings get bigger. Cross-counts go down, fuel is wasted, emissions increase.

Heated O2 sensors (ie: 3 or 4 wires to the sensor, used in LT1 models) last longer than unheated ones (ie: 1 wire to the sensor, used in L05 models) because the heater helps keep them clean during warm-up. But all of them have a finite useful life.

Thnx for the info, i'll go and replace my O2 sensor. After all, it's 21 years old. (and it has 166K in miles)
And as soon i'm in the US of A again, i'll get myself a cap, rotor and some wires. (AC Delco style...)

So I out the new O2 in and mileage still crappy. Starting to think it's bogging down but I HAVE been driving an Lt1 lately....next u o cap and rotor I HAVE. On work bench