3S-FE Missing while coasting and steady throttle, need help.

[nogard]

I have a 1988 3S-FE Manual Trans about 160,000. New timing belt 2 years ago, 1 year old cap and wires. New NGK V-Powers, distributor rotor, distributor (came with new coil).

The car started to have a slight miss in late spring. It was time for new plugs. Put those in, still no change. Tried E3 plugs seemed to work OK. Then I connected Jacobs Electronics Mileage master, car would miss unless I under gapped the plugs by 0.010". Noticed stock coil was cracked distributor shaft was leaking oil. Got a new distributor. Car still missed, took Jacobs unit off, tried E3 plugs but missed. Put a new set of NGK V-Powers in at stock gap. This is where I'm at now. Timing is at 13 deg with test jumper in, AFM spring is leaned out "10 Clicks". Car always ran good with this combination until now.

Idles with slight miss here and there. Good power on full throttle. After a full throttle rev I can smell unburned gas. At steady crusing speed in town or on highway car misses, mostly at around 2K RPM. Car really misses and is jumpy with in gear off throttle "coasting".

I checked all the electrical connections, I have my ignition amplifier grounded with a separate wire to the fender where the main battery ground is. I had a corroated connection on the ignition amp on another camry that made it miss.

I'm frustrated and don't know which direction to turn next to track down the problem. Please help.

Thanks.

[Mike Gerber]

Were the plug wires Toyota OEM or an aftermarket set? The reason I ask is I have seen cheap aftermarket wires fail in as little as 1 year or 20,000 miles. Have you ohmed the wires? Do you know of anybody else around you with a 3SFE engine that would let you swap their wires in for a test? I know it's a pain on this engine, as the cap is part of the wire set.

Mike

[nogard]

No the plug wires are not OEM Toyota, they are aftermarket from Advanced Auto. You are right I should ohm them, I forgot about that, and it is even in the haynes repair manual.

I had an old set of wires from two years ago that I held onto just in case I would need a wire. I forgot to mention that. When I was doing all this work I didn't twist the one of the wire enough while I was pulling it off the spark plug and the metal tip came off the wire. So I grabbed one of the 2 year old spare wires and put that on. This could be my problem.

My gas mileage is also down, I usually get 34-36 MPG, and I'm getting 31-32 MPG. I do not know anyone with the same engine. I don't think it is a pain to work on this engine it isn't bad.

I do have a factory Lexus es250 strut tower brace. Even though it looks neat, I don't know if it really does much for bracing. But it is in the way of getting the air filter/AFM out of the way to get to the distributor. If I'm doing a lot of work I will just take it off, and if I plan to be under the hood for a while I also usually take the hood off. It is a little extra work, but it makes things so much easier and enjoyable.

If I remember correctly the cap and wires that were on the car when I bought it 4 years ago were an OEM set where the wires are part of the cap. But the set I have now the wires will pull off the cap.

Well I will start with pulling off the wires and ohming them. If they are out of spec then I can figure this might be the problem. And if they are out of spec sounds like I need to bite the bullet and go to the dealer$hip and get an OEM set.

I was also considering if I might have an issue with one of the fuel injectors, but I'm leaning more to the ignition system.

[Mike Gerber]

Although a miss can be caused by a fuel injector or even a mecahanical problem inside the engine (bad valve), it is most often caused by a faulty ignition system component. If you didn't have this miss before changing the cap and wires previously and you still have the OEM cap and wire combo, why not just throw those back on as a test. If it solves the problem, just keep those on the car until you can get some new OEM ones.

If new wires don't solve the problem I would next check out the coil inside the distributor. You will need the digital volt/ohmeter again. The procedure and specs should be in any manual. The internal coil in the first 3 generations of Camrys were problematic, especially when they rack up lot's of miles. Also check it visually for any signs of cracking.

Mike

[nogard]

I called car quest, I've had good luck with their wires in the past, and a friend of mine that runs an automotive repair business told me the same thing. The guy at the store said that the company that makes the wires they sell makes a large amount of wires for the whole market. He said most likely the toyota factory wires are made by the same company. I brought up the point that though company's like this make wires for a lot of different suppliers that doesn't mean that you are getting the same product, they could be made to different specs.

I do not have to original set of wires. I have the current cheaper set and the set just like it that I had on before. I bought a set of wires with the cap and a new rotor. This set looks just like the factory set. Where the wires are attached to the cap they are installed with a one way clip. The wires don't plug into the cap like the one I had on the car.

So far it seems to be running better. I think that is was the wires. The set I just took off the car that my be the problem, I've had those on there for the last 18 months. When the car started missing I thought it was the plugs they usually only last a year. When I took them out they didn't look that bad. Putting new plugs in helped with the miss, it was probably still there a little. And then it just got worse. 2 years ago I changed plugs because they needed it, and then I also changed wires. Plugs alone didn't seem to do it. Now that I think of it you are right on saying that the cheaper wires just don't hold up.

[Mike Gerber]

"Putting new plugs in helped with the miss, it was probably still there a little. And then it just got worse."

In my experience, it takes less voltage to fire new plugs. As you put a few miles on the new plugs, they became like the old plugs and the wire(s) couldn't provide the necessary voltage to fire them. Let's hope the new cap and wires solve your problem.

Mike