cobravap

Great Write-up lexmex, Thanks for helping me out as i will be using this to do my plugs. Its stilllll way tooo cold to do that in chicago.

Lil4X

Great DIY, Lexmex! Clear step-by-step photos greatly simplify the task. Thanks!

salimshah

Excellent!

I guess there is no way to torque to spec

Salim

TunedRX300

Lexmex,
Great pictures and DIY instructions.
I wonder does it make sense to replace rear coil(s) when spark plugs are replaced. Used coils can still serve as backup to front ones. Which one is the most difficult and do you know the average mile OEM coil goes bad?

Lexmex

That is an excellent question.

Well the coils themselves cost about $125 USD each, however I would need to investigate to see if the newer coils themselves offer an improvement over the original OEM ones. One of mine died late last year, but I had also been spraying the intake mainfold with some carb cleaner and while on the way to the track, misfire and I was running like a cow. I was already over 100K when mine gave out, however, I had replaced my spark plugs with the old Torquemasters you see just now only a month prior.

Coils themselves can fail for all sorts of reasons. One common one is the fact (as we saw with my old plugs) thay can get corroded and the spark plug gap can widen, thus to bridge the gap so to speak, one needs more power/voltage to get a spark. That can overload a plug. Humidity and climatological reasons can also cause this. Thus at least examining a plug to see the wear is a good preventive measure.

bizzy928

What a GREAT and DETAILED how to!!!

I especially like the hail storm intermission!

If we still had our RX, I would have definitely tried this when the weather was warmer.

What exactly do the coils do? And do all vehicles have them? I remember changing some spark plugs in a 4 banger 91' Camry, and there were no coils. Just a distributor cap and wires... (this shows how much I know about engines)

salimshah

Coil distributor system was, a single coil would produce high voltage and the distributor would provide electrical path to the right plug in a round robin fashion. Distributor ended up being a high voltage switch.

With the coil over plug, the high voltage (coil) directly connects to the spark plug, and the primary side (low voltage) is switched sequentially.

Advantages:
The coil now has longer recovery time as it now has to produce high voltage once per two turns of the crank.
EM is reduced as there are no long spark plug wires.
The round robin switch now works at lower voltage.
Spark time lag, due to spark plug lead and routing is now very controlled.

Salim

Jubane

Problem. I took my car to a garage to get the spark plugs replaced I decided on getting the Bosch +4 iridium fusion plugs http://www.boschautoparts.com/Produc...Plugs/IrFusion

I do not know if its the plugs or they did some sort of error but what is happening is that I am getting ALOT of smoke from the exhaust and it smells rich, like the fuel is not being burned. The truck idles fine but with alot of smoke. From a dead stop when accelerating the car hesitates almost like it wants to turn off and literally feels like one of the coils firing at the wrong time. I am thinking that when they put the coils back and connected them they crossed one of the connections.

Want to get your input as to what else it could be but I think thats what it is. Also if anyone has used these plugs or if it could be the plugs. Thanks

TunedRX300

Go to Autozone and get CEL code read out for free. Could be a bad plug but most likely a bad coil pack.

Jubane

I have gone to autozone before to get a code read out and it will give a code if the check engine light is on. It is NOT coming on in this case which suprised me the problem I am having it should be buzzing and flashing hey there is a problem.

Lexmex

Jubane,

In order to get any code, you might want to pull the battery cables off and let the system reset. When I switched out my plugs, I pull the battery cable (actually I do it every week before I got to the track).

Like TunedRX300 mentioned, a bad coil pack is a likely cause here. It need not be a total failed coil, just inefficient. They could have messed up the connections and that would throw off the firing sequence. I have made that boo-boo a few times on some cars at my uncle's garage.

Jubane

On the connector is there a number that will pertain to its firing order number and also would anyone be able to give me the firing order??? This way I can check the front connectors and see if I can see the numbers on the rear ones.

Jubane

Well truck is back and running smoothly trouble was the spark plugs they were not firing correctly. Replaced the Bosch with Denso Iridium and engine now runs smoothly. Thanks to all for your suggestions

TunedRX300

Thanks for posting back, what is the BOSCH model and part number you used?

Jubane

I used the Bosch Platinum Ir Fusion +4 plugs Part # 4501;

http://www.boschautoparts.com/Produc...Plugs/IrFusion

These plugs are a big