Coil Problems - Toyota Nation Forum : Toyota Car and Truck Forums

Sully720 · 04-30-2011, 07:32 PM

Hi, I have a toyota 5vs fe engine in my truck and after checking my coil packs for a missfire I have found that Im getting no secondary resistance reading on all 3 coils, I have a primary reading of .9 ohms, Im woundering what would cause the the secondary resistance to fail on all 3 coils ? also to add Im getting no codes on my cel
Thanks Sully720

kball · 05-08-2011, 06:25 PM

If a coil pack was bad you would definitely have a cel. How long since your last tune up? Plugs wires etc...

Sully720 · 05-09-2011, 02:59 AM

Hi kball, Plugs and wires done about 10,000 klm's ago, oil and filter done every 5000 klm's, new fuel filter about 3000 klms ago when fuel pump was replaced also new TPS. MAF cleaned, air filter cleaned out. I checked the coil packs by pulling a plug earthing it and all the packs had a good spark, so i went on to test the injector at the ECU they also checked out within spec, then moved on to test the coolent temp sensor and had found I was getting no reading on the multimeter, removed it to find a small crack where the coolent temp sensor plastic wire plug meets the brass nut, so replaced it with a new part, but it's still missing at idle, I then then got a 2 foot piece of rubber hose and used this as a stethascope to listen to the injectors while the motor was running, I could hear all injector pretty well exept one, on the number 3 cylinder did'nt sound as loud, this is also the same cylinder I first suspected to have a bad coil pack and why I checked the resistance of the coil packs, so now Im thinking it may be the injector, as the missing is not present at highway speeds and it accelerates through the gears with no problems, Im going to run some injector cleaner through the motor on my next fill up and see if it helps.
thanks
Sully

jetwhine · 05-10-2011, 10:27 PM

Sully720,

I would try some BG products K44. It works well and is not cheap. There are not that many products that work as advertised. This one in particular works well.

Sully720 · 05-31-2011, 05:23 AM

Back with a update, I ran injector the Toyota dealer injector cleaner through the motor with a fresh tank of fuel, couldn't find any BG products, it didn't help so I eneded up pulling all of the injectors out and cleaning them, this did helped as 3 of the 6 injectors were not spraying properly, but I still have the miss fire at idle and sometimes hard to start which brings me back to the ignition, I have gone through all the basic test of the electrics and carn't find any components out of spec, still getting no reading for secondry resistance on all 3 coils, could it be the problem of a weak spark causeing the miss fire? seems strange that all 3 coils would be bad as it will eventually start. anyone have any idea's ?

Thanks Sully

kball · 05-31-2011, 07:48 AM

Hey Sully, sorry to hear you are still having problems.

When you changed the plugs did you use the dual ground type? Denso or NGK?

This idle miss must be inconsistent, I can't believe you aren't getting a CEL. Have you plugged in a OBDII reader just to see if it says anything? Maybe your CEL light is burned out....?

If a coil was bad it would take out two cylinders which would definitely trip a CEL light. Maybe it's a bad boot? (the part that goes from the coil down to the plug) They are separate from the coils. I think they are fairly cheap to replace.

You said you cleaned the injectors but did you have them tested? Maybe mechanically they spray fine now but electrically they are flaky???

Good luck!

Sully720 · 05-31-2011, 06:26 PM

Hi kball, there NGK dual electrode plugs, when I pulled the injectors out number 3 cylinder had some carbon build up on the tip of the injector, this is the same cylinder I suspected at first wasn't firing. I did get on a scan tool when the problem first began and that show no codes I also did code check after I removed the spark leads 1 by 1 to see if I could pinpoint the suspect cylinder and it triggered the engine light to come on, I will try some dielectric grease on the coil boots and see if this helps.
Thanks Sully

jetwhine · 05-31-2011, 08:58 PM

Sully720,

Have you checked the distributor shaft for play? If that shaft has play in it, it will wobble around and cause a random misfire. Is it still #3 cylinder missing?

Sully720 · 05-31-2011, 09:35 PM

hi jetwhine, it's the 5vz-fe motor so no distributor, Im going to pull the spark plugs out again this afternoon, as I have just over 250 klm's since doing the injectors, hopefully this will let me no if all plugs are firing correctly.

thanks Sully

jetwhine · 05-31-2011, 11:19 PM

Sully720,

Ya you said c.o.p. and I had a brain fart sorry.

Sully720 · 12-17-2011, 09:04 PM

I found the problem to be the injectors, the 1 on number 3 was leaking all the time and the rest were leaking down in 20 min, mt rubber coil boots where also looking a bit worn so I've fixed the by useing some dielectic grease.
hope this helps someone else if they have the same problem.