gtstcactus

I've just got through replacing the valve cover gaskets, spark plug seals and spark plugs on the rear cylinder bank of my 1992 Windom/ES300... All seemed well, it fired up when I turned the key...

I noticed after it had warmed up that the idle seemed to be a tad lower than before doing the gaskets/plugs and it seemed a little rough. I checked all the hoses to double check the clamps were on properly etc, checked all the plugs etc.

After going for a drive I noticed it was mostly ok when revs were above 1.5K-2K. Whenever I stopped the idle would be ok for a little bit then it would drop a cylinder. (I say drop a cylinder as it feels just like it did when my Nissan Skyline had a coil pack on the way out needing replacement causing a cylinder to stop working.) Under acceleration it seems to sort itself (not always tho), then returns at idle... It feels like it might stall but doesn't.

So it starts out ok from cold but when warm the problem occurs...

So clearly I'm going to have to go back in and check some things.... Given that this model doesn't use coil packs am I right in assuming it's probably related to the spark plugs or spark plug wires seeing as I've just replaced plugs and disturbed the wires in getting the valve covers off??

I guess I need to check that all the spark plug leads are properly clicked in place (I did this when reinstalling but will check again to be sure)

I should check all the spark plug leads with a multimeter... perhaps removing and what not has been the death of one of them...

I torqued the spark plugs to the specified level in the FSM, they are the Denso ones specified in the manual, I lowered them in gently with a magnetic spark plug socket. I do have 4 extra new plugs if it's worth swapping them out. I don't have a spark plug tester but I'm not sure they'd be any good with the rear bank as it is.

Is there anything else I should check?? Anything else likely to cause a cylinder to stop firing at idle??

I guess it's not possible to just pull the leads out while the engine is running to find the culprit on this engine with the rear bank difficult to get to...

Any help appreciated... I was so pleased getting the valve covers, plug seals, plugs etc replaced only to have this happen

ES300NZ

sounds like one of the coil packs/leads is not connecting to the spark plug properly and having to 'jump' the last few 'mm', I would re-check that first. If you 'crimp' the lead slightly and check the depth of the connection to make sure they are all at the same depth and one hasn't been pushed upwards that would probably be sufficient.

gtstcactus

I went and checked that all the leads (3VZ-FE doesn't have coil packs) were properly clicked in place and that didn't seem to fix the problem...

I thought I'd pull the leads with the engine running one at a time to see if I could detect a difference and got an electric shock from the 1st one I pulled which made me not really want to repeat the exercise... Is it normal to get a shock when pulling the leads with motor running???

So I think I'll just try testing the leads with a multimeter, tho I'm not sure if I'll get any result as the fault seems a little intermittent but gets worse once up to full operating temp... Also seems worse in drive (instead of park/neutral) I think...

Also I wondered... When removing the top of air filter box, and the big air hose to the upper intake / throttle body I went to disconnect the MAF plug by unscrewing it instead of unclipping it... I pulled it out a tiny bit then realised I needed to unclip instead, so I screwed it back in and unclipped it instead... If this was damaged could it cause this type of problem??? It seems more like a plug / lead issue but I'm not a technician so I'm really just guessing...

ES300NZ

yes. don't do that. disconnect them when the car is not running, or using a pair of insulated pliers, or someting which doesn't conduct. It's 20,000 volts @ 1 milli amp. (roughly). it will hurt alot, but it wont damage you.

I didn't really follow this to be honest, it might just be the 11mth old distracting me though, look if it's before the maf, it doesn't matter, after the maf its a potential unmetered air leak which 'could' cause an issue if it's big enough, which is around ... 1cm round ? that would cause issues.

If you can figure out which cylinder is mis firing you will be well on the way to solving it. (IF it is a mis-fire/non fire).

gtstcactus

I pulled the other leads in the front bank and discovered that they don't give a shock, the one that shocked me is my leading suspect as to the cause of the problem...

I pulled each plug in the front with the motor off then turned it on and repeated with each of the front 3 leads.... I left the lead dangling in the plug hole...

When I did the lead that shocked me earlier there was a spark coming out of the lead (as in the bit that runs along the valve cover when the lead is connected) going to the valve cover... I guess the correct term would be the lead is arcing with the valve cover. The other plugs aren't doing this, and they don't shock me.... Just touching that lead gets you a shock...

So as an interim measure I wrapped the lead in electrical tape covering the area where the spark came out and a bit either side..... It seems to have made the problem not so bad but it's still happening.... Now it's more like it threatens to drop a cylinder but doesn't or only for a second...

So with a bit of luck it's the problem and I can replace it when the shops open and all will be well..... I should probably just replace all the leads as they're probably not been done in a long time...

FWIW i tested the lead with a digital multimeter and there's doesn't seem to be any break in the lead tho I'm not sure if the resistance is ok or not...

Can anyone tell me what leads I should be looking for??? 5mm, 8mm??? Is there a model or type?? Obviously they need the right shaped/angled connectors, I'm just not sure what I'm looking for...

ES300NZ

Partmaster can sell you a boxed set for about $100 (sometimes it's alot more).
Repco have individual leads, you can just remove the lead in the car park, take it in, they will sell you another one for about $15.

8mm is better. it's more silicone (silly cone ?) around the wire.

sounds like your silly cone has a break in it.

gtstcactus

Awesome, thanks for your help.... I'll start with a single from Repco and see if that fixes the problem.

pauloil

you didn't say how many miles you have, but it was fairly common to replace all the wires in volvos after 100K Or so

gtstcactus

The car has done 216,000KMS so I think that's about 130,000miles....

I went to the parts store this morning to get a replacement ignition lead...

Pulled the lead out to take in to match it, they didn't have one so I took it back out and plugged it back in, started the car, put it in reverse and it died... started again, died again... started again and it died... now it won't start....

So I tried pulling one of the spark plug leads and put a new spark plug from my tool box in it, hooked up a jumper lead to the spark plug and the negative terminal to see if there was any spark (as per a Scotty Kilmer youtube video) and there was no spark...

A mechanic who I've met before pulled into the parts store and seen what I was doing and came over... He suggested what I did next:

Next I pulled the wire that goes from the distributor to the ignition coil and put the wire next to the body and there was no spark coming from the coil.... So I think I need to replace the ignition coil..

The mechanic said in his experience he would say it's the coil, not the distributor due to the second spark test we did... He also said it's not 100% certain either...

The current theory is the arcing ignition lead stressed the coil (inconsistent voltage) leading to it's demise....

Anyone care to chime in on this one??? Things are just not going my way at the moment!

LeX2K

Check for spark right at the ignition coil, if none then the coil has probably failed.

gtstcactus

Ok do I do that to ensure the lead from the coil to distributor isn't putting me wrong in the previous test when I had the coil to distrib plug going from coil to body??

How do I check right at the coil?? Just visually or do I stick something in it?? I thought that's what I was doing when I had the coil lead unplugged from the distributor and sitting on the fender to check for spark when turning ignition...

I was going check the coils resistance as per the FSM, I could check for spark at the same time..

LeX2K

Put a wire (or an old plug lead) in the coil and tape the other end to the lift hook or something else so there is a bit of a gap and crank the engine.

gtstcactus

Ok I'll repeat the previous test with a different lead and have the cord extended to the lift hook this time, and I'll do a resistance check at same time..

The highlight of my day so far has been a ride in a big purple tow truck!!!

gtstcactus

I pulled the coil and have done a resistance test.....

According to the FSM the primary coil should be between 0.3 - 0.6 ohms.... I'm getting between 1.2 - 1.5 ohms...

The secondary coil I'm not getting any reading at all or infinite reading.... So I think I can safely call it as the coil being the culprit here.... So I will replace all the ignition leads and the coil also and that should see me right I hope!

gtstcactus

I made a mistake with the multimeter settings when testing the coil for resistance....

I got the primary coil right (I think).... I had the DMM on the ohm range settings.... It has several...
The Ohm options are 2000k, 200k, 20k, 2000, and 200

I used the lowest setting of "200" for the Primary coil.... On that setting I'm gettin between 01.1 - 01.5... The spec for Primary coil (cold) is 0.3 - 0.6 ohms.... so I think I've got the right setting and it seems it's reading too high,,,

The secondary coil target range is 9.0 - 15.0 k ohms, so I used the 20k ohm setting... The reading I'm getting is 8.5k ohms...

So as best I can work out both are outside specified range....

I was at pick a part today and pulled the coils from a couple of VCV10 Camrys and tested them for resistance...
Both of them gave a similar reading to mine for the primary coil and they both read 8.6k ohms for secondary...
So either they just both happened to be stuffed or the coil isn't my problem... I read on another Toyota or Lexus forum of someone getting a brand new coil and having the resistance read outside the specified range which has really made me worry the coil & new leads isn't going to get the car going again....

I've got a coil from a wreckers sitting at the post office which I can't pick up until Tuesday which is driving me mad!

Would the resistance readings I'm getting from the coil expected from a "suspect" coil???

I suppose it's entirely possible that the 2 Camrys I spotted at pick a part didn't start one day due to a coil failure and the owners just gave up and sent them to a wreckers....

In desperation I was tempted to try the ignition coil from a Celica, it was the same shape and size, with the same connections, the part number was the same except the last digit being 9 instead of 7... but then I thought it could do more damage than good so decided against it...