kmchby76

Well here I go again. Let me start of with this, I had a similar problem back in April with a p304 misfire. So I will start off by telling you what I did. Here we go:

1. new spark plugs
2. new plug wires
3. pulled and sent out fuel injectors for servicing (replaced 2 faulty injectors)
4. new fuel filter
5. new pcv
6. new timing blet
7. new water pump
8. new thermostat
9. new drive belts
10. coolant flush

After all that was done, I got my runner back up in running in the begining of May. Now in Novemer I am experiencing a misfire in cylinder 3 . I changed the spark plugs again (using densos from the dealer this time) and plug wires (from the dealer as well). However, I can not find the source of the misfire. The odd thing is, when the runner sits for a few days, I can start her up drive her for about 10 mile before the misfiring starts up again. I even played musical coil packs and the problem still lies in the cylinder 3. I am now stumped. I am open to any help you may have for me.

yota_krazy

next it may be time to check valve clearance, compression, leakdown or a possible electrical fault for that coil pack/wire.

kmchby76

Here's an update. I pulled the timing cove off and set the engine to TDC. Here's what I found. On the cam pulleys, the timing mark on the belt is off by about 90 degrees to the left. I will be resetting the belt later this week. I plan on buying new tensioner pulleys first. I'll update later. Hopefully I will be done this week as I am having carpul tunnel surgery on Monday.

Bonk

Good luck with the surgery. Let us know how your wrists and the car turn out...

MTL_4runner

.....no need for writing in giant orange font, gives people a headache to read.

I am surprised it even ran if the timing was that far off the marks. If so that could absolutely cause all kinds of CELs including misfires etc. Definitely get that fixed first before you do any more diagnosis.

Best of luck with the surgery.

kmchby76

Thanks, I ordered the two idler pulleys, so hopefully I will get them no later than friday. If not then It will be several weeks before I can get her done.

toyota_mdt_tech

Well, I assume you mean P0303 and that is # 3 missfire. First off, if the timing belt was off by 90', it wont run. Second, if only one cam was off by 90', then you'd get a P0301, P0303 and a P0305 (all the same bank) and not just the one cylinder. Did you replace the injectro seat seals? This is where it goes into the intake. These get old, hard and suck air.

kmchby76

Yes they were. When the injectors were serviced, the o-rings and seals were all replaced. Well I set the engine to TDC several times, and the same result hapened. I don't know how to explain it, but the belt is off. I'll try and get some pictures up tomorrow.

MTL_4runner

I assume you are using the timing marks (tiny dots) on the cam and crank pulleys, not any lines that may be on the timing belt. I agree with MDT that the next thing to look at would probably be the injectors/seals (esp if you have already had some replaced). Can you tell us which cylinders those were done on? Did you replace all the seals when all the injectors were sent out for cleaning?

kmchby76

well i never got a chance to get any pictures yet, however I did have my surgery yesterday. Everything went well. As for the fuel injectors, they were all done and the seals were replaced. As for the timing marks, I made sure the #1 cylinder was all the way up, and he marks on the cam pulley were lined upped. With all that being don, the marks on the timinging belt were not lined upped with the cam pulley marks. I will hopefully get some help soon to reset the belt and replace both idler bearings. I will keep you all informed.

MTL_4runner

Glad your surgery went well.

The marks on the belt itself don't matter at all, what is important is that the marks on the crank balancer (set to TDC) and cam pulleys do line up correctly with their corresponding marks on the engine block. It sounds like the belt is on properly after all so I don't think that is your issue.

You might also try a compression test just to be sure all the mechanicals are working properly and there is nothing mechanically causing a misfire.

kmchby76

Ok, just courious as to why the belt marks would shift?

Gadget

If you want to check your cam timing, line up the crank pulley to the ZERO mark. Then look at the cam pullies. They should be lined up with the timing marks vertically. If not rotate the crank one revolution and check the cam pullies again. They should now be lined up with the vertical marks. If not adjust it as needed.

The alignment marks on the belt are only for the initial install. After installation the belt marks will be off about on tooth for every revolution of the crank.

Gadget

kmchby76

Thanks for the clearing that up for me. I'm still about a week or so out before I can dig into her some more.

MTL_4runner

Excellent explanation from Gadget as usual. Just as a side note, I have yet to see the marks on the belt to line up with the timing marks when everything is correctly lined up. The belt's mark always seems to be at least a tooth off (and this is an OEM Toyota belt) so I just disregard the belt marks and only look at the marks on the pulleys/engine block. Once you have the marks set, crank it over by hand to make sure every 2 crank revolutions, all the marks are lined up perfectly again.

kmchby76

Well, just to let you all know, my surgery did go well. I am now in the rehab stages. I did manage to reset my timing belt with some help from my cousin and his friend. Unfortunately, I am still experiencing the same problems. After my runner gets up to normal operating temp (around 10 minutes of running give or take a few) I start experiencing the misfire in number 3 again. If I run a compression test, how do I know if it is a head gasket problem or valves? I will try to get the compression test done next week as my runner is parked at my parents house. I am open to any ideas.

toyota_mdt_tech

I'd be looking at more on the valve adjustment side of things. How is the seoncdary ignition stuff, ie wires, plugs etc?

kmchby76

The plugs and wires are new from the dealer. I will post me readings next week after I run a compression test. Thanks

Gadget

With a standard compression test, if a cylinder is below spec you will not know if it is a piston/ring problem, headgasket problem, or a valve problem. It will just tell you that you have a mechanical problem in that cylinder.

A bad compression test should be followed up with a cylinder leak down test. That will identify the problem area in the cylinder.

Gadget

kmchby76

thanks for the info, is there a write up on how to do a leak down test?