Toyota techs! Help needed!

http://www.youtube.com/watch?v=GvG22YMOzUI

 

Interesting thanks I eill try that can I hook my compressor up to my compression tester line and just turn the regulator on the compressor to 100 and buy pass building that thing. Do basically hookin air line direct into cylinder and reading if regulator goes down

 

Anyone

 

What are the odds of this bring a bad ECM the truck runs and drives nice

 

Have you checked your fuel pressure yet?

 

No did a head gasket test and it's ok. My truck runs great and my mileage is about average I am leaning toward a bad ECM or fuel pressure I will be buying a teste. Any one ever done one on a 3.4 before and got any tips

 

The 4 cyl fires both SPARK PLUGS at the same time. The injectors however are individually controlled.

Very good suggestion at this point.

I would verify fuel pressure, and then consider replacing the injector for #1 before I would look at a bad ECU.

Since the #1 injector is the last in the line, it is also the most common collector of "trash" that has gotten past the fuel filter. Perhaps to save money you could consider swapping the #1 injector with the #2 injector to see if the misfire moves.

 

Already put a new injector in

 

ok. Now it is time to get out the multimeter.

This takes some time, so be prepared. Disconnect the ECU and the injectors. Measure the resistance on each control wire. Look to see if the resistance on the #1 injector is higher than the others. Check the battery ground to the block for voltage drop. If it is more than .1V, remove and clean the ground. Check the strap ground on the back side of the cylinder head on the passenger's side. Make sure both ends are clean and tight.

 

I forgot about something. Has the timing belt area been apart lately? Specifically the lower timing gear on the crank shaft. I have seen 2 cases of "fake" misfire codes on the 3.4 because of that gear. One of them had a slightly chipped tooth causing an off reading. The other one had a barely loose crank bolt that was letting that gear walk out a bit and throwing random misfire codes. An FYI, most, if not all toyota engines measure misfire by the reluctor wheel on the crank with the crank sensor. The difference in speed at each cylinder's firing point is measured and if a slowdown occurs, the ecm determines this as a misfire.

 

Timing belt has 370 000km on original belt (over 200k miles) I am actually doing the belt this weekend. Anything I should look for?

 

Holy $h!t. That's a lot of miles on that belt. Knowing that, it's possible that the belt is stretched just enough to cause issues. Take a close look at the lower timing gear teeth and the crank sensor. Make sure that none of the teeth are broken, and wipe the debris off of the front of the crank and cam sensors. I'd almost bet that after you do the timing belt, your issue will go away.

 

FYI back at you, EVERY manufacturer uses that method for measuring for a misfire. It's the easiest and most accurate.

I agree that a stretched timing belt COULD case a misfire. While I wouldn't rule it out, I would say that USUALLY a stretched timing belt would cause random misfires, not locked onto a single cylinder. But then again Toyota likes to be original, haha.

 

Some manufacturers throw the knock sensors in the mix as well. Don't remember who, but that was a topic in school years ago.

 

I would like to know how a knock sensor could help detect a misfire. Totally different detection sensor using a piezo electric crystal to detect noise. Now if they threw a cam sensor, I could buy that as a possible assistant in checking.

 

And you're being a dick, why? Just remember is from school. I could have had a misinformed instructor. Don't know, don't really care. I work on 99% Toyota. I could care less about others. Have a good day.

 

Still have the missfire

 

You have to take him with a grain of salt. Very knowledgeable but his demeanor has been known to rub ppl wrong. Remember, its the internet and emotions such as sincerity don't always get translated through the key board.


OP, just a rule of thumb as you troubleshoot, do the easiest/cheapest fixes first.

I also feel you should check your fuel pressure (not sure if a dealership can do this). Easiest thing would to be replace your fuel filter. I know Toyota says its "lifetime" but Ive seen plenty of ppl change theirs out for the better (myself included). If that doesnt work, consider your fuel pump. Also change your timing belt .

Either way, these steps couldnt hurt.

 

Did that and no leak

 

Sorry, lost track of this post...

Not being a dick. Just stating facts. I am happy for you that you work 99% on Toyota. It is a good product. However I try my best to be sure that inaccurate information in a thread where someone is asking for help is corrected. No intent at all to be rude. Just clarifying information.

You are right. I do tend to write things where it may rub people the wrong way. It's never intentional. At times I have been asked for help in a dozen threads each day. Sometimes typing in a lot of information I tend to be detail-specific, and not think about someone's feelings.



OP, have you tested the injector signal with a noid light yet to see if the injector is being commanded on? This is interesting that you still have the misfire after all this time. Does it ACTUALLY have a consistent misfire, or is it the computer saying it does? I am curious if perhaps you have a defective crank sensor, or damaged reluctor on the crank.