So after the dealership messed up my plans to do an injector swap this weekend (damn counter idiot), I did the compression test anyway.

I only had a chance to do 4 of the 6: cyls #1, 3 and 4 hit at 180, cyl #2 (problem area) hit at 175-178 and held compression.

SO....after all this, new coil pack, plugs, wires, cleanings, cat and muffler...am I safe to assume (yea I know) that its the fuel injector that is making the misfire happen in Cyl #2?

Thanks
Bob

 

I'm going through the same thing... coil pack= ok; brand new plugs, just did compression on that bank and all are ~180 and holding.

Must be injectors... right?

I'm throwing a 304 CEL so my problem is on the same bank... Why couldn't this happen on the bank without the plenum interference!

 

Im not sure if I follow. If I have some cylinders not quite at 180 does that mean I may have bad injector in those? Or what?

 

Nfrantz007: That's what i'm guessing after searching all over for answers. I figured after 43 Views, someone would have done this and said something...

I'm going to just bite the bullet and get the new injector and go from there. I'll let you know what I find. Hopefully this weekend I'll be able to do it.

Survivorman97: From what I read about compression tests, there will be some variances in the readings...if one of the cylinders is more then 17% off, then you have a problem.

 

like on mine right now..(22r) i got 180 on all 4...before the rebuild i had about 200 on 3 and had 165 on one...that's where the gasket blew.

a few psi (up to like..15 or so i believe) is ok, any thing less should be inspected more

 

Quick question for you guys...with the issue your having, do you hear the enginerev down fast when you let off the gas pedal? Not sure if thats normal or if this is part of the issue.

bob

 

instead of buyin new injectors why not take them to an injector shop where they can be cleaned and bench tested.

 

So for example if you had cylinders at 160, 178, and 170 all on one size of an engine and then on the other side they were at at a perfect 180 what would you think? Runs great though....?

 

Sounds like there is a definate problem with the cyl. hitting 160. The one hitting 170 may also have an issue starting. 178-180 is good. You could do an injector swap or take it to a dealership. My next step is tearing into parts of the engine to test things out.

 

Is this something that guys who flow test injectors could check? Dealerships are so expensive. Im scared to go there and say I have a problem because Im sure they will not only agree with me but find more..

 

I would think so. We both in kinda the same boat right now, we have alot of answers, but unsure where to go from there because the next step is tearing things apart.

 

Just an FYI, for the 5VZFE the factory specs for compression is minimum 145 psi, 174 psi or more, difference between each cylinder 15 psi or less. http://www.ncttora.com/fsm/1996/SIL/...compr/insp.pdf

Nothing wrong with 160 psi.

 

Send the injectors out to like RC--Something--there are alot of companies that do this know. Also, make sure your plug wires are correct--the firing order in a Chilton or crap book like that are wrong--ask me how i know!!!!!EEErrrr--or not clear

Then make sure your Air Assisted Injection Vacumm hose (Off the IAC then Y's at the rear to either side of the intake) are not leaking/causing a vac leak. your Compression numbers are good--

Maybe try looking for a busted valve spring--Have to pull the valve covers......

 

So I went to the closest shop I could find today that would flow test the injectors for me. Said they would do it for $12 a piece, not bad. But as I was talking to the guy who worked there he was telling me that an injector problem would not cause a drop in cylinder compression being that they are above the intake valves. Which I guess makes sense. He said most likely it is carbon build up or the shims on the valves need to be adjusted. He was pretty confident in saying injectors wont cause compression loss and that a variance of 15-20 psi isn't something to be too concerned about..Ill still probably get them serviced eventually with all the miles on them. What do yall think?

 

Ill probably do a leak-down test soon as well to narrow it down some more. Is 160-170 really too much to be concerned with? What other answers might there be?

 

Yeah, I've been told on multiple occasions that 150 psi is where the things are supposed to be...

My 3.4 was check by the stealer, for free ( gotta love the barter system) and everything was 150-147psi, which i was told was fine. My motor runs like a top too.

 

I can't imagine how an injector could cause low compression as they are before the cylinder. I just pulled all five of mine out yesterday and dropped them off at Witch Hunter to be tested and rebuilt for about $18 each.

http://witchhunter.com/

 

That amazes me how much variance is acceptable from cylinder to cylinder. But having the valves run could definitely even things out some I'm sure.

 

What a wonderful Friday this is (can you feel the sarcasm)....Its 18F this morning, so I let my truck warm up for 5 mins....AND ITS RUNNING LIKE . Now I'm getting P0300 and P0302. Sounds like it has no exhaust, jumpin, sputtering, hesitating.

Now I have to find away to install the new injector...if its that....in a cold a$$ garage....

 

P0300 = Random/Multiple Cylinder Misfire Detected

Sounds like from that its more than just a #2 fuel injector.

What do you mean it sounds like it has no exhaust?

Has the timing belt been changed recently by any chance?