***blown MOTOR?***

[streetdreams5520]

You guys think those leak down numbers on a cold motor good?

[streetdreams5520]

The plugs

[streetdreams5520]

Bank 1 plugs looked the same....BTW no smoking and no loss in oil...oil smells good this is crazy....
I was thinking may need short block but idk

[streetdreams5520]

Soooo I got the car checked out by a reputable shop and was told that my tune was good and from the data log he feels I have issues with an injector on bank 1 which is causing a lean mixture on bank 1 side.

Can someone explain how a leaking or stuck injector would cause the issues I'm having... i have ideas.... but what do you guys think?

[jessrayo]

I think the hard parts of your motor are fine, I thought that from the beginning. You do not have a "blown motor". You have an issue either with fuel or with spark.

Now, I'm going to tell you I'm the driver not the mechanic......but when I tell my mechanic something is wrong with the trans and he takes it apart I'm very seldom wrong (unfortunately). He usually tells me what he finds and I have found quite a few problems over the years.... including a few blown motors.

You say you have a good mechanic, what does the air fuel ratio look like across a pull?

Can he run a sensor in the separate exhaust sides?

Is he using yours cars O2 sensor to determine if it is lean? If so did you try to change the sensor?

Can the "miss" be reproduced in a dyno pull?

Can you pressure test the fuel rails during a dyno pull?

I think if you find the right mechanic with good tuning software and the ability to data log, he will fix you right up. If you have a bad injector then replace it. But before you buy a new set of injectors change them from left to right and see if the problems switch from the right bank to the left..... just my opinion....

[HDRDTD]

Even if you had a bad injector, wouldn't it just affect the one cylinder? Why would affect the entire bank of 4 cylinders??

Just curious......

[streetdreams5520]

I was told that bank 1 was running leaner than bank 2. The o2 sensors were showing leaner on bank 1 side. He said the readings from o2 sensors were good so it couldn't be the sensors <I didn't know you can tell from hptuners readings..
Before coming to him he assumed it was o2 sensors but he ruled out out.

I ordered replacement 63 lbs injectors from lingenfelter.

he said if one cylinder had a bad injector the ecu tries to compensate for the whole bank. . Making it leaner or richer.

Other findings was that on my 2 hour ride there I was seeing 8 mpg ... and 14 mpg in 6 gear cruising so something is definately out of wack.

Is it true a bad injector could cause this?

[jessrayo]

It might be a bad injector but it sure sounds like that O2 sensor to me. If the tune is trying to compensate for one bad injector you will have 3 cylinders running a little rich and one running lean. I can't see the plugs well in that photo but it sure does not look that way to me.

A new 02 sensor is a little more than $100 bucks. That is exactly what happens when I run leaded race gas too long and foul an O2 sensor, it dumps fuel and fouls all the plugs on one bank. Are you running headers? You only need to change the front sensors, back ones should be disabled in the tune. If one is bad you probably want to change both front ones and put another set of fresh plugs in it.

Usualy the sensor goes totally out but yours may just be a little fouled and it is enough that it shows fine on the tune even though it is causing havoc.

[streetdreams5520]

jess thanks for continuing to help. i can get new sensors first thing monday morning.

so reading for 02 sensor could still show good but sensor could be bad?

if your sure about that i can install both o2 or just bank 1 monday and wait for injectors on weds

if issue is corrected i can just return injectors

[streetdreams5520]

btw my cats are gutted

[jessrayo]

Originally Posted by streetdreams5520

jess thanks for continuing to help. i can get new sensors first thing monday morning.

so reading for 02 sensor could still show good but sensor could be bad?

if your sure about that i can install both o2 or just bank 1 monday and wait for injectors on weds

if issue is corrected i can just return injectors

To be honest I don't know what it looks like in the tune. I do know from experience on my car that it starts really subtle and then progresses. I think once the injectors ramp up for a problem that doesn't exist the fouling gets really bad really fast. I have been running much larger injectors than you so when mine started dumping fuel I was looking at about 3mpg and the car was really only running on 4 cylinders.

I was getting CEL and the code would read "lean condition bank one" but it was dumping fuel..... I still kind of think you caught yours early enough that it has not got crazy yet.

You could change the sensors from left to right and if that is the problem it should change what is happening to the other side.... Honestly, if you ever put leaded race gas in the car it is just good maintenance to change the sensors every year to keep them from fouling.

[streetdreams5520]

Hmm ok thanks I pmed u

[derklug]

If a fuel injector is leaking enough for the cylinder to misfire, the O2 sensor will actually read lean because of the unburnt oxygen going into the exhaust.

[streetdreams5520]

^^^^ ive been reading that all day on google