The Pepsi Saga: Injector Indulgance

[mra32]

All this speculation could be put to rest with a compression test.

 

Thanks for volunteering mang. I'll be working on it tomorrow after I get the parts, so like 10:00 ish...

[mra32]

HAHAHAHAHAHAHAH.

 

 

 

I replaced the intake gaskets and nothing changed. I definitely did have a leak though. I dunno...fuggit.

[Night Fury]

Car meet cliff?

[mra32]

im thinking i will get a new car once I get a job and i will donate this to anyone on the board who will put a better drivetrain in it. Remember...its got the plaid headliner, all the appearance mods and the dope suspension/brake mods.

[mra32]

ok, i think the "bump" in the exhaust note is a mechanical issue. I had that before I had the problem with the ECM and got a JY one. I can accept that. The terrible idle seems like its a engine control issue to me. I read another thread currently going on and issues were described where the engine coolant temperature sensor was either borked or the wiring for it was. Thats one. ICM was suggested, but thats not so easy to check.

 

I did the oxygen sensor like 25,000 miles ago and it was a Bosch one, so thats suspect.

 

When I was pulling wires off the coils, one seemed to not "click on" like the rest. I tried adjusting the metal piece on the wire, and I think I helped it, but it still doesnt act like the rest. Would this be a source for concern? Can you buy just one spark plug wire? I could probably cut it off and buy a new terminal. Those and the plugs were done at the same time as the O2 sensor

[mra32]

so i broke down and spent most of today doing a compression test. the results are in.

 

1: 185

2: 165

3: 145

4: 150

5: 145

6: 150

 

4 & 6 were the first two on a just run engine. 3 & 5 were done last...I dont know how hot the engine was but the plenum was still burning my arm when i touched it.

 

I broke 2 spark plugs in the rear. They all looked tan. Going to ride the moto to get some plugs right now.

 

could the Bosch O2 sensor be the issue (its not throwing any codes)?

[RobertISaar]

/me wants closeup pics of the plugs...

 

preferably marked from which cylinders they came from.

 

tan doesn't sound bad, that's actually about the color you should see at 14.7:1... lighter colors generally mean it was leaner, and darker would mean richer.

[mra32]

/me wants closeup pics of the plugs...

 

preferably marked from which cylinders they came from.

 

tan doesn't sound bad, that's actually about the color you should see at 14.7:1... lighter colors generally mean it was leaner, and darker would mean richer.

 

No dice...i aint doing that again...actually I'm pretty good with it now...but my arm needs time to recoup from all the stabbing from the alt fanblades and burns from hot metal surfaces. It did seem like the front bank was a little lighter...almost white.

 

Also, I think I might have messed with a vacuum line with all my ruffianing. My brakes seemed different afterwards, like i had to depress the pedal further (NOTE: not harder) to stop. I also might have been retarded and on the verge of heat stroke.

 

Would a crappy O2 sensor do this and not set a code?

[RobertISaar]

borked O2s can cause lots of problems... even without setting codes. the O2 test will pass every time with a sensor that swings above or below a threshold within a certain amount of time. if the sensor has been skewed in either direction, it can pass the test every time and run like molasses in january.

 

but from what i'm reading, it sounds like an occasional, turning constant miss at idle(watched the vid this time, can't hear shit)? hook up a scanner, note exactly what coolant temp it starts doing it more often at, and then watch the long and short term fuel trims, knock counter, IAC Minimum steps, and vacuum.

 

and generally, cylinders 5 and 6 will run hotter and leaner due to their ports being right next to the TB and getting extra air compared to the 1/2 pair, but 3/4 should be pretty good indicators hof how it was running. also: note the runner lengths for the front and rear cylinders: it's different, which means one side will run lean at low RPM and the other side will run lean at high RPM... GM's lovely way of making the LH0 a more rounded engine. the longer runners go to the rear cylinders, shorter to the front.

[mra32]

how am i supposed to scan dis bish

[Garrett Powered]

yeah but the lower plenum is the opposite making it even right?

[RobertISaar]

sorry, i tend to assume everyone has the same toolset as i do....

[RobertISaar]

yeah but the lower plenum is the opposite making it even right?

 

IIRC, the lower is mostly identical, the upper has al of the difference... though it's been a while since i've played with a LH0 lower.

[mra32]

Vid from yesterday. Its better than the previous one in every way.

 

http://s318.photobucket.com/albums/mm432/dieslowlymf/?action=view&current=SAM_0694.mp4

[RobertISaar]

WOW..... it went from decent for a LH0 to rolling idle, funky noise instantly... depending on the temp, i would have to guess it does it when it hits closed loop or enables the knock sensor.

[mra32]

i'll look for a pipe plug and do the wrapping of the knock sensor in a towel trick see if that helps it.

[RobertISaar]

disconnecting the O2 might also be interesting... then the ECM should run on the factory VE tables plus an enrichment IIRC....

[mra32]

nice. thanks for the suggestions. It looks like the knock sensor is only accessible from the bottom. I am without a jack and jackstands right now, but I can change that.

[mra32]

Taking another crack at this, since the car search blows and this thing is good to drive as far as the commonwealth of pennsylvania is concerned for the next year.

 

I did disconnect the knock sensor and the car didnt really improve at all, To my surprise it had a rolling idle as if it had a vacuum leak. Which is interesting and i'll try to inspect the vacuum lines further.

I'll also try to mess with the shit attached to the plenum like the IAC and the EGR.

 

Will the car actually run with the oxygen sensor disconnected?

[tornado_735]

Taking another crack at this, since the car search blows and this thing is good to drive as far as the commonwealth of pennsylvania is concerned for the next year.

 

I did disconnect the knock sensor and the car didnt really improve at all, To my surprise it had a rolling idle as if it had a vacuum leak. Which is interesting and i'll try to inspect the vacuum lines further.

I'll also try to mess with the shit attached to the plenum like the IAC and the EGR.

 

Will the car actually run with the oxygen sensor disconnected?

 

Yeah, I think it just goes to default settings or something.

[RobertISaar]

WILL run, though on default VE tables, + possibly an enrichment, though i can't confirm that,

[mra32]

does anyone know what the vacuum reading should be on this engine at idle? I can just hook up a gauge to the nipple right by the throttle body. Maybe I can try to eliminate/confirm vacuum leak. Also does anyone have a vacuum diagram for this? Whats the little box mounted on the back of the plenum with a green plug that has the little vacuum line to it? Why is the sky blue?

[RobertISaar]

green plug? sounds like the MAP sensor.

 

as far as idle: wifey's LH0 idles at ~40kPa(absolute) at ~650RPM when fully warmed. so that's ~60kPa of vacuum. can't remember the conversion off the top of my head though for InHg.

 

and yeah, i can get you a vacuum diagram. year?

[mra32]

91. I thought the Map sensor was the blue and red plug with the larger vacuum line attached

[mra32]

green plug? sounds like the MAP sensor.

 

as far as idle: wifey's LH0 idles at ~40kPa(absolute) at ~650RPM when fully warmed. so that's ~60kPa of vacuum. can't remember the conversion off the top of my head though for InHg.

 

and yeah, i can get you a vacuum diagram. year?

 

40kpa abs is like 40% of atmospheric, which is like around 30" Hg. so a reading of 18" Hg (gage) should be the same.