FASTFATBOY

The higher the o2 volts the leaner it is.

If it is a 93, check the o2 wires, make sure it is not grounded or broken.

93's depend on the o2 signal alot.

Make sure your little orange seal on the MAP sensor is there and good.


David

NightTrain66

looks like you are narrowing down the problems, just a few more to go.

lloyd

mdacton

I say blame it on lloyd.

thebufenator

Dont the O2's normally go lean when they are dead?

I know the car is already running rich, from all the fouled plugs, so I was assuming that the right O2 was reading incorrectly......

I'll check the MAP seal

thebufenator

I just ran it again, with my foot slightly on the gas......just barely....

it was idling at 1050rpm.
freescan said desired idle was 1075
IAC was at 160
MAP was at .716
BAR was at 1.011
L o2 was 435
R o2 was 910
spark advance was 35

I am assuming I need to open up the IAC bypass just a teeny bit more, as it appears I am almost there.
why are the L and R O2's so far apart? That doesn't make sense to me........specially since it is indicating lean and its running rich right now.
Also, what does the .712 MAP give me in vacuum? I dont know how to convert that.

Dave1980

Usually when O2's do that kind of stuff it points to exhaust leak buff. Not sure, but do you think anything could be leaking at all? Also try swapping o2s from side to side and re check readings.

Injuneer

No.... the higher the O2 milliVolts, the RICHER it is running. 450mV is 14.7:1. 900mV would be closer to (very roughly) 12.0:1 (although the stock narrow-band sensors are not an accurate indicater of A/F ratio for mixtures that rich).

If your long terms are maxed out on the hight side, the ECM thinks its running lean, and is raising the long terms to richen the mixture. What you need to do is determine whether its a "true" lean condition, and the ECM is reacting correctly, or if it is a "false" lean condition, and the ECM is adding fuel the engine doesn't need.

thebufenator

okay, I did have to change the spark plugs because they were fouled out from about 10 mins of idling, so I am assuming its a false lean condition.

Assuming it is, I would think that would point to an exhaust leak obviously...so I'll start checking that.

How do I figure out my vacuum with the MAP signal of .716?

edit, after running again I get a Map of .65 at 1150 RPM

thebufenator

here is another screenshot at a higher RPM.
Still tries to die....but it looks like my MAP is not to low.
http://i2.photobucket.com/albums/y2/...nator/1325.jpg

going to check for exhaust leaks tommorrow, too cold out now

:edit
forgot to add the link

With the throttle position at 9 when my foot is off the gas, is that telling the ECM that I am not in idle?
Will that affect the ability of the engine to idle?

Injuneer

Looking at your screen shot, the barometer and MAP are expressed in "bar". You need to multiply those numbers by 100 to get kiloPascals. That would mean:

Barometer = 100 x 1.015 = 101.5 kPa = 29.96 "Hg
MAP = 100 X .591 = 59.1 kPa = 17.44 "Hg
Vacuum = barometer - MAP = 29.96 - 17.44 = 12.5 "Hg

Whether that is high or not depends on your cam.

The idle speed is programmed in the PCM as a function of coolant temp. In that particular frame the coolant temp is 17*C = 63*F. That would normally elevate the idle above the programmed "hot" idle speed, but I doubt anyone would program it for 1,325RPM at that temp. And the PCM has the IAC motor maxed out at 160 counts, elevating the idle.

The TPP (throttle position percent) show as 11% in that frame. YES, that will alter the idle speed. The PCM assumes you are holding the throtlle open. Its fueling the engine using Cell 18, which is an open loop "load" cell. If the PCM thought the engine was supposed to be idleing, it would be fueling the engine with Cell 16, the idle cell. I do not see TPS voltage displayed in that frame. Have you check the TPS voltage to insure it is under 0.90V with the throttle blades closed? If it isn't you are going to have problems with the PCM thinking you are intentionally opening the throttle. However, if it is above that value, it should be setting a code. Do you have a code foro TPS voltage?

thebufenator

without my foot on the gas, the TPP shows 9, and it tries to idle, but it eventually dies.
it fluctuates between 500ish and 1000ish and dies after about 2 minutes if I let it warm up.

I measured the TPS voltage coming off of the middle wire, it was at .5v with the blades fully closed.

I am guessing that the 93 ECM needs a lower voltage from the TPS to register as closed.....

thebufenator

I took it for a test drive just now.

1. I have the blades cracked to the point where it says TPP is 11. Fully closed shows 9.
Cracked to 11 keeps it from dying....mostly. It died once when I was making 3 point turn.

my TPS voltage is .5 when the TPP shows 9, so I dont know why its showing 9.

a few more bugs to work out with the idle....

2. Brakes suck bad. I guess I need a pump to help the brakes out? How does that work?

Injuneer

Are you reading the TPC voltage across the correct wires (dk blue and black)?

thebufenator

Uhm, I was measuring the voltage the voltage off of the middle blue wire as
the Golen page here shows : http://www.golenengineservice.com/html/tps.html
should I be measuring across two wires? I had the negative lead grounded.

Also, it appears my vaccum at 1050RPM is only 9"......
That doesn't sound right with a LE3 383 setup.....running 12.2 : 1 compression.
Any ways to found out if something is causing me to lose vacuum?
I have looked around and cant find any vacuum leaks....
I heard that too much preload on the lifters can drop vacuum, is that true?
I am running 1/2 turn preload on LS7 lifters right now, should I go to 1/4 turn?

Thanks!

thebufenator

update:
assuming that the middle blue wire is the correct one, an to measure against the ground, to get 0% TPP I need it to be at 0.02V.

When I open the throttle blades all the way, it measures 3.75,
and freescan shows 75% TPP. I am going to assume this is a bad sensor since it wont go to any higher.

what exactly does this control? I know it will tell the compy I am not in idle, but when I go to WOT, what will it affect since its only showing %75? I am guessing it will stay in closed loop mode.....not sure what else it will do.