I took these readings using my scanmaster. I warmed the car up and revved it a bit. I then let it idle and right before the fans come on the engine stumbles and throws an engine light. if I rev the engine the light goes away sometimes... ??? my scanmaster does not have the hole in the back to check trouble codes*! I am so mad! I am trying to contact that mike licht guy to see about having the board upgraded. Anyway. here are the readings. I was unable to determine anything usefull myself as I do not have any experience tuning cars down to the individual sensors and voltages. I am mecp certified and catch on quick but it's a little hard when you are the only person you know that even looks at this stuff. thanks for any help guys:

Maf: 02.
sp: 20
Lp 01.4
Rp 01.4
dtc 84
Lbl 160
Rbl 160
cel 16
Lin 180 +/-
Rin 190 +/-
D2l from 035 - 975
D2r from 035 - 975
ATS 153
Clt 184
Tps .80
Tpp 00
R 900-1000
IAC 00
Bat 13.1
map 9.5
bar 30.4
Acp .03
ccp 00

 

What hole in the back? The DTC codes are displayed as you scroll through the screens. You have "dtc" listed as 84. That's a trouble code. If you set the screen to display "dtc", it will scroll through all the codes, active and stored. If you only have DTC 84, it won't turn on the SES light, since its for the skip shift solenoid (if you have an M6, but we can't tell that because there's nothing in your signature about tranny type).

Your O2 sensors are totally screwed up, or you are running incredibly lean. The fact that your BLM's (long terms) are at 160 is telling you the PCM is adding at least 25% extra fuel over what it thinks the engine needs, and the fact that the INT's (short terms) are at 180-190 indicates the PCM is pouring in another 45% extra fuel, for a total of 70% extra. Yet your injector pulse widths are only 1.4 mSec. That tells me the O2 (not D2) sensors are probably fine.

Then you indicate the MAF sensor reading is "02".... if that's 2 gps, it explains why the BLM's and INT's are struggling to add fuel. The MAF sensor is only picking up about 1/4 to 1/3 of the correct air flow required for the engine to idle. Somehow air is totally bypassing the MAF, or the MAF is simply not functioning correctly.

Your IAC is bottomed out. Yet the engine is idleing at 900-1000rpm. Its cutting off all the idle air it possibly can, yet it still can't pull the idle down enough. Its getting the air from somewhere else - massive vacuum leak???? That would explain why very little air is going through the MAF. Or, do you have the idle speed reprogrammed for something higher than stock. MAP looks OK, so that may contradict the vacuum leak.

Your IAT sensor is seriously heat soaked, if its indicating 153*F.

A couple things....

1. You need to provide ALL the data on your mods. Looking at data like this without knowing what the mods are is almost useless. You also need to provide all the info about your car, like the tranny type. I now I've mentioned this many times in the past.

2. Do NOT page individuals in the "topic". I generally refuse to answer questions that include my name in the topic, since I think its disrespectful to the other knowlegeable people here for you to single out one or two people in the topic.

3. Every once in a while I read the rant you sent me via PM on 6/24...... and it still pisses me off.

 

Here are the new readings after figuring out I had the MAF in Backwards..... durh... I am tired some nights out there*

Trouble Codes: 16 44 64 91 83 84 I should play these numbers haha


Sensors
050
MAF 02
Sp 21
Rp 1.5
lbl 160
rbl 160
cel 16
lin 128
rin 128
d2l 035
d2r 050
ats 89
clt 168
tps .80
r 800
iac 22
bat 13.1
map 12.6
bar 30.4
acp .26
ccp 00

My car is a 1995 silver z-28 with a stock bottom and top end. 58 MM throttle body, ported stock MAF, Pcmforless programming for premium gas, 3.73 gears, 18 inch rear wheels, aluminum d.s., spohn adj. torque arm, all solid rear suspension, bilstein shocks, shorty headers with y pipe leading to one large single cat, one electronic cutout, magnaflow stainless exhaust welded together mostly, not clamped. lt4 knock module, t-56 transmission rebuilt professionally extra strong (thanks kyle!) mcleod dual friction clutch with steel flywheel, deleted egr/air, fan temps lowered, hope this covers mostly all that is needed.

Thank you for your patience injuneer. your a kind person and your knowledge matches that of some of the best engineers I know thanks

 

Just found the trouble codes in the chiltons. on top of the new info...


16 is distributor Ignition System (low resolution pulse) I have an msd 6al and brand new wires, an msd blaster coil, new ign. module and original 95 opti.... What is this pulse code?????:wtf:

44 and 64 are o2 sensors indicating a lean condition which I might have already fixed with my fual pressure fix and the other fixes but I am not sure... how do I know? the other three are the skip shift lamp, skip shift solenoid and reverse lockout solenoid.

I guess those aren't the worst codes and there is not a lot of guesswork as to what the problem might be. I hope my opti isn't bad... is it bad??......

how are my newer maf readings and iac readings is that all ok?

I wasn't sure if with my almost stock application how much worth it it would be to add 1.6:1 ratio rockers, an aftermarket MAF and new fual injectors with the racetronix kit. do I need it yet? I dont know and I can't waste money on somthing that is precautionary.. only a problem keeping the car from running perfect. Thanks again guys

 

ok had a test run with her and the engine was having some horrible stumbling or BUCKING. It would idle ok but kind of high and then when I got on the gas it was kicking up and down because the rpms were spasming. Is it a bad Opti? the car was sitting for a few years and now I am having idle and air fuel problems and throwintg a code 16. is it the death of my long lived opti? i doubt my msd 6al is the problem. the electrical connections are perfect and it is sealed and has been occupying the space where the battery used to be. My volt meter never drops below 13.1 + and it is having this problem. I have stock fuel pump, injectors. Stock opti-spark but everything else is new. I can test the msd tomorrow by unplugging it. I bet somone knows somthing I don't..... I have checked for any vaccume leaks and there is nothing. I removed all the emissions and they are deleted from my pcm. Everything was connected right to the manifold and any open ports were eliminated completely. I need to find out what that iDist. Ign System means. At least if it is the opti, we know what it is and it isn't a mystery. I will be so happy when this thing runs as smooth as when I bought it again...

 

Why aren't you using the tools that people here an CZ28.com have prepared specifically for the LT1? You don't have to look in Chilton's for codes.... Shoebox has them online. I have a Scanmaster manual online.

 

What tools? I do have the scanmaster living document..About to go outside and test some things. I figured if I terminated the wires at the opti boot side if I am careful not to burn my hands I could pop off the spark plug side and see if the spark is getting through. that is my only guess without replacing my wires again to rule them out. I doubt it is the wires with that code 16 dist ignition system low resolution pulse code that I am getting. Anyone know if that opti code (16) is dead opti?

 

okay... I went outside and double checked a bunch of things. i re-seated my opti side of my ignition wires and wiggled them a bit... Spaced my ign. module with 3 washers and grounded the three grounds to the bolt on the higher side. I sanded all the ground connections with sand paper, sanded the nuts and bolts too.. I sanded my red + sign foctory dist. block on the passenger fender until it looked like new then sanded all of the wires that go to it and added a little dielectric compound and tightend them all down nicely. then I did the same for my starter ground and grounds on the same pole as the starter ground. I then reseated all of my coil connections and msd wire harness and re-mounted the msd 6al to the front upper frame rail where the battery used to rub... I then made sure every single vacume connection was tight and not leaking at all. the car is running pretty nice now and it is not bucking like it was last night however.... it will warm up and as soona s the fans kick in it stumbles and throws a light, then the light goes out and it runs fine and the fans stay on and everything seems fine. The only other thing i noticed is my idle will go up a few hundred rpms while driving around a lot. i was hoping this is normal and when I sit it will drop down.. or is it always supposed to instantly return to 800 even when taking off and stopping over and over??? I am not used to an M6 f-body but I know my gf's corrola will idle higher when we are out speeding around. I know my iac is not bottoming out at all any more since I fixed the MAF but I still need to know what throws the code that comes and goes...posted a msg in new england board and got one response. i will see if anyone can datalog it and see what the engine is doing when it does it's funny stumble then ghost light that comes on and goes back out... ??