popsz28

Car is a 1994 Z-28 LT1 with a 6 speed.

I put my car on a scanner today and took it for a drive. Under heavy accelerationthe car would spit and sputter from about 2000 rpms and up. I just bought this from my brother who had been having a hard starting problym and has replaced the following.
Battery, alternator, acellcoil , ignition module, plugs with bosch platinums, msd spark plug wires. Here is what my car was showing on the scanner under heavy acceleration.
RPM________3053 Left Int 128 Right Int 128
Codes&Data 91 1-4 Lamp circuit
OPEN/CLOSED LOOP CLOSED COOLANT (DEGREES F) 229
LEFT O2S (MV) 898 RIGHT O2S (MV) 898
LEFT BLM 133 RIGHT BLM 131
A/F LEARNED NO FT CELL 15
TPS (V) 4.58 THROTTLE (%) 100
LEFT BPW (MS) 15.0 RIGHT BPW (MS) 14.8
AIRFLOW (GM/SEC) 123 IAC POSITION 55
COOLANT (DEGRE'S F) 229 MAT (DEG. F) 126
FAN 1 REQUESTED YES FAN 2 REQUESTED NO
MAP ("HG) 28.8 MAP (V) 4.72
BARO ("HG) 29.6 bARO (V) 4.86
KNOCK NO KNOCK RETARD (DEG.) 12
SPARK ADVANCE (DEG.) 22 IGNITION (V) 12.5
CCP DUTY CYCLE 31 EGR DUTY (%) 00.0
TIME 27:38 DESIRED IDLE (RPM) 800
A/C REQUEST NO A/C CLUTCH OFF
A/C PRESSURE (PSI) 006 A/C PRESSURE (V) 0.26
VEHICLE SPEED (MPH) 042
Does anyone see anything there??? some body????? anybody?????

TobyZ28

Sounds like the Opti. Does it do it under moderate acelleration too? Mines gotten so bad it is barely driveable, I'm about to replace the opti once i recieve the part

ShawnMacAnanny

BLMs are VERY high. should be around 120 i think.

95BlackTA

Put the car in a garage and start her up with the hood open...turn off all lights...let it get warmed up a bit and look for fireworks under the hood...look at all plugs and wires. If you see none, then that should rule out arching. Then you may be looking at opti or a wire thats jes not on there good...Unplus all wires and plug them back in...make sure you put di-electric grease on all of them.

popsz28

Yeah I Think The Blm's Mid Point Are Suppose To Be 128 But Not Exactly Sure If That Would Be Enough To Cause Anything. Also It Seems Like It Pretty Much Always Stays In Closed Loop. One Other Thing That I Am Concerned About Is The Egr It Always Says O% Rather Its At An Idle Or Cruising Or Even Under Heavy Acceleration

jonota

BLM's should be 128, so no problem there. your temp looks pretty high though, and I think at that temp both fans should be on

Have you done a fuel pressure test? It's easy to rent/purchase the test gauge and do the test, can usually rule out a fuel problem.

I will look at the spark advance tables, but if I'm reading right you have 12 degrees of retard???? I will look at what your advance should be at that Map and rpm.

The optispark is always a decent suspect but lets see if we can't find something else wrong...

Jonota

95BlackTA

Yea if you have 12 degrees of knock retard, thats why im thinking you have a bad arching problem...ive had a similar problem before, and it was my wires arching....was giving out all kinds of retard.

popsz28

Knock Retard Is 12 Spark Advance Is 22 Temp Is 229 Both Fans Dont Come On Till 235 Fuell Pressure At Idle Is 39 Fuell Pressure With Koeo Is 41 Fuell Pressure At Wot (vacume Line Off Of Regulater) Is 50

jonota

yes, your spark advance should be around the mid 30's

what doesn't make sense is your saying no knock, but knock retard of twelve degrees, the comp shouldn't be able to take out more than 10 degrees of timing....

you say it spits and sputters under HEAVY acceleration, what does it do under normal driving? what about under 2000 rpm??

Have you done an EGR test?

Jonota

popsz28

At Times The Car Doesnt Act Like Anything Is Wrong With It And Other Times It Doesnt Seem Like It Matters What Rpm The Motor Is At It Just Likes To Act Up Like Lst Night Every Time I Started Out From A Stop Light It Would Hesitate. As Far As An Egr Test I Havent Done Anything Yet Tell You The Truth I Havent Really Give It Much Thought Seems To Easy To Me Lol

popsz28

Where Is Shoe Box Or Olay The Mounted Police When You Need Them Lol

popsz28

I Will Have To Check The Arcing Problym Out Like You Say Hopefully I Can Do That After Work Tommorow Ill Keep You Posted On What Happes With Everthing

popsz28

Another Thing That I Am Concerned About About Is The A/f Learned No?
Is That Normal?

jonota

I don't know about the learned a/f no thing, as I don't have alot of experience with the scanners. I'm thinking that perhaps it was telling the computer NOT to use the learned a/f ratio since it was in power enrichment mode.

If you have the time to pull the opti and inspect it I would recommend it.

No SES, no codes, right?

Jonota

popsz28

you are correct no ses light only code is 91 1-4 lamp circuit. This is my first dealing with an LT1 so what should i inspect for?