1994-95 LT1 Thread!

I have always wanted one of these and watched a guy drive around town for years in a 1994 Buick RoadMaster Estate wagon, White with Wood Grain, Lt1 ! What a sleeper... now it's mine!

Got Cats WinFlash to go with my TunerPro and have the $EE.XDF and ADX

Should I work on my bin file? Should I look for a Impala SS bin, Camaro bin? Police 9C1.bin? What to start?

Hooked up my scan tool to check codes and watch some data. WOW! There's way more stuff there than I am used to. My scan tool actually has 2 engine choices it says, one for engine and the other for trans.

Also picked up a couple PCMs just in case.

There's an excellent tutorial for TunerPro V5 $EE.XDF and .ADX and then Cats WinFlash to read and flash the PCM.
http://ltxtech.com/forums/showthread.ph ... 5-Tutorial"

Also a great tuning thread on the LT1 here:
http://ltxtech.com/forums/showthread.ph ... d1-Version"

Early 1994 LT1 were called Rev B and use a differant XDF. called EEB.xdf Not sure about the ADX because I have not got it working on TP in either version yet?

Diagnostic Trouble Error Codes for 1994-95 LT1 engines.

1994-95 LT1 Error Codes

Code 13- Oxygen Sensor circuit. Check for wiring and connections problems from the O2 sensor back to the ecm. If no problem is found, replace sensor.

Code 14- Coolant sensor circuit-high temperature indicated. Verify engine is not overheating, and correct any cooling system related problems first. Check the wiring and connections to the sensor. Replace sensor.

Code 15- Coolant sensor circuit-low temperature indicated. Verify engine is not under cooling, such as a thermostat sticking open. Check wiring and connections to sensor. Replace sensor.

Code 16- Low resolution pulse (distributor). ECM is not detecting the 4X pulse from distributor. Check wiring connections, especially the pigtail connector from the optispark to main wiring harness. This is the black/red wire that goes to terminal "A" on the pigtail connector. On the 1992-93 ecm, this is wire C5 (green connector). 1994-95 ecm, this is wire B2 (black connector). If wiring checks out, you will have to replace the optical sensor module in the distributor.

Code 21- TPS sensor circuit- high voltage indicated. Check for sticking or misadjusted sensor. Check the wiring connections from sensor to the ecm. Replace sensor if wiring checks out.

Code 22- TPS sensor circuit-low voltage indicated. See code 21.

Code 23- IAT (Intake Air Temperature) sensor. Low temperature indicated. Check wiring and connections back to ecm. If wiring checks out, replace sensor.

Code 24- Vehicle Speed Sensor. This fault should happen only when vehicle is moving. Ignore code if drive wheels are not moving. Check the TPS sensor, and check the VSS connections at the sensor back to the ecm. Verify VSS sensor is faulty with a sensor tester such as a Sunspro Sensor Tester Plus-TM, before condemning sensor as faulty.

Code 25- IAT sensor. Check the resistance of the sensor and verify that it is reasonably within range based on ambient temperature. (see chart). Check wiring and connections back to ecm.

Engine Coolant Temperature Sensor or
Manifold Air Temp Sensor (F & C)
Resistance in Ohms
210 99 185
160 71 450
100 38 1,800
70 22 3,400
40 4 7,500
0 -18 25,000

Code 26- EVAP purge control solenoid circuit. EVAP solenoid circuit indicated as faulty. Check wiring and connections.

Code 27- EGR vacuum control solenoid circuit. Check the EGR solenoid wiring and connections.

Code 28- Transmission Range (1994-95). Check the transmission control range circuit for any opens or shorts. Verify transmission range pressure switch is working. Range "A" is on ecm pin "C28" to terminal "N" on transmission plug in, Range "B" is on ecm pin "C29" to terminal "R", Range "C" is on ecm pin "C30" to terminal "P".

Code 29- Secondary Air Injection. Check the wiring and connections for shorts.

Code 32- EGR Failure. Check for proper vacuum from source to valve. Check all vacuum hoses. Check all electrical connections from egr to ecm. Check EGR for any sticking or binding, replace if necessary. Replace ecm only if all other checks have been verified.

Code 33- MAP sensor signal voltage high. Check vacuum hoses to MAP sensor. Check wiring and connections for any shorts or opens. Replace sensor.

Code 34- MAP sensor signal low. See code 33.

Code 36- Distributor ignition system. Faulty high resolution (360X) pulse or multiple low resolution pulses detected. Check pigtail connector from distributor to main harness for any opens or shorts. Verify wiring is okay before replacing distributor.

Code 37- TCC brake switch error. stuck "ON". (1994-95) Faulty TCC brake switch, wiring or connectors. Verify 12V present at connector and when brake is not applied there is 12V power to the blue wire from the switch and when brake is applied there is no power. Verify this at the ecm Pin C14 (clear connector).

Code 38- TCC brake switch error, stuck "OFF". (1994-95). See Code 37 above.

Code 39- Clutch switch error. Fault in circuit from clutch switch to ecm. Verify connections and circuits for no shorts or opens.

Code 41- Ignition control circuit. Check pigtail harness from distributor for shorts or opens.

Code 42- Ignition control circuit (ignition module). Check wiring and connections from ignition module and ecm. Replace module only after verifying wiring and connections are not shorted or open.

Code 43- Knock sensor circuit. Check ecm for open or short to ground. Check routing of wiring, including spark plug wires near knock senor wiring, reroute as necessary. Replace knock sensor.

Code 44- Lean exhaust indicated. Check for possible lean fuel possibilities, such as low pressure caused by faulty regulator, fuel pump or fuel lines kinked or partially collapse, vacuum leaks, clogged air filter or fuel filter.. Check wiring and connections to O2 sensor. Check ground terminals to ecm. Replace O2 sensor.

Code 45- Rich exhaust indicated. Check possibilities for a rich condition, such as faulty EVAP system canister for fuel contamination, fuel in oil, leaky injectors, faulty fuel regulator or one or more leaky fuel injectors. Also check EGR system for sticky valve or faulty control circuit. Replace O2 sensor.

Code 46- VATS fault (PASS Key). Check for faulty ignition switch and/or circuit to VATS module and ecm.

Code 47- Knock sensor module. Check for faulty circuit from knock sensor or missing sensor. Replace knock sensor after verifying with a tester such as Sunspro Sensor Tester Plus-TM.

Code 48- MAF sensor circuit. Check for faulty circuit from MAF sensor to ecm. Check connections and wiring for shorts or opens.

Code 50- Charging system, low voltage indicated. Check charging system, such as caused by low alternator output, faulty field circuit, open wiring in charging system and battery condition.

Code 51- PROM/EEPROM error. Faulty or incorrect prom/eeprom. Diagnosis should be performed by authorized dealer or qualified shop.

Code 53- System overcharging. This code will set if the ecm sees more than 17 volts, or less than 10 volts. Overcharge is mostly likely the cause of a faulty voltage regulator in the alternator. Have charging system checked before replacing alternator.

Code 55- Lean fuel monitor. Engine running lean during power acceleration. Possible causes include fuel pump failure, restricted filter, restricted fuel lines, or one or more clogged injectors.

Code 58- Transmission Fluid temperature (1994-95). TFT circuit indicates high temperature. Check connections and wiring. Sensor should read between 2.9K-4K ohms at 20C.(68F).

Code 59- Transmission fluid temperature (1994-95). See code 58 above.

Code 61- Air conditioning circuit performance. Check A/C system for possible low pressure in R134A freon.

Code 63- Right bank heated O2 sensor (1994-95). Check wiring and connections to the O2 sensor, open circuit indicated. If wiring verifies ok, replace sensor.

Code 64- Right bank O2 sensor (1992-93). Lean exhaust indicated. Check wiring and connections before replacing sensor.

Code 65- Right bank O2 sensor (1992-93). Rich exhaust indicated. Check wiring and connections before replacing sensor.

Code 66- A/C pressure sensor circuit. Check sensor connector and wiring for opens or shorts. Replace pressure sensor.

Code 67- A/C freon pressure sensor circuit. Check pressure sensor and/or A/C clutch for possible short to ground. Replace pressure sensor.

Code 68- A/C relay circuit fault. Check relay circuit for open or ground condition. Repair as necessary. Replace relay.

Code 69- A/C relay circuit fault. Check relay circuit for open or ground condition. Repair as necessary. Replace relay.

Code 70- A/C pressure sensor-high pressure indicated. Check pressure sensor and/or A/C clutch for possible short to ground or open circuit in sensor wiring. Replace sensor after verifying wiring and connections are okay.

Code 71- A/C evaporator temperature sensor. Low temperature indicated. Check pressure sensor and/or A/C clutch for possible short to ground or open circuit in sensor wiring. Replace sensor after verifying wiring and connections are okay.

Code 72- VSS signal circuit error. Check the VSS and circuit for short to ground or open circuit, a bare wire can cause an intermittent problem. Verify this first. Also check the VSS to make sure no excessive material has built up on the magnetic end, such material from the transmission wearing over a period of time cause deposit fine shavings on sensor head interfering with sensor operation. Wipe clean with paper (not cloth) towel to remove material and reinstall. A newly rebuilt transmission can deposit these quick enough as the transmission is "breaking in". If all else checks out, replace sensor.

Code 73- Pressure control solenoid. (1994-95). Check the pressure solenoid. Normal resistance is between 3-8 ohms at 20C (68F).Replace if out of range. Check lines for damage. Check for clogged filter and replace f necessary.

Code 74- Traction control system (1994-95 F & Y body). Low voltage indicated in traction control circuit. Check for shorted to ground or open circuit.

Code 75- Transmission system-low voltage indicated. Pressure control solenoid possible malfunction. Normal resistance is between 3-8 ohms at 20C (68F). Check ignition power feed to ecm for intermittent or direct open.

Code 77- Cooling fan control relay circuit. Check relay circuit for open or shorts to ground. If no wiring problems are found, replace relay. Be careful as intermittent short or open can only be detected by wiggling the wires and observing any voltage fluctuations to the affected circuit.

Code 79- Transmission Fluid temperature (1994-95 F&Y body). TFT sensor defective or excessive heat in transmission. Check for overheated condition first, low fluid level, faulty TCC lock up or excessive low gear operation.

Code 80- Transmission component harness failure. Possible TCC problem. Transmission slipping due to excessive heat or low fluid level.

Code 81- Transmission 2-3 shift solenoid circuit (1994-95 F&Y body). 2-3 solenoid circuit or solenoid fault. Check solenoid for proper resistance, should read between 20-40 ohms at 20C (68F).

Code 82- Transmission 1-2 shift solenoid circuit (1994-95 F&Y body). 1-2 solenoid circuit or solenoid fault. Check solenoid for proper resistance, should read between 20-40 ohms at 20C (68F).

Code 83- Reverse inhibit system (manual transmission). Vehicle must be under 4 mph to allow reverse operation.

Code 84- Skip shift solenoid circuit fault. (manual transmission 1994-95 F&Y body). Check wiring and connections for opens or shorts. Check solenoid for open or shorted condition.

3-2 shift control circuit (automatic trans. 1994-95 F&Y body). Check wiring and connections for opens or shorts. Check solenoid for proper resistance of 9-14 ohms at 20C (68F).

Code 85- Transmission TCC stuck "ON". TCC stuck on, check the wiring and connections. TCC solenoid pressure port possibly clogged causing TCC to stay locked up, meaning pan will have to be pulled to correct. Check solenoid for proper resistance of 20-40 ohms.

Code 90- Transmission TCC solenoid fault. Check TCC circuit for opens or grounds, check solenoid resistance. (see above).

Code 91- Skip shift lamp defective. manual transmission 1994-95 F&Y body). Check wiring for shorts or open to ecm pin D15 (blue connector).

Code 97- VSS low voltage indicated. Check VSS and circuit for opens or grounds. See Code 72.

Code 99- TACH output circuit (1994-95 F&Y body). Check for loose, damaged, or shorted tach output wire from coil. This is the whit wire on the black connector that goes to the ignition coil. If all checks out as far as wiring, and code is still present you will need to take it to dealer or authorized service repair center.

I have collected these for awhile from people who have posted them for use. If you have some or know what BCC is for post up or let me know and I will update the file name. I may have more so ask if you don't see what you need.

Well I found out today that I have an early Rev B bin. Does not work with the EE.XDF for TunerPro couple things off. Looked at PCM number and it's the same for Camaro, Impala etc... for a couple years so I was leary and one guy told me I would have problems with climate control, speedo...

Climate control still works fine. Not sure if my dynaride still works though? I have not heard it turn on since then, maybe it will. Fuel cutoof on Roadmaster was 108 MPH and the Impala SS is 154 MPH, spark tables were identical but fuel tables were richer!

Took it for a 30 minute drive and no error codes. Drives about the same, seemed a little perkier. One thing it did fix was my steering... yup! When I was on the freeway it would jerk a little when I corected, right or left. Now it is smooth. I was thinking more like a PS sensor or PS pump. But the tune made it go away.

So I now have a 1994 Buick RoadMaster Estate Wagon with a Impala SS tune! :jfj:

I've had an issue with getting clean data from my EE_Auto.ADX in TunerPro V5. Wondering if anyone would want to try my ADX to see if it works?

It's the EE_Auto from TP website with GregBobs Night Dash added. I also a Day Digatal Tuner Dash with 4 open spots(will take requests) Also has BLM HistoryGrams for Right and Left. Also has Knock Counter HistroryGram that works off Knock Counter in ADX file, not working properly yet.

OK, stupid question, just out of curiosity. Are these batch fire or sequential?
Just out to learn basic info about other systems.

1994-95-96-97 LT1 are sequential. Pretty sure 1993-92 LT1 are batch fire just like other tuned port.

1994 LT1 PCM Wiring Diagrams.

1995 LT1 PCM Wiring Diagrams.

I'm answering to rather old topic, but I just recently bought me a 1995 Roadmaster, and I'm interested in the tuning options. So, could I just download a Corvette bin-file here, program it to car and enjoy newly found power? I've already read the original bin from the car, and I tried to compare the Corvette bin (found here) to the original bin with TunerPro, but couldn't find any major differences on the parameters. Or I just didn't look at right settings..

Quote:

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Originally Posted by GunslingerFIN

I'm answering to rather old topic, but I just recently bought me a 1995 Roadmaster, and I'm interested in the tuning options. So, could I just download a Corvette bin-file here, program it to car and enjoy newly found power? I've already read the original bin from the car, and I tried to compare the Corvette bin (found here) to the original bin with TunerPro, but couldn't find any major differences on the parameters. Or I just didn't look at right settings..

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all the stuff you need to tune that car is either on fbodytech.com (disclaimer: my site), in posts on this forum, or maybe on tunercat.com depending on whos software you use to tune.

you are way off track thinking loading a corvette bin will help you.

the reason the vette engine is rated at a higher horsepower has very little to do with the tune. a 'vette is an aluminum headed engine, yours is iron headed. if you load that timing table it'll knock heavily and reduce power (probably blow up in the long term)

not only that but the way the vette ecm works with the other modules in the car is quite different, so loading that bin right up is a bad idea.

if yours is a stock car, only small changes will be benificial. if you aren't hauling heavy loads, maybe a bit more timing advance in some areas, maybe a bit leaner fueling at power enrichment. transmission tuning is also critical and probably where you'll get the best seat-of-the-pants difference (and again, quite different than a vette as well, since the vette is so light and has totally different gearing)

here's a good thread to start reading too, it's not for a b-body like yours but same stuff applies

http://www.gearhead-efi.com/Fuel-Inj...-lt1-M6-tuning

Wow, thanks for the quick reply. Car is pretty much stock. Free-flowing dual exhaust after cats, CAI with usual mods, that's pretty much it. Air pump is removed, and since car has towing package I think it came with mechanical fan, but that has been removed and there's dual electrical fans now.

I'll look into that thread and see what I can pick up from there. Despite asking about the Corvette program, I'm actually not looking for more power. With the towing package gearing the car accelerates really nice for the size. I'm more interested in finding out if I can improve mileage and stuff like that.

EDIT: I forgot to mention yesterday, that the reason I started to look into all this is that the car seems to run cold. Temp gauge never goes past 1/4 of the scale. I noticed, that secondary fan seems to run pretty constantly. Previous owner, who did the replacement, told me he also lowered the temps where fans kick in, so I started to look into those. He had set 90*C for fan1 and 95*C for fan2. I tried to reset them to original temps, but that didn't change the reading on gauge. I also checked the wiring, and it looks like it's ok. Secondary fan has own fuses and relay, and ground for relay comes from PCM. So, it seems that PCM is running the second fan for some reason.

I used $EEHack just to see what my 95 Vette was doing. Hooked it up and started a Adana log drove for 20-30 minutes for data.
Car ran fine, no codes shown. Let sit for three days uncovered in rain and now it won’t start.
I didn’t flash the ECM or anything, so what the he k happened? It will try to start and stumble but die. Getting fuel and fire.
Should I reflash the stock 16212471 ECM?
I know it’s not the $EEhack program, so something I have done without realizing it. Never tried a tuner program before.
Any help greatly appreciated!

Does the SECURITY light come on when you move the switch to ignition? Can you connect to the PCM with EEHack without errors? My first thought is VATS, to be honest. If VATS is the issue then when you turn the key the “SECURITY” light will come on solid and EEHack will rack up errors trying to connect.

Quote:

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Originally Posted by NomakeWan

Does the SECURITY light come on when you move the switch to ignition? Can you connect to the PCM with EEHack without errors? My first thought is VATS, to be honest. If VATS is the issue then when you turn the key the “SECURITY” light will come on solid and EEHack will rack up errors trying to connect.

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no, none of that. Turned over cranked, stumbled and died. Waited two days and
the car actually started anD ran rough for a minute and then smoothed right out.
I guess the Opti might have had moisture in it and when the weather cleared and warmed up it dried out. 95 so opti is vented.
Drove the car for an hour and alll was fine. Turned it off and starts back up, smooth as silk.

Check and or clean the coil wire and all the wiring running to the Opti-Spark, including that electrical wiring harness that plugs into the Opti-Spark.
The wiring for the H2Opump temp sensor is very thin gauge. If it misbehaves, it commands a richer AFR, meaning it might not start, or it might start and run rough. Wiggle test works pretty well here.

If the Opti-snorkel is not working right, it might also give similar symptoms til it dries out.

Quote:

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Originally Posted by LeMarky Dissod

Check and or clean the coil wire and all the wiring running to the Opti-Spark, including that electrical wiring harness that plugs into the Opti-Spark.
The wiring for the H2Opump temp sensor is very thin gauge. If it misbehaves, it commands a richer AFR, meaning it might not start, or it might start and run rough. Wiggle test works pretty well here.

If the Opti-snorkel is not working right, it might also give similar symptoms til it dries out.

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Thanks for that info,I’ll check those out.