sinner

well crap. here is my other post:

https://www.thirdgen.org/techbb2/sho...4&goto=newpost

it still wont start. everything has power.
the fuel pump cycles.
the injectors have pulse.

the scanner cant get any reading what so ever from the ecm. what might that mean?
any ideas here?

Trans Am#5

Do you have spark at the plugs? Are the injector plugs plugged into the correct corresponding injectors? Did you replace the coil or opti before dropping in the motor? Just asking to help track this down.

Corry

Well, I am by no means an expert, in fact, I am a little behind you in my swap....fighting wires lol. On that note, you say the scanner doesnt get a response from the PCM at all? I'd check the power line to the ECM, check the line from the ODBII connector to the PCM. Are you sure the injectors are going? Did you use a "noid" light? I'd also check the spark, I always checked the spark on my tpi motor by just pulling a spark plug bootand pusing the wire up into the boot (My boots weren't too tight on the wires) so that there was metal exposed, and hold it close to the block, spark should be obvious, I also think O'Reilly's/autozone/pep boys should all sell a spark tester, or you could just buy 1 new spark plug and test w/ that. The reason I list all those is I know what a major pita getting those spark plugs in and out is! (Especially w/ headers!)
Just my $0.02

sinner

well, another interesting part, when i turn it over the tach almost looks as if it is going down instead of up. is that normal when you crank over or should it go upwards?

sinner

yes, i uded that "noid"thing to test the injectors.

i have no spark at the plugs as far as i can tell.

GhoSSt

iTrader: (1)

Well, I'd check the coil for power, then the ignition module, and the coil wire on 94 - 95 LT1's is notorious for being bad.

Then I'd look real hard at the opti.

MrDude_1

i have actually had a brand new opti bad out of the box before.


i would be looking reeeeaally hard at that...

Riley's35089rs+

I went through one Uesed opti bought off Ebay..
One rebuilt unit bought at a parts store..
Finally I bought a new GM unit (complete) New waterpump..$1150 all installed. Not a problem since.
The opti install is easy to botch. Not too hard, just easy to botch. If all else fails , let a pro check it out.

Trans Am#5

Let's check the easier thing first. If you can put a plug wire on the coil, do that and have a spark plug on the other end. Then take a pair of long needle nose pliers and hold near the head(touching it). Make sure you are holding the wire by the boot with the pliers. Now get someone to crank the motor and see if you can see spark. The darker out the better but you should be able to a spark regardless. If you do, the coil should be fine then. Next, I'd check the coil wire itself where it goes down to the opti. If thats ok as well...the opti is most likely bad. I chnaged mine prior to the motor even going in. It made things a lot easier. In fact, I changed the water pump, coil, opti, o2's, knock sensor, oil pressure sending unit, water temp sender, etc. Just cheap insurance.

sinner

ok, ill do that. what does an opti cost?

"I'm scared Scoob!"

Trans Am#5

GM PART # 1104032
CATEGORY: Ignition Distributor
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $461.94
OUR PRICE: $230.97
DESCRIPTION: DISTRIBUTOR/OPTI-SPARK
Second design with vent for vacuum line to intake manifold. Fits 95-96 Corvette including LT4, 95-97 Camaro and Firebird. Also fits 94-96 fullsized B-body passenger cars; Impala SS, Caprice, Roadmaster and D body Cadillac Fleetwood Brougham.


Thats from www.gmpartsdirect.com Their shipping is unusually high though. I got all my stuff from Jason Cromer.

Jason Cromer: 1-877-726-8295
email: gmparts@samtaylor.com
Sam Taylor Buick/Cadillac Ft. Walton Beach, FL

His prices are comparable and shipping is cheaper. He's an excellent guy to deal with. Since the water pump has to come off anyway for an opti change...you may want to change that also.

Riley's35089rs+

Yeah the 95 up are a bit cheaper than the 93 94...better design with the vent...be carefull washing the motor. You want to keep the opti dry..

Riley's35089rs+

Good thread here..more diagnostics, per Vader..
https://www.thirdgen.org/techbb2/sho...ight=optispark

Riley's35089rs+

Is that including cap and rotor...it is a 2 piece Kit..

Drastius

Sounds like your PCM might be messed or not getting power. Check that before you buy a new Opti.

Trans Am#5

That is for the complete ready to install opti.

Riley's35089rs+

That is a smokin deal ! Best buy here in Omaha..on a remanufactured unit was...$390.00 complete. I bought it, installed it, and it was junK (Advance Auto)......went new GM. She runs like a champ. Running in 2nd gear, get on it , you better have hold of the wheel, cause you are smoking tires!

sinner

well, today i took a plug wire, removed the boot, and installed the other end on the coil. i turned over the car and there was no fire from that wire. does it have to have a plug in it for me to see fire or was that good enough?
is there a way to test the ecm to see if its working?

sinner

also when i unplug blue from the ecm i get the fans. is that normal? does that mean ecm is ok?

i sure hope so

Trans Am#5

I would have to bet that the PCM--not ECM--has power to at least if the fans come on when removing the blue blug from the coil.

You'll have to put a spark plug on the other end of the wire and just like stated above...hold to the block with the pliers by the boot. Then, while someone is cranking, you should see a spark. This would be a good indication of a coil thats at least firing. Did you buy new wires?

sinner

yes, the wires are all new, ill get a plug and try again.

sinner

ok, i used a spark plug and still no fire.

so what do you guys think now?
i have 2 plugs going into the coil, but there is a thirs there, a 3 prong that is purple.
could that be it?
what dp you think that is?

sinner

does a 1995 have a MAF sensor?
is it a MAF plug?

sinner

also, the coil has 12v when the key is on, but nothing changes, pulses or triggers the coil

Drastius

95 has a MAF and a MAP. I'm not sure if you have to have it connected in order to start, quite possibly.

Trans Am#5

The very first time I tried to start my car after the Lt1 install...it inly cranked but didn't start. The only thing not connected was the MAF. I connected it it fired up immediately.

sinner

ok guys, ill definately try that after work today.

sinner

is the MAF by the intake?
where is it located?

its looking to be VERY exspensive!

Trans Am#5

Yes, it's between the air filter and throttle body. They are expensive. Try and get one off of a friends car just to see if the car fires even though you need one regardless.

Z28ricer

iTrader: (2)

This should help you spot what your missing josh

sinner

ahhhhhhhhhhhhhhh.

that helps a lot.

i went to a dealer today and got a diagram too,
i definately dont have a maf sensor.
thay p's me off too, case i was supposed to have bought a COMPLETE motor & harness.

the sensor is 2 days out from egypt here, i will post my results.

so what did it disable in your cars without the MAF?
i am a little confused still as to why this would stop spark from the coil.

wm_sorg

Any progress?

Riley's35089rs+

Dont think that will stop it from starting..might throw a code...but it should still have spark....I ran mine with starting fluid. without the maf sensor or any of the system connected..

sinner

well, the MAF did not finish the equation. the bastard still wont start.

any more ideas guys?

Riley's35089rs+

OPTISPARK
https://www.thirdgen.org/techbb2/sho...ight=optispark

mat89RS

hmmm... well.... at the point you're at now, maybe faulty wiring at like connector c100 ?


Once, comming out of my driveway my car died, I couldn't get it to start so I went trough everything. Sure enough, the optispark had give it away.

Could be your problem.

sinner

which is c100?

not sure here, i am a novice

sinner

i dont think it is the opti, cause i get no spark from the coil

Trans Am#5

A coil is considerably cheaper than the optispark. Try buying one. It can't possibly hurt.

Riley's35089rs+

how did you check the coil?

mat89RS

oh ! well if you got no spark, you're not looking neccesarily looking at the right place.


have you checked if the coil was getting power from the ECM ? (pink wire) ? if so, yes, replace the coil

Have you checked for injectors pulsing ?

What year is your car ?

Have you wire the VATS module properly ?

sinner

i tested coil by putting a plug on the end of an old plug wire and turning it over

the pink wire has 12v to it

there is pulse

mine is a 92 with a 95 in it

thatsme

I had the same problem with my 95 lt1. It turned out i missed a wire to power the ecm. runs great even without the MAF sensor. I'm still cleaning up the wiring harness but mine runs. If you're using the stock harness there is an orange wire for constant battery to the ecm and two pink wires for ignician on. I believe these were seperate from the wires to power the injectors and the coil. An easy way to check if the ecm is powered up is to hook a test light to a positive source and find the wire coming out of the ecm for the MIL light. The ecm grounds this wire to turn the light on. If the ecm is powered up the test light will light without the engine running.

mat89RS

I tend to think about vats when an lt1 just doesn't start, are you sure you repinned it correctly ???


did you bypass the fuel relay and starter enable relay ???

maybe buy another wiring harness on ebay for a few $, I can completly repin it and label everything for you . I also have a spare VATS module if you want it, 40$.

thatsme

My 95 lt1 would run for two seconds without a vats bypass.

mat89RS

thatsme, then you have a faulty ECM or faulty vats, the car should not crank, spark or get fuel if the vats in not enable.

thatsme

According to the helms manual its doing what it's supposed to do. My wire to the selenoid on the starter is dirrect so that would bypass the vats and the ecm kills the spark and the injectors after two seconds. I don't understand why its done that way but thats what the book says it does and thats what it did. Once I hooked up the bypass module it ran like it was suppoesd to.

sinner

im gonna try replacing the coil and the other piece that is on the coil.

i have power to everything all the way to the coil, but then nothing after that.

i will post my results, and i hope this helps others too, if i knoew this was gonna take a year and over $6k and a million headaches i woulda bought a 4th gen that ran.

sinner

here is a new post i need help on with the same issues

https://www.thirdgen.org/techbb2/sho...hreadid=197747