RE: 94 Hard Starts, Runs Good ???

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RE: 94 Hard Starts, Runs Good ???

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Corvette Forum >> Corvette Models >> Corvette C4 Forum >> RE: 94 Hard Starts, Runs Good ???

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RE: 94 Hard Starts, Runs Good ??? - 4/27/2008 4:33:36 PM

mech259

Posts: 1720
Joined: 1/22/2006
From: Lumberton, Texas
Status: offline

Have you checked for codes? Can you get any scan tool data?

_____________________________

L.B.
ASE Master Certified
L1 Emissions Certified
1986 C4
1969 RS Z28 Camaro
1970 Chevelle SS 396 (under construction)

(in reply to OzoneTrash)

Post #: 11

RE: 94 Hard Starts, Runs Good ??? - 4/27/2008 4:50:08 PM

OzoneTrash

Posts: 25
Joined: 2/17/2007
Status: offline

I have no codes. This is in the code history DTC #36: Distributor Ignition System High Pulse. I didnt recheck today after have the new problem. I will have to check tomorrow. I am on my way to work now. Yes shift work "sucks"...

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Post #: 12

RE: 94 Hard Starts, Runs Good ??? - 4/28/2008 9:17:38 PM

mech259

Posts: 1720
Joined: 1/22/2006
From: Lumberton, Texas
Status: offline

Was your Opti you replaced rebuilt or new? The reference to high means the high data rate signal from the Opti, which has a low data reate and a high rate. High data rate usually refers to camshaft and low to crankshaft. If you look at pulses on an oscilloscope, high data looks like a lots of pulses and low are few and they have to work together. If you have high data problems, that will affect injector pulse rate which sounds like your problem. The reason I asked about your replacement Opti, rebuilts usually suck and are of low quality. If it is new, I would look towards ECM replacement, but your would need to verify crank and cam sensor inputs to really check it.

_____________________________

L.B.
ASE Master Certified
L1 Emissions Certified
1986 C4
1969 RS Z28 Camaro
1970 Chevelle SS 396 (under construction)

(in reply to OzoneTrash)

Post #: 13

RE: 94 Hard Starts, Runs Good ??? - 4/30/2008 12:51:47 PM

OzoneTrash

Posts: 25
Joined: 2/17/2007
Status: offline

I just rechecked my codes and still nothing.

The opti is new, I upgraded to a MSD vented cap.

I did notice that it only stalls out when its cold. I let it warm up today and it ran pretty good. It has always had a little hestitation at take off.

How do I verify crank and cam sensor inputs ?

quote:

If you look at pulses on an oscilloscope, high data looks like a lots of pulses and low are few and they have to work together. If you have high data problems, that will affect injector pulse rate which sounds like your problem.

Does this also effect the no spark for the 20 seconds while cranking ?

Thanks,
Steve

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Post #: 14

RE: 94 Hard Starts, Runs Good ??? - 5/2/2008 4:36:26 AM

mech259

Posts: 1720
Joined: 1/22/2006
From: Lumberton, Texas
Status: offline

Well, you have to go to the ECM and measure voltage @ the pins while cranking to see if your signal is making it to the ECM. Don't have the pins handy here, but you can probably find out which they are and use a DVOM to measure with.

_____________________________

L.B.
ASE Master Certified
L1 Emissions Certified
1986 C4
1969 RS Z28 Camaro
1970 Chevelle SS 396 (under construction)

(in reply to OzoneTrash)

Post #: 15

RE: 94 Hard Starts, Runs Good ??? - 5/2/2008 5:30:49 PM

OzoneTrash

Posts: 25
Joined: 2/17/2007
Status: offline

I just ordered a used ECM/PCM off ebay $75 shipped from Canada, it should be here next week. I will have to flash it and I will give it a try. I have C.A.T.S. Tuner and a couple of stock and modified vette BINS to play with. I'll keep you updated.

Thanks 4 Your Help,
Steve

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Post #: 16

RE: 94 Hard Starts, Runs Good ??? - 5/23/2008 4:06:54 PM

OzoneTrash

Posts: 25
Joined: 2/17/2007
Status: offline

Sorry it has taken me so long to reply. I ended up getting 2 different PCM's. I messed up and the 1st one was OBD2 so thats why its taken so long to update. I just got a 16188051 out of a 94 Buick with a LT1 (According to the VIN). I installed it as is just to see whats up, it started right up and then died about 6 seconds later, and thats all it would do. I have 4 different 94/95 Corvette Auto bins or lt1 files, so I flashed the PCM with one of them and now I am back at the same place I started. I tried all the files I have and the same tihing. I'm now thinking TunerCat is corrupting the file as it flashes the PCM, does this happen? I'm using version 2.15 with the EE. I tried flashing the PCM with a Z28 file and it starts hard and only runs for 6 seconds with it. Now Tuner CAT wont let me reflash it back to a vatte file. It keep giving me different errors. So now Im pretty sure it is a PCM problem with a CATS problem on top of that.

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Post #: 17

RE: 94 Hard Starts, Runs Good ??? - 6/20/2008 3:07:43 PM

OzoneTrash

Posts: 25
Joined: 2/17/2007
Status: offline

I''m still in the same boat. I just installed a new programmed PCM and still the same problem. To refresh what my problem is, hard starting (cranks 4 a while before starting) and once started both engine cooling fans come on cold or hot. I was reading on the f body forums and someone was having the same problem and it was the temp sensor plug so I checked that and nothing. Anybody?

Thanks,
Steve

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Post #: 18

RE: 94 Hard Starts, Runs Good ??? - 7/5/2008 12:28:38 AM

OzoneTrash

Posts: 25
Joined: 2/17/2007
Status: offline

I give up. This car is going on the car lot as soon as I get home from vacation next week. Time to say enough and cut my looses. I just bought a 73 L-82 Vette with a 4 Speed & 383 Stroker and it’s been great so far.

Someone mentioned the ignition switch, could this be the problem. I''''''''m not going to change it, I was just wondering. I have enough new parts on this car already. I''''''''m not putting any more money in it. I am going to be taking off the some of the parts and I will be putting them on e-bay.

Problems:
-The car has no spark for 6 - 7 seconds during cranking. After that I get spark and it runs great.
-A/C Worked Great Last Year, It Don’t Work This Year
-Both Engine Cooling Fans Run All The Time

-This car has ZR1 wheels, New Rear Tires, good front tires

-Miles : 83k

-Color : Aqua

-Car is in fair condition

-Stereo System:
Alpine CDA-9857, Audio Control EPIC-160 In Dash Bass Maximizer W/ 160dB SPL Display, JL Audio 5.25" VR Series Coaxials Speakers "Front", Bose in rear, 2 Infinity Perfect 12" Subs, Audiobahn A3200E Amp for subs, HiFonics Zeus 440 4 channel amp pushing front and rear speakers

-New Parts :
PCM “GM Rebuild”, 1.6 Crane Roller Rockers, New Opti “GM” With MSD New style vented cap, MSD Blaster Coil, Plugs/Wires, SPL Triple Snorkle Cold Air Intake, Granatelli MAF, Injectors “Rebuilt Ford Racing”, ICM, Coolant Sensor, Fan Relay, Fuel Pressure Regulator, Auto. Antenna, Air Foil In Throttle Body, I’m sure there’s more but this is all I can remember for now.

-This car was been backed into by the previous owner, I have pictures of the damage done "Not Bad". He had to replaced the hood. No front end alignment parts were damaged. It was turned into the insurance so no clean carfax. I have a clean Wyoming title.

-If I leave this car as is and take nothing off, what should I ask for it? I''''''''m guessing around $8500. I''''''''m not forsure what it is worth. I know I have a lot more tied up in it.

I will add pics as soon as possible.

Thanks,
Steve

< Message edited by OzoneTrash -- 7/5/2008 10:51:29 AM >

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Post #: 19