94 Hard Starts, Runs Good ???
 

I’m stuck with this one. I have read the other threads on the same subject but my problem is a little different.
Car cranks for a while before it starts (about 15 – 20 seconds). Once it starts both cooling fans come on about 3 seconds after the engine starts. No codes but service engine light is on. I can hook up my scanner and hit clear codes the light will go off and fans will stop for a couple of seconds then they both come back on. I have done about everything the FSM says.
Here’s a list of what I have done so far to remedy this problem. What am I missing ?

Parts Replaced:
Granatelli MAF, Injectors, ICM, MAP, Coolant Sensor in Water Pump, Fan Relays, Fuel Pressure Regulator

Stuff that I Checked :
Fuel Pump Pressure is 41psi with vacuum off FPR. Is 41psi good enough? But that still don’t solve the fan problem, Removed and Cleaned IAC Pintle, The FSM says for the fans running possibly a faulty ECM, I have installed 3 different bins and nothing.

Any help will be appreciated.

Thanks,
Steve

RE: 94 Hard Starts, Runs Good ???
 

Cold motor?

Or hot motor?

Or both... ?

RE: 94 Hard Starts, Runs Good ???
 

That sounds like an ECM problem to me. I am by no means, as many will attest, an expert.

RE: 94 Hard Starts, Runs Good ???
 

It does it cold or hot. I'm starting to thing ECM myself. I thought I had a ECM won on ebay but I was wrong, it sold. I was told to check the temp with my scanner to see if the ECM thinks the engine is hot, if so it will cause this problem also.I'll update with that info.

Thanks,
Steve

RE: 94 Hard Starts, Runs Good ???
 

Have you checked to see if it is spark or injector pulse? Both are related to Opti distributor cam sensor. Do you have a noid light to check injector pulse and a spark checker for spark?

RE: 94 Hard Starts, Runs Good ???
 

I dont have a noid checker. I did just change the opti-spark with a new GM with a new MSD vacuum vented cap. I also change to a new MSD coil. Changed all the plugs and wires at that time also.

RE: 94 Hard Starts, Runs Good ???
 

Still need to check for spark and injector pulse. Also, is the 41lbs of fuel pressure instant when key is turned on?

RE: 94 Hard Starts, Runs Good ???
 

My noid light came in today. I have injector pulse while cranking but no spark. After about 20 seconds give or take I get spark and it starts. After seeing I have no spark I didn't recheck the fuel pressure. What is giving me the delay in spark. I have new Opti, new coil, new ICM, new MAF. I cant think what else I have replaced.

Thanks,
Steve

RE: 94 Hard Starts, Runs Good ???
 

If you have injector pulse and no spark, chances are you do not have dist. probs. Have you checked your 12v supply to the coil?

RE: 94 Hard Starts, Runs Good ???
 

I have 12v to the grey connector red wire with black strip, no voltage on the white wire. No voltage to both wires on black connector. This reading is with the ignition on.

I just went to take it for a ride and now when I give it throttle it stalls really bad. This is new, its never done this before. At higher RPM's is seemed to run alright.

RE: 94 Hard Starts, Runs Good ???
 

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

RE: 94 Hard Starts, Runs Good ???
 

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"...

RE: 94 Hard Starts, Runs Good ???
 

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.

RE: 94 Hard Starts, Runs Good ???
 

I just rechecked my codes and still nothing.

The opti is new, I upgraded toa 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 Iverify crank and cam sensor inputs ?

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

Thanks,
Steve

RE: 94 Hard Starts, Runs Good ???
 

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.

RE: 94 Hard Starts, Runs Good ???
 

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

RE: 94 Hard Starts, Runs Good ???
 

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 medifferent errors.So now Im pretty sure it is a PCM problem with a CATS problem on top of that.

RE: 94 Hard Starts, Runs Good ???
 

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

RE: 94 Hard Starts, Runs Good ???
 

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 thesome of theparts 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