Ok, for history on the subject, here are links to all previous threads regarding this matter:

LINK 1

LINK 2

Here's the update:

All the spark plugs have been changed, and all the plug wires are verified good, and connected properly. A solid spark is making it to all the cylinders. Fuel pressure is at around 45 PSI. All fuel injectors have been verified that they are squirting fuel. A compression test was conducted, and acted normal. All electrical connectors and sensors have been verified to be working properly. The drivetrain is also moving as it should. The engine grounds have been verified to be good. My PCM is alive, as it will communicate with my Hypertech just fine, and it's getting signals from all the sensors.
However, the car still just cranks and cranks, but will not turn over. While cranking the engine, I'll get a back fire from the exhaust, but that's it. I just can't figure it out. Everything that makes an internal combustion engine run is present.
I need ideas on what this could be. Please give any info that may be helpful. I may not be able to check on this thread until Monday morning, so I may not be able to respond to questions until then.
TIA for any help!

 

The biggest clue I see in your post is the backfiring through the exhaust....

Timing belt Jump a tooth or two?? Oh by the way... while at it find a way to read the impedance of the Coolant Temp sensor and the IAT.

For the Coolant Temp Sensor....the readings you are looking for are.......

At 71*f degree it should read about 3.1 Kilo Ohms
At 81*F degreee is should be at 2.5 Kilo ohms and
at 90*f it should be by the 2K ohm range. engine temp that is... read it while engine is cold.. if you need the Impedance at colder temps reply to this thread and I will send it to you or visit Injuneers web page. Injuneers readings at hot engine temps are way diff than mine though. I tested a new sensor myself and the readings match with a Thermistor/Temperature Table Generator that I downloaded from an Electronics Manufacturing Companys website. they did match my readings within less than a half degree so I will stick with my results for the time being.



Why do I think the Coolant Temp sensor could be the culprit??

Because I did some testing on my car and everytime I modified the Temp reading by half the car would refuse to start. Meaning if the engine temp was in the 70's range and the Temp Coolant Sensor was reading 1 Kilo Ohm the car refused to start... or it would take a very long crancking time and slowly would start to fire up.


Its only 9 dollars or less. take a reading wiht a Digital Volt Meter if you own one. Or take the plunge and buy the sensor. If it does not work for you, at least you end up with a new sensor. Its a cheap sensor and in your situation I would try it first.


Marvin

 

I had the EXACT same problem in my beater. My dumb *** switched up the plug wires. I would check that. check shoebox's page for the diagram

 

The timing is probably way off. Possible causes, among others, include mixed up plug wires, improperly installed Optispark, malfunctioning Optispark. I didn't read the links, but the first question to ask is always "what was the last thing I changed immediately before it stopped running?"

Rich Krause

 

yep.

 

Your timing is off. I did read your other posts. Your problem obviously occured when you over reved the engine before it hooked up. The compression should be lower than normal even though it is equal from cylinder to cylinder. I understand you now have spark to all 8 also.

Your previous method of checking the valves condition when number 1 is at TDC will probably not work since the intake closes too soon. Even if the timing chain has slipped, the valve will more than likely be closed before TDC even if it is delayed. So they will both be closed at TDC like you where looking for.

I suggest you check the position of the rotor when #1 is at TDC. A bit of a chore since the outer half of the opti has to come off. I suspect you will see it is pointing toward or skewed toward the #2 contact. Be careful since the rotor contact is very wide and can be deceiving. You should have checked it when you replaced the opti.

 

But if my timing is off, that would mean that my timing chain slipped, which I've heard from a few places that that's basically impossible. Is there anything else that could cause timing to be off?

All the plug wires have been verified installed correctly, and I'm 99% sure the optiwas installed correctly. It's a '97, so it has that key hub thing. We made sure it was linned up, and that the Opti fit flush without forcing it on.

I'll see if I can get some test equipment for the coolant temp sensor. I'm just wondering how I can verify what the temp of the actual coolant is.

EDIT: Oh yeah, nothing was changed in the recent past. Car is basically stock with an MSD ignition (wich has been bypassed), and the Hypertech programming, which has been flashed).

 

same thing happened to me and it was the opti not installed correctly. i swear i put it on right and didnt move it when i took it off and put it back on but it fired right up after reinstalling the opti. i didnt read your other posts, but if any engine doesnt want to start and then backfires after repeated tries its the timing thats messed up somewhere, be it the wires got crossed or you didnt have the opti in this case installed correctly. with everything else working its got to be the timing messed up somewhere. id concentrate my efforts on that. Trey

 

I'll be reinstalling my new OPTI Tuesday probably and I'm wondering what I should look out for to make SURE I am doing it right. I don't wabt to do all this again unless it's to install a cam. Also my car has 136,000 on it so should I replace my timing set while I'm there or should the old one be ok? Thanks!!

 

Ding ding ding, we have a winner! After tsting absolutely everything, the last hope 9or so I thought) was going to try another PCM. The person couldn't make it out until Sunday evening, so I figured I would check out the Opti again during the day. I pulled it off, put it back on, and viola, the car cam alive. Everybody says that it doesn't make sense that it was on incorrectly, but it was , somehow. Even though I have the later style Opti, and we thought we lined up the key, AND we made sure it fit flush without having to force it on, it somehow didn't sit right.
Me, and a few other people are just shocked at this. Thanks a million for the suggestion, as I wouldn't have considered the Opti the problem after I had just changed it.

Regarding your future Opti install, follow THIS guide. Do ALL the steps it lists. Don't skip any of them, or it will probably actually add time your swap (it did for me). A couple of socket sizes were a little off, but the procedure is very thorough, and definitely got my through it. A word to the wise though. After installing the Opti, and reconnecting all the plug, and coilwires, reconnect the batter, and fire the motor up. It won't need any accessories, or the water pump connected for it to run. Just verify that it will fire up and run, and then turn it off. This could save you A LOT of work later, if you find out it went on wrong. It task a little extra work to put on the water pump because the gears may not line up right away, but that's not a big deal, and DEFINITELY worth it. If you want any specific tips, feel free to ask me.
As fas as the timing chain, at actually seems like a lot of extra work. I believe you have to drop the oil pan too. I know it says when changing the timing chain gasket, that you have to shange the oil pan gasket as well. I don't know about the specific, though. I'm going to wait untill I do a cam swap for me to change the timing chain, otherwise I'll just be doing all that work all over again. Good luck with your install, and thanks to everyone for their help!

 

Thanks for the info and congrats on finding the prob. Mine is already off and I'm waiting for the new one to arrive right now. I'll look through the link you sent.

 

No problem, and good luck on your swap.

 

glad you got it running again. Trey