Car cranks but won't start.
 

I have a 1996 Collectors Edition Corvette. The engine will crank but won't start. I've replaced the Opti Spark and wire harness. I've replaced the Coil and harness. And I replaced the control module and harness. Currently I am getting a code 1361. I also placed a spark detector on the #2 cylinder and don't see a spark. One thing I noticed is that the new coil harness has 3 wires and the old has 2. The center coil wire is connected to the white wire on the control module. The other wire is connected to a red wire. I'm new to Corvettes but not to working on cars. The car ran great for the first 6 months I owned it then it stopped and wouldn't restart. For many previously owned GM's that has always pointed to the Control Module. I replaced it with an auto zone special with no luck. Then ordered an ac delco from Rock. also ordered the coil and wire harnesses at the same time. Still no luck. Finally replaced the opti spark. The car started a couple of times then back to the same problem. Cranks and cranks but won't start.

Welcome to the forum. You need to pull some codes before you throw any more parts at your car.

Have you tested for proper fuel pressure with the key on and when cranking?

Sorry I wasn't on line, grand kids attacked.

I have checked codes. I keep getting a P1361. Ignition Coil Control Circuit Low voltage. And once in a while I get the P035 Oxygen sensor. Fuel pressure is at 42 PSI. I pulled the oil sending unit and noticed that when I crank the engine no oil spits out. Both the Camaro's would spit oil out. On the Camaro the oil sending unit shuts off the electric fuel pump. Is this the same on the corvette? Or does it shut off the ignition? Also is there a Fail safe other than the oil sender that may be a problem? I also noticed back firing through the intake. I rechecked and I'm now getting spark at the #2 cylinder.

I'm going out to get an oil filter and oil. I also plan on putting a mechanical oil gauge on as well. I can put in a T so that I can keep the stock sensor also.

Have you considered over riding the oil pressure switch to test your theory?

I'm willing to try just not sure which wires to connect. I also dont have a lot of room to work back there. There isnt much slack on the oil sender wire.

I am really confused now. I pulled the oil sending unit out and was about to put it back when I noticed another oil sending unit below the first. The oil sending unit on top has a 3 wire connector and the one underneath has a one wire connector. Both look to have stock connectors on them. Is it normal to have two oil sending units or did the previous owner make some modifications? I can under stand having one electrical and one mechanical but not two electrical sending units.

3 wire is OP Gauge and fuel pump switch. Single wire is for 'check gauges' light and CCM.

Thank You. I'm learning a lot about this car. I'll swap out the 3 wire sending unit and see if that helps.

I wouldn't yet I don't think - you mention the P1361 and replacing some related parts. As tough a reach as the OPS etc is I might avoid the effort.

Since owning the car I've had doubts about the gauges on the car. I already have the oil sender out I might as well replace it, it's a cheap part. What concerns me is that when I crank the engine oil does not come out of the open port where the oil sending unit goes. I'm going to add a T at the port and connect the new 3 wire sending unit and a mechanical gauge as well. I'm concerned that I may have no oil pressure meaning a blocked passage or bad oil pump. I'm hoping the mechanical gauge will show some oil pressure when I crank the engine. If there is no oil pressure then I've solved why the car won't start, and I have to figure out why there is no oil pressure.

As it turns out I have zero oil pressure on the Mechanical and electrical oil pressure gauges. So I think it's safe to say the car won't start because of the oil pressure safety switch.

What else can cause no oil pressure? Bad Oil Pump? Clogged passage? I checked the oil, it's at level and looks like oil. not milky?

I have no history on the car. It has 130k on the odometer and other than the engine is in great shape. The car always ran a little hot, about 110, which according to what I've read is common for the C4. Oil pressure was normal except when idling at a light and it dropped to about 5. As I mentioned before, I had my doubts about the gauges. Then again I'm old school and really like mechanical gauges.

Any suggestions on what I could try short of pulling the engine?

I'd like to thank everyone for the advice. Because of the codes I was receiving pointing to the coil I never would have thought to look at the oil pressure. I can't say I like the result but at least I know where the problem is and won't be throwing parts at the problem.

Oil pump drive?

You'll have to pull the oil pan and remove the oil pump to see what's going on, and possibly the intake manifold. With 130k on the engine, I'd probably opt for light hone and re-ring, and rods/ main bearing replacement, and get the heads done.If you can do it yourself it will likely be $500 - $600 for parts including a valve job if everything is otherwise good. You will have a like new engine, as long as you don't get a case of the "while I'm in there"s...

Here's Why....... I'm wondering how long that engine has been run with no oil pressure, and if all is ok. Engine damage happens fast with no oil pressure, and even if you get it running, after all that work, I'd hate to see you have shavings in the oil, and need a rebuild anyway.

Drain the oil and look for metal particles.....hopefully you dodged a bullet.

Unless the gauges were completely faulty, I've had some oil pressure except when it wouldn't start. I drained the oil and pulled one of the valve covers. I used a magnet in the oil to check for shavings and visually inspected the oil. No shavings and the oil looked relatively clean. The valves up top were very clean. Typical oil on the rocker arms and puddled here and there. No sludge of any sort. Very clean for 130k. The next thing I'll try is taking off the intake. From what I've read, I should be able to get to or at least see the oil pump drive with the intake off. I'm hoping I can remove the drive and test it. On older GM's you could use a long screw driver and insert it into the oil pump, spin it and see if the oil pump pumps oil to the top of the engine.

I've taken engines apart, taken them to a machine shop then put them back together before, but I don't have the machinery to properly hone cylinders or plane the heads. If It comes to that, there is a local machine shop that I've used before and trust. If I'm going to all that trouble, I would prefer to have a pro do the work.

Do these engines run that clean? I've pulled 350's out of 80's era camaro's and they always had some sludge on them.

If you can get away with only pulling the intake, that's fantastic. Just so long as all is otherwise good, it'll be fine.
Should be a simple fix, and clean up the engine bay while your at it.....

Further Information
 

The more parts I remove the more I realize this engine has been apart before. New gaskets, bolts not torqued or incorrectly torqued. The oil pump works fine however there is still no oil pressure. It appears that the cam bearings are shot and the oil is pumping up but dropping right back in to the pan. I've decided to pull the engine. The question I have is... Is there a different engine that I can use in this car with out to much trouble. It has the 4l60-e Transmission or I would have used a GM crate. I'm not fond of the LT1 but I also don't want to spend a fortune swapping engines.

Cam bearings are pretty rare to lose that much oil pressure....Getting another engine is a good option only if it is low mileage. It would also depend on what your looking to do. There are plenty of good LT1s on ebay, that you could use to keep your Vette going while possibly doing an at home rebuild?

Might even find an Lt4 (330 hp) engine if you look around. But just to hone it, cam bearings, and cleanup shouldn't take more than a month or so. Of course...while you're in there....you could make it a 383 and while you're in there... get some better heads and so on and so on....down the rabbit hole we go......

But really...about a week at the machine shop, re-assemble, and put it back it. They will even reassemble it for around $150 -$200 f you don't have the tools or skills. But...get a good machine shop that will not give you the runaround, because they could take forever reassembling it.