Car wont start after disconnecting and reconnecting battery

[JamesRS2000]

This has happened several times now. If I disconnect the battery to make a change on anything and reconnect the battery, the car will not start.

The car is an 84 crossfire Vette. I have made several changes that required me to disconnect the battery and each time I reconnect it I spend about an hour trying to get the car to start again. Eventually the car will just start, but I need to find out why it is doing this.

The car will just not fire any fuel from the injectors, it will crank just fine but there is no spark and no fuel.

The car has had this problem since I purchased it about 4 months ago and I have been upgrading parts that were in need of replacement anyway, but I have not as of yet stopped this problem.

So far I have replaced these items: Distributor, O2 sensor, Plugs, wires, cap and rotor, MAP sensor, fuel pump, fuel filter, and throttle bodies re bushed.

The key fob that I have says Amenity and does not look like a Corvette factory fob, but I think that I still have the factory Theft Deterrent Module.

You guys have any suggestions?

James

 

[vee93]

1. Are you sure the battery is the correct battery for your Vette?
2. Check the battery connections on both ends.
3. Is anything left on inside the Vette overnight, i.e., mirror lights, A/C, heater, radio.
4. Any aftermarket stuff connected inside the Vette?
5. You might need to test for a pinched or shorted wire.
6. As for the Amenity fob.... It's definitely not a stock item, but if it's working, I can't see that being the problem unless it's activating the VATS --which I've heard can be
a puzzling mystery wrapped in an engima full of questions with the early C4s.

 

[John Robinson]

You did not mention changing the TPS or testing the one you have. Also if I were you I would do a continuity check on the battery cables.

 

[David-F]

If you are sure it's not getting spark then you will have to rechevk that the ECM is getting power there is a connector coming off the battery "+" cable that goes to the ECM this is what can be removed if all you want to do is clear codes. This connector dose have problems with crousion deing so close to the battery. Also make sure you get a check engine light on with the key on. But if you are not sure if it is getting spark then check to see if it is. If it is you need to check the fuel pump relay when the key is first turned on there should be a 2 second fuel pump prime if there is not check the relay if the relay is not working the car can still start if it cranks fast and long enough to turn the oil pressure fuel pump switch. Also if you have an early 84 make sure the coolant has been updated to the two wire pin terminal sensor and not the original barrel terminal sensor this can cause some start up problems.

David Fulcher

 

[JamesRS2000]

Thanks for the replies guys,

Yeah vee93, the battery is the correct one for my year Vette. As for drains and what not overnight. The car does not have any problem cranking the starter, it just doesn't start. I used the FSM and traced the wires it suggested and it suggested that I had a HEI problem. I installed an old distributor and I haven't had the problem since, but that was just replaced yesterday. I'll keep you posted if the problem pops up again.

John, I tested the TPS and adjusted voltage to the .525 as is stated in the manual. After finding a dead spot in the TPS I replaced it anyhow.

The problem still persisted after that, but as I mentioned above, I replaced the distributor last night and the car has been running properly since.

 

[JamesRS2000]

David,

I tested ECM voltages and checked for codes. None. I also traced out the wires stated in the FSM and that eventually led me to the distributor. I tested voltrages at the ECM and they all looked good, but I thought I might have been dealing with an intermittent ground issue that is why it was not working after battery disconnect. I was wrong it appears. As for the fuel pump, when I turned the ignition on I could hear the fuel pump prime for about 2 seconds or so, so I knew the FP relay was working properly. I also checked the oil pressure sending unit and the wiring appeared okay. I observed as I cranked the ingnition that the oil pressure would climb, so I figured it was working properly as well.

The coolant sensor that you mention I have not heard of. Are you referring to the sensor on the passenger side head, or the one on the intake by the thermostat housing?

James

 

[KOPBET]

Were the IACs replaced or otherwise removed/inspected when the TBs were off?

 

[David-F]

The sensor is on the front of the intake. Now for a few more checks. One you need to check for power to the injectors with the key on if you unhook one of the injectors turn the key on you should get power to one of the terminals if not there is a fuse to check. If that is good also check the terminal going into the distributor cap the larget wire going to the bat terminal will some times get loose and cause problems. What you need to do now is confirm weather or not the ECM is getting an ign. pulse from the distributor or not. If you have a scan tool you just check for RPM while you crank the engine over. If you have a tach/dwell meter you can hook it up to the tach lead on the distridutor cap and check for rpm. If you are not getting a tach signal drom the distributor the injectors will not operate. Now there is a problem the can effect the HEI distributor a problem that showed up more on trucks then Corvettes and that is when oil would travel up the shaft in the distributor and when it did it would damange the magnets on the shaft which would reduce the pulse that would be induced into the pick up coil. Some of the problems that can occure when this happens is hard starting and stalling. You see if the shaft is not turned fast enough there will not be enough voltage to triger the ignition module. Now this can sometimes happen even it there is no sign of oil but most of the time there is. A scope would work well at checking this but I don't think you will have one. If you are getting a pulse then there is a good chance you may have an ECM problem but I would realy like to get a scan tool on there before I go that far.

David Fulcher

 

[JamesRS2000]

Just to update you guys.

I have had the car running for over two days now and have disconnected the battery twice to test whether or not it was going to fail like it had been doing. I am glad to report that it is working perfectly. The distributor was the problem. I have to assume that the 7 pin module inside the distributor is bad, or maybe the pickup is defective. I will tear it down and have the parts tested when I get the chance, but I am just glad that the Corvette is running perfectly again.

Thanks for the advice and direction guys, it is greatly appreciated.

James

 

[vee93]

Yeah!!!! Glad you worked it out!!!
Uhm..., now come and fix my A/C problem, will ya!?!!!