CA Vette Chick

Work recently done:
oil changed
fuel filter changed
fuel pump changed (47 pressure)
injectors cleaned & tested to specs- passed, installed.

Car started & ran 15 min - the mechanic ran out of fuel- got 5 more gallons and now can't get it to turn over.

Q: my battery is now @12.5. Is that enough volts?
Q: how much gas should I have? Is reserve enough?

Thanks.

A Peter C4

Yes 12.5 should turn over and start. Yes 5 gal. should be plenty, when my reserve light came on I drove another 15+ miles and gauge went to last bar, I stopped and filled tank and it took 16.7 gal. So I still had 3+gal. after gauge dropped to 1 bar in my 94 Coupe. When reserve light came on there were 2 bars showing. I would say there are about 4+ gal. when reserve comes on. You say it won't turn over, so it won't crank over now? Or it cranks over but not start?

aklim

OK. So just to be sure, are you saying it won't crank? If that is the case, the question is whether the starter is getting the signal. Do you have an idiot light you can hook up to the starter?

CA Vette Chick

It cranks but doesn't start- I thought it might be the icm- changed that out (because there was no paste left) but she still isn't starting...

pcolt94

Check fuel pressure.
Do you hear the 2 second prime from the pump in the rear when key is turned to ON?
Check for spark off the coil.
Check drive for the injectors using a noid light.
Check all plugs, pins and connectors, re-seat. (coil, ICM, opti, ECM etc)

Your mechanic should be able to do all of this.

Cool down the ECM with a ice (cold) pack and see if there is any difference. Keep water and moisture away from ECM.

JimLentz

Any codes showing up?

hope2

I would turn the key on and off 10 times and listen for the fuel pump to operate (prime) each time for a couple of seconds. Then try to start.

pkincy

I agree you need to do the normal checks. Is there fuel at the injectors? Is there spark at the plugs.

Do you have fuel pressure?

I have burned up a fuel pump before by running the tank dry.

aklim

IDK about the year but mine is a 91 and WILL NOT do the prime by repeatedly turning the key to run. IIRC it is a 5 minutes wait between prime. What are you looking to do?

aklim

That old wives tail will never die, will it? That is so bogus.

A Peter C4

Most in tank pumps rely on fuel to stay cool, I guess that's why it is said to refuel when at 1/4 tank or under. It makes sense to me, but what do I know. AIR<FUEL<SPARK engine should run.

aklim

Do you want something that raises that much heat boiling the fuel? Id think not. Besides, Tom400CFI could run an old pump for over 30 minutes with no "coolant" before it died. If running almost empty can kill a pump, you should buy stocks in Walbro since I only fuel up when it is just past empty. No fuel, no spark. No spark, no current to pump.

aklim

https://www.corvetteforum.com/forums/c4-tech-performance/3727420-gas-mileage-real-vs-what-ecm-says.html

For those who believe in the cooling effect of the fuel or old wives tail

CA Vette Chick

Thanks all- it sounds like I'm going to need a new opti. Suggestions?
Not looking forward to taking out these major components.... good advice appreciated!

pcolt94

Suggestions??

Did you test or check or have someone check the items I indicated to check (post 5). That's pretty basic things to check before you do major work to the engine. And most who do an opti replace the water pump also since it has to come off as well (Another expense).

It may or may not be the opti, most of the time the opti causes a runbility problem. The optical sensor in it usually does not just stop working which would cause the engine not to run but it does happen.

pkincy

I concur. I am on my original opti on my 93 Corvette, but changed my higher mileage 93 Camaro opti 5 times. 4 of those times it was something else.

Now I did learn that I could change the opti in a Camaro in an hour after doing it that often, but that is not much of a marketable skill these days.

on the Corvette there is a bit more interference in front of the balancer that might cause some complications.

CA Vette Chick

I don't have any equipment to test/find out what codes are being thrown. I know the injectors are working, haven't checked the spark plugs- though I know they haven't been changed in a while.(4 years)

The mechanic - although experienced with other cars - was NOT familiar with Corvettes and after the Vette was started, started to hose down the engine.... well when it cut off, and wouldn't start again he "washed his hands, the engine started, I'm outta here bs"....

now I'm doing the work (the other choice is to tow it to a trusted shop- but I know that's going to be bank)...

Should I really get to the opti, check it (how?) reassemble the engine, try to start the car, and disassemble the components again if the opti is bad (is this too much whine?)

i want to some day drive her!

pkincy

I had a leak in a small water hose that got the front of my engine wet with hot steaming water several years ago. I put the car up and ordered a new Opti due to the water killing my OEM opti. 1993 40th with 41,000 miles and original Opti.

Took 2 weeks to order and get the new Opti and another 2 weeks to get some time to change it out. Went out that day and the car started and ran fine. So sometimes the solution is to do nothing for a relatively long time and see if the opti simply dries out. Now if it shorted you are sol, but who knows. Wait a month and see what happens.

Oh, also, never use this "mechanic" again.

CA Vette Chick

Oh, also, never use this "mechanic" again.[/QUOTE]

agreed! So I'm not having problems with the water pump- I know I have to take it off - question: do I really need to replace this? ( it was replaced about 5 years ago along with the thermostat) or is this one of those things you just do because I'm there? BTW I am planning to change the opti & the spark plug wires (and the spark plugs- nervous about this though)

pkincy

Pretty easy to replace as it has to come off, but if it has few miles on it then save some money. A big help is a razor blade holder to make the blade a scraper at the end of a 10-12 inch handle and a brass brush for cleaning gasket surfaces on the block after the water pump is removed.

But I wouldn't pull the opti until it had a few weeks to dry out so you can see if it is really a problem or not. Particularly as this is not a DD for you.