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View Full Version : Engine Stumbles and Dies

CJ_ZR1
10-28-2012, 11:56 AM
So we got the car back together at 2 am Saturday morning and car is idling around 1000-1200 rpm, after idling around 3000 rpm on first start up. We changed the oil and left at 6 am for a 90 mile trip to a Corvette show. Car ran very well except for stumbling (drops 500-1000 rpm and back up in less than 1/2 a sec) 3 times on way to show, SES stayed on for most of the trip.

On the way home after the show the car experienced more of the stumbling and then completely shut off while going 75 mph. The dash and lights stayed on, just the engine shut off. I pulled over, came to complete stop, turned key to off position, and then started car back up. Car started and I proceeded to catch up with the other 3 vettes I was following. Car ran good for a few miles then started the stumbling again, occurring every few minutes. In the 90 miles back home, car shut off a total of 4 times.

New FIC SS injectors in car and fuel pumps changed May 2012 using ACDelco GM#25163473.

Going to pull codes today and post up...
XfireZ51
10-28-2012, 01:58 PM
Don't take the fuel pumps for granted even tho "new". Did you change fuel filter?
CJ_ZR1
10-28-2012, 03:21 PM
Don't take the fuel pumps for granted even tho "new". Did you change fuel filter?

Yes, I did changed filter
secondchance
10-28-2012, 04:19 PM
I suggest that you check the MAP sensor hose. Except at the ends, where you need elasticity to slip over connections, this hose should be hard plastic. If a soft vacuum hose was used for this connection, as the car slows down, engine vacuum will suck the hose shut sending incorrect info to the MAP sensor resulting in stalling.
Symtom described where after stalling car starting up ok makes this a suspect.
scottfab
10-28-2012, 04:34 PM
This could be tough to find. Starting at fuel is probably easiest but
if you were in under the plenum the DIS maybe involved. (loose connector).
Obviously the trick is to get the failure to happen while looking at fuel pressure. Having a gauge attached to the windshield is easy enough but
getting the stubble/fail after that could get frustrating.
Maybe you'll get lucky and see the fuel pressure drop while idling for a long period.
Hang in there. You'll find it.
scottfab
10-28-2012, 04:36 PM
I suggest that you check the MAP sensor hose. Except at the ends, where you need elasticity to slip over connections, this hose should be hard plastic. If a soft vacuum hose was used for this connection, as the car slows down, engine vacuum will suck the hose shut sending incorrect info to the MAP sensor resulting in stalling.
Symtom described where after stalling car starting up ok makes this a suspect.

There is also the well known oil build up in that short hose. I've arrange mine to slope such that it can not happen again. I don't recall it ever stalling out though. Stumble yes.
Daniel_Mc
10-29-2012, 11:59 AM
Hummmm I WONDER whatsoever could be the problem... Did you watch ALL of the gages on the dash? :blahblah:

Daniel