IM trying to help buddys daughters car run. It has a quad4 auto. This is an unusual no start situation.

Tiny
UPINSMOKE
  • MEMBER
  • 1997 PONTIAC SUNFIRE
  • 320,000 MILES
Sunfire came to me with a crank sensor code on and no start. They brought it to me from their family mechanic, who had it 5 months and informed them the motor was blown, and 2500 for used one installed. I installed new sensor, cleared code, code hasnt returned. Still no start.
the girl said she drove at highway speed, and car started running rough--and shaking--and die. No prior warning signs so she claims.
if you crank cold, car runs for 1 second, and dies.
if you recrank immediately, it will stumble and fire but not start.
if you let the fuel pump sit for 5 secs with key on, it will start for a second again. If I introduce propane into the intake, the car will idle. But if I try and idle it up, it will misfire due to lean unless I up the propane.I would consider that normal. If I let the car idle to normal operating temps, and shut off the propane, the car will run on its own, and die as soon as you increase throttle. Now the things ive tested.
compression is 185 all across.I changed plugs with known good used ones I had. I put in new fuel filter I had as heavy rust on old one. It wasnt clogged. Fuel rail has no schrader valve, so I could not test rail pressure, nor test regulator. (Regulator seemed to not be full of fuel).
my scan tool said fuel pump was at 40% duty and I saw tool change on the open loop closed loop fuel circut. If I ran the car on more propane I saw duty cycle increase. Map sensor reaDS 33Kpa at idle. No detonation.
i do not have a noid kit, but I conclude injectors fire as car will idle warm on its own. Can they be plugged? Doesnt go with the sudden condition. I cant help but think the computer is commanding fuiel bypass. But why? Just a trickle of fuel is getting into the cyls.
all this idling and running, and I even drove car up onto car hauler today, and no MIL's. Passlock is not blinking.

i took a fuel tank out of a smashed car that ran, and put it in to eliminate the possibility of weak pump/contamination.

i have a used fuel rail/injectors/ harness, and regulator from same smashed car I can stuff in to test.
Wednesday, September 14th, 2011 AT 12:56 AM

4 Replies

Tiny
UPINSMOKE
  • MEMBER
  • 3 POSTS
No change with pump/tank swap.
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Wednesday, September 14th, 2011 AT 1:10 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Are you able to get a fuel pump pressure reading at the fuel filter? As far as the injectors, you need to check voltage to them. They may not be getting enough from the PCM. Did you try blowing out the fuel line since there was rust in the old fuel filter? This sounds fuel related since you can run it on propane. If the fuel pump is producing the correct amount of pressure, something is stopping it between there and the engine.
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Wednesday, September 14th, 2011 AT 3:10 AM
Tiny
UPINSMOKE
  • MEMBER
  • 3 POSTS
The used fuel rail/injectors/ harness, and regulator from same smashed car solved the issue. Bad injector, just not shorted.
I cannot say for certain if there was more than 1 issue, as I sorta shotgunned parts on hand at it.
Just stuck a new set of plugs, and we are gonna make a young lady happy for cheap.
Ps, I am a graphics guy, not a mechanic by trade.
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Thursday, September 15th, 2011 AT 2:49 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Well, you did a great job regardless of your vocation. Keep in touch if you have other questions in the future, and I'm glad you got it fixed.
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Thursday, September 15th, 2011 AT 2:56 AM

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