Tuesday, March 24th 2020
Here's my social distancing project. Hoping you can help.
Chasing a ghost the last few months. Bad injector?
My 87 Daytona Z has a transplanted 2.5 turbo flex-fuel engine with slightly bigger Bosch injectors from a 93/94 Spirit / Acclaim. I'm thinking being this old the pintle contact surfaces may be worn but don't want to throw away money. However, in case I'm right, fuel injectors are re-manufactured so what's the opinion on the best source???
SYMPTOMS
A few months ago, only on startup, it began running very rough for 5-15 seconds then cleans out. Such a short time makes it impossible to test while running. Under heavy acceleration, it's a little rough at certain rpms. It's also lost about 2 ½ mpg but other than that seems OK. Weirdly, maybe every 6 startups it starts fine.
THEORY
I'm no expert but after lots of testing (details below) may be a fuel injector isn't fully closing??? After shut down gas would leak out, puddle and temporarily flood the intake on startup (rough running) then would continuing to run slightly rich (lowering mpg). When starting properly maybe the leaking injector was on the open head intake valve and the gas went directly into that one cylinder so it would only be rich for a few piston strokes?
WHAT I'VE DONE
That's it. I'm stumped.
If required, replacing injectors looks simple but very involved. Any trick way to do it rather than removing the entire fuel rail?
Thanks for your help.
Stay safe, DDBob.
Here's my social distancing project. Hoping you can help.
Chasing a ghost the last few months. Bad injector?
My 87 Daytona Z has a transplanted 2.5 turbo flex-fuel engine with slightly bigger Bosch injectors from a 93/94 Spirit / Acclaim. I'm thinking being this old the pintle contact surfaces may be worn but don't want to throw away money. However, in case I'm right, fuel injectors are re-manufactured so what's the opinion on the best source???
SYMPTOMS
A few months ago, only on startup, it began running very rough for 5-15 seconds then cleans out. Such a short time makes it impossible to test while running. Under heavy acceleration, it's a little rough at certain rpms. It's also lost about 2 ½ mpg but other than that seems OK. Weirdly, maybe every 6 startups it starts fine.
THEORY
I'm no expert but after lots of testing (details below) may be a fuel injector isn't fully closing??? After shut down gas would leak out, puddle and temporarily flood the intake on startup (rough running) then would continuing to run slightly rich (lowering mpg). When starting properly maybe the leaking injector was on the open head intake valve and the gas went directly into that one cylinder so it would only be rich for a few piston strokes?
WHAT I'VE DONE
- No error codes
- No gas around fuel injectors so assume seals are tight
- Ran 2 bottles of Seafoam in 4 tanks of gas (no difference).
- Sprayed carb cleaner into the intake (spotless before spraying), no difference.
- Used my homemade smoke machine to test for vacuum leaks then a vacuum gun, no leaks.
- Battery (12.4V) & alternator running (14.6V)
- Swapped ignition coil, no difference
- Injector connectors clean and tight
- No bare wires in injector harness
- Injector voltages are good and LED test light flickers.
- Ground wires good: Stock fuel rail & intake manifold ground wires good but cleaned them anyway. Also has the FWDPerformance 4 sectioned 4 gauge ground wire kit modified to use much larger screws & bolts to different frame locations. Additional homemade fuel rail and alternator housing ground wires. All grounds & sockets cleaned or replaced throughout the car with several other additional grounds added. From past painful & very expensive lessons I'm a big believer in good electrical grounding & cooling esp in Chrysler products. FYI: Corroded sockets and/or bad grounds will dramatically slow-down turn signal frequency.
That's it. I'm stumped.
If required, replacing injectors looks simple but very involved. Any trick way to do it rather than removing the entire fuel rail?
Thanks for your help.
Stay safe, DDBob.