I'm using an XFI and 50lb high Z injectors. For cold starts, I have to crank up the after start fuel curve off the top of the chart to keep it running after it fires, or it stalls out. The car runs fine, there does not appear to be any vacume leaks and the O2 readings are reasonable. Is anyone else using the 50lb high Z's and what does your after start fuel curve look like?
XFI and 50lb High Z Injectors
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Eric Stage I
TurboTweak Guy
- Joined
- May 25, 2001
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- 2,667
You may want to add more fuel in the warm-up enrichment table (vs. coolant) instead of afterstart.
XFI and 50lb High Z
Are you saying that the cranking fuel table factors and the after start fuel table factors are applied on top of the warm-up enrichment table (vs. coolant), so that by raising the warm-up enrichment table (vs. coolant), I can lower either or both of the cranking fuel table and after start fuel table ?
Are you saying that the cranking fuel table factors and the after start fuel table factors are applied on top of the warm-up enrichment table (vs. coolant), so that by raising the warm-up enrichment table (vs. coolant), I can lower either or both of the cranking fuel table and after start fuel table ?
Eric Stage I
TurboTweak Guy
- Joined
- May 25, 2001
- Messages
- 2,667
Cranking fuel is only used during cranking and should not be used to try and fix stalling issues. Only use enough pulsewidth to start the car without too much cranking time. If you have too much cranking fuel, it could flood, or sometimes it will cause the engine to "stumble" to life, instead of "cleanly" coming to life. It could also start to foul the plugs and run rough for a few seconds.
I don't know for sure because I don't know how the program is written, but afterstart and warm-up enrichment "should" be added together and used once the engine starts running. Afterstart is more of a short term thing to help keep the engine running just after it fires off and maybe a short time after that. Warm-up enrichment is used throughout the warmup period until the car comes up to operating temp. You kind of have to balance the two, to get a smooth startup and good cold manners.
It's also possible your afterstart is not being applied correctly, with regards to afterstart "start" and decay. So you may want to play with those also.
Have fun!
I don't know for sure because I don't know how the program is written, but afterstart and warm-up enrichment "should" be added together and used once the engine starts running. Afterstart is more of a short term thing to help keep the engine running just after it fires off and maybe a short time after that. Warm-up enrichment is used throughout the warmup period until the car comes up to operating temp. You kind of have to balance the two, to get a smooth startup and good cold manners.
It's also possible your afterstart is not being applied correctly, with regards to afterstart "start" and decay. So you may want to play with those also.
Have fun!
Eric is right on the money
His knowledge of the EFI systems used on these Turbo Buicks amazes me. He leaves no stone unturned......
