Reply With QuoteMay need a little bump in fuel pressure?
Lower idle speed after new injectors
Just replaced the stock/original injectors in my '95 540iA (92K miles) with with new Bosch/Ford Design II D5B injectors (19 lbs/hr). Idle speed went from 750 RPM and slightly rough to 600 RPM and rougher. No leaks detected at injectors. Vacuum leaks were looked for about 6K miles ago and manifold gaskets were replaced by the dealer. Acceleration is smoother now but the change in idling is perplexing - and annoying - after new injectors. New ICV needed? Mistake to use the D5B injectors?
Thanks for the help!
Jeff
5-10 Grand Master
May need a little bump in fuel pressure?
Super Moderator
The original injectors on you car flowed 240 cc or 22.85 lbs, the
replacement you put in is 19lbs or 204cc... I would disconnect the battery and wait about an hour or so and reconnect it so the fuel map can relearn,
your new injectors won't flow as much as the old ones did but maybe the computer can compensate for the flow rates at idle
Originally Posted by jhsmd666
New Bosche OEM fuel pressure regulator also replaced at same time. Thanks for the suggestion re: battery disconnect so fuel map can relearn.
Jeff
3 Grand Master
Yeah....what's the logic behind replacing the injectors on a V8 M60 with 19# mustang ones? I'm confused...
best, whit
2 Grand Master
???
Ralph Mendoza Jr. - Long Beach, CA
Major Contributor
At least you might get increased fuel...
economy at the expense of lower peak power output.
Super Moderator
5-10 Grand Master
Bill R. are these figures in cc? I would guess so... but doesnt 220cc translate to roughly 20#? And thus 240 would be like 22#? I have an M50B25 non TU, I think it has the 170's stock, I am going to 310cc which I think is 30#, but I thought an "upgrade" for the M30 was 19#... but that shows that they have ~21# stock...
Super Moderator
Yours actually has 180's stock, as far as the upgrade goes on the
m30 it works out to approx 10cc's less with the mustang 19 lb over the stock bmw, but i guess on most cars the old injectors are dirty enough and worn enough that they still gain with the newer injectors, that and the spray pattern is better on the new designs. However they still need to take into account the angle on the nozzle which is listed here... Any replacements should have the same angle since that is dependant on the shape and direction of the port ,manifold and head...
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