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After market injectors? Hope this helps you!


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#1 croquest87

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Posted 28 October 2018 - 03:57 PM

I had 2 sets of injectors that l bought new  set from fic the other trilogy.
Anyway the story is  l couldn't get them to work on my all stock 89 Conquest without the translator and 3" gm mass. So after my car started running like crap on warm up w pair of old stockers  l made a decision to figure out why in the F... do these things not work as l have over $500 invested in 4 aftermarket  injectors. They would make my car idle like crap/lots of hesitation at variety of rpms.

After about one hr of playing around w clips resistors mass sensor temp sensor IAC/TPS reset  the works nothing and car runs and idles like crap lol

Couple of Budweiser's later some deep thoughts hey why dont l turn the fuel pressure up? Right  makes sense?

Cranked that pressure up from 36 to around 43 psi car smoothed out on instant at idle. Shut the car off and waited couple hrs for the Budweiser to clear lol. After l drove the car around and no hickups whatsoever. No mass no translator just some good old fuel pressure.

I am assuming that these low impedance Delphi's  are tested somewhere around 43 psi and that's where they like it.

I give all the credit to good old Bud!

Edited by croquest87, 28 October 2018 - 04:13 PM.






#2 importwarrior

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Posted 28 October 2018 - 04:01 PM

Yes they say 43.5 PSi for delphi injectors.

Also a peak hold injector controller might help also.

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#3 croquest87

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Posted 28 October 2018 - 04:12 PM

Good to know thank you. Car runs great again. Probably old news but new to me so l figure to post something about it for newbie and seasoned starquester alike.

Edited by croquest87, 28 October 2018 - 04:15 PM.


#4 croquest87

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Posted 28 October 2018 - 04:24 PM

View Postimportwarrior, on 28 October 2018 - 04:01 PM, said:

Yes they say 43.5 PSi for delphi injectors.

Also a peak hold injector controller might help also.
Peak and hold? What is all involved on a stock car? Thank you

#5 ucw458

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Posted 28 October 2018 - 07:53 PM

Low impedance stock style injectors are a peak/hold driven type.  High impedance aftermarket injectors are a saturated driven type.  This just describes the way the injectors are driven.  Stock injectors 2-3 ohms, aftermarket 10-15 ohms.  Removing the stock injector resistor pack may also help aftermarket injectors run better.


All aftermarket injectors (unless otherwise stated) are rated flow @ 3bar or about 45 psi.  If you are running them at a lower pressure you are not getting the rated flow.  Therefore the engine will not get the fuel it needs.
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#6 croquest87

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Posted 28 October 2018 - 08:39 PM

View Postucw458, on 28 October 2018 - 07:53 PM, said:

Low impedance stock style injectors are a peak/hold driven type.  High impedance aftermarket injectors are a saturated driven type.  This just describes the way the injectors are driven.  Stock injectors 2-3 ohms, aftermarket 10-15 ohms.  Removing the stock injector resistor pack may also help aftermarket injectors run better.


All aftermarket injectors (unless otherwise stated) are rated flow @ 3bar or about 45 psi.  If you are running them at a lower pressure you are not getting the rated flow.  Therefore the engine will not get the fuel it needs.
Aftermarket injectors l have now are low z and about 2.5 ohms.
So if l go w high z or high impedance  injectors and eliminate resistor pack and have full  12v on one side of injector stock ecu will safely control them by pulling the ground?  I have done this on my 87 mpi car already which is controlled by Megasquirt. Just not sure about stock ecu? If it has been done?  I would like to put it into works. Thank you.

Edited by croquest87, 28 October 2018 - 08:51 PM.


#7 ucw458

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Posted 28 October 2018 - 10:45 PM

If you have low resistance injectors then you don't need to modify anything.
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#8 croquest87

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Posted 29 October 2018 - 05:03 AM

View Postucw458, on 28 October 2018 - 10:45 PM, said:

If you have low resistance injectors then you don't need to modify anything.
Thank you

Edited by croquest87, 29 October 2018 - 05:04 AM.





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