George Posted December 5, 2014 Report Share Posted December 5, 2014 iron head 3.4 = 93-95 F-body engine. LQ1 injectors are more like ~22.5. If I were to get 24 lb/hr injectors would the computer learn to reduce the duty cycle to get the fuel mixture correct? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 6, 2014 Report Share Posted December 6, 2014 24/22.5 = 6.7% extra fuel will be injected without O2 correction. to combat that, the ECM will drop the BLM(long-term trim) to 128/1.067 = ~120. that is WELL within the correction limits for either a 91-93 or 94-95 LQ1 calibration. more often than not, the factory calibration is going to be off in one direction by that amount, so you could see a BLM of 112 or around 128. what I would be worried about with changing to other flowrate injectors would be the transient characteristics not matching up(injector opening/closing times vs both time of commanded pulse and vs battery voltage). those issues tend to be most prevalent when pulsewidths are at their lowest(idle/overrun) and less noticeable when more fuel needs to be injected. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted December 10, 2014 Author Report Share Posted December 10, 2014 Got my 3 new injectors yesterday. No real way I could tell for sure that they are what they say they are. Didn't say FJ105 or FJ105T anywhere on the injector bodies. Just a long string of numbers that bring nothing up on Google. Installed them tonight. The car runs and drives fine, no black smoke and no audible pinging or knocking, but I can feel a vibration at idle especially in gear. It vibrated a bit before while idling which is why I wondered if something weird was going on in the first place (used to idle silky smooth, say, early in the summer). I feel like it probably vibrates a bit more now than before though. Not completely surprising considering I now have 3 different types of injectors that physically look nothing like each other. In fact, my new FJ105 has a different outlet end than the old one from '97. Not sure if it fixed the ECM weirdness or not. Drove it a few miles tonight. It never acted like it was going to die, but can't really tell much from that because I'll need to see how it feels in bumper-to-bumper traffic. Kind of disappointed that the idle is less smooth than I'd hoped. Guess getting all 6 brand new and perfectly matched injectors would have been the way to go if I wanted a silky smooth idle. Then again, maybe there is still something else wrong with the car other than injectors. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted December 14, 2014 Author Report Share Posted December 14, 2014 Pulled the plugs. Looks like those who thought I should replace all the injectors were right. Yes, yes, you told me so. The stock GM injectors run significantly leaner than the Standard replacements and the car runs rich enough to have triggered a trouble code 45. Total waste of $100 ($90+gaskets and O-rings). Lift toilet lid, insert $100, and flush. Overview of the plugs. Top row is 1 3 5, bottom row 2 4 6. 1=Standard FJ105T 3=Standard FJ105 (1997) 5=Standard FJ105T 2=Original GM 4=Original GM 6=Standard FJ105 (new) Closer view showing 6 4 2. 2, 4 = Original GM, looking like they run much leaner than the rest. 6 = Standard FJ105 (new) mostly all black, running richer than the GMs by far. Closer view of 1 3 5. 1, 5=new Standard FJ105T. These look to be running richest of all, no hint of insulator color shows even with camera flash. 3 = Standard FJ105 from 1997. Running richer than the original GM, looks close to the other new FJ105 (but different nozzle design, old one has single nozzle jet while new FJ105 has triple jet design similar to FJ105T). Looks pretty well matched to the other FJ105 in pics, though when I eyeballed it I thought the newer one looked slightly richer than the old one. Probably didn't notice any idle roughness the past 17yrs because 1 slightly rich injector probably doesn't make that much difference. Lesson learned: Mixing brands and models of injectors is very likely to end up very unbalanced. Best to replace as a set, unless you replace with the exact same brand and model, then that would probably be okay. Even FJ105 vs FJ105T doesn't look like a good mix as the newer FJ105Ts appear to run slightly richer than the FJ105s to my eyes. I don't care about the rough idle so much as I don't want to risk killing the cat with a rich mixture so I'll probably drop $170 on a full set of FJ105Ts from eBay unless someone has a better idea. Quote Link to comment Share on other sites More sharing options...
George Posted December 14, 2014 Report Share Posted December 14, 2014 When I talked to the place I got my injectors from about warranting them (GM, Ford, Mopar OE parts dealer, they don't sell cars) they told me the standard sales rep said the injectors with the T suffix is OE replacement and the plain part number is an improved design. But then again that was the sales rep talking. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted December 14, 2014 Author Report Share Posted December 14, 2014 (edited) I'm not really sure what the story is on the T-series. The FJ105 has been around a long time, 1997 at least, and predates the T-series. I had thought the T-series is just a newer version of the FJ105. The FJ105T appears to flow better (plugs look richer) and they do cost slightly more at Rockauto than the non-T versions. The FJ105Ts are apparently a "customer favorite" on Rockauto. On the other hand, when I do a Google search, I find people saying the T-series is the cheap budget line that's made in China, so I'm not really sure what to think. Neither the FJ105 nor FJ105T looks anything like the OEM though. Maybe I should just try to track down some FJ105s rather than using FJ105Ts is those really are budget Chinese stuff. Can't find a whole set of them for a very low price, but I might be able to get 4 to match my other 2. UPDATE: Emailed SMP with the #s off the Rockauto injectors. They said: Of the numbers you gave, 01D008B does cross to FJ105 and 01D073B crosses to FJ95T. WTF?!?! Could Rockauto really screwed up that badly and sent completely wrong injectors? UPDATE 2: Looked up some FJ105T and FJ95T pics. FJ95T definitely has the shorter nozzle and the body matches the ones I got from Rockauto. FJ95T are 17# injectors for the 3100 SFI V6 whereas I need 15# injectors. No wonder they run so much richer! Edited December 16, 2014 by GnatGoSplat Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted December 27, 2014 Author Report Share Posted December 27, 2014 Still chasing an inexpensive way to get a matching set of injectors. An 86 Firebird w/2.8L could use FJ9, FJ27, FJ11, and FJ105 injectors. https://www.rockauto.com/dbphp/x,carcode,1251313,parttype,6224,d,1986_PONTIAC_FIREBIRD_2.8L_173_cubic_inch_V6_Fuel_Injector.html The newer 2.8L in the Cutlass only specs the FJ105. Any reason why some of those alternates couldn't work on the newer 2.8L? Pics I've found of an FJ9 actually looks identical to the FJ105 I have. Mainly looks like none of the Bosch style body injectors are spec'd for the newer 2.8L, but older SMP FJ105s had a Bosch style body and they fit fine. Found these. http://www.ebay.com/itm/DELPHI-FUEL-INJECTORS-AUDI-BMW-WV-15-LBS-UNIVERSAL-FJ9-/231184280886?pt=Motors_Car_Truck_Parts_Accessories&hash=item35d3a82d36&vxp=mtr Good price for new injectors. Quote Link to comment Share on other sites More sharing options...
Twinpilot001 Posted December 29, 2014 Report Share Posted December 29, 2014 I had a 86 chev= with 2.8 - had to have 2 injectors replaced. Years later i scrapped the car -yet removedall injectors & fuel rail. saved & recently tested all injectors - all same spec ! i was surprised! yet my idea is get over to aparts wrecker -u=pull? & remove a few complete sets! Test & use as ness. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted January 17, 2015 Author Report Share Posted January 17, 2015 I bought the eBay injectors I linked to. $90 for 6, brand new. They do look brand new, and do say D3581BA on them. Can't find anything indicating that's a Delphi part # though. On the other side, they say "9", one actually says "FJ9". They are identical to the late 90s Standard FJ105 in even the smallest detail, from the blue ring to the nozzle, only difference being the silkscreened numbers, so I don't think these are really Delphi but old stock of Standard FJ9s. Coil resistance is pretty high, around 15.7 ohms, so the injector driver in the ECM should be pretty happy with that. Installed them yesterday and the car finally idles smooth. Drove it around a bit and seems just fine, no check engine light, no pinging or knocking, no signs of trouble. Exhaust smell is also considerably less strong. Hopefully I can consider this issue done for good. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted January 18, 2015 Report Share Posted January 18, 2015 Hopefully it's a wrap. What did you do with your older injectors? Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted January 18, 2015 Author Report Share Posted January 18, 2015 Went out for lunch and then did some shopping, seemed fine all afternoon so I think it's good. So far just put the old injectors in a box. I'll probably throw them up on eBay. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted January 19, 2015 Report Share Posted January 19, 2015 So your 88 purrs like a kitten? Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 19, 2015 Report Share Posted January 19, 2015 I hope all is fine with that thing! Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted January 20, 2015 Author Report Share Posted January 20, 2015 So your 88 purrs like a kitten? The 89. So far so good. It did cross my mind that maybe I could have used some weird-looking modern plastic injectors like this: http://www.witchhunter.com/flowdatapix/dl25319306.jpg Those are 16.6# so might need a little ECM tuning though. However, they would fit but I would have needed EV6 to EV1 connector adapters. Don't know if modern style plastic injectors are more reliable or last longer. Seems like they must use some new-fangled technology to make them so skinny. Could be they also atomize fuel better, the skinny plastic Bosch Design IIIs supposedly do over the old big-body injectors. They're also pretty cheap on eBay. Probably would have been of little to no real world benefit and more work if I have to burn a new chip, but for some reason putting in something so weird and different looking sounded like a more interesting project. Totally not going to do it, just something that crossed my mind. Quote Link to comment Share on other sites More sharing options...
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