so ive read that the XJS uses a ~19# injectors (lbs per hour). my old NA 3800 series II (L36) uses identical injectors. before i lumped my old 3800 for my Blown 3800 (L67) which uses 32# injectors, i upgraded my L36 to 26# injectors and the stock PCM adjusted the tables quite well. ive still got these injectors and i could easily order 6 more for $120.

how do we think the factory PCM will handle the upgraded injectors? too much fuel, no change, etc? give me your feedback.

TIA.

 

I think it's the impedance levels that might cause a problem...

 

I am not sure of the flow rate on the V12 injectors (I'll loook it up when I get home) but I do know the pre-HE used the largest injectors, I beleive there are 3 different flow rate injectors used in the V12 over its life.

 

well i look forward to finding out. the Delco tips are slightly different, but ive got 19# and 26# injectors laying around.

 

i heard some people upgrade to the xj40 injectors but i couldnt find the post where this was from

 

Sorry M can find specs of the injectors anywhere. BMW V12 injectors are pretty cheap on ebay might be worth investigating these. If you go too big the on-off-on throttle response will suffer at lower RPM.

I think the 26lb would be ok and good for 500hp NA on 43psi rail pressure

 

i think im just gonna stick with some fresh 3800 injectors. theyre identical in every way except for the tips.

 

im wondering what pound injectors i should upgrade to, because i think my injectors are shot and my car barely idles below 1000 rpm, and hesitates leaving idle.

 

everything ive read suggests that theyre 19#.

 

they have different top ends not the typical barbed ends from teh xjs injectors

 

you should still be able to clamp it easy, or splice in some quick connects.

 

can you post pics of how to do that?

 

Unless you have over fueling from multiple injectors stuck open it is unlikely to be injector related.

I would be looking for ignition issues first, check timing and make sure all HT leads are going to the right plug.

The XJS only runs 38psi fuel pressure and is good for around 300hp so 19lb injectors sound about right. Injectors are flow rated at 43.5psi so the 19lb injectors are only flowing 17lb. By increasing the fuel pressure to 58psi the 19lb are good for just over 400hp.

 

what warrjon said,right on.

a good cleaning of stock pre-he injectors should work well.
no need for more volume flow,.

my injectors were rusted and could not be properly cleaned, so i decided on a completely different approach.
12 new 21# Honda injectors, but had to make fuel rails , from scrapyard, guy said aluminum hand rails from a restroom! go figure?
best part is no clamps and hoses, just simple o=rings, much more safe,(like leaks&fires), along with AeroQuip fittings&stainless steel flex lines.

if your gonna go for it? no rusty steel fuel tanks&lines,, plastic fuel cell,aluminum lines, hi-volume pump&filter. top o the line adjustable FPR.

and my usual remark, 16yrs ago.

OH, yesterday, had the car out for a car show, lot of Corvettes&muscle car stuff, a few sporty cars, mine really got some attention.

thats what its all about, recognition for your personal work!

 

well, the only reason i started this thread was because the previous owner had told me that the injectors had all been cleaned and sequenced. with that being said, only 11 actually worked and they all had different pulse rates.

 

M90, the injectors may have been cleaned properly, but rust or debrie from steel tank or lines or rails, may have caused some crap to get into one of the injectors, plus dirt may get into a fuel regulator, and upset the air/fuel ratio.

darn just so many things , and then possible electronic stuff, acts up.

i had no choice for what i did, it was and old car, and i always try to go as close to perfect as i possibly can!

 

my tank has been cleaned and relined as well. also the swirl tank was bypassed.