Here in-lies my dilemma...

My 1989 Formula 350 Convertible is all original (as original as it can be) 36K miles, original crappy paint, original interior etc, unfortunately it has the original Multitec injectors.

I purchased a set of Bosch III's and plan on installing them just for the sake of driveability reasons, but I am thinking of also having the original ones rebuilt, so that if I ever sell the car, I would have them to go with it.

If you were looking at an otherwise all original car, but noticed that it had aftermarket injectors, would it raise a flag? Also at car shows, do you think it would it be considered a modification? I know they will look different, but the original ones are really crappy from 89-92...

What are your thoughts???

I am also replacing the injectors on my wife's 1987 350/M5 car, but it is a driver, so I am not that worried about originality on it.

Really this is for Scott M, as I know he does the car show thing a lot with his pristine 996 point judged car.

 

I wouldn't consider a fuel injector an important asset. They eventually need replaced. No different than a spark plug in my mind. Besides ... in the end, a teenager will end up paying what you want and wrapping it around a tree anyway.

 

In all actuality, I would replace them if you want to. The show scene for our cars is not like a 57 Chevy that was concourse restored to perfection. Most people wouldn't know and as already mentioned, they could be considered a wear item like brakes, batteries, belts and hoses.

 

Since I bought 2 sets, they said that they would clean my OE ones for $13 each... that's $104... I might have them do it just so I have them ready, I can't see it going down in price...

Scott, one thing, the injectors, the Bosch III are yellow, if they were gray or black I think it would be easier to get away with it... I considered painting them so they were not so obvious... Then my head starts spinning... Am I over thinking this??? AHHHHHHHHHHHHHH

John

 

^^Ugh, why is it always so hard for people here to use "to be" between "need" and past participle??

Anyway, I would rebuild the originals, how bad can they really be in terms of drivability if they are basically brand new?

Or, you could rebuild them, throw the Bosch ones in, and then swap for the originals for shows--best of both worlds IMO.

 

Are the injectors really bad? The dead give away is a frequent dead miss. Also the resistance measures differently with a DVOM on bad injectors. If they're actually bad I'd change em out. But then I'd be more likely to pick up a few sets of used injectors and make a matching set. Or use injectors that look close enough. I wouldn't be afraid to paint a set to make them less obvious either. At any rate, most shows aren't going to bump you into a modified class over fuel injectors.

 

Drew,
That is what I was thinking.. There is a real definite LOP when the car warms up at idle, it smooths out as soon as I give it a little more gas, or when the idle is high, but low idle it is like I am not firing at all...

I think masking them off and then painting them is my best bet... A nice Gray or Black will make it less obvious than the Yellow... If it was on my Yellow T-top car I would like the yellow, its a nothing car IMHO, LG4->LB9/A4 conversion... Nice car, but worthless in the current market...

John

 

Once the gray Multecs short circuit, they are not worth rebuilding. I replaced mine with black, flow matched, Bosches on my '89. The same ones used on earlier TPIs. No one has ever noticed.

 

Yeah that sounds like an injector failure... I think the miss in the Iroc is a bad injector too. I agree there's no point in rebuilding them, just toss the junk injector and replace it with a good used one. The only bad thing about that, is that you're dealing with mismatched injectors, and they're used so you might have to swap them a few times before you get a good set that works for a length of time. With the 3.1 swapping injectors took maybe 30 minutes, so it wasn't a big deal. On a TPI car I think it'd get really annoying. Worse yet, GM claims the problem with Multec's failing was due to fuel injector cleaning solvents damaging the coils. Personally I think they were just poorly made. When they work they're supposedly a more efficient design then the earlier injectors, but they've got a really bad rep for good reason.

All the ignition parts on the Formula are Accel, no one ever notices because I rattle canned them black. You could probably leave the injectors a bright color and no one would know, but I tend to hide anything that might look out of place.

 

I say replace. We're always leery of L98 C4's that we take in here that have original injectors -- we've yet to have one that actually runs well with originals, so we generally see replaced injectors as a plus, even on low mileage cars.

 

John, who is servicing your injectors? i'v heard Rich over at cruzen wont do multi's as they arent worth re-upping as Drew mentioned. a friend sent me a vid of multi's on a flow bench and when cold they all would flow evenly and once hot they would strobe,drip, bad spray patterns and such. they removed them, popped them in the freezer and re tested when cold and all happened again.

i have some SVO's in my formula, before my current motor went in i had them serviced by Rich and it was a good thing, one was pretty far out of spec, all were within 3% when i got them back.

 

I ended up going with Bosch III's from Southbay... The price was right, the reputation was great, I did not read one bad thing about them... I ordered them on Tuesday night, got them Friday, Frank helped me a lot...

What I am going to do is paint them gray on my 89, but leave them Yellow on my wifes Yellow 1987 Formula 350/M5... On the Vert, I plan on using a little Bulldog then spray them with SEM Charcoal... should make them look as factory as possible.... I love the yellow, but it stands out waaay too much on an otherwise Gray/Black engine.



John

 

Id keep the OEMs but clean an put them away for future. put in the new ones and enjoy your car.
I have 99% of all my cars oem parts in storeage plus a few NOS items

 

yea iv also heard those mulitecs are bad news, im already having problems with my 3.1 mpfi firebird, should i replace my injectors as well. i am leaning more towards that, but im not sure, what injectors to get, i assume these http://www.southbayfuelinjectors.com...8_3.1_TPi.html
are the correct ones for a replacement, but the details say "TPI" and i need something for MPFI, lil confused.

 

You might try posting in the V6 forum or contacting South Bay Injectors (since you're looking at their products). The V6 engine uses smaller (rate wise) injectors. I believe somewhere around 15#. TPI is a form of MPFI. So it appears you're looking at the correct, stock replacement, fuel injectors.

https://www.thirdgen.org/forums/v6/

We have two vendors that specialize in fuel injectors that you can contact:
South Bay Fuel Injectors - https://www.thirdgen.org/forums/member.php?u=88662
and
Injectors Plus - https://www.thirdgen.org/forums/member.php?u=124926

 

i think,yes,you are overthinking this