Injectors 2.8L MPFI, would you replace?

[GnatGoSplat]

89 Cutlass 2.8L, 229k miles. This is mostly an "I can't decide so I'm soliciting opinions" question.

 

Car was dying intermittently and randomly (i.e. pull out of the driveway, it dies, but started right up). Also had IAC troubles when nothing seemed wrong with the IAC.

Checked injectors, and these are the readings I got (after subtracting 0.3-ohms for lead resistance):

 

11.0 12.0 11.3

11.8 11.9 8.8

 

Saar found GM spec is something like 11.8-12.6 ohms. I found that same spec in my 94 FSM, but that's for SFI injectors. Not sure what acceptable range is for old 88-93 MPFI Multec injectors, couldn't find it in my 89 FSM. I've read SFI vs MPFI injectors are slightly different somehow, I so I kind of wonder if resistance specs may differ.

Obviously one is clearly bad. 2 are lower than the 94 spec.

 

Due to work and the fact the wife and I are now car-pooling and I'm stuck at work till 5:30 now, no way I'll be able to get used injectors locally. I'll have to buy new and they're at least $30/pop, probably closer to $35/each at Rockauto with their high S&H.

The car has high miles, 229k, and tranny is dying a slow death (3rd gear slipping when cold). So I'm mainly looking at spending minimum $$$ to keep my heap on the road.

 

Taking heapiness of the car into account and cost of new injectors, would you advise that I should replace the marginal 11.0 and 11.3-ohm injectors?

I'd replace them all with new, but you know, old heap with dying tranny... also, the 12.0 ohm one is a replacement Standard FJ105 I put in back in 1997, so I think it's fine to replace in onesies.

 

Made a poll, in case you don't want to say anything.

 

EDIT: Another option, found "GB Remanufacturing" remanufactured injectors, set of 6 for about $86.

http://www.ebay.com/itm/Reman-OEM-Pontiac-Fuel-Injectors-1989-1993-Grand-Prix-3-1L-OHV-/251735659889?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A1989|Make%3AOldsmobile|Model%3ACutlass+Supreme|Submodel%3AInternational|Engine+-+Liter_Display%3A2.8L&hash=item3a9c9d5571&vxp=mtr

Would be cheaper than buying 3 new ones.

Edited November 30, 2014 by GnatGoSplat

[rich_e777]

I vote for just the one to start with. Now that's out of the way Ive always wondered what would make the resistance change over time? Long term I would start planning an engine and trans swap from something with considerably less miles, might even luck up on a rebuilt trans in a smashed up 1st gen.

[RobertISaar]

Not sure what acceptable range is for old 88-93 MPFI Multec injectors, couldn't find it in my 89 FSM. I've read SFI vs MPFI injectors are slightly different somehow, I so I kind of wonder if resistance specs may differ.

 

same range, I pulled those numbers from a 91 or 92 service manual for a LH0.

 

Now that's out of the way Ive always wondered what would make the resistance change over time?

 

couple of things can do it, resistance going up is the wire degrading and otherwise slowly becoming an open circuit. resistance going down would indicate that current can skip portions of the coil, so even though current increases, the magnetic field the windings create to move the pintle up and down weakens.

[GnatGoSplat]

Being the same range for the LH0, I'm more leaning towards replacing the 3 or just buying the whole set of remans. Wife initially thought I should replace the 3. She has no experience to back up her opinion, but you know, women's intuition and all that. Replacing them all with remans would be slightly cheaper than buying 3 new, although I'm a little leery of remanufactured stuff sometimes. Also, seller claims they are remanufactured by GB Remanufacturing, but he told me "I cover my injectors for 2-years" and GB only has a 1yr warranty. So I wonder if they're really remanufactured by GB Remanufacturing or he remanufactures them himself and he just picked a company by random when listing the auction? I have to wonder because I've ended up with what I suspect to be knockoffs and fakes buying from eBay before.

 

I'm thinking injector resistance can go down over time because injectors are just solenoids using an electromagnetic coil. I'm guessing the wire is probably similar to transformer wire which has an enamel coating to prevent the windings from shorting together, and with heat from both the engine itself and electrical current in the windings over time, that enamel probably wears and deteriorates and eventually some of the windings make electrical contact, shorting together, and reduce the resistance.

[Nas Escobar]

I would buy from someone that has 100% ratings on eBay. http://www.ebay.com/itm/Reman-OEM-Buick-Fuel-Injectors-1987-1989-Century-2-8L-OHV-/251732892892?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ACutlass+Supreme&hash=item3a9c731cdc&vxp=mtr If they're reman, they're probably either GB's or stock GM stuff. With the extended free returns, I don't think you can really "lose".

[GnatGoSplat]

I would buy from someone that has 100% ratings on eBay. http://www.ebay.com/itm/Reman-OEM-Buick-Fuel-Injectors-1987-1989-Century-2-8L-OHV-/251732892892?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ACutlass+Supreme&hash=item3a9c731cdc&vxp=mtr If they're reman, they're probably either GB's or stock GM stuff. With the extended free returns, I don't think you can really "lose".

 

Yep, that's the same seller of the refurbs I linked to.

I'm just concerned about getting junkyard injectors that some dude refurbed in his garage if you know what I mean.

Although like you say, he does have 100% feedback and that's cheaper than buying 3-new.

Definitely hoping to pull the trigger on something today so it'll get here by the end of the week and I'll maybe be able to drive the car next week.

[George]

I had a similar situation with my '94 Cutlass LQ1. At 150K an injector or many started leaking, dumping fuel in the intake while car was off. I either had to crank a long time or floor the gas pedal to lean it out enough to get it started

Not having a way to figure out which were leaking I replaced all of them with remanned by Autoline (bad decision). It ran perfect for a month then started cranking longer sometimes. Within a 6 months 1 failed resulting in an intermittent violent surge at idle (400- 1500 a few seconds then die. Thought it was a vacuum leak. I did find a couple of small ones with no resolution. I finally took it to the dealership, they found the faulty injector. They said anything less than 12 ohms was considered faulty. One measured 11 ohms. Then again this was for a '94 lQ1.

the injector was replace under warranty, but labor was a lot. I wish I would have bought NEW ones, I still might just to be done with it. It still cranks a while sometimes.

[GnatGoSplat]

I never did hear back from that seller as to whether they're genuine GB Remanufacturing or remanufactured "in house" and what's the minimum ohms I could expect.

Your story about remanufactured injectors is making me think I should probably just go with some brand new Standard brand (since I seem to have had good luck with the one) and replace the 3 that are below GM spec of 11.8ohms.

[Nas Escobar]

Yep, that's the same seller of the refurbs I linked to.

I'm just concerned about getting junkyard injectors that some dude refurbed in his garage if you know what I mean.

Although like you say, he does have 100% feedback and that's cheaper than buying 3-new.

Definitely hoping to pull the trigger on something today so it'll get here by the end of the week and I'll maybe be able to drive the car next week.

 

I know, but he had them cheaper than what you had found them in your link. I thought you would be more interested then.

 

If he hasn't responded, then that's not a good sign. Although, if one of the parts store in your area offered online discounts with free pickup, I'd do that instead.

[GnatGoSplat]

Ah, they were $79.99 in my link too, on Sunday. Guess one set was on sale Sunday and the other on Monday. Looks like both links are $89.99 now.

 

It's strange because he responded really quickly to the first question (about the warranty). Guess either he didn't see my 2nd message to him, or just doesn't want to answer for some reason. Checked my eBay Sent and I did send the other questions.

 

Local parts stores (O'Reilly and Autozone) are both $60/each. The ones at O'Reilly are even refurbs with a $14 core.

 

Looks like 2-to-1 think I could just replace the one really bad one, but I'm also concerned their resistance will decrease with temperature so I think I'll go with 3 new ones from Rockauto. Gonna have to make a decision soon, at any rate. I think I totally have aboulomania.

[jman093]

Whether you go new or reman, replace all 6. You'll be glad you did.

 

Did you check rockauto? They're probably a hell of a lot cheaper.

[GnatGoSplat]

Yeah, Rockauto is where I was looking where they're $30/each+s&h. Those are for Wholesale Closeout which only has a 30-day warranty. They had 2 Standard FJ105Ts and 1 Standard FJ105 last time I checked, so even buying new closeout, they'll be somewhat mismatched. Normal price is $50/each.

I'd prefer to replace all 6, but if I buy new, these bitches are expensive.

 

Sent another message to the eBay guy with the refurbs and still didn't hear back. I likely won't buy from him if he selectively ignores messages.

[Garrett Powered]

my new way of doing things is- get all the same ohms going on, then get a couple extra in the package, then send off all eight to Witch Hunter for the rebuild, and data sheet. then and only then, will you really know.

[George]

How do you get a hold of him?, I might do that.

[Night Fury]

I replaced all 6 in my 88 from rockauto, IIRC mine ohmed similar to yours.

 

And my W is at least 2x as heapy as yours

[GnatGoSplat]

Didn't think I could trust the eBay seller of the refurbs since he ignored 2 messages I sent him asking the same questions.

Ended up buying all 3 of the new wholesale injectors Rockauto had for $90 total. So in the end I'll end up with 2 Standard FJ105, 2 Standard FJ105T, and 2 original GM. Not ideal, but wasn't a problem with 5 GM and 1 FJ105 for 17yrs so hopefully it'll run and drive fine with this mismatched combo.

Cheapest I could find a set of matching new (FJ105T) was $170 from eBay. Would have cost over $300+s&h from Rockauto.

The FJ105Ts are kind of cool looking in pics. Too bad you can't see them.

 

If it doesn't work out, I'll be sure to post my experience so we can all learn from my mistakes.

 

Been thinking if I should move the 2 GM injectors to the 2 spots where their connectors are accessible so I can check their ohms without pulling the plenum in the future. I'd guess those will probably fail sooner than any of the others since they will be the oldest.

Edited December 4, 2014 by GnatGoSplat

[George]

I was also thinking Accel brand all new injectors, 6 for $240.

What size injectors are in the 2.8L, 3.1 and the 3.4?

[RobertISaar]

the aluminum head 2.8/3.1 should be 16.7 lb/hr, a small port 3100 is ~17.5(as is the iron-head 3.4).

[GnatGoSplat]

Finally got a response from the eBay guy. Looks like he does rebuild them himself.

 

Sorry I was not around and my wife had no idea how to answer the ohm question. I do the work, I put in some interchange numbers in to reference the injectors to the fitment chart. It must have picked up a name of another company as the brand. These are factory OEM redone by me and yes they are all a minimum of 12 ohms. I don't just ohm test them though, I do all coil load testing needed to simulate all driving conditions these injectors would ever face. Ohm measurements are the most basic of tests to be done but an injector with a good ohm rating can still have coil issues so we don't put much thought into it as we do the load testing. Thanks

 

It sounds like he probably knows what he's doing. He's right about the ohms thing too which is why I might be more confident had I bought a whole set of injectors. I'm not sure I would have bought them even if he'd replied sooner though. It's easier for me to trust the work of a big company than just "some guy". He does have 100% feedback though, and very well could be a reputable injector expert, so it would have complicated my decision. Oh well, I already bought the 3 new so I'm not going to agonize over what I could have or should have done.

[George]

Personally, I think you did the right thing, buying new.

[George]

the aluminum head 2.8/3.1 should be 16.7 lb/hr, a small port 3100 is ~17.5(as is the iron-head 3.4).

 

Is the iron head 3.4 the LQ1? I should have been more specific, I was wondering about the LQ1.

[GnatGoSplat]

Personally, I think you did the right thing, buying new.

 

Thanks, as a aboulomaniac, a little validation goes a long way.

[RobertISaar]

Is the iron head 3.4 the LQ1? I should have been more specific, I was wondering about the LQ1.

 

iron head 3.4 = 93-95 F-body engine.

 

LQ1 injectors are more like ~22.5.

[Galaxie500XL]

IIRC, the LQ1 injectors have a unique spray pattern, to ensure fuel going to both intake valves.

iron head 3.4 = 93-95 F-body engine.

 

LQ1 injectors are more like ~22.5.

[Galaxie500XL]

When I was working on that old Allante a good while back, I replaced all 8 with new Standard brand injectors. Made a huge difference, and the owner reported recently that he's still getting nice service out of the car.

I never did hear back from that seller as to whether they're genuine GB Remanufacturing or remanufactured "in house" and what's the minimum ohms I could expect.

Your story about remanufactured injectors is making me think I should probably just go with some brand new Standard brand (since I seem to have had good luck with the one) and replace the 3 that are below GM spec of 11.8ohms.