I just picked up this 1992 Formula 350. It is amazingly nice. The only problem is it turns over but won’t start. I will figure it out and get it started soon.

 

Obviously check for spark and fuel psi.
I'd bet the fuel injs are stuck shut and possibly the tank and pump need addressed.

If you ever want to sell, let me know, i was interested in this one a few yrs back through a friend but could never get the contact info.

 

Was this at a tow yard? Looks really nice.

 

Interesting. How did you know about the car? What can you tell me about it?

 

hopefully you'll get more posts soon so i can PM you

 

I sent you a PM.

 

Wow, brand new member that joined today with 3 posts under his belt and his PMs are already unlocked.

Note: This isn't a dig at you. It just doesn't normally seem to happen.

 

I got lucky I guess.

 

It's a quality post 😉

 

Beautiful car Tonyjp! Congratulations on the purchase.

 

Thanks. I am really looking forward to having it.

 

I spent a little time getting it running today. It is running rough. The gas is definitely bad. Can I siphon most of the old gas out of the fuel filler neck? I think it will run great once I get the old gas out.

 

Yeah you can siphon most of it. Recommend a fuel injection cleaner and fresh filter as well.

 

I believe there is a anti-siphon device in the filler neck. I might be getting that confused with the other '80s & '90s GM cars & trucks I'm into though.

The wishful thinking answer is. Yes, it will run great after it gets some new fuel it. Maybe someone has already done everything below to the car.

The most likely outcome is. No, you will be replacing the original Rochester Products Multec fuel injectors, rebuilding the fuel rail with an O-ring kit, replacing the fuel pressure regulator, replacing the fuel filter, dropping the gas tank and maybe replacing the tank, sending unit and fuel pump hanger assembly, and fuel pump.

To do that you will be dropping the rear axle assembly, so it is just hanging from the lower control arms and removing the rear part of the exhaust system.

If your car still has its original RP Multec fuel injectors the ones made from 1989 to 1992 are retroactively defective by design. The insulation on the coil winding can't stand up to HEET, most fuel injector cleaners, modern gasoline that contains ethanol. It dissolves the insulation on the wire, and they will short out and do so at random and with changes in temperature. You can test them, and they will test just fine but they won't be.

You will chase your tail around in circles trying to fix the problems and drivability issues if you follow the standard and recommended dialogistic procedures.

My standard diagnostic procedure is they are all bad. Throw all 8 in the trash. Replace them all with brand new Delphi fuel injectors. The nice thing is the new Delphi fuel injectors are a drop-in replacement for the original RP Multec fuel injectors and they look a lot like the original RP Multec fuel injectors.

If the OEM GM "AC" catalytic convertors in the N10 dual cat exhaust system aren't already rattling around like rocks in a Folger's coffee can, they will be before long if the misfires continue.

 

Nice 1992 Formula 350 with CC1 T-tops and the required black PW7 Diamond-spoke wheels. I'd give my left nut to have it. You have a rare car there and a very late production one too that is well optioned. I'm sure you have noticed the black valve covers instead of silver valve covers, lack of Tuned Port Injection call-out on the throttle body cover plate, and the rough cast TPI runners. Toward the end of 1992 3rd gen production GM was running out of parts. The rough cast TPI runners are left over 1991 C4 Vette parts.

If TTOP350 was looking to buy it then I know it's a great car.

My 3rd gen passion is 1987 to 1992 Firebird Formulas & Trans Am GTAs, and 1989 Turbo TAs.

 

I agree. Hope for the best and prepare for reality.

 

When you get a chance post a nice clear in focus picture of the fuel injectors. Take a picture of the ones next to the throttle body in front of the runners on the driver's side. If you remove the fuel injector wiring harness clip from an injector look for a stylized RP logo on the connector body of the fuel injector.

 

Here is my SPID label.

 

I rotated it be easier to read.

I was actually going to ask to see it and the labels on the driver side door. I was interested in the production date. The SPID label is exactly as I expected it would be.

 

Here is a link to the Compnine Build Sheet for your car.

Your car was built April 15th 1992. Tax Day!!! LoL

Not as late as I thought it would be. They must have run out of parts earlier that I thought.

Compnine Build Sheet for your 1992 Formula 350

I saved the Compnine Build Sheet as a PDF file for you too. It's attached below.

I have no idea why it didn't put the RPO codes in alphabetical and numerical order. I swear it did in the past.

Some of the descriptions are a little off too. Later on, I will translate them into 1992 Firebird Formula.

AAA = Standard Equipment
CC1 = T-tops (Your car has the redesigned 1991/1992 low dome height lightweight Lexmar acrylic plastic T-tops with LexAR 100 Coat for scratch resistance. They scratch really easy too.) The glass T-tops are heavy AF.
1SZ = Formula Option Group Package Discount
R6A = Formula Value Package (Includes CC1 & UX1)
R6P = Performance Enhancement Group (Includes G92, N10, J65, and KC4) G92 Performance Axle Ratio will not be on the SPID Label unless the car is also 1LE.

 

Awesome formula 350!! that is a very desirable setup!

 

Thanks for this information. It's awesome that you have access to it.

 

It looks like the last oil change was 11-16-2000. It has about 150 miles after that was done.

 

If the fuelpump is working,
you can remove the fuel filter,
put a hose on tank line to a gas can,
put fused power to the fuel pump relay test wire,
(may need key on)
then the pump will drain most of the fuel fairly quickly.

 

It’s running good. I just put 20 miles on it.

 

I am going to change all the fluids, get new tires and do a tune up before I put many more miles on it.

 

Here are the door stickers

 

Did you by chance get a picture of the fuel injectors as described in post #17?

 

I didn’t see RP anywhere. Is that good or bad?

 

Maybe I have misremembered the little stylized RP logo being on them on the top between the connector and the fuel inlet of the injector. Or maybe it's just hard to see it the way you are looking at it.

I'm 99.999% sure though that those are the factory original RP Multec fuel injectors.

The 1989 to 1992 ones are defective. They fixed the problems with the insulation used on the wire for the coil winding for 1993.

With a next oil change sticker of February 2001, I am assuming this car hasn't been on the road since then. Sitting for 24 years I would at least want to have them cleaned. No reputable business that services fuel injectors are going to touch these RP Multec fuel injectors.

They might still be good as far as the insulation on the coil windings go if the car has been off the road for so long. I don't remember when gasoline started having the 10% ethanol in it. Maybe the car has never had HEET or the like or fuel injector cleaner ran through it that contains harsh solvents. GM had a special fuel injector cleaner for these RP Multec fuel injectors that didn't have harsh solvents in it.

Thing is these days you will be hard pressed to find high octane Premium Fuel at a normal gas station that doesn't have at least 10% ethanol in it. I don't know which fuel injector cleaners you can pour into the gas tank these days that won't harm the RP Multec fuel injectors.

​​​​​​Maybe @southbay08 can tell us if those are the original RP Multec fuel injectors and if there is a fuel injector cleaner you can pour in the gas tank that would be safe for them.

 

Yes they are definitely multecs!

 

In all honesty if you didn't check the resistance yet when they are hot and cold I would do so.
even if the coils are good I would not keep them as they are so problematic. We do not clean our injectors by putting a cleaner in the fuel. They go onto a bench where we can flow them at various pressures.....sometimes the injectors will flow fine and then shut down at certain pressures due to failing coils , we check the spray pattern, we see if the flow within speck, check the resistance and so on

 

Eject the multecs with extreme prejudice and install some nice new Delphis from Southbay.

 

Yup, RP multec injs. Ditch them (but keep with removed parts, I'm weird)

 

I got a box nearly full of them. I'm not saving them. I just haven't thrown them away yet. The box isn't all the way full.

 

as I rebutted to my wife, if it’s old car parts, it’s not hoarding.

 

The car currently runs good. I am not against replacing injectors now. Should I wait since they are working well or just replace them?

 

If the car is running just fine and has no misfires with a butter smooth idle and there aren't any hesitations when rolling into the throttle, then don't worry about them for now.

Try to run 91 octane E00 pure gasoline if you can find it. Where I am I'm super lucky and can get 87, 91, and 93 in E00 pure gasoline

If your car starts having weird drivability issues don't spend too much time chasing your tail in circles. Do the proper troubleshooting but if it points to the fuel injectors replace them.