dchoran

'84 stock with CrossFire / Throttle Body Injection (TBI), 50M miles

I was getting a little minor periodic surge at idle (600 to 400 to 600 to 400 to 600 to 400.......) so I did the following stuff:

checked all vacuum lines - OK.

dealer checked timing and compression - OK.

cleaned the throttle bodies thoroughly.

replaced PCV, EGR, fuel filter, air filter (K&N), etc........

replaced all eight plugs.

new MSD cap-rotor-coil -cover.

new Magnecor KV85 wires.

both IAC's replaced in the throttle body.

NONE of that stuff fixed this "minor" annoyance. It is still there.

Now I am thinking of replacing the two fuel injectors in the TB.

Looks fairly simple and straightforward - any advice on removal and installation???

Deals online for new injectors??????

Really don't know what else to try.

THANKS for the help in advance.

Dave H. Appleton, WI


Yeah, I know, a 26 year old car ain't gonna run like new, but I'm a perfectionist.

dchoran@athenet.net

FICINJECTORS

We have had great success with this.

powerpigz-51

Check the fuel pressure?

kangi

Dave, are the shafts on the throttle bodies tight? I have the same surge and I've noticed just a minute amount of play in the TB shafts. Apparently any play at all means there's a vacuum leak. I'm sending my TB's to DCS to have bushings installed when I put the vette up for the winter. I do also plan to send the injectors to FIC to have them rebuilt, seems like a pretty good deal. Good luck!

CFI-EFI

That is a great video. I have a problem with with some injectors and I received some great advice from Rich. I would have sent them in for evaluation and cleaning, by now, but their future is uncertain (the injectors future, not FIC's).

If the spray pattern looks good, I doubt the idle "hunting" is the fault of dirty injectors. A vacuum leak at the throttle shafts can be diagnosed. Besides a vacuum leak, improper synchronization or a lack there of can cause idle problems. With all the work you have had done, Dave, has anyone done a "TB balance"? Even with questionable injectors, my 170,000+ mile oil burner idles smooth as silk at 600rpms, even in gear.

RACE ON!!!

dchoran

Does anybody know if you can buy new injectors from FIC for an '84???

I can't find them on the FIC website

FICINJECTORS

we sell new TB injectors for everything but the crossfire. We beloeve that the OEM Rochester TB is better than the replacements available in the aftermarket. We have tried several and our rebuilt OEM out perform and out last the others.

FICINJECTORS

Dave email and PM sent thank you

Hot Rod Roy

Yeah, your right. Your 26 year old '84 can run BETTER than new. Mine does! Just stick around with these guys, and you'll learn all kinds of neat tricks to make it run GOOD!

You should have seen the look on the face of that SLC600 Mercede$$ driver that challenged me recently!!!

A nice thing about the Cross-Fire is that you can easily see the injector spray patterns. If they are uniform and with an even spray pattern, they're probably okay. I'd suspect a vacuum leak in the top plate of your intake plenum. There's a bunch of screws there, and the gasket surface is pretty skinny, so that's an easy place to have a vacuum leak.

Rohn

vacuum leak !

dchoran

OK guys - I guess that CrossFire DOES have some advantages - I just have never watched my injectors in action. Will do this weekend.

In any case, I'm gonna get the original injectors rebuilt by FIC in the offseason - $75 is a deal. One step closer to "1984 perfection".

Recently I put Bosch Platinum IR Fusion plugs in, a set of Magnecor KV85 / CN25 wires and a new MSD coil-cap-rotor-cover.

Simple and easy mods. All for just a few hundred bucks total. WHOA.

This sucker with 50M miles on her runs like a bat out of hell!!! Faster than my modified 2005 FLHTCUI!!!!

Feels like zero to 60 in 3 seconds with a stock 350ci / 205 hp engine

Luv it!!!!

Now - isn't there a safe way to check for vacuum leaks???

Can you buy "smoke-in-a-can"????

Thanks

Dave H.

CFI-EFI

If your injectors have a poor spray pattern or show other problems that rebuild and cleaning is a great idea.



What modifications? you just bought some fancy, over priced, replacement parts. Any increase in performance is a only a testament to the deferred maintenance you took care of.

RACE ON!!!

Hot Rod Roy

When you check your injectors, look for non-uniform discolorations inside the throats of your throttle bodies. If the patterns of the front and rear throttle bodies are about the same, you're okay. Use a good spray carb cleaner in the throats regularly.

To help you find vacuum leaks, first check for loose bolts on your intake plenum cover and the bases of your throttle bodies. Spray some Engine Starting Fluid around the edge of the gasket while the engine is running. If the engine speeds up, you've found a leak. Some mechanics like to use a propane torch (UN-LIT!) to flow a little propane gas where a leak is suspected.

jhammons01

That's the video!!

I've been looking for that...........thanks!

dchoran

Sent a set from an '84 to Jon this morning.

Hoping they come back looking/working like new???

Jon must be on vacation - no emails or phone calls returned this week.

VERY unusual. Hope all is well with Mr. B

Dave H. Tuesday 4/6/10 6pm central

CRUZN C4

Could be the fuel pump.

Rohn

intake manifold plenum top or TB shaft/bushing worn. 59K miles the TB shaft wear may be unlikely. I wonder if that slop in shaft can be determined other than grab shaft and wiggle? spray that perimeter with carb cleaner again....

dchoran

Rohn or others,

Is that what would be considered that dual intake air cleaner cover that sits atop the throttle bodies???

Thanks.

Dave H.

Rohn

No, it is what the throttle bodies are attached. A lid.

ETRBUJ1984

My mechanic is working on my car as we speak for this exact problem. Does your car ever shut its self down if you don't give it a little gas..... and have we found any solutions? Is it the injectors or that fussy fuel pump?