Hello my old friends and new people. I haven't posted in almost a year! My car has been in storage until recently. My Brother modified his mustang cobra so much that it wouldn't run and had to borrow my car for awhile to get to work. HA!

My car is a 91 Formula with the 305 TBI. It has over 200K on it. My brother had it tuned up to thank me for letting him drive it for a few weeks. New plugs and wires, coil and distributor cap fuel filter and pcv valve.

It hasn't been right since.

I checked the firing order of the plug wires, and they are correct.

There are no trouble codes stored in the computer because I had replaced most of the the little doohickeys under the hood before I put it up. (Except for code 12) I haven't replaced the IAC valve or throttle position sensor because I figure there would be error codes if they had malfunctioned. I still plan on replacing them soon, but not if I need a new engine.

Last night I replaced the fuel pressure regulator and fuel meter cover because I noticed a strong fuel smell and the obvious lack of power. It didn't seem to help. It feels like it's missing under a heavy load, but starts and idles just fine. It shudders and bogs down at WOT, but doesn't stall. It can't really make it up hills very well.

There is no smoke except for on starup. (valve stem seals)

The car burns only a little oil. Less than 1/2 quart down between changes. It's always been like that.

I watched the fuel injectors spray, they look good., but i'm no expert. The throttle body is clean. I can't find a fuel leak anywhere, but the strong fuel smell is coming from around the fuel inejctor. (duh) This is why I think its a TBI problem.

I'm patiently going through process of elimination, but have run out of ideas. Any suggestions would be appretiated.

Thanks!

(PS: okfoz, are you out there? I still have the car!)

 

Rule number 1, never let brother touch your car OR his car without supervision .
Next, check your wires. Sounds to me like a bad wire if I had to pin point it on something. I have this problem at higher engine speeds from cooked wires, which reminds me, now that I'm home....
Check all the connections on the spark plugs and the dizzy. Don't forget to check the wire going from the cap to the remote coil. All should have a positive snap when they've made a good connection.

 

Sounds more like a vacume hose. Check your lines that connect under the housing of the air filter. Also check your charcoal canister for the proper connections. If you don't find it in the lines you probally have a leaking injector.

 

i would suspect spark. if it was a vacume leak, it would be very noticable at idle, and not so much at WOT.

the other thing that can bite you in the *** on these cars, is the cat. at 170k my cat clogged up, and the car started, idled and drove ok, but had ZERO power, and would shutter, shake, and nto want to go anywhere under heavy load.

 

Yikes! I checked and some of the plug wires are stuck to the headers. Melted. upon looking, there is no way for them NOT to touch the headers. The old wires used to clear them.

I'm wondering if I should get a new set of extra long plug wires so they can be routed around the headers. I'll ask on the exhaust board.

I couldn't find any uplugged hoses, and the ones to the air cleaner lid produce vacuum. Could the fuel smell be coming from the charcoal canister? I've never even looked at the early fuel evaporation system. I'll go look at that right now.

The cat is two years old, It's some sort of perfomance high flow cat. The exhaust gasses are clear, but smell really bad. The exhaust flows freely. I'll ask this on the exhaust board, too.

Thanks for all your help, guys.

 

let us all know what it was once you find it.

 

I seem to have two separate problems.

I statred the engine in the dark and could se electricity hitting the headers. I'm suprised the car runs at all.

The charcoal canister was full of sludge and insects and a screw. I spilled it all over the place! I was so mad! I guess that after 13+ years, the evaporated fuel really collects. I would imagine that it's never been cleaned out. What;s supposed to be in there? I thought it had stuff similar to an aquarium filter in it.

I'm going to get some good wire looms on friday and see if I can route the plug wires better. Now I'm going to do a search on how to restore the charcoal canister and thermac valve systems.

Thanks again for all your help, I guess it wasn't a TBI problem after all.

 

The canister collects the gas fumes and filter it through charcoal. Over time the filtration wears out as with any type of filter that is sucking gasoline. I don't know if those can be serviced or not. I thought they were hermetically sealed. I could be wrong though. Best bet is to go to your local bone yard and find a decent one from the same year and model for around $5.00 to $10.00 with the control on it. Good luck

 

The purge valve and little hose on the canister was clogged and the cansiter was cracked on top next to the electical connector.
That's where all the gunk spilled out of, water may have been leaking in ther, too. It was a mess.
After reading the haynes manual on the subject, I'm suprised at all the crap on the engine that's only there to control emissions. What a pain. I'm inclined to remove all of it and register my car at my uncles address way out in the country where there are no emissions requirements.

Until then, I may see if autozone has a generic cansiter or just go to a junkyard like you said. I'll bet most of them from GM are the same in many vehicles.

 

Actually they are very different. If you can find a GM vehicle of the same year it might be the same as yours. I found that Cadilac has some of the same part numbers as the Camaro and vise versa. The only difference with the parts with the same number is the price. If you need a canister for a Caddie your going to pay 3 to 4 times more for the same part number just because it's for a Cad. Same with the Corvette. I go to the boneyard maybe once a month just to see if there is anything I might want that is in good shape. Canister's are in abundance and very cheap. I've bought 2 in the past and both have been good. Don't get sucked in to paying $75.00 to $100. for a new one.

 

Ok, thank you.

The used ones you bought, were they from low mileage vehicles? I'm not sure if I was just unlucky to have a canister that had ruptured because it was clogged, or if they just wer out after a lot of miles and years. How heavy should a good one be? Mine was so full of sludge that I'm assuming a good one would be almost hollow and very light . How much charcoal and other filter material is in one?

 

I must be getting good at this online help thing.
Glad to see you found the wires the problem. Get some good 8mm wires like MSD's. Any GM HEI kit will work so long as 4 are long, 2 medium, 2 short. That's how the MSD's came.
As far as the cc can, IMOP, dump it and forget about it. I haven't had any issues with my car since removal. Maybe a slight smell of gas from under the hood every once in a blue moon when I've been romping on it HARD. But that might just be from the fuel splashing all over the top of the TB.

 

It wasn't fun, but I got it done. She runs great now. I got some MSD Superconductors and some heat sheilds to make sure they wouldn't ground out like the old ones did.

I got lucky and found a canister from a Camaro at a junkyard that was smushed in 1993 with only 12,000 miles on the odometer. The canister was the only good part left on it and the old hillbilly there was suprised to sell it. $5.

One of the fuel injectors is dripping a tiny bit, so I'll eventually have to replace them.