Hi, I posted my trouble with TBI hissing after acceleration and I messed with my new cap and rotor and I got the car to run great for about 20miles. Than the same thing happened.

The idle will be funny. I would put it in reverse and the car would dip to 300 and get up to about 500. From there if I hold it in reverse or in drive the car would start shaking a bit and the RPM's would raise. From there, the hissing starts. I would accelerate and the TBI would hiss for few seconds after I let off the pedal.
The car is extremely sluggish, but if I go past 1/4 thorttle it gets power. I thought my cap and rotor were the problem so I bought a new accel one. NO avail. Than I tried using my stock cap and rotor and the car did the same thing. The connection between the rotor and the distributor is rusted, and I am thinking that might be the problem. Maybe my wires might be the problem. But how can you explain the cars great driveability for about 20miles after I fuked with the distributor.

Should i change/clean the iac.
TPS?
Wires???
How can I clean the rusted distributor? Would baking soda work??

Are there any tips on changing the cap and rotor that I did not do???

Please help

 

Computer throwing any codes?
Set the timing?
Check plugs for lean/fouling?
Vacume leaks?

 

The hissing would be a indication of a vac leak.
It's possible that you disturbed a vac hose while changing the cap. That would be pretty simple to locate.
If it isn't a hose then a gasket leak might be the trouble.
A few yrs ago my TBI had some drivability issues and it ended up being the intake gasket.
With luck, yours will just be a hose, check all of them thoroughly, if it's a hose it ought to be possible to locate just by listening for where the source of the hiss is.

 

Sorry, I forgot to mention few things.

First, I checked all of my vacum lines and they were fine. The hissing I narrowed down to the TBI itself. Its like normal hissing in the TBI but the RPM's increase and the car almost surges.

Today my car ran great for about 20miles. So, something must be sticking or not working right.

The timing was about 8 advance (new chip) and everything is new in the ignition but #8 sparkplugg and the wires.

I am replacing the wires once I get some money.

The hissing is from the TBI and it hisses right after I let of the pedal. It sounds like its either not getting a spark and that ECM is compensating for something.

I do have a bosch 02 sensor, but I did not have problems with it up untill now.

This all happened after I got a new cap and rotor.

 

I haven't worked on a TBI for a couple years.
But IIRC there's the throttle stop screw that can be adjusted, did you touch that?
If that is open too far the IAC tries to compensate, but it can get to the point where it can't hold a steady idle.
There are some TGO tech articles that address that, I think.

It was okay with the new chip before you changed the cap and rotor??

Edit:
It started coming back to me after i thought about it for a while.

The throttle linkage should stop against the tip of that adjustment screw, at which point the blades should be almost completely closed.
The stop screw is located about 3/4" above the throttle shaft on the same side as the linkage.
If the linkage lever isn't contacting the screw, then the throttle blades are being held open, causing an air leak, and the computer tries to compensate by changing the signal to the IAC. But it ends up "hunting" and can't really stabilize.
It may be that you bumped the throttle cable bracket and dislodged either the throttle cable or the TV cable, and that's preventing the blades from stopping against the screw, because of tension on the cable. Creating an air leak past the throttle blades.

Check to see whether the linkage comes to rest against the stop screw.

 

Everything was fine for 12000 miles with the new chip. I just might have to switch to stock and band aid it with an AFPR. New wires are on the top of my list.

Is there anything I need to know when I change the cap and rotor???
The metal that rotor goes over is kinda rusted/corroded. Is there a way i can clean it without damaging it. Would baking soda and water do the trick????
I am confused.

 

Did you read the edit on my last post?

 

Went to Advance auto parts, and had them test my ignition module. While I was taking it out in the parking lot I noticed that the wires from my pickup coil were really brittle. I handled them really softly and I noticed few kinks and strips to the bare wire. I freaked out. Than my connection to the module was full of black grease, the plastic part around the connection was broken totally. So I guess my pickup coil, at least the wires, pointed to a decent problem. Do you think that my pickup coil would do such a thing, as messing up the driveability.

I put in new wires, that you make yourself, and they threw my engine idling so erradically that I had to put in my old wires back on.

I am just stumped cuz I have no money till firday.

What else could you think of as my problem.

Note that I had really good driveability for few miles there in between.

 

help. anyone!

 

My LT1 was giving me alot of grief that was similar to yours, and was causing a huge headache because it was not throwing any codes.

The car would run great for about 20 miles and still run great while cruising. After about 20 miles, the car would nearly die off of the line, even under super feathered acceleration. Then it would just about die when coming to a stop, both problems caused during a sudden vacuum fluctuation.

I narrowed it to a sensor problem because it would run great when cold (open loop) but like garbage when warm (closed loop - sensor readings factored more heavily into the motors operation).

I replaced the MAP (manifold absolute pressure) sensor and the car ran great. If memory serves me right from when I had the 305 TBI in the car, the map was located on the cowl on the right side of the engine. I cant say for sure if that is your problem, but it was on my LT1. The engines are different, but the function of the part should be the same. The part was about $30.00 at Auto Zone.

 

Map might be the problem. I never looked into that.

Here are my problems as of now.

i will just change my distributor after i took it out today.
The pickup coil is one of the things that is not right with my car. The wires are way to stripped and instead of replacing it and taking apart, I'll just replace the whole distributor.

Here are my symptoms.

It idles fine (most of the time), sometimes I'll leave it in reverse and the RPM's would drop under 500 where the car backs it right up to normal idle. Sometimes it will die like this but rarely. When I messed with the distributor cap I go the car to run great, i am just not sure of whats going on. The car would behave like there is no power if I take a right turn. If I press the pedal, sometimes the car would go the same speed as before I pressed it. Than once I get past a certain point the car picks up pretty good. So, I have no problems with top end power, however my bottom end is sluggish.
And my tranny seems to be shifting right, and it shifts all the gears without problem.

I don't know what to do anymore. I really did not want to dive into sensors, but I might have to replace them.

 

Is the torque converter going bad and might the stall speed now be lower than before? I am not a tranny guy, but it sounds like the engine is being robbed of its power before it gets a chance to make any. I dont know if a torque converter can do that, maybe a tranny guy can chime in on this.

 

Well, I highly doubt the tranny since the car would have power untill I idle.

I went bought a new distributor and I got it in. I set the timing at 8 advanced, its brians chip and that where my car ran before.

The car drove sweet untill I stoped to idle for a bit. Than the rpms first went under 500 than rose up to 800. The car starts hissing as soon as it passes 600 and the car just kept on hissing after that. When I drove it, the hissing would go up and it would go down. When I come to a stop the hissing would not stop. The cra drove itself without me touching the pedal at 25mph.

I am totally stumped.

It feels like a sensor telling the computer something uncorrect, so the computer compensates with crappy idleing.

I am not sure...

Please any help will be great.

 

swap in a carbed 350, problem solved

 

Thats an idea!
For now I need to get my car runing at least ,right.
So I can save up money for the 350 top end.

 

Re-built the TBI and new injectors. Runs fine for a while than if I am to stop and idle the car would surge up and the hissing fiasco begins. Sometimes it wont hiss as much, and sometimes it keeps hissing even worse now.

TBI rebuilt now, checked all the cables they were all fine.

Could timing be doing this.

When I installed the distributor I had it advanced about 14# and it actually ran better. The more I retarded it to 8 for the chip the more it started to studder.

It might be the timing, or a sensor.

So, I am off to a junkyard looking for sensors tommorow.


Let me know if you guys have an answer for me!?