Hi eveyone,

I searched and found some information but not quite what i was looking for.

I took a 180 mile trip and now i have problems with my 88 305 tpi.

It has lost power and i mean you can really feel the difference. Nothing like before


1) I get a hissing sound and seems to be coming from under the car. When i pass cars or something it will echo so i hear it more clearly.


2) I know the converter is very old if not stock.


3) I checked to see if it glows and does not. Also the engine temp have not gone up.

4) It is also running rough, kind of vibrating.

5) Idle RPM have also dropped. it can idle at 600 compared to 800 previously

6) Idle in drive is also down. Used to be about 550 - 600 now it is 400-500

7) In the past it has always been running poor ( performance wise) when warm and excellent when cold To the point you actually get glued to the chair .

Anyone have any suggestions to what it could be? I ordered a cat. from summit so it will flow better. Maybe it is the solution?

 

Possible that it is your converter.

If there is not an easy way to look and see it aka unbolting it or if it is welded, they do make exhaust back pressure testers, you can get them at Sears and they screw in to the manifold where the 02 goes temporarily.

U can also test it with a vacuum guage although it doesnt work quite as well as the exhaust back pressure tester.

Another thing you might want to check, the inj may be going south. If exhaust tests reveal nothing, ohm them out and see what they are. Stock should be at or near 17ohm, regardless they should all ohm out within 1-2 ohms of each other.

later
Jeremy

 

I agree with 3.8TransAM,

ohm the injectors and check your fuel pressure.
Does the SES light come on ??

If so,
I would also check your MAF sensor

Can you locate where that "hiss" is comming
from exactly?? Its most likely part of the problem


Good luck

 

Hi guys,

Well the cat is welded on so I will have the shop cut and weld the new one. Either way i know I need a better flowing one now that i have headers and cat back.

I heard about the pressure test. They do it at the shop were i will do the cat change. I want have them do the test since they will change the cat. either way.

I know my injectors are all at 17 ohms. I checked when I had the edelbrock TPI kit installed about 2-3 months ago.

I have not been getting any SES light other then a while back due to faulty EGR valve. I replaced it last week and worked fine afterwards.

It is hard to locate the hissing as it is most apparent under load and as rpm gets higher. which I could run sisde by side the car hehehe

 

Follow 3.8TransAM's advice and have the exhaust
back pressure tested

Since your injectors are fine, you should check your
fuel pressure at the rail (40psi or above)

Just a place to start

 

Okay guys, i checked my injectors and when warm they all ranged in the 18-19

BUT GUESS WHAT?!?!?!

I droped the car off to have the cat. converter swapped out with the catco high flow from sumitracing. I ju,ped over backpressure test since i was gona change the cat either way.

So I picked up the car but first i asked to see the old one and man was it BAD. the whole thing was collapsed and there was huge lose chunks in it which I guess depending on the day and their orientation inside the cat. would cause high backpressure thus my problems.

After seeing it i knew emediatly what to expect once i would start the car and sure enough i was impressed Really impressed.

Started up nice and sounded differently. I backed out and then while facing straight I dipped the gas and it spinned the wheels. Something I could never do before so you can imagine my level of excitement hehe

I could do it in the past but only while doing a turn at the same time....

No more constapated 305 TPI WOW is all i have to say.

Also I guess my milage is finally gona see some improvements compared to the 11-12 mpg i was getting in city traffic driving like a granny.

Ohh, all downshifts much faster and glues me to the seat. Now i finally got to see the gains from the mods i have made I want more now!

byebye

Sam

 

Your welcome :-)