Cascade Crew

miamivice

Alright, so after speaking with Mike tonight he convinced me to post up on the boards to try and trouble shoot my 1987 Trans Am and to get the thing running again so I can actually commute to school and my internship next quarter.

For those of you who don’t know, the problem started about a year ago last Feb. while changing the thermostat. Both of the bolts holding the housing broke and everything went downhill from there.

Ian helped change out intake manifold with a new one and we go to start the car and it wouldn’t turn over. Well, since I needed the car back on the road ASAP I had it towed to the shop and after a ton of money, they got the car running (but it ran like sh*t) and they said that it was due to one of the injectors leaking (and in the process, new plugs, wires, and a cap and rotor were put in). Anyways, go to change the injectors at Mark’s place and had an interesting time with other bad injectors and several times on startup the car backfired and some of the teeth broke off of the flexplate. I ended up driving home on the same injectors I drove up on. Took the car back to my place and put it up on jackstands and with Ian we up in a new flexplate (and starter). However, this did not solve the problems. Ever since I go the car from the shop way back when I not only had problems with it running rough but when driving I did not have brake pressure at low speeds. Mark and I eventually put in new injectors a few months ago.

Several people guessed that the brake issue was due to a vacuum leak and probably the brake booster, so Ian gave me another one and I swapped that last week and it still is running rough. (I had assumed that the brake issue and the bad idle where linked to one another but maybe I was wrong – 2 completely different things??) Anyways, go to start it up and it is still running real rough at idle, nothing like it was before I got into this whole mess.

ANY IDEAS???? What should I go about doing next?

Dewey316 · Posted: Tue Feb 27, 2007 10:56 pm Post subject:

did the new brake booster make any changes at all to the brakes, or did it do nothing?

It sounds like it could be a vacume leak, have you sprayed around with a can of carb cleaner, to see if you could spot a leak? Since it started having problems after your took the intake off, i would tend to lean towards the vacume leak myself.

izcain · Posted: Tue Feb 27, 2007 11:09 pm Post subject:

I would say exactly what Dewey has said. You can also get a vacuum gauge and take some readings as well. What conditions does the car have in the brakes? Hard pedal? soft?

Xophertony · Posted: Wed Feb 28, 2007 1:01 am Post subject:

i would suspect the TPI rnner gaskets. you screw up one of those the car is going to run like ass. spray carb cleaner there as well as around the vacccume lines.

Quasi-Traction · Posted: Wed Feb 28, 2007 1:33 am Post subject:

check all the lines to the Brake booster. If none are loose or seem brittle or like they might be broken, look to other places....(intake, injector seating, ect...)

I'm not much of an expert with TPI, but check if the mating between the lower intake and the heads is sealing.

Also do a Compression test on each cylinder...start with that and work your way "up" on the intake. Check spark plugs (even if they're new) and your signal to each wire (a timing light should be a good enough check).

Keep us posted. We'll try to help in any way we can!

Twilightoptics · Posted: Wed Feb 28, 2007 8:33 am Post subject:

Check the timing also. Timing can drastically effect vacuum.

chevymad · Posted: Thu Mar 01, 2007 10:20 am Post subject:

Does it smooth out at speed? I'm thinking the EGR valve may be stuck open. That will act like a vacuum leak, but there won't be any external signs of it. Usually makes the idle very rough but will smooth out when you go to drive around.

miamivice · Posted: Thu Mar 01, 2007 1:18 pm Post subject:

Xophertony · Posted: Thu Mar 01, 2007 6:02 pm Post subject:

that is sounding more and more like a sticking EGR valve.

miamivice · Posted: Thu Mar 01, 2007 7:50 pm Post subject:

ok so assuming its the EGR...i have to just replace that? any way to test to see if that is actually the problem. i went on schucks.com and there are couple diffrent ones. which one do i use:

http://www.partsamerica.com/ProductList.aspx?parttype=282&searchfor=EGR+Valve&ptset=A

also, as far as removal...i know the plenum has to come off (AGAIN!!! Mad

), but do i have to take the runners off too??

anything else i should know.

Twilightoptics · Posted: Thu Mar 01, 2007 9:58 pm Post subject:

Shouldn't need to take the runners off.

You can test it by blowing through one hole on the bottom and seeing if air comes out the other hole on the bottom.

Not sure which one, but don't forget a new gasket for it.

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

Did you swap to a different intake, or did you just replace the gaskets? Did you remove the EGR when you did the intake? Did the car run allright BEFORE you did the intake? If you swapped to a new intake, was it a used intake, or a fresh, store bought brand new, open up the package intake?

I currently suspect a mis-matched EGR gasket or if you swapped to a different used intake, a clogged EGR passage...

miamivice · Posted: Sun Mar 04, 2007 4:38 pm Post subject:

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

if you still have your old intake, with EGR, take it off, take the old gasket to the parts store, and ask them for a new one (OEM is better if you have a GM dealership around) and swap it.

Mangus · Posted: Sat Mar 10, 2007 11:56 pm Post subject:

miamivice · Posted: Mon Mar 12, 2007 2:29 pm Post subject:

ok finally was able to get the dang thing out. damn bolts were hard to get at.

Twilightoptics · Posted: Mon Mar 12, 2007 2:33 pm Post subject:

Yeah you might be able to clean it and lube it to make it function... but i'd just get a new one so I don't have to dink with it anymore.

Would be great to see your car! I've only seen the pictures. I hear it's purdy.

miamivice · Posted: Sat Mar 17, 2007 10:14 am Post subject:

updates...well i drove the car yesterday for the first time in forever!

thanks everyone for all your help and bearing w/ me...

guess it was a bad egr valve all this time. swapped that with a new one and the car turned on w/o any stalling or idling issues.

small little problems/questions.
...from the other post, i had some issues with the turn signal lights coming on randomly. thus, to prevent the battery from draining i unhook it every time when im done playing w/ the car. well every time i plug it back in and go turn on the car the check engine light comes on and stays on. but if you turn the car off and turn it back on its gone. why does it do that?

problem 2, sometimes when i go to turn put the key in to turn on, you just hear a turning sound for a long time and the motor wont start. if you try again it turns right on. whats wrong?

chevymad · Posted: Sat Mar 17, 2007 10:42 am Post subject:

It cranks for a long time no start, then try again starts right up correct? Sounds like it isnt building fuel pressure right away.

It may just need a fuel pump relay. It's possible you are cranking the engine until it builds oil pressure, then the oil pressure switch is powering up the pump. The relay is supposed to supply power before that to prevent long crank times. Make sure its supplying power.

If thats not it, hook up a fuel pressure gauge. Start motor then shut it off. Watch the gauge and see how long it takes for the pressure to drop off. Should hold for quite awhile. When you go to start it again, watch the gauge.. If it doesnt start until the fuel pressure comes up you've found the problem. After that you need to isolate if its the fuel pressure regulator, pump, or injectors leaking down. Block/clamp off the return line, then cycle the key real fast to build up some fuel pressure, watch the gauge again. If it holds now you need a fuel pressure regulator, if it leaks down the regulator is OK.

Next you have to disconnect the main supply hose from the fuel rail.. then connect it somehow to the pressure gauge. Again cycle the key really fast. You don't want to build too much pressure and blow something apart. Watch the gauge again. If it holds pressure now, you have an injector leaking down. If it still bleeds off you've got a problem with your fuel pump. Either the hose that connects the pump inside the tank is leaking or the pump itself is bad.

Xophertony · Posted: Sat Mar 17, 2007 11:39 am Post subject:

so i don't know about other fuel injected cars, but if i turn the key on (and the pump primes) and i turn it off and back on real quick, the pump does not prime again. if i wait 3-6 seconds THEN it will prime again. is this not normal?