Corry

Alright, in an attempt to get my car running better than it's pitiful 158 HP, I have been looking to eliminate all codes on th computer (Fortunatly I haven't had the maf bug come to my TA yet!!!) It is a TPI motor, still not sure if it's 305 or 350...(Yes at 158 HP it was running like absolute sh*t!)
Current Problem: By the scan tool, and exhaust smell the motor is always running lean. Not enough to set the code though. Usually while idleing at a light, the thing will seems to sputter and nearly die, then revs back up again, and settles back to a normal idle. Just after it revs up I get the lean O2 code. My question is could it be an *extreamily* old fuel filter causing this, or should I be looking more at the fuel pump? The pump makes good pressure, but could it be momentarily having a problem. I already bought the fuel filter in anticipation of changing it anyways. Next problem is where exactly is the filter? By the Helm, it looks like it is in the middle of the rear crossmember. I hope this isn't the case because I don't have a jack/jackstands, nor could I use any in my apartments parking lot! So can the filter be changed while the car is on the ground?

Second question (well, ok technically 3rd Are 305 and 350 alternator/water pump belts identical? Reason for asking: Recently I learned the hard lesson, replace a worn belt...or it'll take down other belts with it! I ended up having to change the Alternator/water pump belt, and going by those absoluty sh*tty pathetic...etc dyno results, I figured it was a 305, and bought the belt accordingly. Well, when I went to put it on, with the alternator in the position closest to the water pump, I had to stretch that belt w/ a screwdriver to get it on. My guess was wrong belt since the old one used to sit about mid way-slightly above midway up the bracket. Maybe it's just cause it's a new belt?! I can't imaging even a new belt being that hard to install!
Thanks


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Corry Lazarowitz
clazarow@voicenet.com
clazarowitz@hotmail.com
1987 Pontiac Trans AM (GTA?) 350 or is it a 305?! TPI
SLP 1 3/4" headers, 3" cat back (stock cat
MSD ignition.
MSD Blaster SS coil.
3.73 Rear end gears
Accell 8.8 Wires
Bosh +4 Spark Plugs (Don't know if they really help but hell!)
Holley AFPR
Race Built Automatic trans ('vette servo, shift kit, tightly packed clutches)--just needs titanium gears now!
Newly gutted cat (the car gutted it's own cat!)
Hypertech Chip (Just found out I had it! :eek
More soon when funds are avail...

rezinn

I think you would have problems changing the filter while the car is on the ground, I do mine with the car backed up onto ramps. A bad fuel filter could cause many problems, its best to just change.

Have you changed the o2 sensor? That can also cause sputtering symptoms. Is your catalytic converter old? Might want to check that out.

The belts are identical, it is normal to have to pull the accessories away with a lever and tighten them down, or was the belt too short? After a couple hundred miles it will stretch out a little and you can retighten it. Sometimes those guys that give you the belt at a parts store could screw up too.

Corry

O2 sensor was replaced 6 months or so ago when the headers were put on

I plan on changing the fuel filter anyways...hadn't thought of ramps...wonder if I could get away with it hehe

And the cat? Check the sig, It blew its guts out on I-35! lol It *was* plugged hehe, not anymore...gonna suck when I have to go to the emmissions sniffer again!

How bout the belts, and any other ideas on the O2 prob. Forgot to mention, if you pop the hood, and try to rev the motor if you are fast, you can pull the blades about 1/2 open, and let the spring return it in less than a second or so. When you do this on my car, it hesitates, and makes a noise that sounds like a loud hissing noise. A mechanic said it's probably a pinhole leak in a gasket. I used carb cleaner to test for and such leaks and couldn't find anything. Could a lack of fuel cause the same thing? Also usually only when it's cold, it will sometimes knock just before it stops hesitating, and goes. I know that was akward, but thats when I have noticed it happening. Any more ideas?

EDIT: Edited for spelling mistakes



[This message has been edited by Corry (edited June 16, 2001).]

Corry

Does anyone know?
ttt

whiteroc

Do you have a 2 wire heated O2 sensor? If not -that may be your problem. You would be running in open loop mode the whole time. The O2 sensor needs to heat up to 600F to work correctly. The heated type O2 doesn't need to heat up because it is electrically warmed up. Your car would be way down on power, run lean if the ECM has no reference as to what the fuel requirement is at part throttle. With headers the engine would breathe better and need more fuel. I bet you have bad gas mileage as well as being down on power. Hope this helped.


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89 IROC-Z 5.7L
130,000 MILES
2.77 GEARS
K&Ns FILTERS
ALL FREE MODS
FLOWMASTER MUFFLER
PERFORMANCE RESOURCE CHIP
Best 1/4 E.T. 14.37 @ 95 MPH
Best 1/8 E.T. 9.22 @ 76 MPH
Best 60ft. 2.07

Vader

Corry,

Nobody but you knows, aince you have the car and we can't look at it.

If it's a GTA, it will not have the fender side vents. Only the TAs had the side vents. A 305 will have a VIN code 'F' in the eighth position, and a 350 will have the code '8'.

Check the EGR valve.

Replace the HyperScrap PROM with an OEM PROM, then recheck error codes.

Check manifold vacuum at idle. It should be steady and between 17-19" Hg. A bouncing vacuum reading can indicate a sticking or damaged valve.
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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

[This message has been edited by Vader (edited June 16, 2001).]

Guest

Sounds like the belt is too short.

And I know this doesnt help, but it is possible to change the fuel filter on a stock 85TA TPI car without raising the car up at all. Its no fun mind you, but doable. Im sure you could do yours as well if its not lowered.

Check for loose connections/leaks between the MAF sensor and the throttle body. And if you dont already have one, get a voltmeter and check the TPS setting, make sure its right and doesnt jump around when you open the throttle up. The engine does not have to be running to check that.

Corry

Don't know about the heated O2 sensor...have to check that later (after the sun starts to set...too hot now!) but it does get into closed loop. However, before it sets that lean condition it has tons of power, makes me think it's a 350 again! Then about a mile down the road, it loses most of it's initial get up and go.
As for the motor/gta? I have done extensive research on this. In '87 some of the GTAs did end ep w// the side scoops since they were just converted T/A's...and some were done wrong..plus my car may have been a parts car at one point...some things point to that possibility. If the motor was swapped out, the VIN doesn't help one bit. I can find out if it was a GTA or not easy enough, just $35 to pontiac historical services. The motor? Well that belt was too short, but was it mislabled, or did 305's and 350's use different Alternator/waterpump belts? I.e. were the crank poullies different...did they use the same water pump? Is there any easy way to ID it w/o pulling the heads? The block casting numbers are most likely on the back of the motor, or sides which are almost as cramped w/ all the emmissions garbage that is next to impossible to tell. All I need is some kind of minor difference like that belt, I am sure there is some minor detail that can give me a better idea than the Dyno (@158 HP...timing waaaaaay off, fuel filter, Throttle position sensor, etc broke...) As soon as I get the fuel filter done, I will check it on the local 1/8 mi. track and hope for something conclusive...

I replaced the EGR valve ~2 years ago, and re-tested it a few days ago and it checked out fine.

The chip wasn't my idea...I found out it was in there about 1.5 months or so ago. I plan on burning my own proms eventually (I'm a CS student! hehe )


As for the vacume, I'd prefer to make that last resort sicne a vac gauge will cost me $35 and I can't afford it 'till the 30th.

A review/info I forgot to mention... The main problem is it hesitates. You pull the throttle down and let it spring back, and it sounds like it's choking, it throttles down, then recovers and comes bac a little above idle. Then returns. When you first pull the throttle open you hear a loud sucking like noise just until just before it catches then it either goes away, or the exhaust noise covers it up. The hesitation is less noticeable after it gets good and warm, but it is also down on power after it gets good and warm. And it is always running lean.

So I guess I'll go w/ my gut, and what at least sorta makes sense to me and thats the fuel filter, and I'm sure it needs to be changed anyways!




[This message has been edited by Corry (edited June 18, 2001).]