Just picked up my 89 GTA 5spd, 305. This is gonna be long, but detailed as I need to give all info to get good info =-) I drove the car home last weekend---No problems The previous owner had run 87octane on the last tank, so I started off with 89 plus and a bottle of Chevron Techron cleaner. This Fri night I got my first check engine light. Checked gas cap and replaced generic locking cap as it did not seal properly. Changed plugs, wires, cap and button this Sat. Drove out Sat night and topped off with 93Premium, no lights. Today drove about 60 miles in 95+ degree weather and stopped car, turned off, no problems. After sitting ten minutes tried to restart but would only run for about 1-2 seconds and die. After 15-20 tries she fired up and took off. Check engine light on for about 3-4 minutes and went off. Car ran ****ty while on. Drove home and check codes. Got a 13 and 14, o2 sensor and coolant sensor. I suspect the coolant sensor was and old code as the previous owner had installed a new radiator because of a leak. Anyway, I cleared the codes and started up to get another Check engine light. Checked new codes and got 34, MAF sensor. Have not gone any farther yet. The car has had a small miss at low rpm and idle since I got it. Thought that tune up would help, but didn't. Up in the top rpm range seems to smooth out a bit, but not perfect. Car has new fuel pump on it from previous owner. While doing the tune up I also noticed that the knock sensor locking cap was severely melted and out of the housing. Made repairs and reinserted sensor into housing. As far as I know the motor is stock except for a KN airfilter and only has 111,000miles on it. I've always played with the old Poncho 400's and trying to learn this damn TPI **** is definetely different. Could it be the Techron gas treatment causing a vapor lock? Or would the MAF do this? Any advice I can get is greatly appreciated as my wife will have my *** if I waste too much on this toy

 

I wouldn't overly worry about the small miss at idle and low rpm. My car has been doing that since I got it. and I've had it for 2+ years. Only when it gets hot. Probably a vacuum leak or and EGR problem. As to the other stuff I have no idea. I don't think you'd get vapour lock from higher octane gas. I do pretty much what you just did to pass emissions testing. I run 90 normally since that's the lowest my gas station seems to have, but I put 94 in it for aircare, and methal hydrate. Is 34 a MAF or maf relay (or burnoff relay) Relay's are $15/each so it might be worth replacing them. My 2 cents...

 

Thanks WalterSB,

According to my Haynes manual, 34 is a MAF sensor, but I'm going to start with the relays first. As for the fuel, I was more concerned with the Techron cleaner I put in than the 93 octane gas. I know that the cleaner is mostly alcohol and thought it may have created something funky or a vapor lock. Is you ROC a 305 or 350? Another thing I forgot to mention is that the previous owner said he occasionally got a check engine light when it rained or was very damp outside. I just wonder if moisture was affecting the MAF then? I also noticed (and forgot to mention) that right under where the air filter assembly ties into the intake, more to the right side, are two bolt holes. Looks as if something was there before, the metals still shiney, but I cannot find any pics to find out what.

 

It's a 305 TPI (it's in the sig, I'll look at those 2 bolt holes today) I get check engine light on hot days when drive over 70 mph or so... and it's an oxygen too rich one.. 45? I think. moisture affects the MAF because the wetter it is, the humidity goes up and O2 concentration goes up.

 

The 2 bolts... if they are directly opposite the throttle cable bit, is the throttle postion sensor. I'd look for some hanging cables. It probably isn't that expensive. Might need it for cruise control. I dunno what else.

 

Thanks WalterSB

The TPS is there and hooked up. These two boltholes are in the center portion of the intake, not on the side. If I stand directly in front of the car, I'm looking directly at the holes. They are just left of center, but in the front, under the trottle body. Looks like about a 3/8" bolthole. They are staggered about 1 1/2"-2" apart.

 

Don't suppose you could take a picture? Or steal someone else's from here and edit it. I can't find anything like that on my TPI. I have the Y intake thing, then the MAF (with 2 bolt holes on the side) Then the throttle body, 4 bolts bolt the throttle body to the plenum. The only thing under that I have is loopback coolant hose.

Rich

ps. Isn't a 305 a 5 Litre engine?

 

Pics of bolthole location

 

Took another look, I have those bolt holes, covered in dirt but nothing in them. Looked at a car with AC today. The AC pulley used one of them for a brace but that's it.

 

Thanks Rich,

I guess they're just there. The car has working AC and pulley bracket looks correctly mounted. But I did do some good things last night. The other day, the car got a tick above 220*, I've heard this is normal, but too hot for me. It also threw a 14 temp coolant sensor code and another 34 MAF code. So last night I changed the temp sensor, MAF power relay and MAF burn-off relay. The other thing I did was drain a bit of coolant and add a bottle of Redline WaterWetter coolant additive and water. It stays hot enough down here that I'm not worries about freezing the block in the winter. I drove the car hard afterwards and at idle for 20-30 min my temp never went above 195* while driving it stayed around 175-180*. No codes anywhere! I'll chase down all the gremlins before I'm done. I hate that damn SES light!
But the WaterWetter is the way to go, probably put in my other cars just as prevention. I am going to do another tune-up this weekend as it seems the car lost a little power when I put in the cheap AutoZone wires, cap, and Delco standard resistor plugs. Thinking of going with a new Accel coil,wires, cap and button and maybe NGK or Delco platinum plugs. Everything I've read says to stay away from the Bosch. Just wonder if I'll be able to tell a difference. What kind of plugs you runnin? I took out Autolite plats and Autolite 7.5mm wires. Just seems like its got a little less now.

 

I'm running bosch platinum but I'm only doing it because I'm not willing to spend any money on the motor itself. since at some point I'm going to replace it. It has more than enough power for me atm. It's just a 305. I do have accel 8mm plug wires. Never replaced the cap so I have no idea what brand it is. I just let it go, do what I need to pass emissions testing and beat on it every day when I drive When/if I have the money, I'll put a 350 in and maybe stroke it to 383