Our car is a 1986 Trans AM with a 305 TPI. It is completly stock with 30k actual miles. We have owned the car since 2006. I am having some odd problems with it.

We live in the Smoky Mountains, and often drive in the national park. The car does not like accending steep grades. One drive takes us from 2100 elevation to 5600 feet. The car runs warmer than usual, and smells gassy when we stop. If we drive up turn around, and drive back down the gas smell goes away. There are no fuel leaks.

Sometimes the car does not want to start. Usually this happens when it has sat for a few days. It turns over fast, and acts like it is not getting fuel. Often turning the key to off, than back on, and it will start right up. When it does this the check engine light will come on and stay on until the engine is shut down and restarted. Than the light goes off and stays off.

When the fuel tank is filled and the car is parked leaning to the left or with the front up higher then the back, fuel drips from the area near where the fuel filler enters the tank. I'm pretty sure that there is a small pin hole at the seam were the filler enters the tank. If I remove the tank, is it possible to have that area soldered over to seal it up?

The o2 sensor is new. The center of the original one fell out of the base.

The car runs great on the highway. No fuel smell. I converted the single electric fan to a stock dual fan setup several years ago. There is sn aftermarket 195F fan switch that switches two hd relays that power both fans together. The original fan control triggers a relay that turns the fans when the ac is on, or if the oe fan switch is tripped. The car has a three flu hd copper radiator and a 195F thermostat. On the highway it stays between 190 and 195. When climbing a long grade it runs 220F.

Any help is appreciated. No one around here wants to work on this car, and I am perplexed.

 

Have you read the codes from the ECM? They should tell you what triggered the check engine light, and that will help you diagnose your starting problem.

Your other problem sounds like it is related to cooling. These cars have more issues than the average car when it comes to cooling. Obviously, going downhill is a lot easier on the engine and therefore it won't heat up as much. Driving on the highway you are probably not on a steep grade, and moving fast enough to get plenty of airflow through the radiator. I'm guessing that the combination of altitude, extra engine load, and insufficient airflow are inhibiting proper cooling.

My 88 GTA has similar symptoms when it gets above 200 degrees of coolant temperature. I get the odd smell, and it loses power and sometimes quits until it cools off. I'm not sure what the odor is, nor what it might be related to, but I do know that it only happens above 200 degrees. I have reconfigured the dual fans to come on at a much lower temperature, and that seems to help quite a bit. You should read the stickies in the cooling section on this board.

Yes, it is possible to remove the tank and have it soldered.

 

Thanks a lot for the info. I have some places to start looking.

I should have gotten the code or codes before making this post. Before I changed the o2 sensor, that was the only code that was showing up.

I am off from work on Thursday, and will check the codes then.

This smell is either gas or unburned fuel. If it is dumping fuel, it is not doing the Cat any good!!! The cat does not seem overly hot, and is not glowing like a couple of them that I have seen. I have wondered if the fuel tank is trying to pressurize, but since there is a leak in the filler neck, it can't build sufficient pressure, or vacuum whichever is the case? Any chance it is forcing fuel vapor out of the fuel fill leak?

The car has been sitting in the garage since Sunday noon, and there is no trace of a fuel smell anywhere around the car. We stopped on top of the mountain for a minute Sunday AM, and the smell was so strong it would knock you down.

My cooling fans run at 195F, but apparently they are not effective. The engine does not stall, and even runs well going up the mountain. I was doing a pretty decent job of staying right behind an LS powered car on the cruise Saturday. I have wondered if the computer is dumping fuel into the engine to try and keep it cool? I have thought about replacing the OE fans aftermarket cooling fans that move more CFM's.

If we pull off of the road and let the engine idle, it cools right back down to 195F in a few minutes, so it does not seem that the radiator is inadequate. It makes no difference if the ac is on or not, and the outside temp does not seem to affect this issue.

It seems that the the first thing is to fix the known problems, the fuel tank leak, and check the computer codes.

 

I does should like you have a few issues. The cold start injector is problematic on the 85-88 tuned port. It sound like maybe a connection at the timer switch maybe to fault for the harder cold start. Has this allways has running issues ? There was a drivilibility issue with the aum memcal is 86. As far as running rich a bad ect, leaking injectors, leaking fuel pressure regulator a higher than normal tps reading . A scanner would be a useful tool to check the sensor readings and ohm the injectors when hot. But pull any codes first if there are any.

 

Thanks,

The first project I am going to tackle is to replace the fuel tank. Dorman makes an OE replacment, and Delco has the fuel pump. Both are available through Summit Racing. Then I will not have to worry about that part of it any more for a while.

It seems that a scanner is also in order.

The hard start problem is intermittent. Sometimes the car starts right up, and other times it is difficult. The first time I noticed it was when we had trailered the car to a show. It would not start inside of the trailer. I tilted the trailer, released the brake, and let the car roll out by gravity. It started right up, once sitting in the parking lot. Now it seems to come and go. I thought at first that the problem was worse when the car sits for a week between starting. However, that is not the case. It seems more of a random problem, unrelated to anything else.

As for driving issues, as long as the car is being driven in town or on the highway, it runs fine. Awesome throttle response and power for a 305 TPI. The operating temps stay in the 190F to 195F range, and the engine runs perfect.

The temp increase and unburned fuel smell occurs when driving up a long mountain grade. That is the only time it happens. Unfortunately, we live in the mountains and have lots of grades to accend. The smell is not noticable while moving, but is stout when the car is stopped.

When decending the grade the engine cools down to lower then normal operating temp, somewhere in the 185 to 190 range. The smell goes away. Once off of the mountain the temps return to normal 190F to 200F. The t-stat is a 195F, and the fans both engage at 195F or when the AC is on.

 

Doing some reading about TPI's, to try and understand the set-up. Just from speculation, it sounds like my car's problems could be related to a possible leaking injector, or a failed cold start injector. It sounds like the 85 to 88 models with the cold start injector are prone to problems. There are kits available to block off the cold start injector, and than have the ECM reprogramed to operate like the 89 and up models that don't have a cold start injector. Some of the kits include a block off for the EGR valve. Is there an advantage to this mod? Thanks in advance for insights.

 

Getting rid of the ninth injecter is a good idea. The 89 tpi programing uses all eight injecters for cold start enrichment. Going with southbays bosh 3 19#hr offer a great idle quality.
The egr has a temp sensor that often fails and causes a code 32. This can be reprogramed out aswell . The egr lowers cumbustIon temperature but if seems like using a egr causes more carbon deposits in the intake.
If you do replace the injectors now would be the time to put in a new regulator and crossover tube o-rings
http://www.ebay.com/itm/Chevy-TPI-SBC-Cold-Start-9th-Injector-Block-Off-Delete-Kit-/380643829414?pt=Motors_Car_Truck_Parts_Accessories&hash=item58a023e6a6&vxp=mtrhttp://m.southbayfuelinjectors.com/p...7&product=1500

 

Also on the fuel tanks, I would look for a good used 91-92 tank. They have the 1LE baffling in them. I can find them cheap. Have it PSI tested at a rad shop and touch up the silver solder on the neck if needed.

I'm also wondering if the psi in the tank is pushing a fuel smell/vapor out as you go up the mountain because, the higher you go the less air psi is out there and the gas tank is trying to equalize.
Its like going up in small unpressurised plane, you need to open a bag of chips or sodas before you leave or they could just blow open. Ask how I know lol

220degs is normal for the 195 t-stat and your fan switch witch is prolly a 195-shut off temp.
if you want it cooler, you'll need a cooler stat and fan switch.
I have also had better cooling luck with the aluminum plastic stock rads.

 

Thanks for the info.

Did not get the chance to look at the car on Thursday, my day off. This morning when I got off work, I got the codes with the engine cold, engine not running, and the key on. The car had not been started in 6 days. The codes are 12, 13, 32, 34, and 54. 12 is normal for a non running engine. The code for the O2 sensor is probably left over from a few weeks ago when I found the center of the O2 sensor hanging by the wire. I installed a new sensor, but did not clear the codes. I looked up the codes in the dealer service manual, it appears that some of them may be due to the engine being cold, and not running.

So, on my next day off I will run the car to operation temp, and then check the codes again. Would I be better off to clear everything and see what resets? The battery has been in the car since 2010, so it may have accumulated codes that are no longer a problem? This car is very original with only 30K miles on her. She still has the original spark plugs. Some of the original vacuum hoses look dry rotted. I am thinking that maybe I should replace them in case vacuum leaks could be causing some of the problems? My hearing is not good. There could be a minor vacuum leak and I may not hear it, although recently at two shows recently no one mentioned hearing a leak.

And to top it off, the car started right up perfectly, ran perfect, and the light went off immediately after starting. When this car is running right, it runs text book perfect. No smoke, and no smell, good throttle response. It was recently driven from Atlanta to NC, about 175 miles, and it would run for an hour before the light came on. Stop for a few minutes, and the engine would run for an hour without the light, then the light would come back on. Sometimes, the light will stay on for a while, then go off and stay off for the remainder of a trip. Usually it resets after turning the engine off for a few minutes.

 

Start with the code 54 and 32 more than likely a corrosion issue at the fuel pump relay.
http://www.gmtips.com/3rd-degree/dox/tips/ecm/prom.htm

 

Thanks Brian. I will check that on Monday.

 

I checked for corrosion issues at the fuel pump relay. There was no visible issues, however everything was cleaned, tightened up and put back together. The air filter was replaced, and a couple of vacuum hoses replaced. I cleared the codes and topped off the fuel tank with ethanol free 93 octane.

So far the car starts well and is running well. No codes have reset since the system was cleared. Since it has been an intermittent problem, only time will tell if the problems have been resolved.

 

The car was a little hard to start today. It set one code, 54, and the light stayed on continously. The car ran well, and was driven 12 miles at 60 mph. The light did not reset when I got back to the house, shut it off, than restarted it. Since it has a continous light on now, maybe it will be easier to find. I am going to concentrate on that fuel pump relay and socket.