I just took my 87 GT with stock original 2.8 (54 k miles) out of storage after 6 months, and man is it running rough. Just a little history before getting into the problem. Last August (2018), the engine was completely resealed and tuned with new plugs, wires, cap, and rotor. A new water pump and belt was also installed. The car ran like a dream. No sputters or stalls or money lights. On the way to the storage unit in late October, I filled the tank with premium fuel and added the recommended amount of Stabil fuel stabilier and drove it approximately 10 miles to the storage unit. No problems getting there.
Now the present. I picked the car up and immediately upon cranking it was obvious that it was misfiring. Giving it some gas seemed to smooth it out but it was still noticeably running rough. Coming to a stop, the car would idle and then the rpms slowly would decrease and then the car would stall. Needed to put it in neutral and give it gas to keep it running. As the car begins to die, the money light comes on when the engine really begins to cough and spit, but giving it gas, and the light goes out, and the rpms increase to 1.5 k, sort of like a cold start in the morning. Sometimes the car wouldn't stall, but the idling would be extremely rough and the light would come on, but then go out after a couple of seconds while giving it gas. Acceleration is lethargic with a noticeable hesitation when pushing the gas. Once at highway speeds, the car seems to run fine and smooth, but again, coming to a stop, the idling condition I described would continue. I drove the car approximately 7-10 miles from the storage unit to my garage.
Getting it home, I checked for a code and it throws a code 33. A quick look up shows that I should check for vacuum leaks and the MAP sensor. However, I am wondering if the code I'm observing is just an artifact of the rough idling and near stalling being caused by another issue. I say this because the money light goes out once the rpm's recover. Is this a typical symptom of a faulty MAP sensor/vacuum leak?
I know that this topic has been discussed ad naseum on this board, but hopefully, with the detail I have given and the circumstances I've described, someone may have had a similar experience after taking their Fiero out of storage and can give some advice on where to start (provided it is not indeed a vacuum leak or MAP issue)? I have purchased a new AC Delco MAP sensor, but it won't arrive until Wednesday. Also before I swap the MAP, I would like to test the old one. Is there a good thread that discusses how to do this?
I'd really appreciate any help you can give me.
EDIT: I failed to mention that I can hear the fuel pump prime for about 2 seconds when I turn the ignition on.
[This message has been edited by Akheron (edited 04-29-2019).]
Code 33 will set when: - TPS is less than 1.6% AND - for more than 5 seconds, the MAP signal is greater than 69kPa with AC off or greater than 75kPa with AC on "Engine misfire or a low unstable idle may set Code 33."
I think the MAP sensor is unlikely to be the problem. But one common test is to unplug it from the harness. If you do that, does it run much better? Typically bad gas is the main suspect in this situation, even though it sounds like you did everything you could to avoid that. Can you burn through it and freshen up the fuel? If the gas is bad enough it could clog injectors. I'm not sure if fuel system cleaners are effective, but I might be tempted to dump a bottle of Techron in it.
If your car has Multec injectors, those are kind of notorious for ethanol related corrosion. But if they're factory injectors then they shouldn't be Multecs.
Before you start throwing parts at it, consider what you did before you put it away - you added a tank of premium gas and some fuel stabilizer. All fuel stabilizers are not created equal and running premium gas in a low compression motor is not a good idea. I put some supposed miracle stabilizer in my boat once and it ran like crap until I filled it up again. Take it out and blast it down an interstate for a while and fill it up with new regular gas.Or drain the tank and put fresh gas in. If that doesn't work then start throwing parts at it.
Thanks for the suggestions. I highly suspect the fuel as well. Any suggestions on how to empty the tank without removing the tank from the car? I know this tank has a baffle in it so I'm not sure if it will block a siphon hose from reaching the bottom. Due to its stalling out, I'm a little concerned about getting it out on a freeway, especially here in Chicagoland, and running the fuel out of it. I still plan on testing the MAP, won't be able to get to it until this weekend. I'll post back with what I find.
On a different note, I did buy a used tank from a salvage yard and plan on having it restored. Would it be a good idea to simply change the tank? This would allow me to inspect the hose on the fuel pump for rot as suggested. I'm leaning towards doing this due to the fact that I have no idea about the maintenance and repair history of this car. For all I know, the fuel pump could be the original pump.
If the fuel hose is rotted on the inside of the tank, any recommendations on brand/type of hose to use? I ask because I have read that some of the hoses that come with new fuel pumps tend to fail prematurely, and I'd really like to avoid that.
Buy hose that says "For fuel injection". You'll notice its a lot stiffer and robust. Put a battery charger on it, disconnedt the fuel filter (replace it with a new one) jump the terminals at the fuel pump relay and empty the tank. Put new fuel (87ron) and a can of injector cleaner Drive hard.
Well, I think I may have found the problem. I got home and cranked the car to see if there was any improvement. Nope. But as I'm scanning the top of the engine I notice that the EGR valve is "dancing" on top of a "stem". Well, that's odd. So I reach over and push the EGR valve down, and low and behold, the idling stabilizes. I let go of the EGR valve and it pops up on its own, and the coughing and spitting returns. Correct me if I'm wrong, but I thought a failed EGR valve would result in a high idle situation? Anyhoo, the part is on order, and hopefully, I can install it this weekend. Any advice on the "do's and don'ts" of changing an EGR valve?
Originally posted by Akheron: Correct me if I'm wrong, but I thought a failed EGR valve would result in a high idle situation?
A cracked EGR *tube* will cause high idle, because it allows the engine to suck in more air from the environment (bypassing the throttle). But a bad *valve* allows it to suck unintended exhaust into the intake instead, so it stumbles.
...as I'm scanning the top of the engine I notice that the EGR valve is "dancing" on top of a "stem". Well, that's odd. So I reach over and push the EGR valve down, and low and behold, the idling stabilizes. I let go of the EGR valve and it pops up on its own, and the coughing and spitting returns.
I got in my trusty '88 Formula this morning, started it up... and the engine sounded like it was running on somewhat less than six cylinders. It was very rough. I was quite puzzled as the car has always run so well. I turned off the engine, opened the decklid, and looked around. There didn't appear to be anything visually wrong. So I left the decklid open, started the engine again, and went to have another look.
And then I noticed something really weird.
It's probably the original EGR valve on this 2.8 engine... and it was looking mighty strange. I didn't take a picture of it on the car, but the picture below is what the EGR valve was looking like while the engine was running. There appear to be three rivets that hold everything together, and anyway... all three rivets had let go, probably due to 30 years worth of corrosion. (EDIT - I just noticed in my image below that two of the rivets had probably rusted away long ago, and the last one finally let go.) So while the engine was running, the pressure of the exhaust was pushing the entire diaphragm housing of the EGR valve up as far as can be seen in the image below. The end result was that the engine was struggling to run with the EGR valve wide open.
I pulled the EGR valve off a GT parts car here, and the Formula is now happily purring again.
[This message has been edited by Patrick (edited 04-30-2019).]
Well, I think I may have found the problem. I got home and cranked the car to see if there was any improvement. Nope. But as I'm scanning the top of the engine I notice that the EGR valve is "dancing" on top of a "stem". Well, that's odd. So I reach over and push the EGR valve down, and low and behold, the idling stabilizes. I let go of the EGR valve and it pops up on its own, and the coughing and spitting returns. Correct me if I'm wrong, but I thought a failed EGR valve would result in a high idle situation? Anyhoo, the part is on order, and hopefully, I can install it this weekend. Any advice on the "do's and don'ts" of changing an EGR valve?
Great catch glad you found the problem
[This message has been edited by wftb (edited 04-30-2019).]
The solution wasn't that hard to find in this case but for cars in storage a long time, I highly recommend buying a Fuel rail injector cleaning kit. With pressurized fuel injection cleaner ( like OTC) flowing directly into the rail under pressure, the injectors get a thorough cleaning. In the tank injector cleaners are typically not concentrated enough to do a good job of cleaning the injectors. Applying cleaner direct to the rail usually does it. You can buy these injector cleaning kits on eBay for about $70. The cleaner is $12 a can on amazon. On an old vehicle like a Fiero, injector cleaning often produces a great result.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
