Hello everyone, I'm having trouble with the engine in my 1987 Fiero 2m4. Right now, it has no power at all, resulting in the engine stalling whenever I put any load on it. This all started a couple weeks ago when the IAC valve gave out and made the engine run horribly. I replaced the IAC valve with a new one and it didn't seem to fix the problem. After I replaced the IAC valve, I had no power in the lower gears (specifically 4th gear) at 2000 rpm and when climbing hills. When I stepped on the gas in 4th gear, it would just violently vibrate and wouldn't accelerate, like it was running rich or lean. I looked around the engine and found some busted vacuum lines, so I replaced them. It didn't help. I then found a broken spark plug wire on cylinder #1, so I replaced all of the wires. I also found the o2 sensor was giving me erratic readings, so I replaced that as well. Here's a list of all that I replaced: - fuel filter - IAC valve - o2 sensor - spark plug wires - spark plugs - vacuum lines I also noticed my catalytic converter is glowing orange and I don't think it should. I tested the vacuum pressure and the exhaust back pressure to see if the converter was clogged. I keep getting normal vacuum pressure and exhaust back pressure, which tells me that it's not the catalytic converter or a random vacuum leak. I have tested the fuel pump flow and pressure as well. I am getting a steady flow and 13 psi on the pump, which is what it should be. I tested the map sensor and the throttle position sensor too, which are both working normally. When I snap the throttle wide open in neutral, it seems like it really struggles to accelerate. But when I open it slower, it gets up to 5000 rpm pretty quickly. My dad and I are currently working on building the Arduino ALDL scan tool from hackster.io so I can read all of the sensor data live. After hours of testing and inspecting parts on the engine, I haven't gotten anywhere. I could really use some help and would appreciate any help that anyone can give me.
Hello everyone, I'm having trouble with the engine in my 1987 Fiero 2m4. Right now, it has no power at all, resulting in the engine stalling whenever I put any load on it. This all started a couple weeks ago when the IAC valve gave out and made the engine run horribly. I replaced the IAC valve with a new one and it didn't seem to fix the problem. After I replaced the IAC valve, I had no power in the lower gears (specifically 4th gear) at 2000 rpm and when climbing hills. When I stepped on the gas in 4th gear, it would just violently vibrate and wouldn't accelerate, like it was running rich or lean. I looked around the engine and found some busted vacuum lines, so I replaced them. It didn't help. I then found a broken spark plug wire on cylinder #1, so I replaced all of the wires. I also found the o2 sensor was giving me erratic readings, so I replaced that as well. Here's a list of all that I replaced: - fuel filter - IAC valve - o2 sensor - spark plug wires - spark plugs - vacuum lines I also noticed my catalytic converter is glowing orange and I don't think it should. I tested the vacuum pressure and the exhaust back pressure to see if the converter was clogged. I keep getting normal vacuum pressure and exhaust back pressure, which tells me that it's not the catalytic converter or a random vacuum leak. I have tested the fuel pump flow and pressure as well. I am getting a steady flow and 13 psi on the pump, which is what it should be. I tested the map sensor and the throttle position sensor too, which are both working normally. When I snap the throttle wide open in neutral, it seems like it really struggles to accelerate. But when I open it slower, it gets up to 5000 rpm pretty quickly. My dad and I are currently working on building the Arduino ALDL scan tool from hackster.io so I can read all of the sensor data live. After hours of testing and inspecting parts on the engine, I haven't gotten anywhere. I could really use some help and would appreciate any help that anyone can give me.
Are you getting any engine codes "right now?"
A hot catalytic converter almost always means there's too much uunburnt fuel getting into the catalytic converter. It could mean that, for example... you're car isn't completely burning fuel off during the combustion process, or there's a misfire and a lot of the fuel is making it past the exhaust into the cat. The thing I find odd is that often time when a car is running too lean, the exhaust manifold will glow red (and not the catalytic converter). Which doesn't make a lot of sense to me... but that's been my experience.
If your car is running poorly, the glowing catalytic converter is more likely a symptom resulting from the poor engine performance. When the engine bogs or stumbles in idle... that's almost certainly a problem with fuel delivery (too much or too little) or an ignition issue (not firing). The first thing that comes to mind as a potential source of problem is... the Throttle Position Sensor. I'm not suggesting it's bad, but it could be set improperly... meaning that it's telling the ECM that throttle is much higher than it really is.
Without a doubt a glowing catalytic converter means the mixture is too rich or the ignition is not firing all the cylinders. The cause of this could be the fuel injector that is stuck wide open or possibly a bad coil or ignition module. Time to scan the ECM and look at the performance of everything in the engine. My guess is the ignition and that is easy to check with a cheap spark tester. .
------------------ " 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 "
Important sensor is the water temp sensor for the ECU. This can flood the engine if thinks it's colder than it is. Can check it with a multimeter - there's a table online that tells you what resistance it should be at what temperature. Pretty simple and worth checking.
EGR is important. Can bog the engine and make it stutter if it's the wrong type or not working.
Speedometer looking good? Also can make the engine run poor especially at idle
Important sensor is the water temp sensor for the ECU. This can flood the engine if thinks it's colder than it is. Can check it with a multimeter - there's a table online that tells you what resistance it should be at what temperature. Pretty simple and worth checking.
EGR is important. Can bog the engine and make it stutter if it's the wrong type or not working.
Speedometer looking good? Also can make the engine run poor especially at idle
I figured out the problem. It was the coil pack for cylinders 1 and 4.
