I’ve got a 1985 V6 Fiero, that sat since 2004. Since getting it, it ran but I still went ahead and replaced fuel injectors, pump, pressure regulator, distributor, spark plugs, and ignition coil.
I just finished all this and have been having problem after problem getting it started. Now I’ve reached a point where I know there’s spark, and fuel pressure, but I don’t think I’m getting power to the injectors. I checked for codes and was getting a code 42 (electric spark timing) and have done basic diagnosing with no success. I had trouble understanding a lot of the instructions for testing electrical power to the injectors, but I believe I have found that there is no power to the 6 wire plug next to the intake manifold.
Anyone run into similar circumstances? Or an idea on what to check first?
Have you verified that when you replaced the distributor...that the timing is correct? It has to be put in the exact same position as the original. Unless you mean you just replaced the cap/rotor.
Your FI fuses have no voltage on both sides of the fuse?? Do your hazard lights work? If yes, then your Ignition Switch may have failed or need adjusting to make a better connection. There should be power on the switch's pink wire with the key turned to the run position.
Ok, the hazards did turn on—how does that mean that the ignition would be bad? And to test this do I need to start pulling apart the steering column to get at it or is there an easier way?
The Fiero ignition switch is not covered by the steering cowling. It is mounted down where your knees are, and is the upper switch (with violet writing) shown here:
There should be 12vdc on the pink wire with the key in the 'on' position:
If there is no power on that wire, then the ignition switch has failed or may have slipped out of position.
Thanks for the help, I got to it and then stopped when I saw how difficult it was to actually test.
Before I try removing it and risk messing one more thing up, I looked into a couple other options and realized that it does start with starting fluid, and the six-pin connector to injectors is getting positive power, just no ground when cranking. (I still don't seem to register power at the fuses, so that last part is confusing to me)
How do I go about diagnosing this issue? Everything with the ECM seems to function correctly which makes me think it doesn't register the engine turning over?
More specific information would be helpful. You get power on the pink wires in engine's FI connector? What wires exactly are you testing? The return wires to the ECM at this connector are light green and light blue and so should also have power on them with the key on/engine off (ie: injectors not grounded). IIRC, I believe the Ignition Control Module in the distributor signals the ECM to turn the FI control on (someone correct me if that's wrong). Still, the four pin connector on the ICM is a known weak point, and can make a poor contact even if it visually seems fine.
[This message has been edited by Rexgirl (edited 01-24-2022).]
Yeah I am getting power on the pink wires but nothing to the blue or green ground wires in the middle.
I'm still a little confused on just how it works but I know ICM does tell the ECM when to start sending signal to the injectors. I read a lot about testing circuit 423 (Est) and the Bypass circuit, but I still am not sure about how exactly I test that.
Ok now I’m really confused I pulled the intake manifold off and then checked again and suddenly had power and ground to the six-pin connector when cranking. Then I pulled the fuel rail and found two injectors not firing (5 and 6). One of them just had an issue with the plug and the other I sprayed electronics cleaner on the contacts of the plug and then all six injectors started spraying fuel.
I then put it all back together and it wouldn’t start. I’m getting power and ground to the six-pin and it will start right up with starting fluid, but it still doesn’t run.
I pulled the fuel rail up just a little bit while still connected to the fuel lines and was able to watch them spray fuel.
I’m now getting a code 33 (MAP vacuum pressure low or high) but all the connections appear to be good. I’m seeing that it connects directly with the fuel pressure regulator. Would it be worth it to replace that again or is there any way to test it?
I did check the order of all the plug wires, they seem to be in order. I replaced the ICM and MAP sensor, spark plugs (again) and the plug wires and it won’t start still but I did verify it will still fire with starting fluid. While changing plugs I also checked compression and got the following: 1: 150 2: 120 3: 150 4: 147 5: 130 6: 150 Does this appear to be normal? I think it is but figured I’d ask since I’m not very familiar with this stuff.
I’m at a complete loss as to what could be the problem. Any help would be greatly appreciated.
You may be back to basics. Like Skybax wrote, you might want to verify that the distributor and rotor are correctly timed. For example, the rotor should be pointing at #6 when the rocker arms on #3 (which might be visible through the oil filler cap) are rocking.
Also, if you haven't fully checked the four wires that run from the ICM to the ECM, doing so might be a good idea. Their connector, plugged into the distributor, can and does fail. The wires are shown here in the lower left:
[This message has been edited by Rexgirl (edited 01-25-2022).]
I finally was able to do the diagnostics from the GM service manual and found all the connections are good between the ICM and ECM.
I went to try and check timing and realized I can’t use my timing light when it isn’t running, so back to your suggestion, what is the best/easiest way to crank the motor by hand?
My suggestion is to 'static time' your engine. You can find the timing mark here: https://www.fiero.nl/forum/...030531-2-030839.html IIRC, it's the widest of the three marks on the harmonic balancer. To verify that the balancer is still accurate, you may wish to use a straw through the #1 spark plug hole and confirm that piston is at TDC..
I read through the entire GM service manual today and made a list of things to check, timing being the first thing, but before trying any of it I decided to try starting it with starting fluid again. Each time it started it would sputter huge clouds of grey and black smoke but it ran a little longer each time. Finally after four or five attempts it kept running but sat at ~2500 rpm. The exhaust manifolds started glowing red so I shut it off and the next time I started it they didn’t glow at all.
It will now start on its own (but takes a really long time to sputter to life) and idles at about 2000 rpm. The check engine light came on and I got code 35 and 45. I started to diagnose it but then the light went away. I also found that when I let off the gas at all it will leave huge clouds of grey/black smoke from the exhaust that smell terrible.
Do any of these things seem to point to anything obvious? Is it possible this would be a sign of the oxygen sensor being bad and causing the engine to run rich?
Hey, 'hunter - red-hot exhaust manifolds and really fast idle kinda sound like a vacuum leak to me. Check all your vacuum hoses and replace any that look the least bit cracked or broken. Include PCV and MAP hoses, fuel pressure regulator hose and fuel evap system plumbing. Don't overlook any tee's or couplings that might be lurking around. 18 years is a long time for the elements and small fur-bearing mammals to inflict harm on plastic and rubber bits. Gaskets can also deteriorate over that kind of time; a compromised throttle body gasket can let in more un-metered air than might be expected. Just my $0.02... Keep us in the loop - Chris
Well I got it started again and began pushing on wires and seeing if anything changed, when I pushed on the two-pin tach connector on the distributor cap the idle went back to normal, and I noticed that one of the pins on the connector had come loose. I bought a new one, installed it, and it started up and ran perfectly.
Once it was starting and running well again I let it idle in the driveway for awhile and pretty soon the idle dropped even more and immediately I got codes 35 and 45 again. I cleared them and let it run again, this time they didn't come back but when I drove it around the block the idle got really rough and then it died on me. Now it'll start but idles horribly but doesn't throw any codes. I had to leave the house then so I haven't done any diagnosing yet but figured I'd let you know what I'd gotten to so far.
I went back to try and do some diagnostics today and am not really sure what to do. It was running again but very rough, and then it stalled, and won't even start anymore. It still will fire once every few seconds but that's it. But this time starting fluid doesn't help at all, which tells me it's probably an ignition problem. I pulled a plug and found it is completely black (looks like it was running rich) but still gets spark. These plugs were just changed too, so I know they're good.
I ordered a new O2 sensor just to make sure it's getting the right fuel/air mixture and because one of the codes involved that sensor. Anyway, I'm not exactly sure what else to check if I'm getting spark and starting fluid won't even help. It's annoying too cause I had just gotten everything out to check timing but now I'll have to do a static time. I can't imagine that's the problem though since it hasn't been touched since the car started running.
I finally had time to go through and test each vacuum line and replace the ones that don’t leak, but it still won’t run. I also just got a new O2 sensor in, the original one was black and covered in soot but I assume that’s normal after so many years.
Put a fuel pressure gauge on the fuel rail..(valve provided under that small metal cap)..crank the starter to get a reading...should be about 35 lbs.
Stop cranking and watch the gauge. It should hold pressure or drop very slowly for about 2 minutes. If the pressure drops quicker than that, your injector(s) are leaking.
[This message has been edited by Gall757 (edited 02-11-2022).]
Does it fire for the first crank or maybe second, but then doesn't again? That would indicate it's firing on the cold start injector.
Also your root problem is most likely all 6 injectors are stuck shut from sitting so long. Take the upper intake off and test each injector with a 9v battery and alligator clips. Stuck injectors make a different sound than a free injectors. Free the injectors by wacking them with the handle of your screwdriver.
IF YOU REMOVE THE INJECTORS YOU NEED TO VERIFY THERE IS NO FUEL LEAKING!!!!!!!!!!!! READ THE MANUAL ON HOW TO DO THIS. Or better is just not to remove the injectors. Just fix them by wacking them with the screwdriver while they are still in place.
[This message has been edited by phonedawgz (edited 02-12-2022).]
I had to leave town for a couple of weeks so I didn't have a lot of time to look into this until yesterday.
I checked the timing (as well as I could without it running) and it appears to be correct or at least close enough that it wouldn't be the culprit. I checked and replaced almost all of the vacuum tubes, and I found that the tube between the MAP Sensor and Fuel Pressure Regulator has a leak, but I've had a hard time replacing it. I bought the tubing but can't seem to find the right fittings anywhere. Any ideas on what to do about that?
I also checked the fuel pressure, and it was getting 46 psi but quickly dropping. It wasn't doing that before and I don't see any fuel leaking below the car. How would I check for leaky injectors and what do I do about them?