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| Fiero random power loss and engine codes (Page 2/3) |
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Vintage-Nut
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AUG 18, 10:56 AM
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ArthurPeale
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AUG 18, 11:52 AM
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| quote | Originally posted by Nytfury:
I think my next step is probably to buy a Delco ICM just to take that variable out of it, the spark plug wires are brand new Delcos so I really don't think they're causing the problem. |
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New, out of box parts can be bad. It happens. At least the wires are easy enough to test with a multimeter.
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sdgdf
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AUG 18, 03:09 PM
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| quote | Originally posted by Nytfury:
I checked it today and it doesn't feel like there's anything lose inside the cat, you have any other ideas? |
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Get rid of the cat. 
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Patrick
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AUG 18, 04:23 PM
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| quote | Originally posted by sdgdf:
Get rid of the cat.
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That's crap advice.
Why get rid of a functional component that does nothing to impair engine performance while at the same time reduces engine emissions? If the cat has been compromised in some manner, that's a completely different situation.[This message has been edited by Patrick (edited 09-18-2023).]
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Nytfury
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AUG 19, 07:15 PM
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| quote | Originally posted by Patrick:
You haven't given us much to work with. No mention made of year, of engine, of spark plug wire condition, of spark plug condition, of fuel pressure etc.
Basic maintenance needs to be done, and a scanner or laptap with WinALDL (and cable) will tell you what information your ECU is getting from the sensors.
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87 gt 2.8 128,000 miles, brand new plug wires, spark plugs are fairly new and good, fuel pressure is good. Basic stuff has been done, grounds have been checked and I even added some additional ground cables, the harness has been checked and all the connections are good. new coil, distributor cap and rotor. I have a GM ICM in the mail now aswell as a ACDelco upgraded map sensor (even if it isn't the problem I've seen some people say it helps the "hunting idle" issue which mine does) I'm usually able to troubleshoot problems reasonably easily by myself so I'm not as good at communicating all the info sorry. I have an OBD2 scanner so I figure that won't work, I'll try to find an adapter
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Nytfury
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AUG 19, 07:20 PM
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| quote | Originally posted by sdgdf:
Get rid of the cat. |
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I have thought about doing this, because I have a little shudder while cruising and have heard that could be a cat issue, but I don't suspect it to be the issue in this case.
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Nytfury
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SEP 18, 09:17 PM
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I figured i'd continue this, still having problems even with the car. I have good fuel pressure (43 psi prime and about 36 at idle), I checked my MAP sensor readings and they are spot on. The way the car feels when it starts running poorly is similar to if I remove one of my fuel injector bank fuses, but I've checked all the injectors and actually had them out and cleaned them not too long ago. Tested the wires running to the injectors and they have about 11v source with the car off so it should be acceptable. I am close to trying to find an ECM to swap in just to confirm that's not it. The worst part is its completely random when it decides to run bad, one drive it will run perfect and go right up to speed and idle smooth, but then randomly when I start it after letting it set overnight it feels like I'm running on 3 cylinders.
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Vintage-Nut
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SEP 19, 08:08 AM
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Without Any ECM Diagnostics Codes?
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82-T/A [At Work]
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SEP 19, 09:09 AM
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| quote | Originally posted by Patrick:
That's crap advice.
Why get rid of a functional component that does nothing to impair engine performance while at the same time reduces engine emissions? If the cat has been compromised in some manner, that's a completely different situation.
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We don't know what kind of cat he has... but I definitely recommend replacing the catalytic converter if he has one of these (which was factory):
These cats are the older charcoal "pellet style" of catalytic converters which were factory on I ... THINK? all Fieros? I know every 84 that I've had has had one of these. But I can't remember if any of my V6s have had them...
But it's the much much older style of cat. They are far less likely to clog, but they are more restrictive... and actually aren't as efficient in converting the emissions to less harmful gasses as the newer ones are anyway.
I think there's a happy medium for catalytic converters that can benefit both emissions and performance. On my 2006 Pontiac Solstice (years ago), I replaced the factory catalytic converter (which was the newer style), with a free-er flowing 300cfm catalytic converter. It made an ENORMOUS difference in performance from the mid to upper RPMs. I think to some degree, the 1-7/8ths inch exhaust piping is just a little bit too small for the V6 Fiero also... and when upgrading to a ~2" or a little larger, it makes sense to go with a larger flowing cat too.
EGR though... man, that's just old technology. When I replace the ECM / engine control system in my 87 Fiero... I'm going to disable the EGR, and the cold start injector as well. I know the EGR can be used to "cool" the engine as well, but that can also be done with a better air/fuel mixture.
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Nytfury
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SEP 19, 02:08 PM
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| quote | Originally posted by Vintage-Nut:
Without Any ECM Diagnostics Codes? |
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I will double-check them later, but the CEL stays off when it's doing it.
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