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| reaching my wits end with this one (Page 1/2) |
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cartercarbaficionado
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NOV 25, 09:35 PM
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I've tried and tried and tried and I can't get this thing to run right anymore, a new icm makes it run so much better but the icm burns out or somehow fails within a few hours of it being installed and when it warms up it keeps idling up more and more til its sitting at 2500 rpm and the only reason its not higher is i turned the minimun air screw all the way out since it was at 4000 rpm and now for whatever reason the rad fans are stuck on. I just helped my friend fix it and there's like 1500 into a car that cost 5k, any help is appreciated
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lateFormula
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NOV 25, 11:08 PM
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First and foremost, you're missing at least one valve cover. That's not good, you need the valve covers.
ICM - Any quality ICM should come with a packet of thermal grease, which needs to be applied to the metal surface on the bottom side of the ICM. You can always use a silver containing thermal paste for a computer processor for improved heat transfer. If you do not apply the thermal paste, the ICM will fail in short order.
Idle speeding up - If the idle goes up rapidly after starting, like if you were to push on the accelerator pedal; that would indicate a vacuum leak on the intake. Those intakes have several vacuum hoses and multiple gaskets where a leak could be present. Now if the idle increases slowly over a few minutes, that would point to a throttle position sensor that is questionable, and likely changing it's signal to the ECM as it warms up.
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Patrick
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NOV 26, 12:53 AM
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| quote | Originally posted by cartercarbaficionado:
...i turned the minimun air screw all the way out since it was at 4000 rpm
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There is no "minimum air screw" on that engine. Sounds like you've only complicated things by messing with the factory set throttle plate stop.
| quote | Originally posted by cartercarbaficionado:
... and now for whatever reason the rad fans are stuck on.
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Turn the A/C off.[This message has been edited by Patrick (edited 11-26-2023).]
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theogre
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NOV 26, 08:15 AM
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& now you mess w/ "minimum air screw" will need to set it right after you problem is fixed.
see https://web.archive.org/web...erocave/idlestop.htm
ICM is installed wrong as above said or burn from other parts being bad.
see https://web.archive.org/web...t/~fierocave/hei.htm
High idle often = vac leaks
see cave vac leaks
But you can't drive > 35mph mean IAC did not reset often causes High Idle because ECM just guessing to keep running.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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cartercarbaficionado
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NOV 26, 08:55 AM
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| quote | Originally posted by lateFormula:
First and foremost, you're missing at least one valve cover. That's not good, you need the valve covers.
ICM - Any quality ICM should come with a packet of thermal grease, which needs to be applied to the metal surface on the bottom side of the ICM. You can always use a silver containing thermal paste for a computer processor for improved heat transfer. If you do not apply the thermal paste, the ICM will fail in short order.
Idle speeding up - If the idle goes up rapidly after starting, like if you were to push on the accelerator pedal; that would indicate a vacuum leak on the intake. Those intakes have several vacuum hoses and multiple gaskets where a leak could be present. Now if the idle increases slowly over a few minutes, that would point to a throttle position sensor that is questionable, and likely changing it's signal to the ECM as it warms up. |
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was doing valve lash since i did a headjob and that's the last picture I have of the car since I left it parked in a garage ignoring it for the sake of my mental health, I purchased the acdelco icm and the cheapo duralast one and so far the one the car came with (delphi) is the only one that works but the car runs like garbage and has no power.
and I figured it's probably the sensor but it doesn't matter if it's unplugged or not and is the only one the car will work with for whatever reason? I've tried 3 or 4 now and they just don't do anything at all, at least when I advance the arm on this one at idle the engine idles up a bit then falls on its face due to lack of fuel and air
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cartercarbaficionado
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NOV 26, 08:57 AM
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| quote | Originally posted by Patrick:
Turn the A/C off.
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I may be new here but I'm not quuuite that dumb. I have turned the ac off and the fan will kot turn off unless I undo the power wire making me think maybe the sender has shorted somehow. also the air screw on the throttle body somebody called the minimum air screw with the guide on how to tune it
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cartercarbaficionado
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NOV 26, 09:01 AM
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I've reset it multiple times and set it using the factory adjustment method and the "tried and true" method that involves undoing the iac and making the engine idle with that screw at 550 rpm
as for the icm why is one just fine but it keeps killing or messing with other ones?
also wouldn't a vacuum leak be all the time and I have driven the car like this since it was my only car at the time so I know the iac is correctly tuned. I also did the short pins on the ALDL connector and letting the motor run before driving it method. it's not like I went here first I did try to repair it myself correctly
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fieroguru
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NOV 26, 09:33 AM
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Focus on 1 issue at a time.
High idle is a vacuum leak. Since you had the heads off, it very well could be the EGR tube. When these get old, just looking at them sideways will make them crack. Could also be the brake booster hose or the hose from the throttle body to the intake, but my $$$ is on the EGR tube. It passes exhaust gasses through it, so the longer it runs, the more it expands, and that likely makes the crack bigger. Short term you can remove the tube and install block off plates - the tube will have to be ordered https://rodneydickman.com/a...809df327005e765548ca
ICM - as mentioned, themal compound and grounds are the two biggest killers. My guess is you have a ground issue... especially if you had the heads off.
Fan running all the time... don't worry about that now, the other two are keeping you from driving the car. The relay is grounded to trigger the fan, either from the HVAC controls, the ECM, the temp switch, or owner installed fan switch/jumper wire. Disconnect one at a time till the fan stops to find the cause.
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Patrick
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NOV 26, 05:46 PM
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| quote | Originally posted by cartercarbaficionado:
also the air screw on the throttle body somebody called the minimum air screw with the guide on how to tune it
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Whoever this "somebody" is, ignore any future Fiero advice from them.
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cartercarbaficionado
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NOV 26, 09:09 PM
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| quote | Originally posted by fieroguru:
Focus on 1 issue at a time.
High idle is a vacuum leak. Since you had the heads off, it very well could be the EGR tube. When these get old, just looking at them sideways will make them crack. Could also be the brake booster hose or the hose from the throttle body to the intake, but my $$$ is on the EGR tube. It passes exhaust gasses through it, so the longer it runs, the more it expands, and that likely makes the crack bigger. Short term you can remove the tube and install block off plates - the tube will have to be ordered https://rodneydickman.com/a...809df327005e765548ca
ICM - as mentioned, themal compound and grounds are the two biggest killers. My guess is you have a ground issue... especially if you had the heads off.
Fan running all the time... don't worry about that now, the other two are keeping you from driving the car. The relay is grounded to trigger the fan, either from the HVAC controls, the ECM, the temp switch, or owner installed fan switch/jumper wire. Disconnect one at a time till the fan stops to find the cause. |
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it's looking like it's a replacement tube already and possibly a stainless one though j was gonna remove the egr eventually anyways since the evap system has been renoved correctly, also yeah I'm thinking it's ground d the more and more I think about it, though I wonder why it won't kill the Delphi part,
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