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
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.
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)
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.
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
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
But you can't drive > 35mph mean IAC did not reset often causes High Idle because ECM just guessing to keep running.
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
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 $$$ is on the EGR tube. It passes exhaust gasses through it, so the longer it runs, the more it expands, and that likely makes the crack bigger. Short term you can remove the tube and install block off plates - the tube will have to be ordered https://rodneydickman.com/a...809df327005e765548ca
ICM - as mentioned, themal compound and grounds are the two biggest killers. My guess is you have a ground issue... especially if you had the heads off.
Fan running all the time... don't worry about that now, the other two are keeping you from driving the car. The relay is grounded to trigger the fan, either from the HVAC controls, the ECM, the temp switch, or owner installed fan switch/jumper wire. Disconnect one at a time till the fan stops to find the cause.
High idle is a vacuum leak. Since you had the heads off, it very well could be the EGR tube. When these get old, just looking at them sideways will make them crack. Could also be the brake booster hose or the hose from the throttle body to the intake, but my $$$ 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.
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,
Okay, lets slow down and take a breath before we go tearing any more components off the car.
I just did up the top of my 2.8 so all this is fresh in my head.
First thing I want you to do is get the ICM running right. Make sure you use thermal grease when you install it. Make sure the contacts on your connectors are clean (Higher resistances means high load across the ever fragile ICM.) Make sure your plugs are in good shape and gapped appropriately.
Dont worry about the high idle or the fan until this is done. Period.
Once that is done, start the engine, when it starts high idling block the intake of the throttle body. That baby should be sucking hard and when you palm closes off the port it that engine should stall almost immediately. If it doesn't, or sputters a bit before stopping, you have a vacuum leak. Usually when this happens it will be accompanied by a hiss since wherever the leak is will be trying to draw a ton of air. (I am shooting from the hip and guessing its either a cracked line, or the metal tube for the IAC that goes into the back of the throttle body.) The fierostore METAL line kit is worth every penny, I put them on my 2.8
Okay, lets slow down and take a breath before we go tearing any more components off the car.
I just did up the top of my 2.8 so all this is fresh in my head.
First thing I want you to do is get the ICM running right. Make sure you use thermal grease when you install it. Make sure the contacts on your connectors are clean (Higher resistances means high load across the ever fragile ICM.) Make sure your plugs are in good shape and gapped appropriately.
Dont worry about the high idle or the fan until this is done. Period.
Once that is done, start the engine, when it starts high idling block the intake of the throttle body. That baby should be sucking hard and when you palm closes off the port it that engine should stall almost immediately. If it doesn't, or sputters a bit before stopping, you have a vacuum leak. Usually when this happens it will be accompanied by a hiss since wherever the leak is will be trying to draw a ton of air. (I am shooting from the hip and guessing its either a cracked line, or the metal tube for the IAC that goes into the back of the throttle body.) The fierostore METAL line kit is worth every penny, I put them on my 2.8
gonna be regrounding the engine before doing any of that since the factory ground is no longer continous when we tried to start it the other day, and since someone's been using butt connectors on most of the connectors I'll be sautering solid connections there instead. I am suspect of the computer since a shift cable gasket has been bad for an unknown amount of time. note: we bought this for 5k and we were told "Oh yeah you can drive it across the country right now" and after it broke 5 times we got to drive 400 miles home. now to be fair to the guy we got it from a hose and a shift cable end breaking over and over were not his fault
gonna be regrounding the engine before doing any of that since the factory ground is no longer continous when we tried to start it the other day, and since someone's been using butt connectors on most of the connectors I'll be sautering solid connections there instead. I am suspect of the computer since a shift cable gasket has been bad for an unknown amount of time. note: we bought this for 5k and we were told "Oh yeah you can drive it across the country right now" and after it broke 5 times we got to drive 400 miles home. now to be fair to the guy we got it from a hose and a shift cable end breaking over and over were not his fault
Cleaning/repairing the grounds and soldering connections is good. Worrying about the computer is not. Don't overcomplicate your procedures. My 86 GT had no grommets between the firewall and the computer, the center carpet was wet and ruined when I pulled it out of the junk yard and the computer was perfect. Finish the grounds and other connections, they follow my instruction in the previous post. If you allow your mind to race and start replacing stuff that isnt bad this is going to get even more frustrating and expensive. You probably just have a vacuum leak. . .
Absolutely check grounds. Had a very similar problem with my 2.8 ICM. Gave up on it and swapped in a 3800 but found I was missing my engine to body and body to frame grounds in the process. I already bought the parts so the engine still got swapped. It was annoying to see that I could've saved some time and money but just looking for grounds first though.
Absolutely check grounds. Had a very similar problem with my 2.8 ICM. Gave up on it and swapped in a 3800 but found I was missing my engine to body and body to frame grounds in the process. I already bought the parts so the engine still got swapped. It was annoying to see that I could've saved some time and money but just looking for grounds first though.
in that case this car has always been missing a ground and the only one looks like crap, it only has an engine to battery cable style ground, do time to run 5 different grounds to everything that draws major power and at least a good 00 gauge wire to the body
Originally posted by Dukesterpro: Cleaning/repairing the grounds and soldering connections is good. Worrying about the computer is not. Don't overcomplicate your procedures. My 86 GT had no grommets between the firewall and the computer, the center carpet was wet and ruined when I pulled it out of the junk yard and the computer was perfect. Finish the grounds and other connections, they follow my instruction in the previous post. If you allow your mind to race and start replacing stuff that isnt bad this is going to get even more frustrating and expensive. You probably just have a vacuum leak. . .
just gonna reground the engine since it smoke tested with no leaks for the vaccum so I'm pretty sure since it's only an issue when its warm it's the ecm attempting to learn or go into full closed loop and getting wonky **** since this car has never had at least one of its engine grounds
