Help Please

[84VetteXram]

I am brand new to the forum. Have worked on cars since I was a kid but nothing really big. Basically enough knowledge to be dangerous. My current issue(s) started out and continues to be a high idle issue, 1100-1900.


A few weeks back it threw a code 22. I replaced the TPS, code went away but the idle issue continued. I replaced the IAC's, coolant temp sensor and the high idle continues. It seems to be sporadic, once warmed up and driven a bit, it will settle down to around 1000, which actually seems normal, but, I know it is not. So, anyway the other day the code 22 came back. I went through the FSM diagnostics and everything checks out until diagnosing circuit 417.


I will admit I am an idiot on electrical issues so please bear with me. When I disconnect the white ECM connector and check for open or short to ground, I get open (DVM set to ohms). But, I am not sure what that means? It says if circuit 417 is OK, then it is faulty ECM connector pin 5 or ECM. Does open mean it is ok?


I have ordered an ALDL USB connector to get more data.


In the meantime I decided to clean up the tangle of wires around the distributor. The car has been modified with an Xram and some other ignition modifications (I think). I decided I want to get rid of all the Accel add ons since I use this vehicle on the road and have no interest in tracks.


In the distributor there is an Accel Performance Control Module (35363), there is also an Accel 300+ Racing Ignition. I was thinking to get rid of the Racing Ignition anyway, I guess the Control Module would need to be replaced so I would just leave it in there.


My question on the Accel 300+ is. Can I simply take that out? If I can how would I connect the wires? I do have the FSM and will look there as I wait for the ALDL to arrive to troubleshoot the high idle issue.


In the meantime, thanks for any advice. I will post updates and hope to add some value back in the future.

 

[Hot Rod Roy]

The first thing to check when you're fighting a high idle is a vacuum leak. Is this a new problem, or have you been fighting this since the X-Ram was installed? The gasket surface between the intake manifold and the top plate is a notorious spot, but there are plenty of other potential locations!

 

[Toms007]

First off Welcome to CAC....

While reading your post, the first thing I thought was "a vacuum leak". I believe those were notorious for them. But Roy already covered that. Thanks you Roy.

 

[Hib Halverson]

We can be of more help to you if we knew what model year Corvette on which you are working.

As for the "open" in circuit 417...if that circuit if open (ie: infinite resistance) that is not ok. It means somewhere in circuit 417, the circuit is broken and has no continuity. You need to repair that then road test.

On replacing the TPS...some model years require adjustment of the TPS after installing a new sensor. Check your Service Manual to see if that is necessary.

 

[Toms007]

I assumed (maybe wrongly), by his username, 84VetteXram, that his Corvette is an 84 crossfire....Maybe I am missing something.

 

[LLC5]

I am brand new to the forum. Have worked on cars since I was a kid but nothing really big. Basically enough knowledge to be dangerous. My current issue(s) started out and continues to be a high idle issue, 1100-1900.


A few weeks back it threw a code 22. I replaced the TPS, code went away but the idle issue continued. I replaced the IAC's, coolant temp sensor and the high idle continues. It seems to be sporadic, once warmed up and driven a bit, it will settle down to around 1000, which actually seems normal, but, I know it is not. So, anyway the other day the code 22 came back. I went through the FSM diagnostics and everything checks out until diagnosing circuit 417.


I will admit I am an idiot on electrical issues so please bear with me. When I disconnect the white ECM connector and check for open or short to ground, I get open (DVM set to ohms). But, I am not sure what that means? It says if circuit 417 is OK, then it is faulty ECM connector pin 5 or ECM. Does open mean it is ok?


I have ordered an ALDL USB connector to get more data.


In the meantime I decided to clean up the tangle of wires around the distributor. The car has been modified with an Xram and some other ignition modifications (I think). I decided I want to get rid of all the Accel add ons since I use this vehicle on the road and have no interest in tracks.


In the distributor there is an Accel Performance Control Module (35363), there is also an Accel 300+ Racing Ignition. I was thinking to get rid of the Racing Ignition anyway, I guess the Control Module would need to be replaced so I would just leave it in there.


My question on the Accel 300+ is. Can I simply take that out? If I can how would I connect the wires? I do have the FSM and will look there as I wait for the ALDL to arrive to troubleshoot the high idle issue.


In the meantime, thanks for any advice. I will post updates and hope to add some value back in the future.

Make sure that your throttle plate is shutting all the way closed at idle, carbon build up, adjustments, or damage are the most common reasons. If it is not shutting completely, your idle speed will be high and you will set a tps code.

 

[bill81vette]

Welcome to CAC!!!
enjoy!!

 

[DonB]

Welcome to the forum. There are some very smart and dedicated people here that love to help keep Corvette's in "Tip-Top" shape. Good Luck