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88 GL High Idle Issues


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Hey Everyone,

 

So I've been having this issue for a while now. While I'm in neutral, by pushing in the clutch or sitting in neutral the idle will spike to around 3,000 and slowly drop down to around 1,500. I've also been having this issue where upon first starting the car I have to hold down the gas pedal until some gas moves through the system or the car will die. Once it's running for a minute, it generally stays around 1,000-1,500. Not sure if these issues are linked, but I thought it would be good to give a little history of what it has been doing.

 

I did change the intake manifold gaskets about a week ago, but it was doing this before that anyway. Let me know what you think. If anyone can link to another thread if this question has been asked that would be great too. I can never find info using the search bar.

 

this is that it's doing ---> 

Edited by YnotDIY
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Your idle speed control is sticky.Clean it w/carb cleaner.

 

Holding the gas pedal down w/starting CUTS OFF the GAS.

It is not starting normally because there is too much gas.

 

You might also have a leaky injector(look for dripping after shutdown) or corrosion on the coolant temperature sensor connection.

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Idle air control valve and or the coolant temperature sensor.

 

Wouldn't hurt to check both.

 

hmmmm good time to note I actually removed my coolant temp sensor when I put in a new radiator a week ago. The one I had was corroded and it was actually cheeper to wire the radiator fan to a switch. I know people have done this before. Could this be my issue? Any way past it since I no longer have one plugged in? I'll check the AIC too. Could a vaccum leak casue this?

Edited by YnotDIY
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Your idle speed control is sticky.Clean it w/carb cleaner.

 

Holding the gas pedal down w/starting CUTS OFF the GAS.

It is not starting normally because there is too much gas.

 

You might also have a leaky injector(look for dripping after shutdown) or corrosion on the coolant temperature sensor connection.

 

I think we are missing eachother. I'm not actually holding the gas pedal down while I start the car....rather after I start the car I have to hold it down for a bit to keep it idling. Then after maybe a minute it usually idles normally. I was also thinking maybe fuel pump? but I'm really just guessing. Is the idle speed control different form the idle air control? sorry I'm mostly a novice at this.

Edited by YnotDIY
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The CTS [coolant temperature sensor] is the 2 wire sensor on the lower part of the thermostat housing.  The ECU uses it to monitor the engine temperature, and adjust the fuel mix for temperature.  It dopes the job of a choke on old carburetor engines.

 

The thermoswitch on the radiator only turns the fan on and off.

 

The 1 wire temperature sensor on the thermostat housing only operates the temperature gauge on the dash.

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ahhhh DaveT thanks for the clarification. You're always coming through for me. Whenever I look up CTS it gives me the rad thermo switch as an image. I'll check mine out and see what it's looking like. Any chance someone could post a link for me to an aftermarket one? thanks in advance.

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So I think my issue might be that wires that are starting to pull away from the plug for the Idle Air Control Valve  :banghead: . The ones that are pulling away are not coming fro m the IAC itself, but from the plug on the car side. I want to make them more secure by cutting into them and adding more wire, but the frayed parts are literally NEXT to the plug...like they want to back out of it. any idea on how to fix this anyone? Is it possible to take apart the plug and fix the wires that way? Any help would be appreciated. Hell if anyone wants to snip a plug with a lot of extra wire from a car they arent using ill take it!  :D​ 

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  • 2 weeks later...

Just wanted to update this incase anyone ever searches it. I ended up taking the car into the shop (plz don't kill me) because I have no time to mess with it due to school. Anyway long story short...they told me they are stumped. Said they didn't know how to find codes for it and that they couldn't get it to idle high. Then they said they could, but it went back to normal. Called them and told them how to get the codes (via a thread from here ((thanks ya'll)) ), but it was wild for me to get that call. I've never heard of an auto shop being stumped with a car. I suppose there's a first time for everything. I'm pretty sure I'm dropping the car off the JimBo so he can take a look at it. Ya'll would know him as The Desert Fox with his 84 DL. Hopefully he has some insight. The novice here is pretty lost atm.

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It's roughly 30 years old.  You have to find a mechanic at a shop that is likely over 45 plus to have experience working on them when they were new.  About 10 years ago, they were pretty much gone from my area, I doubt there are many around here that would know how to deal with the systems that old, except odd specialty guys, and a few of us nuts on forums.

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More news, car is flashing error code 34 EGR solenoid. DaveT I saw on your website an EGR swap to a toyota one. Any idea what yr that might have been? Would it be possible my symptoms could be caused by the solenoid? Also, guy at the shop told me the IAC is reading 11+ volts when it should be around 10V. actually he said it should read 1V with key in on position for 1min. then switch to 10V like normal. He said it always reads over 10V and never reads at 1V. Thinks it could be ECU related...insights anyone?

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Back when I wrote that page, the years between the car brands were about the same.

 

The year isn't critical. Size of the solenoid and the ports you want similar. Pretty much anything from 80s through 90s likely had one or more. The junkyard I got them at let me go wander with a wrench and I gathered around 10 various units. Still using the same ones today.

 

I have never experienced any noticeable to the driver symptoms associated with the 34 code. Code 34 says the solenoid coil is open or shorted, or the wiring to it. It will fail emissions testing.

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More news, car is flashing error code 34 EGR solenoid. DaveT I saw on your website an EGR swap to a toyota one. Any idea what yr that might have been? Would it be possible my symptoms could be caused by the solenoid? Also, guy at the shop told me the IAC is reading 11+ volts when it should be around 10V. actually he said it should read 1V with key in on position for 1min. then switch to 10V like normal. He said it always reads over 10V and never reads at 1V. Thinks it could be ECU related...insights anyone?

 

Somebody needs to check continuity of the white wire between the idle control and pin 45 of the ECU before condemning the ECU.

Wire turns to GR on the ECU side of the connector.

 

The 10-11 volt dilemma is pure bullshit.

 

An inoperable EGR will lead to detonation at cruising speed.

I have a solenoid if needed.

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  • 2 weeks later...

DaveT is this the one you snagged from the dealer? I want the SPI one I believe. Is that for Single Point Injection? Thanks for all the help ya'll. The plan is to swap that CTS and fingers crossed that fixes the issue. I have found no vacuum leaks and for now the solenoid seems to be working although I'm planning to swap that out as well when I have the time. If anyone can confirm this is the part I need that would be awesome. 

 

https://parts.subaru.com/p/Subaru_1988_DLGLGL10RSRX-WAGON-TURBO/SENSOR-ASSEMBLY-TEMPERATURE/49232416/22630AA030.html

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Alright update on my idle issue....so Ive noticed after a short drive, say 10min. to the store, when I come back to start the car it usually fires then stalls out. To get it to fire I have to HOLD DOWN the gas pedal until it starts then I can let off. When I have to start it this way HOLDING DOWN THE PEDAL the idle gets all wild. it will idle at around 2,000 and even a little blip on the gas will send the idle to 3,000 for a while until it comes to rest at 2,000.

 

NOW CHECK THIS

 

While it's RUNNING I unplug the IAC connection and it goes to idle at around 500. Next, I turn off the car. With the IAC still unplugged I try to start it (nothing of course). THEN plug the IAC back in, go to start again and it's idling normally around 500 or so. 

 

What's up with this? This method for "re-setting" the idle has worked nearly every time. Am I letting the computer re-calibrate something with this method of trying to start with IAC un-plugged?

 

I have a new Coolant Temp Sensor on the way (only $89), but I was thinking maybe it's a distributor issue or something? 

 

If this sparks anyones mind please let me know.  I'll update as I find out what's up with this.

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Somebody needs to check continuity of the white wire between the idle control and pin 45 of the ECU before condemning the ECU.

Wire turns to GR on the ECU side of the connector.

 

The 10-11 volt dilemma is pure bullshit.

 

An inoperable EGR will lead to detonation at cruising speed.

I have a solenoid if needed.

 

Naru,

 

I'm going to check for a toyota solenoid at the yard here this week. If one doesn't turn up can you send one to Michigan? $$$?

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  • 2 weeks later...

Just to update this thread I swapped to the new coolant temp sensor (the two wire one by the thermostat) and it fixed my issues greatly. There is still a little issue with the idle, but it is no where near as bad as it was so most of my problems were with the CTS. I'll update again as I swap EGR Solenoid and other idle related parts down the road. Thanks everyone for the help.  

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