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High Idle Occasionally


Chriskaw440
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Have you guys tried replacing the TPS?

 

 

I have not done it yet. hopefully i will get to it this weekend. I don't think it has anything to do with my check engine light, But it does not hurt to replace it since I already have it.

 

I have not looked at what it takes to replace it, But it does not seem so hard judging by its location. However not sure if there is any adjustments are needed.

 

I will update when I get it done

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sound like it is similar to what I am going through. except I get a code 45 leaking injector.

 

I have cleaned out all carbon from the entire intake. it behaves for a couple of weeks and then acts up. I get the high idle then sometimes I get a low idle like it wants to die. I am baffled

 

 

I have a feeling we actually do have the same problem, The reason you do not get a code is because that code is only on California Vehicles.

 

so we need to get together and go over what each of us have tried to solve the problem and hopefully we can both can find the solution to the problem.

 

Does you vehicle also have times where the idle drops low and starts to act like it is going to stall. or do you just have the high idle problem.

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sound like it is similar to what I am going through. except I get a code 45 leaking injector.

 

I have cleaned out all carbon from the entire intake. it behaves for a couple of weeks and then acts up. I get the high idle then sometimes I get a low idle like it wants to die. I am baffled

Have you checked your MAF sensor? You know how the wiring can be wiggled and it will work right again. Mine would go up and down then stall sometimes.

 

I have a feeling we actually do have the same problem, The reason you do not get a code is because that code is only on California Vehicles.

 

so we need to get together and go over what each of us have tried to solve the problem and hopefully we can both can find the solution to the problem.

 

Does you vehicle also have times where the idle drops low and starts to act like it is going to stall. or do you just have the high idle problem.

I don't think it is only for cali vehicles as I have gotten it on my 95 XE here in canada. I think I remember you telling me the procedures for testing it. I had the catalytic converter replaced and it hasn't come back since. It used to come on every few months but it hasn't in a long time now since the replacement.

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Have you checked your MAF sensor? You know how the wiring can be wiggled and it will work right again. Mine would go up and down then stall sometimes.

 

 

I don't think it is only for cali vehicles as I have gotten it on my 95 XE here in canada. I think I remember you telling me the procedures for testing it. I had the catalytic converter replaced and it hasn't come back since. It used to come on every few months but it hasn't in a long time now since the replacement.

 

 

My 1991 nissan manual clearly states that federal emissions vehicles do not have the code 45 leaking injector. Don't know where canada falls in that though.

 

However they may have made a change to add that to later models. I do not have a later model so I cannot confirm.

 

 

and Yes I have checked the MAF wiring. I even hooked Up my spare MAF to it and I still get the error.

Edited by msavides
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My 1991 nissan manual clearly states that federal emissions vehicles do not have the code 45 leaking injector. Don't know where canada falls in that though.

 

However they may have made a change to add that to later models. I do not have a later model so I cannot confirm.

 

 

and Yes I have checked the MAF wiring. I even hooked Up my spare MAF to it and I still get the error.

 

 

Mine never acts like it wants to stall.....either always about 800 rpm....or sputtering just over 1000...and the usual sometimes almost 2000 steady, then after a minute or two or three.....gradually falls back down to normal. Its been better since all my work....but still something not quite right.

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Mine never acts like it wants to stall.....either always about 800 rpm....or sputtering just over 1000...and the usual sometimes almost 2000 steady, then after a minute or two or three.....gradually falls back down to normal. Its been better since all my work....but still something not quite right.

 

 

After reading mu nissan repair manual there are 4 conditions to cause the aac to adjust your idle up.

 

Ac turned on

steering wheel turned quickly

electric defroster turned on

Headlights on high beam

 

there is instructions on how to test to see if your aac is getting the signal to up your idle. I don't remember off hand

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After reading mu nissan repair manual there are 4 conditions to cause the aac to adjust your idle up.

 

Ac turned on

steering wheel turned quickly

electric defroster turned on

Headlights on high beam

 

there is instructions on how to test to see if your aac is getting the signal to up your idle. I don't remember off hand

 

 

yep, and thats what the AAC (Iac) is suppose to do...adjust the idle speed up a notch to compensate for the extra load placed on the engine by the accessories.

 

it should adjust up just a few rpm's though.....not nearly 1000 rpms LOL

 

My AC is not even working or connected (no belt either)

 

maybe one day I will test it with my special tool...........the sledge hammer in the back shed.

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yep, and thats what the AAC (Iac) is suppose to do...adjust the idle speed up a notch to compensate for the extra load placed on the engine by the accessories.

 

it should adjust up just a few rpm's though.....not nearly 1000 rpms LOL

 

My AC is not even working or connected (no belt either)

 

maybe one day I will test it with my special tool...........the sledge hammer in the back shed.

 

I Think my Idle problem is fixed. I went on a wheeling trip today and i had a perfect Idle all day. No issues at all.

 

The part I replaced was indeed the TPS. It is a total PITA to adjust though. took about 30 tries an almost 2 hours.

 

now i just need to get rid of that check engine code 45 problem.

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finally...lol...can you give us some pointers on adjusting the tps bud?

 

 

i wish i had some times that could magically make it easy to adjust. However only adjusting one of them does not make me a pro. It would take me just as long to do another one I am sure. The only thing I can say that can help is IT IS A PAIN IN THE A$$. Sometimes being mentally prepared for a battle is better than what happened to me. Thinking it is just 2 screws and that it was going to be a simple thing and then reality slaps me in the face and says OH no your going to have to work to get this thing fixed.

 

However if you are an extremely patient person who is unflappable in the face of failure (like the person who can build a house of cards and when they fall can just start right over again without getting pissed off.) This job is for you.

 

basics of the install is this.

replace the sensor with a new one. tighten the screws enough to still allow the sensor to move. The hook a ohm meter to the top 2 pins on the sensor itself (not the wiring harness connector)

disconnect your aac harness connector (on the top front passenger side of the engine should be 4 plugs there, it is the 2 pin plug)

start the engine

set your idle to be 700-750 rpm (Manual Transmission) using the screw on the manifold drivers side next to firewall.

(screw turns toward the firewall lowers idle screw toward the front of the engine raises idle)

there should be continuity with the accelerator pedal in rest position and it should be open at your base idle plus 250rmp + or - 150rpm

 

So if you set your base idle at 750 you should make sure that sensor is open at 1000rpm + or - 150rpm but have continuity when the pedal is released.

 

Sounds Easy! Unless you are extremely Lucky (like win the lottery Lucky) your going to be playing with this for a really long time.

 

after it is set. turn off the engine. reconnect the AAC and connect the new tps to the tps harness and the tps sensor plug. (do not do this with the engine running or your ECU will wig out and give you a high idle about 2000 rpm.

Edited by msavides
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  • 3 weeks later...

Go to Harbor Freight and pick up a cheap-o multimeter. They are only a few bucks and cover all the general functions - volts AC and DC, amps, ohms (resistance), etc. Definitely a handy tool...

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I finally got my new TPS in the mail today......now to see if I have the patience to deal with it. Guess I need to go buy an Ohm Meter too.....

 

 

I wish you luck.

 

And my idle has been still perfect.

 

 

Stupid check engine light!!

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thanks! found both my volt meters finally and did more research on replacing the TPS....hopefully it will go well.

 

Mine doesn't have a check engine light...its the old school red and green flashing lights on the module under the passenger seat...but thankfully

all is normal.

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success. First try. took about 20 minutes. I did my best to set the new sensor to the same position the old one was in with a flat head screwdriver (turning the mechanism the throttle plate shaft goes into on the sensor) attached to the throttle body in as close to the same position as old one was in also...set idle speed, shut off engine, reconnected everything, started up, test drove for a few miles, drives great....got my idle just a tad higher than 750....more like about 760 but I can live with that. Checked ECU for codes..."55" (all normal) Truck seems happy so I'm happy.

 

Now I'm going to go do yard work....

 

Oh and the new sensor was only $11.65 (beck arnley) on closeout at Rock Auto parts. (for 5 speed manual)

Edited by Chriskaw440
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success. First try. took about 20 minutes. I did my best to set the new sensor to the same position the old one was in with a flat head screwdriver (turning the mechanism the throttle plate shaft goes into on the sensor) attached to the throttle body in as close to the same position as old one was in also...set idle speed, shut off engine, reconnected everything, started up, test drove for a few miles, drives great....got my idle just a tad higher than 750....more like about 760 but I can live with that. Checked ECU for codes..."55" (all normal) Truck seems happy so I'm happy.

 

Now I'm going to go do yard work....

 

Oh and the new sensor was only $11.65 (beck arnley) on closeout at Rock Auto parts. (for 5 speed manual)

 

 

Cool.. Got out an get a lotto ticket now. Your extremely lucky.

 

I got the same deal at rock auto in November. I did not think they had anymore. But good score.

 

Mark

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Cool.. Got out an get a lotto ticket now. Your extremely lucky.

 

I got the same deal at rock auto in November. I did not think they had anymore. But good score.

 

Mark

 

 

I was just saying to myself...."oh please oh please just work ...." Drive around a lot early today and it seemed ok. sometimes it pauses at 1000 rpms as it drops from driving speed, and then settles right at about 760 rms nice and smooth. With 252,000+ miles on the engine...I know it will never be pefect again but at least it seems like the wild rpm days are behind me now....finally.

 

so this spring I replaced: all hydraulic lifters, new plenum gasket (of course), all new vacuum lines, new spark plugs, new power steering high pressure line, new IAC valve, new distributor cap & rotor (today), seafoamed intake system (via brake booster vacuum....lots of pretty white smoke!)

 

I may replace the EGR stuff since I believe its all original.....next pay day

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I was just saying to myself...."oh please oh please just work ...." Drive around a lot early today and it seemed ok. sometimes it pauses at 1000 rpms as it drops from driving speed, and then settles right at about 760 rms nice and smooth. With 252,000+ miles on the engine...I know it will never be pefect again but at least it seems like the wild rpm days are behind me now....finally.

 

so this spring I replaced: all hydraulic lifters, new plenum gasket (of course), all new vacuum lines, new spark plugs, new power steering high pressure line, new IAC valve, new distributor cap & rotor (today), seafoamed intake system (via brake booster vacuum....lots of pretty white smoke!)

 

I may replace the EGR stuff since I believe its all original.....next pay day

 

 

The pause at 1000 rpm is normal in a manual. From what I was told it is controlled by the ecu to allow for better syncro shifting. after a few sec it figures out that you are not going to shift and settles down to normal idle. I am thinking of putting in a federal ecu to take care of my check engine light. since federal in 91 did not have the injector trouble codes. I will see if it works. But first I want to install the Mass air flow sub harness to see if that takes care of the problem.

 

Mark

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The pause at 1000 rpm is normal in a manual. From what I was told it is controlled by the ecu to allow for better syncro shifting. after a few sec it figures out that you are not going to shift and settles down to normal idle. I am thinking of putting in a federal ecu to take care of my check engine light. since federal in 91 did not have the injector trouble codes. I will see if it works. But first I want to install the Mass air flow sub harness to see if that takes care of the problem.

 

Mark

 

 

ah interesting to know...thanks. (obviously I don't have that same manual LOL!)

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