[DeCrepe]

Hey there everyone, happy to be part of the tracker family. Just picked up a '90 with 199k mi (mostly towed behind an rv) and already enjoying having a manual again.

'90 Tracker, 8V, 1.6L, 5 sp, 4wd, 2dr soft top

So I have need of a little assistance in fixing a high (2k-2.5k) cold idle that also surges. When first started it has a surge of about 500rpm and once warm it's sitting at 1500 with about a 1-200rpm surge.

I've found a couple older threads here with details on checking several items, but unfortunately the pictures are no longer populating so I can't see what's being pointed out. Based on descriptions I'm pretty sure I've found a couple items but wanted to make sure.

geo tracker high idle after warm

Hey all, First off im a new member and new tracker owner. I love this little truck and have some major plans for this ride. First off, the truck cranks and warms up fine. Once it is up to running temps the idle starts to creep up. All the way to 3k at times. Any ideas on this? Vaccum...

www.suzuki-forums.com

1990 Geo Tracker lurching at all RPM's

First of all, I will describe the issues. To start it, it takes two attempts before it will run, and then it will not stay running unless I blip the throttle every couple seconds, and this will not go away until it's warm, which my voltmeter temperature sensor says is 160 F on the radiator...

www.suzuki-forums.com

I have decent heat but the gauge doesn't come up much above cold (assuming the sensor is worn, will ohm it out when I'm home.) Also need to replace the blower motor, but that's relatively straight forward.

There's also an odd whirring/gear sound coming from (seemingly) the rt front tire whenever I'm coasting above 20mph with the clutch in or for that brief moment between letting off the gas and the vehicle being slowed by the engine. Which, if I put it in neutral and lightly push the shifter toward any gear (with clutch in of course) the sound slightly dies down... Maybe a clutch issue?

Lastly, I doubt the ecu has been touched so I'm going to get new caps on the way for that (still haven't searched for the thread with that info yet.)


Thanks everyone!

 

[Bex]

Welcome to the forum. Regarding the cold start, when your engine starts from cold, it should rev to about 2000 rpm, and within about 5 seconds or so, you should hear a very definite drop of about 500 rpm, so the idle should now be about 1500 rpm. Then, over the course of about 5 minutes that idle should reduce to a steady 800rpm or so. Does your engine start that way?
The idle, when the engine is warm, will surge when there are vacuum leaks and the ECU loses control of the idle. One way to check is to pinch each of the vacuum hoses that you see with a pliers. No vacuum hose should change the idle, other than the hose going from the airpipe by the air filter, to the ISC (idle speed solenoid). When you pinch that one, the idle should reduce. All others should stay the same. If you find one where the idle changes, you’ve found a vacuum leak on that circuit.
Note that the temperature gauge on the dash is not connected to the ECU, and runs off of resistance. The best way to see if your engine is actually warming up properly is to get an IR thermometer and point it at the thermostat housing, where the temp should be around 170F when the engine is properly warmed up . My temp gauge as sat at 1/4 for 20 years. The needle there is only really important if it is suddenly sitting at a place where it never sat before.
Regarding the whirring at the right front tire, if you jack up the car and spin that tire, do you hear the noise??

 

[DeCrepe]

Did a little checking on the tracker in between jeep work.

Ohmed out the coolant sensor and at temp we have 348.x ohm (slowly creeps up and down). However when the sensor is unplugged the engine stays at a steady 1500rpm without any noticeable variance. Shutting everything down and reconnecting the sensor causes it to hunt/surge between 1500-2k for a bit and then wavers between 1400-1600. Pinching vacuum lines and running the blower & headlights make no difference.

Vacuum hoses look alright but I'll be replacing all of them due to their age and the spark plug wires have certainly seen better days (some worn almost entirely through to the core.)

I couldn't find any definitive answer on the rating (outside of temp) for the ecu caps. Do we need a low esr rating or so long as they're the correct volt/cap/temp values I should be good? Is there a recommended mfg? I haven't opened my ecu yet but if it's a common failure I want to get them done anyhow.

I'm still waiting on my svs manuals to show up so I don't have documentation to reference, but I assume the isv, egr, and pellet valves are all under the aluminum intake but above the throttle body? I found a pic on another thread from an 89 and that's what I'm guessing.

Lastly, does anyone have pics they can attach to show how the dash comes apart so I can pull and clean the vents? I think there may be a mouse nest in there as it smells of urine at times when the blower is running.

Thanks!

 

[Bex]

Regarding the coolant temp reading, was the engine fully warmed up when you took the ohms reading? When cold, the ohms should be about 5,000 or so ohms, and when the engine is fully warm, then 350 ohms or so. So, if your engine was fully warm, then your reading is fine, but if not……the ECU takes the reading from various sensor, the ECT (coolant sensor) being one of them, in order to maintain idle. When you remove the sensor completely, the ECU reverts to a predetermined table, which would be why your hunting would have stopped. When checking the vacuum lines, make sure you also check the ribbed hose coming off of the air filter for cracks, etc.
If you do a forum search for Mouser caps, you’ll find the info for the caps as well as where to order them.
The isc (idle speed solenoid) location: follow the vacuum line that comes off of the air pipe from the air filter. He attaches directly to the isc.
The EGR will be on the left side of the engine, from the vantage of standing in front of it.
If you know where the throttle position sensor is, the wax pellet valve is just to the left of it, behind a metal plate….again from the vantage point of being in front of the car. Or, more easily, most locations in this photo:

 

[DeCrepe]

It was certainly up to temp, so this weekend I'll be tearing into the engine a little more to check the remaining items.
Thank you for the pic, it's much more detailed than the one I found. Plus knowing the proper search terms to find those caps will be spectacularly helpful.

Now I just need to sort how the dash comes apart so I can clean the ducting.

Again, thank you very much my friend!

 

[Bex]

Here from the 1991 FSM. Your car will be the same. The photos came out in the wrong order. You do the center console first, then the glove box and finally the dash. I’ve never done this (nor do I ever want to….lol)

 

[pmdawntech]

This has been helpful since my 92 has a surge at idle but purrs like a kitten otherwise and my 90 has a surge while driving around 2500 rpm. Thinking it's both a vacuum and the throttle body sensor. in each. I wanted to chime in to say whatever you do, be oh so careful with the dash and vents. The years have not been kind to the plastic and are oh so brittle. If it doesn't budge, check for another screw before using any force and I strongly suggest a plastic trim pry wrapped in a soft rag. Good luck!

 

[DeCrepe]

Alrighty. I finally got around to replacing all the vacuum lines, cleaned the egr, and replaced spark plugs, wires, cap, rotor, and valve cover gasket (slight leak from rock hard original).

Idle is much better and it doesn't rapidly surge during initial warmup but still has a slow 1-200 swing when warm and idles around 1400rpm. And it has a slight sucking sound coming from the engine... Almost like the sound you get when putting a finger over the hose attachment for your house vacuum and can hear the air rushing around it. Haven't been able to determine where it's coming from yet.

Still need to pull the ecu and check/replace caps (have a couple power supplies I'm rebuilding as well so I'll do everything at once) and probably clean any other easily serviceable valves/parts of the engine.

Questions:
1- The line between the bottom of the egr mod and the bottom of the egr (larger dia than the vacuum hoses)... Does that have to be any specific type of hose due to function? The original was quite swollen and spongy on the egr side.

1a- Should I be able to move any parts of the egr once it's adequately cleaned? There appears to be a plunger in the top orifice which I assume should move up to allow gasses to pass... I wasn't about to put any real pressure behind attempting to move it as I didn't want to damage it.

Thanks a million everyone!

 

[Bex]

That sucking sound is obviously a vacuum leak. You can pinch each vacuum hose individually and see which one changes the idle…none should, (The 90 has an electric ISC, rather than one connected to vacuum as in the 91+ vehicles).
The diaphragm of the EGR should be able to be pushed forward toward the radiator, when the engine is off. It doesn’t move a great distance, however. The diaphragm itself is protected by a metal ‘housing’ so if you push on the metal, you won’t damage the diaphragm. It’s easier to check this with the EGR off the car, IMHO, particularly as you want to ensure that the diaphragm snaps back strongly on the spindle it rides on, when you let it go.
You never answered the question in post #2 about what your idle does in cold start. Do you get that 500 rpm drop in. Idle, about 5 to 10 seconds after startup?

 

[DeCrepe]

All vacuum lines are new at this point unless I missed one somewhere. No change in idle with pinching lines, unless it's not up to temp yet... At which point pinching the small line on the can causes it to begin to die.

Dang, I thought I had answered the idle drop question. Not 5-10 seconds, but within 20 or so it does (from 2700 down to 2200). Turning on the headlights does cause a 300rpm rise now with an odd fluttering sound (almost like a diaphram pump).

It also shutters/lightly diesels when shut off.

 

[Bex]

Normally it’s advisable to do these tests with the engine fully warmed up. However, 2700 rpm at cold start is pretty high…..it would appear that you do have a vacuum leak somewhere, or something that is increasing the idle. The 500 rpm drop that you hear should be an immediate drop (even if it’s at 20 seconds) rather than a slow decrease. Did you pinch off all the vacuum hoses? Even the brake booster hose?

 

[DeCrepe]

I pinched all the small vacuum hoses I could get to without removing anything from the engine. The larger hoses (like the one from the can next to the radiator that goes down towards the pass axle) I have not. Those larger diameter lines are the only ones I haven't replaced yet.

The 500rpm idle drop is obvious when it happens, the rest of the time before and after that though it does have a slow decrease in rpm that occurs. Not as much before, but certainly after (as expected I would think) until we reach a warm idle of 13-1400 which from what I've gathered is a tad higher than desired (800 I believe is the target?)

We do have that newest addition of a diaphragm flutter sound when the marker and especially headlights are turned on if it's an indication of anything. Hard to track down specifically where sounds are coming from when it's running (and dangerous to get too close with a long beard 😂).

 

[2013GV]

Brake booster hose and booster itself are an obvious check. Pinch the booster hose close to the manifold, if idle drops, remove hose from booster and plug with a tight fitting something ( bolt etc) if idle is still ok, then its the connection into the booster or the diaphragm in the booster thats leaking.

They do make beard nets.

Or a mis fitted surgical mask?

 

[Bex]

Do you have A/C by any chance? If so, what happens to the warm idle when the A/C is on?
You are correct that the factory spec for idle is 800 rpm.
In front of the engine you should see two vacuum solenoid valves, one should be a green/blue and the other is brown sitting together. The brown one has a vacuum hose that goes toward the back of the engine, and provides vacuum to the throttle opener, which is meant to fully close once the ECU comes online (and would provide the 500 rpm drop). With the engine warmed up, what happens when you pinch that vacuum hose?

 

[DeCrepe]

I do not have ac, though the harmonic balancer has an unused section that may have been for it.
Pinching the vacuum hose off the brown solenoid does nothing to the idle when warmed up.
I suspect the large line coming off the side of the booster is the vacuum line? If so, it's rock hard and unable to be pinched (as all the larger vacuum lines are, those are getting replaced this next weekend.) If that is the line you speak of, I'll at least pull and plug it just to check in the next day or two.

Yeah, I should use something to keep the beard out/off of the engine 😂