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I've officially found the most unsolvable idle issue...

The dark green/orange wire is power in to the injectors, along with power to many other components, like the coil and comes from the ASD relay.

The injectors pulse on the ground side at the ECM. I don't think the issue is the injectors.

First thing I'd do is clean the IAC, just to eliminate gunk as your issue. Do a battery volt test with the engine running. IAC is voltage sensitive and can do all sorts of weird things when the voltage is low. It can be an early indicator of a general charging or battery issue.

Check your manifold bolts for tightness. Just the right amount of vacuum leak and the ECM will try to adjust, it usually tries to adjust for the proper air/fuel mix for optimum CAT function rather than best engine performance. The vacuum leak can change at the manifold as the motor heats and cools.

Like EcoMike said the O2 sensor has to be suspect. They often don't throw a code until they are way bad. The first thing to check is O2 sensor wires melting on the manifold or on the exhaust.

Your shift points acting up does indicate a possible TPS problem. The engine management ECM and the trans management TCU share the same TPS and wiring. If all else fails you may have to OHM test the TPS circuit and check for wire, splice or connector issues. TPS will often throw a code if it is much out of wack (unlike the O2 sensor which won't).

Sorry again, I was at first thinking this was a Renix, I do have vision issues (getting old sucks).
 
Ecomike said:
Wouldn't an open EGR (error) and a working O2 sensor make the ECU add fuel and raise the idle speed? Thus running the engine rich (smell at the exhaust), with the O2 running lean, but the engine actually running rich?

Never gave the EGRs much thought, never had a bad one since I had a 78 Dodge, and when it went bad I could smell the carburetor side of the EGR rubber hose smoking like crazy, it stunk, and was easy to diagnose. but your comments have me thinking. Never read of a confirmed issue cause by an EGR here except yours. Not even a failed tailpipe issue that I recall. But I see your point, has me thinking now.
Click to expand...

Off topic, this is for Renix only, but the EGR being open at low RPM or even low vacuum can make a motor want to stall or run really poorly. EGR only is supposed to work through a fairly narrow vacuum/RPM range, mostly during cruise conditions. For some unknown reason (to me) it slows down the cylinder burn and acts almost like using a higher obtain fuel. I've had them screw up for various reasons, from a split diaphram, carbon jammed pintle/piston, through electrical issues. Usually the last thing I look at. :)

Like mentioned the 97 has no EGR, just a little info.

Last thought for his issue, is the notorious clogged CAT. They usually rattle for awhile before they completely screw up.
 
Downstream o2 sensor, or connector.
How many miles?
Any codes present?
Might not throw one anyway, until the ecu determines the cat is no good.
Like they said, it's "common" for anything post 1996.
 
Last edited:
Transpoquick said:
Downstream o2 sensor, or connector.
How many miles?
Click to expand...
234k but the sensors are new. This is my third set, something keeps frying them. I'm thinking I have a short maybe. I've narrowed it down, because the same thing is frying my TPS since I'm on the 3rd one... It's something in that wiring harness, does anyone know where I can buy one?

Sent from my SM-G930V using Tapatalk
 
Well wait a sec.
Lets deal w/ the tps thing first.
You sure its n.g.
You have to find the "reference" voltage first and then the "signal" voltage.
Any chilton or Haynes manual should be able to give the info.
 
Do that first, boneyard would be the best place for a harness, a intermittent short will be hard to diagnose.
Sounds like a downstream o2, or connector(cut it off and butt splice it, I.E. remove the connector)
No codes present, would be the best indication on early obdII vehicles that its a o2/cat. prob
That'll drive ya' nuts.
 
W1zardofozz said:
234k but the sensors are new. This is my third set, something keeps frying them. I'm thinking I have a short maybe. I've narrowed it down, because the same thing is frying my TPS since I'm on the 3rd one... It's something in that wiring harness, ....
Click to expand...

Excess fuel or coolant loss through the combustion chambers will ruin O2 sensors. You are using NTK O2 sensors, not Bosch, right ? If all the sensors test good, that leaves wire harness issues, but you still need testing to confirm, or to rule out, the wire harness, and the sensors.

You should also test/inspect the battery and alternator and test/inspect/clean/snug all the battery/alternator/ground wire connections and wires. Low voltage will reboot the PCM and idle settings are deleted. Low voltage while driving can mess with the PCM and cause odd symptoms.
 
Last edited:
I am a Renix guy, but on the early years there is something called the ASD relay. That stands for automatic shut down. What it does is that it keeps the battery power on the ECU for a few seconds after you turn off the switch. That give it time to set the IAC (idle air controller) to set for the conditions needed at start up. If the relay goes bad, the engine starts up crappy and it takes a while for the ECU to adjust the IAC based upon the TPS and rpms to get the idle speed to the right place.

So I would swap the ASD relay with one of the others and see if things change. After that, I would pull the IAC and clean out the throttle body where it mounts with carb cleaner using a spray can of carb cleaner and q-tips.
 
ASD was fine, IAC/throttle body was fine, TPS ground tested fine

However when I ohm tested my injectors, the reasons were between 100-400 ohms. That's a lot higher than 12 ohms. Could it be something in here?

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W1zardofozz said:
ASD was fine, IAC/throttle body was fine, TPS ground tested fine

However when I ohm tested my injectors, the reasons were between 100-400 ohms. That's a lot higher than 12 ohms. Could it be something in here?

Sent from my SM-G930V using Tapatalk
Click to expand...
I should also note that my vehicle was running

Sent from my SM-G930V using Tapatalk
 
Sounds like you need to learn how to use a multi meter?

Never heard of "tested for voltage drop from battery to ground and it was 12 v through and through." unless you are testing for a huge drop in something like a starter circuit to the starter and in that case voltage drop of 12 volts is very bad, and I doubt that is what you meant?

And you do not test anything for ohms with the power on "I should also note that my vehicle was running"

You disconnect the electric pigtail on one injector at a time (so you do not crisscross them later), and test the injector while it is totally isolated electrically for vehicle power and wiring.

You test resistance using the 0-200 (for most meters) ohms scale, power off from the sensor ground wire at the sensor to battery negative post, and you wont less than one ohm. Test the meters internal resistance by shorting the two test leads, if the meter reads say 0.9 ohms and the sensor wire ground reads 2 ohms, then take 2.0 - 0.9 = 1.1, means it is 1.1 ohms actual resistance for the wire.

About 1.0 ohms or less is OK. Over 1 ohm is a sign of corrosion, loose contacts...

Should be about .2 ohms on good wiring.
 
Alright, so I replaced a few couplers on my "custom" air intake, and replaced the throttle body gasket. The jet engine sound is gone and my idle is steady, but it's idling sorta high now. About 1000. However, it still struggles to return to idle after getting on the gas. I think I've narrowed it down to bad circuitry in the IAC. Or just a bad IAC (yes, I cleaned it and the throttle body) Does anyone have reference ohm and voltages to the IAC?

Sent from my SM-G930V using Tapatalk
 
Ecomike said:
Sounds like you need to learn how to use a multi meter?

Never heard of "tested for voltage drop from battery to ground and it was 12 v through and through." unless you are testing for a huge drop in something like a starter circuit to the starter and in that case voltage drop of 12 volts is very bad, and I doubt that is what you meant?

And you do not test anything for ohms with the power on "I should also note that my vehicle was running"

You disconnect the electric pigtail on one injector at a time (so you do not crisscross them later), and test the injector while it is totally isolated electrically for vehicle power and wiring.

You test resistance using the 0-200 (for most meters) ohms scale, power off from the sensor ground wire at the sensor to battery negative post, and you wont less than one ohm. Test the meters internal resistance by shorting the two test leads, if the meter reads say 0.9 ohms and the sensor wire ground reads 2 ohms, then take 2.0 - 0.9 = 1.1, means it is 1.1 ohms actual resistance for the wire.

About 1.0 ohms or less is OK. Over 1 ohm is a sign of corrosion, loose contacts...

Should be about .2 ohms on good wiring.
Click to expand...
My bad, by "testing for voltage drop" I meant I put the red lead on the hot post, and the black lead to the ground on the frame and the engine. It stopped working Monday due to volt drop because it was only reading 2v, hot post to ground. Cleaned it off, everything ran great aside from the current issues.

I'll test everything again after lunch. I think I've got it narrowed down thanks to y'all. Stay radical

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