Erratic idling

[bigalpha]

Pita..., What was your first clue?

Might hiss if loose enough, hard to hear small leaks. Keep in mind some of those bolts hold the intake and exhaust at the same time. Those bolts are notorious for getting loose.

A stethoscope or just a long piece of vacuum hose used as a stethoscope can help you hear small leaks.

My first clue was all the oil covering the underside of this POS I'm driving around

Oh boy, I'm excited about this prospect. I'll be freaking excited if it fixes my problems.

Thanks for the advice. Will update again later.

 

[bigalpha]

I went back out and really put some muscle into those upper manifold bolts. A few of them barely moved. Is there a limit to how tight those should be?

I tried getting at the lowers, but everything was still really hot. I'll do it on a completely cold engine.

Just tightening those bolts just barely made a huge difference in the idling when in D. It's still a little high, but it's not crazy high. The idle in the P and N are much better, though they'll still get really high. It just takes a little longer.

The hose that goes from the airbox to the exhaust. What does that do? Mine was partially unclipped and when i re-clipped it, the whole elbow (heat shield and all) moved independently from the rest of the exhaust. I think that's where the exhaust leak/sound is coming from. How do you fix?

 

[Harlee&Tahoe]

The hose from exhaust to airbox is for cold startup, airbox will suck warm air from around manifold to heat up faster.

 

[bigalpha]

Well, the vacuum hose that runs to the little motor that opens the flap to let the hot air in the airbox is disco'd.

Can this cause any issues or anything? Seems like it wouldn't, since the later models don't have this feature.

Can I just completely disco the hose or something? It's always in my way.

 

[Harlee&Tahoe]

Just be sure to plug the vac line.

Also the nut in the very back of the manifold next to the firewall is next to impossible to see and will require some extensions and u-joints

 

[bigalpha]

Where does the vac line run from? There's not even a hose or anything, all I have is the small actuator that the line runs to.

 

[Harlee&Tahoe]

Soft line from actuator to back of airbox (temp sensor); hard line from back of air box
to nipple on intake manifold(just behind vac. line tree).

 

[89xj]

Well, the vacuum hose that runs to the little motor that opens the flap to let the hot air in the airbox is disco'd.

Can this cause any issues or anything? Seems like it wouldn't, since the later models don't have this feature.

Can I just completely disco the hose or something? It's always in my way.

plug the end of that hose or remove the hose and plug where it was connected.

intake and exhaust manifold share the same bolts and you need to get underneath to tighen them all. i was completely missing one of the bolts towards the back of the engine.

have you connectd a vacuum gauge to the system? that should tell you if you have a leak.

what helped my renix high idle was cleaning the ground wire connection located on the drivers side fender wall in front of the windsheild washer fluid tank..

 

[bigalpha]

Soft line from actuator to back of airbox (temp sensor); hard line from back of air box
to nipple on intake manifold(just behind vac. line tree).

The airbox has two nipples, one doesn't look functional. Right now, there's something connected to the functional one.

 

[Harlee&Tahoe]

The airbox has two nipples, one doesn't look functional. Right now, there's something connected to the functional one.

???
The one on the left side is the vac. supply line, follow it back to the intake man. and plug it. If already plugged, nothing to worry about. System disabled.

 

[bigalpha]

Sorry, I don't think I'm being very clear in my description.

The actuator that's connected to the airbox and the hose that runs to the exhaust pipe. It has a port to connect a vac line to.

The top (cover) of the air filter box has two nipples that you can attach a vac line to. One of the nipples looks functional. The other nipple is solid plastic and does not open into the airbox cover.

The nipple on the airbox cover that is functional is already in use by something else.

What's the source of vacuum for the actuator that's connected to airbox and hose that runs to the exhaust line? Should that be plugged into the airbox instead?

 

[bigalpha]

So I took the MJ to Advance Auto and had them check the electrical.

The Battery registers are 'good', the charging system registers as 'good' but it indicated that I have a small drain in the electrical system.

How do you go about finding these 'drains'? I have already double-checked the 3 grounds in the engine bay and they test out at 3ohms or less.

 

[Ecomike]

So I took the MJ to Advance Auto and had them check the electrical.

The Battery registers are 'good', the charging system registers as 'good' but it indicated that I have a small drain in the electrical system.

How do you go about finding these 'drains'? I have already double-checked the 3 grounds in the engine bay and they test out at 3ohms or less.

Looking for them can be quite draining!

Just probe around for hot wires when they should be dead with a meter.

 

[bigalpha]

I've tested all the ones I could quickly and easily access to no avail. The hot wires should test exactly what the battery tests, right?

 

[Ecomike]

I've tested all the ones I could quickly and easily access to no avail. The hot wires should test exactly what the battery tests, right?

Only if they are supposed to be hot at the time. Do you have an alarm?

How big is the drain? Is it even relevant to the erratic idle?

Some hardware stays hot all the time, like computer memory and dash clock.

 

[bigalpha]

No alarm. I traced the hot wires from the battery and tested as many exposed areas as I could. It all came back the same voltage as the + and - on the battery.

Not sure if it is relevant to the erratic idle, which is why I posted it up here. I figure that if there is a short or something in the system somewhere, it could be fubaring everything. I know the RENIX is sensitive to everything.

 

[bigalpha]

The printout says 11.18A for the drain test.

 

[Ecomike]

No alarm. I traced the hot wires from the battery and tested as many exposed areas as I could. It all came back the same voltage as the + and - on the battery.

Not sure if it is relevant to the erratic idle, which is why I posted it up here. I figure that if there is a short or something in the system somewhere, it could be fubaring everything. I know the RENIX is sensitive to everything.

11.18 amps is quite significant. If it is a hot wire with burned insulation rubbing on the body, that periodically makes better contact, and draws more current, especially if that line feeds sensors, ECU, etc, it can cause eractic engine behavior. I would start with inspecting the alternator first. 5-90 is real knowledgeable about the alternators, and their wiring. PM him with an invite to this thread for some advice. I would also check all the red wires near the battery, but sounds like you did that already.

Next I would check the ignition switch and wiring harness connector to it, those are frequent sources of melt downs, and shorts, etc.

 

[bigalpha]

Can rubbed off insulation that doesn't contact any other metal cause a drain too? One of the hot wires has some areas that the insulation has come off, but isn't burned or melted and doesn't look like it contacts anything else.

I'll have to dig deeper into the wiring and making sure it's all a-ok. There's lots of oil in the engine bay.

Thanks for the advice. I'll give 5-90 a ring too.

 

[Ecomike]

Can rubbed off insulation that doesn't contact any other metal cause a drain too? One of the hot wires has some areas that the insulation has come off, but isn't burned or melted and doesn't look like it contacts anything else.

I'll have to dig deeper into the wiring and making sure it's all a-ok. There's lots of oil in the engine bay.

Thanks for the advice. I'll give 5-90 a ring too.

Only if it gets wet with salt water, or antifreeze across a path to ground, or moves and touches bare grounded metal. Wrap it with electrical tape.