Double check EGR tube for leaks on the back side.

Check for vac leak at butterfly shaft.

Thanks Justice for the quick reply!

Now that you mention it, I think the EGR tube has a crack in the accordion part. How does that affect the operation of the motor? I doubt replacements are available, can I JB weld that sucker?

I'll spray some cleaner around the throttle body later tonight. I put a new lower plenum on recently and checked for vacuum leaks after. Came up with nothing. I guess I'll hook up my vac gage and see if I'm getting 18in HG at idle.

When I first bought the truck, I was only getting an EGR code. The vacuum lines were routed wrong to the EGR solenoid and the EGR valve was missing the gasket. I've tested both solenoids I have with a 12v source and can hear them click open. I'll have to check if they are holding vacuum.

JB Weld will work good for a temp fix but wont last long. Try the putty type should fix it long enough for you to continue to troubleshoot. Probably not your main issue but a hole there will throw off your tuning. Should still be able to get a new pipe from the stealer. Got one for my 89 a couple years ago..

FWIW - My 89 developed a crack in the accordion tube as well. For $20 and a 6 pack at a muffler shop they brazed it shut after work. Dealer price was $120 IIRC.

Yeah I didn't think about having it brazed. Great idea!


I think I've solved the EGR problem. So far no reoccurring check engine light. I went through the FSM and checked over the EGR solenoid, AFM , and TPS. I actually didn't have any codes for the AFM and TPS this time since I reset the computer some weeks ago after doing the lower plenum and I'm pretty sure it was my fault they were present anyways. But the EGR solenoid...

Both solenoids I had checked out ok electrically, no vacuum leaks, no EGR valve leaks, nothing physically wrong that I could see besides a small crack in the EGR tube. I remember seeing small puffs of smoke coming from the EGR tube when I seafoamed the motor. Then it clicked, it should be sucking air into the crack not puffing out smoke. I took off the EGR valve, everything was clear. Then I removed the throttle body. The EGR outlet into the intake manifold was packed with carbon. It was like a carbon stalagmite. Cleaned out the port and now the truck runs great. It really runs good now, I'm amazed really.

Something that I should have realized, if you open the EGR valve at idle it should stall the truck out or close to it. Wasn't doing that before.

Thanks guys for your help!

Next up is replacing the fan clutch.



Edit for mongo : https://www.youtube.com/watch?v=F5axlwCBXC8

Between me and the wife - that's "our song".

Dear Abby is the source of my tag line. Glad to meet another fan.

Welcome to the wire. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Joe,

I have a good EGR tube from a 94 sitting out in the garage. - yours if you want it.

Also, Memorial Day weekend putting together an off-road trip on Sunday. If your interested, let me know will send details.

~ Jon

JDavis: Yeah I will gladly take the EGR tube. Much appreciated! Are you looking for anything in trade? I don't have much in the way of parts.

As for the Memorial weekend, I should have my OME coils by then (backordered 'til the 23rd). If I can get them in before that Sunday I might be up for a shakedown of the truck. Send me some details and I'll run it by the boss(wife).


Did you ever get down to the Tumwater Pick N' Pull?

Nothing in trade, buy me a beer on the trail sometime <img src="/forums/images/graemlins/cheers.gif" alt="" />

I installed heavy duty OME coils and torsion bars on my rig about two months ago. Love them, especially for towing the camper.

Sent you a PM with the details - let me know. Always trying to more Monteros out on the trail.

I've been to the PnP in tumwater a few times. I was actually debating on going down this week.

~ Jon

I know this information has been gone over before and some of the information is spread over different forums and the FSM but I want to try to record some of my findings and fixes with my Montero in hopes it might help others down the road.

I've had a problem since I bought my Montero roughly 2 months ago with a sharp drop in RPM when I let off the throttle. If I was cruising along and let off the gas, the RPM would drop 250rpm or so then shoot back up. It was really noticeable when the truck was in 4lo because the trans was locked to the motor. It was almost like a engine brake on a diesel, maybe not as extreme.

It became more pronounced after I cleaned the throttle body.I think some of the problem was a clogged EGR passage that I recently fixed.

From my understanding, and I could be off, but when the motor goes into decel the Throttle Position closed circuit tells the ECM that the throttle is closed and allows exhaust to come in through the EGR and also allows the Idle motor take over to control idle/decel.
(Please let me know if this wrong so I can edit it out if need be.)

At first I thought my Idle Air Control Motor was bad but it tested in the 40 range in resistance which is correct for the black housing IAC. I had already unclogged the EGR passages and did a troubleshoot on correcting the check engine light for that. Last to check was the Throttle Position Sensor. From what I can tell, it looks like someone had installed the sensor incorrectly.

So to adjust it:

I used some brass shim stock that was .025(FSM says .0256 or .65mm) between the stop screw and the throttle body lever.

Loosen the (2) 8mm bolts.

Connect your electrical tester to pin 1 and pin 2. If you are looking at the TPS from the passenger side, pin 1 is closest to you.

Rotate the TPS clockwise.

Then slowly rotate the TPS counterclockwise until it breaks continuity.

Tighten up the (2) 8mm bolts.

In reality, it shouldn't move from the factory unless it was tinkered with or replaced at some time. But it might be something to check and adjust if you have just cleaned a metric ton of built carbon out of your intake/emission system.

Today's drive home from work should tell me if I've done any good.