vacuum

[rlmccook54]

HELP!
Several of the vacuum lines looked like they were going bad.
This is a 1990 Forerunner v6. It has been running pretty well but there is a little hesitation and roughness. The 4 lines on the top left side, each about 3 inches long were not looking good and they might have been original. I bought 5/32 and 7/64 enough to replace. Now the idle is very rough and the brakes seem to have lost the power assist. I took them off very carefully one at a time and first replace them with the 5/32. Then I tried the 7/64. No help. The lines are attached to a small round device with a cap.

[jetwhine]

rimccook54,

Sounds like maybe the EGR modulator? There are alot of things that can make it run rough. When was the last tune up. Mainly spark plugs?? Maybe by replaceing the lines it has made a slight problem worse now that you have proper vacuum. Have you checked for stored check engine light codes?? I would do that before doing anything else.

[rlmccook54]

Thanks for getting back to me. Yesterday morning the truck was running well except for just a little sluggishness from time to time. Highway mileage was still around 20mpg which is what it always has been. Not sure of last tuneup. After installing the 4 lines which are around the EGR it is now idling very rough and slow. The plug wires to the two rear cylinders on the passenger side bank somehow were up against the EGR assembly and the plastic clip holding them together melted to the assembly. I tested both the plug wires and both were showing less than 25 ohms resistance. To pull a code requires something called an SST which I don't have. But the check engine light does not stay on when the engine is running.
Any more ideas?

[jetwhine]

rimccook59,

No special tool required. Just use a paper clip and short out the two female pins in the diagnostic box on the passenger side wheel well, it is black and has a flip top lid. The pins you will short are the ones that you would use to check the timing. They are posted on your hood on the inside. They should be TE1 and E1. Once you have them shorted then turn your key to the on position without starting, if there are any stored codes you can read them by counting the blinks. Another thing you can do is remove the hose that goes to the EGR valve. plug it, and see if the idle improves. If it does, then you might have a bad EGR valve.
Also, 25K ohms is good on the wires.
If you replace the plugs use only Denso or NGK and no substitutes. Denso should be a K16R-U and the NGK should be BKR5EYA and no others.

[rlmccook54]

jetwhine,
I tried pullin the hose off the egr and it improved the idle. Thanks. I ordered a new egr and it looks simple enough to replace. Fingers crossed. Since I couldn't remember the last tune up I bought a set of ngk plugs and distributor cap and rotor. I couldn't belive my eyes when I pulled the old cap off. The number 2 plug in for the plug wire was broken! More than just a crack, too.

[jetwhine]

rimccook54,

Well that might be all there is to it. So let me know how it goes. You might want to spray some liquid wrench on the nuts and or bolts that hold the EGR valve so you can get it off easier. It should not be that bad. I think those vacuum lines go to the 4WD system. I'm thinking that the tune-up will fix most of your problem (I hope).

[rlmccook54]

Jetwhine,
I replaced the EGR this evening. When the vacuum line is attached to the top of it the engine idles very rough. Detach it and it smooths out. I haven't gotten the plugs in it yet. We keep getting these storms and I am working outside and I have to drive some so between working on a hot engine and the rain I just haven't gotten them in. I did put 1,000 miles on the truck last weekend so it still goes pretty well.
The tip for the liquid wrench was spot on.

[jetwhine]

rimccook54,

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