Egr valve or something else??

[bigbertha]

Hi All-

Got another question for you.

For a few months, since the stalling, bucking surging debacle, I have had the EGR modulator hose at port Q disconnected from the top port of the EGR valve and plugged with a screw. The truck has been running fine ever since. I just got a new EGR modulator and tried to reconnect that vacuum line but the truck is still bucking, hesitating and surging at around 1500 rpms as soon as I do this. When I disconnect the hose and replug with a screw, the truck is back to normal, smooth power all the way up.

When I check the EGR valve itself, as per FSM, it checks out fine.

From the reading I have done, the EGR modulator was supposed to be the problem. It clearly is not. Any thoughts as to whether this is EGR valve related or something else?

I have already gone over the whole engine with a hose to my ear and carb cleaner and water to find leaks. All vac lines are replaced and I get a steady 20 on the boost gauge at idle.

I do not want to now replace the EGR valve, which checks out fine, and have the truck still be bucking and hesitating after that $179.00 bear of a repair. (well... bear for me anyways)

truck smells strongly of exhaust when EGR modulator and EGR valve are not connected. You can smell it 30 feet away. Gives me a headache and probably won't pass inspection like this. Would like to get this fixed asap.

Thanks!

 

[High Desert]

I've had my EGR plugged for two years. No exhaust smell, I'd say that was another problem, maybe related to the surge problem, but no reason for the smell just from disconnecting those componets. (I'm sure I'll be corrected if wrong) could be the EGR tube deal, but it would be making noise if it is split.

I'd still put money on the EGR valve being stuck open or closed. Be worth going to a pro to have it checked. From what I hear the COST of the EGR is not near as hard to deal with as is the actual removal and replacement job. I understand that is a PITA. But I dunno, i'm dodgeing that bullet for now.

 

[dogboy2]

Oh don't I know your pain....

 

[dogboy2]

fumble fingers here.... too quick for my own good on the above post

Here's the skinny: I have BTDT. Started with plugging the modulator like you with similar positive effect. Next I replaced the modulator, then replaced the EGR valve, and then as it was still behaving like yours, I replaced the two BVSV's and only then did the truck run like a champ and pass emissions well within the limits. Each successive replacement part improved the overall running condition until the entire problem was eliminated.

Moral of the story: you may have multiple failed components that are related in the same system. Just because your EGR tested O.K. doesn't mean that the internal diaphram isn't fatigued with years of use and failing to perform properly under operating conditions. Similarly, yes you can pull the BVSV's and test them too but at some point, they too will fail if they are original. So for the hassle of removal, you may as well make a pre-emptive repair and replace them.

Good luck and I HTH,
-dogboy- '87 FJ60

 

[dogboy2]

truck smells strongly of exhaust when EGR modulator and EGR valve are not connected. You can smell it 30 feet away. Gives me a headache and probably won't pass inspection like this. Would like to get this fixed asap.

You are running a bit rich without the EGR system functioning, and yes it probably will fail emissions like that. The EGR system recycles the exhaust back through the fresh intake fuel/air mixture to reburn any unburnt fuel from the combustion process contributing to create cleaner exhaust at the tailpipe.

When you get your EGR system dialed in (the Toyota Emissions FSM is invaluable for this), do yourself a favor and do a complete tune-up, including a valve adjustment if you haven't done one recently and you should pass emissions.

HTH too,
-dogboy- '87 FJ60

 

[bigbertha]

thanks guys

Many thanks for the words of advice and empathy. I'll definitely be replacing the bvsvs when I do the egr.

any advice on the egr removal? PB Blaster the large nuts I imagine.

 

[dogboy2]

remove the air horn so you will have better access. PB Blaster on all connecting bolts. should come right off.

patience and monkey finger dexterity to install the big nut on the bottom flex pipe when reinstalling. leave the mounting bolts loose and then jimmy the new EGR valve around until you can get the nut to thread, then tighten it all down to spec.

hth,
-dogboy- '87 FJ60

 

[MDH33]

Don't forget to check and clean out the exhaust gas filter that lives down below the EGR modulator on the manifold in front of the carb. It has three vacuum lines coming out the top. This always gets plugged up and can cause the bucking, hesitating you describe. I had the same problem which was a combination of the exhaust gas filter and EGR modulator both being clogged up.