fishon1213

I just finished a head gasket and timing chain job on my 85 4runner. I have adjusted the valves and rough set the timing. I can't keep it running unless I keep on the gas. When it is running there is a loud hiss coming from the egr area. The egr itself does not seem to be leaking. The hiss seems to be coming from the part I have pictured below. It is a round plastic piece with a few vacuum lines going into it. What is it?

http://i292.photobucket.com/albums/m...3/PHTO0086.jpg

jason191918

That looks like the vacuum valve for the EGR. Check the lines for a vacuum leak.

fishon1213

Ok, so I think I found out it's the EGR modulator. So what to do, replace it, or can I bypass it?

jason191918

Is the modulator leaking or the vacuum lines leaking? If you "bypass" the modulator you may as well scrap the entire EGR system (unless you have to pass emissions).

fishon1213

I don't have to pass emissions. All of the lines seem ok and when I sprayed everything down with carb cleaner there was no change. The egr modulator itself seems to be making the noise.

jason191918

If you pop the top off, there is a filter in there. Maybe it is just dirty? Or can you tell it is cracked or something like that? Or you can get a new one or just scrap the whole system. Up to you.

fishon1213

Here's another for your sig

Jason rocks!!!

jason191918

Take it you fixed it...? Thanks for the compliment.

AndYota

Are all 4 lines hooked up to the modulator valve? I've missed the bottom one before.

fishon1213

No, I haven't fixed it yet, but I am now 99.9 percent sure my problem lies with the egr system. All of the hoses are hooked up, I think the modulator valve is cracked. If you hold it, it vibrates consistently with the hissing. I think I'll probably scrap the whole system.

jason191918

That's what I did!

Jay1

What do you get ride of?

fishon1213

Well, maybe the egr system isn't my problem. I have plugged all vacuum lines associated with the egr and completely removed the modulator. I have done everything short of remove the metal egr pipe and make block off plates. Still no change. The truck will start up and run great for a split second, then it hissess(like its sucking in air?), rpm drop and it dies.

4Crawler

iTrader: (3)

A buddy had that problem in his '85. Turned out to be a fuel injector that had a damaged seal/seat and was getting sucked into the intake (and out of the fuel rail) under high vacuum situations (like idling). You could move the injector in and out by hand.

fishon1213

Thanks for the idea 4crawler. I'll check out the injectors tommorrow. I do smell fuel a little but I assumed it was from several times of starting up and stopping. Got any good pics of the injectors?

fishon1213

Well, per 4crawler's advice I checked out my injectors this morning. It seems they could definitly be my problem. Injector #4 could be moved in and out about 1/16th inch. All other injectors seemed to be dryrotted at the seals also. Keep in mind this truck sat forever and the top end was recently taken apart, moving stuff around. So two questions.

1. Would a bad injector seal make a bad enough vacuum leak to make the motor not stay running on it's own?

2. There is a injector rebuild/service kit on ebay for like 14 bucks, anyone have any experience with these?

fishon1213

Any advice? I'd like to fix this ASAP.

4Crawler

iTrader: (3)

I think the injectors had 1 or 2 o-ring seals plus a seat that they fit into on one end. When I had my injectors rebuilt, they came w/ new seals. Never tried a kit, but that will probably work if it is for the right engine. Injectors fit into the intake then the fuel rail slides onto them. Lube the seals w/ gasoline before installing.

fishon1213

Well I went to the parts store and bought the injector seal kit. The kids will go to bed in a few hours and I'll go install the new seals. I am also going to replace ALL of the vacuum lines I can. For which I bought a bunch of hose. My wife wasn't to happy. LOL Get it, hoze. I know, I know. So since I can't go work on it right now, I am just curious.

Could a vacuum leak at the injector be bad enough to keep the motor from idling?

I cant wait, I hope that is my problem. I just don't know where else there could be a vacuum leak. It runs great for 10-20 seconds, starts hissing loudly, then dies. It's gotta be a vac leak. After having this motor torn apart forever now, I can't wait to hear it run correctly.

84sr5yoty

If you're going to tear into the motor that far to replace the injector seals, then send out the injectors to get ultrasonically cleaned and rebuilt. You'll thank yourself later!