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intake manifold passage way from egr valve
Topic Started: May 4 2011, 10:46 PM (4,027 Views)
twocolts
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I need some help. I have a 1993 geo metro with a 3 cyl. Motor was just rebuilt.Ever since I got it back it has had a surging on aceleration. I have replaced, fuel filter, ignition coil pick up in the dist., new cap and rotor, fuel injector and pressure regulator. My mechanics seem to be useless in figuring this out. When I got home ysterday I decided to check to egr valve. When I picked up my geo I specificcaly asked if he had cleaned it , he said yes. The port on the top with the biggest hose ( the other is vacume) was clogged with oily carbon and soot. I took off the egr valve and found it was all clogged up. The passages inside the intake manifold were allso full of it. I scooped out as much as I could. I believe that the manifold shoud have been cleaned which is obvious now that it was not. My question is this. If the passage way that goes to the bottom of the throttle body is still clogged could that be causing this lack of power and stuttering on aceleration?
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Deleted User
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You're on the right path. With the EGR valve removed, exhaust should come out of the front hole in the intake manifold, and the rear hole should suck.

Surging is typically a vacuum leak. Lots of hoses in there. Look carefully. There is a hose diagram on the inside of the hood.

Someone's going to chime in with the officially approved method of squirting something on there which will produce a rise in RPM when you find a hose leak.

I'm thinking Bad Bent has this card . . .
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twocolts
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Thanks Geo Glen. I did spray starting fluid on the intake manifold at the head gasket but did not think to spray the hoses. I will try the hoses . Once again, if the passage to the bottom of the throttle body from the eger is clogged do you think that it would cause this problem. Will the only way to clean the manifold out is to remove it. Could a person spray a carb cleaner into that back passage and clean out the buildup?
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Bad Bent
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Facetious Educated Donkey

And I've been told two different fluids to use, spray Carb cleaner is the safer and you will notice a change in rpm if there is a leak. Starter fluid is #2 and it explodes a little easier. ;)

Here is the "official" EGR thread; Metro EGR System It's likely the carbon is caked in the manifold/block/intake manifold passage. But you might get lucky.

The EGR is passive so I would continue to concentrate on the vacuum leak for some surging, and have the TPS checked for proper voltage. Click on http://geometroforum.com/topic/2787796/1/ to start with.
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Johnny Mullet
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Fear the Mullet

"Check Engine" light on?
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Bigr2009
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When cleaning the passages I used a old speedo cable as like a rooter on my drill. There was like a small tip on the end for a gear and I cut it at an angle to dig better.
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work car
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obsessed!!

harbor reiught sells a super small drain opener for 3.99 works awesome in the end of a drill!!

http://www.harborfreight.com/10-ft-spring-steel-drain-trap-cleaner-96043.html

i use this plus some small engine tuneup from pb blaster company eats carbon for breakfast lunch and dinner!!

http://www.blastergroup.com.au/lawn-mower-tune-up.html
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ogoz23
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where did you vuy the pb blaster small engine tune up and how did you use it?
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ogoz23
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buy
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work car
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obsessed!!

i got it from farm and fleet. tractor supply has it also. spray GENEROUS amounts of spray while roto rootering untill 12+ inches inside the manifold.
Edited by work car, May 6 2011, 12:14 AM.
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twocolts
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no check engine lights
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Bad Bent
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Facetious Educated Donkey

twocolts
May 4 2011, 10:46 PM
I need some help. I have a 1993 geo metro with a 3 cyl. Motor was just rebuilt. Ever since I got it back it has had a surging on acceleration. I have replaced, fuel filter, ignition coil pick up in the dist., new cap and rotor, fuel injector and pressure regulator.
If it didn't surge before, you got the engine rebuilt, and now it surges, there is something the mechanic missed in re-installing the engine... whatever they did. Now you have some new parts but don't add more until you are positive it's not a leak or missed connection.

So basically what happens is the leak adds air to the manifold and combustion, like when you press the gas pedal the butterfly valve in the TB opens, the TPS tells the ECM what you did and the ECM adds gasoline to match the air. It does so until it reached equilibrium.

If you have a vacuum leak then the air is being added as if the pedal were being pushed and the rpm will increase, the ECM reads the O2 sensor and it says 'lean' and the ECM adds gasoline until the idle drops to the TPS reading then goes up again.

It's probably a good idea to replace the vacuum hoses one at a time according to the sticker diagram on the hood of your car. Start with the MAP sensor. Although the vacuum hose looked good it broke off when I went to remove it. Use a mirror if you have to in order to inspect/replace the lines. Get 10' of vacuum hose and take your time replacing the lines. :)
Edited by Bad Bent, May 10 2011, 09:57 PM.
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earthtoad


Has anyone taken a good hard look at the exhaust manifold "Bump" at the location where the EGR dumps into the exhaust manifold ??.....Anyone see any way to design/Fab/locate some type of Port/Opening so you could just unscrew an Allen Screw/Bolt and run some sort of Roto Rooter into Head EGR Passage w/o unhooking so much "Stuff"....... :ermm:
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