EGR woes

[cygnus58]

1994 1.0, TBI new ehxaust valves, valve seals, rings, cylinder wall deglazing, rod bearings.

OK, after the rebuild, and cleaning the passages, I expected maybe a simple bit of diagnosis.

Wrong!

Thanks to, believe it or not a link to an Autozone diag page while there were a few obvious errors I now understand for the most part what each component does.
Seems basically that the VSV, Mod, and valve are alll in series (vacuum wise)to provide vacuum to valve based on temp, back pressure from exhaust, and load.

Heres the deal...

EGR valve:

off engine, lots of exhaust exiting port for valve input -good
without rag stuffed in intake port, VERY high idling, - good
cleaned additional carbon out of back pressure supply port to modulator

on engine, applying suction to valve almost stalls engine, never let it tho.
nice stream of exhaust out of modulator supply port

Modulator:

applying pressure to backpressure hose via party balloon pump allows flow through modulator, pretty straight-forward.

VSV:

was taken apart by previous owner, and lower o-ring is bad, i accept it should be replaced although internally the ball valve was functional.

Aside from that, there is NO vacuum into the VSV from TB!
Also the hose next to VSV input (to right) going to canister has no vacuum as well.
or is vacuum at those ports too low normally to pull on your fingertip?

I have read that ECU will throw code If EGR is not functioning but am beginning to believe that is not true as with all that was wrong from the start (clogged exhaust manifold port, head plugged, EGR valve WAS plugged, and now no vacuum in from TB I think all ECU does is look for shorted/open VSV solenoid and or wiring...All it wants is 35+/- ohms on that connector.

Have not seen EGR code since we bought it, and just this Friday milage was at 43 MPG.

I realize this system is essential for emmisions, lowering temps, and maybe better milage but am getting frustrated.

Not knowing internals of throttle body, is there a part of that which would clog and not have vacuum at only the two ports for VSV and canister?
Obviously MAP has vacuum or performance and MPG would suffer greatly.
have unplugged that hose previously and the engine does NOT like that..

Used Metro parts are quite a distance from us here, and am considering using a VSV from a JEEP. My '88 Cherokee has one very similar in operation and the only question I must consider is coil resistance to try one of those easier to aquire valves in the GEO.

For now timing is advanced as far as to not ping, and we luckily live in area that doesn't require high rpm 65 mph drives. Concerned about valve wear.
We will baby the G10 until we can come up with a fix......

They should have made these 3 speed autos with overdrive!!!


apologies for long post, but all info was important I think.

Joe

[jtgh]

good post. you are hot on EGR, good write up, others will benefit.

Aside from that, there is NO vacuum into the VSV from TB! BAD, !
Also the hose next to VSV input (to right) going to canister has no vacuum as well. Bad.
or is vacuum at those ports too low normally to pull on your fingertip?

they are at full vacuum at all times those to ports .
the ECU gates them on , when it needs it.
EGR usually over 2500 it gates up to 70% throttle.

the stall test is passing , very good ! that is the hard part.


guessing:
1: TB gasket backwards.
2: someone put a bb in to vac hoses, nahhhhh.

problem is the TB, just find where it is blocked inside.

EGR monitor started 1994 in suzukis, code 51 . IIRC. ( calif cars eariler.)

take a bit of driving to set it.

your on the right track, i mean, your 43mgp is going to make them blush.

cheers.

[cygnus58]

Thanks for your quick reply Jerry.
will try to find cause of no vacuum at those two ports first, and persue replacing VSV after.
Will post back when I have any results.

[jtgh]

very interesting what could cause that.?

[jtgh]

photo.
you might luck out and just jam a soft rod thru these nipples.

not sure if they take a turn in side, no bailing wire
id try somthing soft and plastic,
that will bend and not break.

a tiny TyeWrap comes to mind. or?


some swifts have 3 nipples others 2 , depends on market.


you might be badly coked up under trottle plate, blocking the port holes.

EGR + PCV = coke formation.

that little cam , in there , is cute. !
1 liter. cool. to be we dont have more 1L cars here.

[cygnus58]

funny you should mention Tywraps.
I looked inside the TB today and saw directly behind the nipples what appeared to be VERY small holes directly above the throttle plate.
Inserted the wire part of a baggie tie and it went thru into the TB!
They are not plugged at all. (sprayed with gumout anyway) If I spray it in other end of either hose while idling it does affect idle downward.
I guess since it wasn't warmed up (IAC bypassing much of main opening) and throttle plate was closed in idle position, they wont have any vacuum to speak of??
If only above 2500rpm to 70%, that would kinda make sense. Another safeguard against EGR happening when it should not maybe? These are really tiny, maybe 1mm if that. I must get ahold of a vacuum gauge and run it on that port at highway speed with a long hose to find out more.
Maybe if I get the VSV issue dealt with I will actually have EGR...
thanks for checking in, and for the pic.

Joe

[cygnus58]

ran a vacuum/pressure gauge on the hose to VSV today.
at 45-55 mph depending on throttle position, average was 12-15 in. on level ground.
When connected to the exhaust nipple on the EGR valve, could barely develop 1-2 psi.
that doesn't seem right, maybe I still have some plugging in the intake, as we neglected to check it out while it was apart.
The VSV off my jeep was bad, still have to get something around for that part of the whole deal.
I suppose I should drop the exhaust manifold and see what I can clean out in the intake bend.
Tried the drill and stretched spring method with little success from the EGR port but I read to use a stiff piece of metal like from a wiper blade....should try that too b4 removing exhaust....

[jtgh]

this is Metro-ville and that TBI can port a little diff, then my B16.
but the basic ops is same.

you are on track .

cheers.

[cygnus58]

Got the VSV problem solved, now with vaccum gauge teed on EGR valve, i'm getting about 2-3 inches from Modulator.
If applied by "mouth" from under hood, it takes about 4-5 to fully open EGR valve.
So i am leaning towards very slight clogging in bent part of intake nearest head not actuating modulator to full output.

So close to full operation!!

When it's done, i'm putting a dedicated gauge inside to monitor the whole system for vacuum to EGR valve.

Funny side note, without tee, (just vacuum hose to modulator output), it goes to almost 12 in?? I don't get that but...and EGR valve leakdown test passes when hose is pinched after applying vacuum by mouth.

[jtgh]

you are on a ROLL.

that valve is 3 way,
on ,off ,and purge.
you see if the VSV slams shut with full vacuum , a vacuum gets trapped in the EGR diaphram ( Note I am illegally calling Vacuum a physical object ,which is wrong but convient)
so the Suzuki valve, bleeds atmospher into the EGR diaphragh , allowing it to retract.
is that your funny reading.
or have I found that your reading is bad, the purge is failing.
the FSM has the steps, but they are simple.

i imagine your VSV works just like mine on b16. cant imagine why not.?

I am a polluter on this forum Metro.Im a sideKicker over the wall.
you invited me here so, who knows what errors I might spit out.
lol.

your sig. renix, of benix Renault fame? like in early jeeps, you are right, they do succubus, ( it could tell stories)?