I need some serious tuning help...

[SpoolinGLH]

Alright guys.... Just got the car running.. its a '85 Omni 2.2 ,Matt Wright SMEC Cal. +40's,t3/t4 50 trim and all the other mods to support it.

This whole car is out of wack and I do not know even where to start.

The Fuel is set at stock 55psi and its burning the *%*& out of my eyes its running so rich at idle. Its running about 12.5 on the Wideband at idle. And It only gets about 13hg of vacumn at idle!!!! I pulled the plugs and they were all wet. I pulled cylinder 2 plug and smoke/steam came out of the hole? What would cause such a rich condition?

[turbovanman²]

Sounds like a compression/cam timing issue or maybe even a burn't valve.

Did you install the 3 bar map?

[SpoolinGLH]

Yeh Its installed.....its a Menegon Head with new valves , So I hope there not burnt....If the cam timing is off I know it will mess with the Vacumn but what about running rich?

[cordes]

I wouldn't think that 12.5:1 would leave the plugs wet,but perhaps the cam timing is off so much that there is not a complete burn? I would triple check the cam timing, and go from there.

[SpoolinGLH]

ok...when i first started the car it was running at 10.4:1 then as it warmed up it when to 12.5....I will double check the cam timing,compression and some other stuff tomorrow and report back... btw what would cause low vacumn besides the cam timing being off????

[turbovanman²]

Did you install a 3 bar map????????


If it all checks out, install a stock cal and see what happens. If you leave the 3 bar hooked up, the +40's act like stock due to the voltage scaling. If it runs ok like this, then its the cal. I always like to run new engines on a known working cal for this exact reason,

[SpoolinGLH]

Alright guys... I spent ALL day trying to tune this car. I am no further now then what I was before. The Cam timing is dead on. The car is still running very rich at idle at 12.5:1. I checked the wires to the map sensor and they all check out fine. With the AIS plug in the car is constantly searching to find the correct idle.. When I unplug the AIS it raises the idle and runs better. ....very frustrated Any Ideas guys???


Edit: I tried to lower the fuel way below 55psi and it still does not seem to matter....And it has the 3 bar map...

[cordes]

You said that you remove the AIS plug and the car runs better. I would reset the idle by removing the brake booster line, letting it wind out for a few seconds so that the AIS motor closes, unplug the AIS, plug the booster back up, adjust the idle using the screw on the TB to it is at 900RPM, then shut off the car and plug the AIS back in.

That will eliminate that being too far out.

I know that it takes my shadow about 50mi of driving to learn the idle and run well. That is an SBEC, so I would think that the SMEC would be similar to that more so than the LM which doesn't take nearly as long?

[Anonymous_User]

Were you able to lower the fuel pressure? Any chance the return line is not capable of flowing enough to keep the fuel pressure down? I've seen this several time with stock old fuel lines and a 255 lph pump.

If the cal is close, though, 55 psi should be correct.

You say the cam timing is definitely spot on, have you tried moving it a tooth just to see what happens?

[turbovanman²]

Alright guys... I spent ALL day trying to tune this car. I am no further now then what I was before. The Cam timing is dead on. The car is still running very rich at idle at 12.5:1. I checked the wires to the map sensor and they all check out fine. With the AIS plug in the car is constantly searching to find the correct idle.. When I unplug the AIS it raises the idle and runs better. ....very frustrated Any Ideas guys???


Edit: I tried to lower the fuel way below 55psi and it still does not seem to matter....And it has the 3 bar map...

Did you put the stock cal back in???????????????

[SpoolinGLH]

Did you put the stock cal back in???????????????

I do not have a stock cal.

[SpoolinGLH]

Were you able to lower the fuel pressure? Any chance the return line is not capable of flowing enough to keep the fuel pressure down? I've seen this several time with stock old fuel lines and a 255 lph pump.

If the cal is close, though, 55 psi should be correct.

You say the cam timing is definitely spot on, have you tried moving it a tooth just to see what happens?

I am able to lower the fuel pressure but it makes little difference to the reading on the wideband....I did move the cam one tooth today and it would barely run, so I put it back to stock.... For some reason im suspecting a bad map sensor...because I unplugged it and it seemed like it did not make a difference.... what should the voltage be at idle? btw its a gm 3 bar map....

[turbovanman²]

I do not have a stock cal.

You need one before you destroy your engine.

[Anonymous_User]

You need one before you destroy your engine.

Agreed. Excessively rich can destroy an engine. Wash down the cylinder walls, eliminate the ring seal, thin out the oil, tear up the bearings. Ask me how I know.

[1FastCSX289]

I wouldn't think that 12.5:1 would leave the plugs wet,but perhaps the cam timing is off so much that there is not a complete burn? I would triple check the cam timing, and go from there.

I agree that 12.5 is not THAT rich. It would smell a bit rich at idle, but not enough to soak plugs and make your eyes water. Depending on the temperature, my car idles at 12.5.....that is until it warms up to operating temp and then it leans way out. Ive never noticed any issues with the plugs and such. Even 10:1 isnt really rich enough to soak plugs.

Do the plugs look like this on all cylinders? Perhaps you have a stuck injector?

[SpoolinGLH]

UPDATE....Alright guys... I was thinking all last night and I think the problem lies possibly in the cam/timing. The vacumn is WAY to low at idle around 12-13 hg. I hooked a vacumn pump up to the map sensor and pumped it to 18hg and the car leaned out to 14.7 on the wideband and it ran wonderful. The idle straighted out and it just purred. That tells me that the map sensor and the computer thinks the car is at cruising speed and is riching the fuel mixture. I took the map sensor off the pump and plugged it back in to the motors vacumn and the wideband went down to 10-11 and the idle started to go up and down again.......Any thoughts?

Im going to try and change the cam,retime it and go from there....

[Kevin]

It's possible the cal is just too rich for that level of vacuum... It would be quite odd though since usually they'd tune for lean everywhere in vacuum.

What cam are you using?

[Anonymous_User]

Any thoughts?

Sounds like a compression/cam timing issue

perhaps the cam timing is off

You say the cam timing is definitely spot on, have you tried moving it a tooth just to see what happens?

I DO have a thought, but......

Hope adjusting the cam timing solves your problems!!!

[turbovanman²]

Use a timing light to verify cam timing.

Another member had a similiar issue and Matt forgot to scale it for a 3 bar.

[gvare001]

This may sound stupid but are you sure you have a 2.2 cal, not a 2.5. Also have you double checked your ignition timing?