SES light ?

[xxxscimitarxxx]

my 92 had a hissy fit the other day and popped a little backfire on start up from cold....

I turned off ignition, turned on, and re cranked it....

started up but then ran lumpy/cammy....(all warning lights off)

l let it run like this for about 20 secs but it didnt clear by it self so I blipped the throttle and it immediately ran smooth.....but

the SES light then came on and stayed on.

however the engine then seemed to run fine (i havent paperclipped it yet)

It now goes through this process on every start even when warmed up.....starts.....runs lumpy.....blip throttle to clear....SES light comes on....engine runs smooth

any ideas

(have l blown something off on the backfire?....I couldnt find any visible pipes blown off)

[Hammer]

Do you have a high idle once the motor clears up?

There's two hoses that can blow off on a backfire/hickup.
The MAP sensor hose at the back of the plenum.
Another hose that connected to the front left side of the plenum. This happened to mine. I was able to get it back on without pulling the plenum.

Hope this helps.

[xxxscimitarxxx]

idle was a couple of hundred higher l would guess

i checked at the back of the plenum and found a rubber connector that had two holes for a pair of metal end pipes pointing up vertically just behind the plenum and a little low (I havent got a manual to hand right now so will look into this later)....however this connector did not seem to be a tight fit on the two pipes...it wasnt blown off.....but when l pulled at it, it came off the two pipes easily...l pushed it back on but it didnt make a difference to what was happening

I will have my son recheck hoses that he can get too

[Hammer]

That's the PCV connection. You need a new one if you can find one. The MAP sensor hose is just to the right of that a bit. Small hose going from under the plenum to the fuel regulator area. If you do a search here you should be able to find information on that.

[xxxscimitarxxx]

Ah....OK....PCV

as for MAP sensor hose......seem to recall a small hose going to a small pressure regulator/diaphram looking object just above the PCV....that was connected ok at that point

[-=Jeff=-]

Ah....OK....PCV

as for MAP sensor hose......seem to recall a small hose going to a small pressure regulator/diaphram looking object just above the PCV....that was connected ok at that point

no the MAP is on the bracket on the very end of the plenum, hose is under that.. you can reach from the top to fell it, but not sure if you can see it from either side

[ZR1Vette]

What you checked was the PCV connector (hilited with a red arrow) and what Jeff is referring to is the MAP sensor hose hilited with a yellow arrow (shows the nipple the hose attaches to)>>

http://i17.photobucket.com/albums/b79/MRBLU/ZR1fuelpressureregulatorannotatedho.jpg

[Dynomite]

What you checked was the PCV connector (hilited with a red arrow) and what Jeff is referring to is the MAP sensor hose hilited with a yellow arrow (shows the nipple the hose attaches to)>>

Great picture ZR1Vette.......even I can now understand what is going on :thumbsup:

I just need some pictures like that highlighted in red and yellow identifying the vaccuum lines and parts under the plenum :D

[ZR1Vette]

Ask and you shall receive ;)

Forward line under front of plenum (green arrow...red arrows are pointing to the IM forward plugs)
http://i17.photobucket.com/albums/b79/MRBLU/ZR1plenumliftedevapconnectannotated.jpg

Vacuum line coming from forward vacuum pump...good spot to hook up a vacuum tester>>>
http://i17.photobucket.com/albums/b79/MRBLU/ZR1rightsideTBvacuumlineannotated.jpg

Overview>>
http://i17.photobucket.com/albums/b79/MRBLU/ZR1underplenumareacleanedup.jpg

[Dynomite]

Ask and you shall receive ;)

Forward line under front of plenum

Vacuum line coming from forward vacuum pump...good spot to hook up a vacuum tester>>>

Overview>>


ZR1Vette.....you are DAMAN :thumbsup::thumbsup: Thank you :thumbsup:

[xxxscimitarxxx]

YES INDEED....TRULY DAMAN.....excellent pics

Thanks to all so far.....

so re my SES prob lm now guessing lve popped a pipe somewhere

[secondchance]

YES INDEED....TRULY DAMAN.....excellent pics

Thanks to all so far.....

so re my SES prob lm now guessing lve popped a pipe somewhere

That port on ZRVette's pic has to be connected to underside of your MAP sensor. Your MAP sensor is under aluminum trim behind the plenum held on with 2 black torx head bolts.

Make sure that vacuum line is hard plastic (non-collapsible) with rubber fitting on ends only to slip over plenum fitting and over MAP sensor nipple.

[xxxscimitarxxx]

So... from all acounts thus far l could have popped the MAP sensor hose....or at least l hope l have as it seems l can get to that one easily ans lve checked all other more visible conns

does the MAP connection failure explain the grumbly start up until l blip it and the SES comes on

if its the case and l fix it (or other hose leak).....then l think l also recall that l cant clear the code by just a battery disconnect......?

will it need a scanner tool to clear it?

[secondchance]

So... from all acounts thus far l could have popped the MAP sensor hose....or at least l hope l have as it seems l can get to that one easily ans lve checked all other more visible conns

does the MAP connection failure explain the grumbly start up until l blip it and the SES comes on

if its the case and l fix it (or other hose leak).....then l think l also recall that l cant clear the code by just a battery disconnect......?

will it need a scanner tool to clear it?

Disconnected MAP vacuum hose will make the car run like hell, including grumbly start, and trip SES light.
SES code can be cleared by disconnecting the battery for about 30 seconds plus, if I remember correct.
I am sure someone will chime in and correct me if wrong.
Also, make sure you use factory MAP vacuum hose or fabricate out of hard plastic except for both ends. Soft hose will work for a while until heat and oil soften it at which point motor will stumble at high vacuum condition (low rpm). I found this out the hard way.:cheers: