IROC-J28

ok so my 91 RS has been sitting in the garage for about a yr and a half. It has an exhaust leak at the pass side manifold where it meets the y-pipe. The thing is 100% original besides the flowmaster 40. All of a sudden when I pulled it out for the first time in over a yr it has ths crazy probem where it runs and idles like a dream as long as the hood is open but as soon as the hood is shut,the idle drops to about 600-700 rpm and the thin wants to die. This has never happened before and I'm stumped. I've cheked everything around the throttle body, the coil,distributor, wires, all the smog junk. It's weird, any ideas?

UnderCover89TBI

iTrader: (25)

That is weird. Maybe the hood is bumping the air cleaner which is bumping something else causing a vacuum leak? Kind of a weird problem. Maybe a picture of the engine bay will determine if something is out of place.

IROC-J28

yeah it sounds like a massive vac leak when the hood is down but of course there's no way to inspect it and the when I open the hood it all clears up and runs like it should. I'll try to post up a couple pics when I get home

vistageek92

iTrader: (2)

My bet is that the hood is pressing down on the air cleaner and pinching or making some vacuum lines leak somehow. Look at the under side of the hood and see if there are any scratch marks where the air cleaner could be resting. also, take the air cleaner off and run the engine with the hood down. That'll eliminate some possibilities

IROC-J28

ok so i removed the heat fabric clot off of the under side of the roof and removed the throttle body collar and then bolted the air cleaner back down. it sits about 2-3 inches lower now.... the idle doesnt drop as much but it still drops and now all of a sudden when i get on it and drop it from 3rd to first it falls on its face!! I mean it does have 2 yr old gas and oil and the tank only has about a gallon in it but i mean this thing jus wants to die when u get on it. Im thinkin either theres a vacuum leak somewhere, or this massive exhaust leak is screwin with the ecm. I let it idle with the hood open till it reached closed loop then took it for a spin. it cruises fine until u get on it. Any more ideas???

UnderCover89TBI

iTrader: (25)

Get some good gas in there pronto. Gas turns to varnish over time, 2 years is quite a long time. It wouldnt hurt to run some Techron cleaner in it too. improper fuel quality can mess things up. You gotta eliminate things one by one...If it were my car i'd also change the fuel filter.

IROC-J28

yeah i jus threw a tank of 89 sunoco in and a bottle of lucas..... no difference, about to take a ride to summit and pick up a set of headers, y-pipe, high flow cat, smog delete pulley, a/c delete pulley, e3 plugs and a set of wires. Ill try to get it all in before it gets too late and let you all kno the out come. im thinkin i gotta fix that exhaust leak before things get any better

UnderCover89TBI

iTrader: (25)

Yeah didnt think so. But its possible. May have to run longer the cleaner has to work its way through

xX89RSXx

iTrader: (1)

Injectors might start sticking after sitting long too.

IROC-J28

thiss is pissin me of seriously now. I've changed everything. The thing runs like a track star until ii shut the damn hood then the idle drops to the foor and it sputters like it wants to die. Been tryin to figure this out for two weeks andd in the proess I've spent almost $1000. I mean iit runs like a brand new car now as long as the hood is open. Someone please give me some ideas

IROC-J28

and I have confirmed the hood is not touchin anything when it's cllosed. Nothing is getting pinched. I can hear the idle start to drop even before it's all the way latched down by the safety latch.

UnderCover89TBI

iTrader: (25)

it has to be that'd be the only thing different and to do it before the hood is even closed all the way...

one92rs

iTrader: (5)

ok i have a question. do you have a under hood light. if so unplug it and remove the wire from under the hood. let it lay on ther fender and try to reclose the hood.

IROC-J28

Tried the hood light last week, no change. Every one who has stopped by my house have all said its and air flow restriction problem..... which would make sense..... if the car wasnt 10000% original, and its never done this before.

UnderCover89TBI

iTrader: (25)

I dont feel like reading. Did you take the air cleaner off altogether and see if the car changes with the hood closed?

88gunmetalgta

iTrader: (1)

When I pull my car into my shop, it only takes like 30 seconds of idling for it to start to run like crap, even with the door still open. My exhaust dumps underneath the car. I would guess your car is unhappy with the amount of exhaust gas its ingesting.

the solitaire

I have a stock 305 TBI with an exhaust leak on the passenger side as well.

Normally it's no problem to let it sit and idle. I can close the hood and the car runs good.

When outside temperatures get high 'ish and the engine is warm I had some idle issues when backing the car in my garage which involves some maneuvring at crawling speed.

If that were the problem here, the car would/should run fine with the hood closed and the fan on. I don't think exhaust gas in the cause here.

Only reason I could think of is that closing the hood causes a shortcircuit or mass connection somewhere.

Error codes?

one92rs

iTrader: (5)

so this car has the stock air cleaner and all on it. remove the air cleaner and try it. maybe the coil wire is arcing off the air cleaner with the hood closed.

t-top havoc

iTrader: (3)

Any kind of aftermarket alram, lighting, relays, etc
or ground wires along an edge where shutting the hood may cause some jostling of wires? Possible a critter got in & gnawed something?

IDK-- just throwing a bone

IROC-J28

had the factory air cleaner when it started acting up, first thing i did was remove it and ran it with out a cleaner, no change. I bought the edelbrock 1002 air cleaner, no change.... now theres a new problem, it wont stay running at all now with the hood up. I can start it and it sputters as its starting then if i tap the gas it clears up and runs good then randomly out of nowhere the injectors spit out a burst of gas and the throttle body starts to hiss really loud then it sputters out... a couple times it would hiss and quickly die like some one turned the key of.... thinkin throttle position sensor but i could be wrong. but i gotta fix this then continue trouble shooting the hood closed problem.

IROC-J28

no alarm or anything. matter of fact i even un bolted the map sensor from the cowl area to see if it changes anything.... obviously it didnt

xX89RSXx

iTrader: (1)

Did you inspect the injectors wiring? Any pinching or exposed wires?

IROC-J28

no exposed wres... Although the injector plugs are wet. Prob from when sprayed seafoam spray into the throttle body cleanig it up. Riight now this thing is jus dumpn gas into the engine at idle. I'm gonna change the tps tomorrow and see what that does

92SuperCoupe

Let me know if you figure out the problem. It's a 1992 rs with a 305 TBI..Once you start it up it barely idles and is like the engine is getting way too much gas (you can smell it). I'm not sure about exhaust leak, someone cut this one off right at the passenger door. Could that be causing it?

one92rs

iTrader: (5)

both of yall prolly need to pull the iac and clean them and the seat. then go to the home page to the tech articles and due the minumum idle reset.

the solitaire

And check the contacts on the inside of the distributor cap on the way.

Just a thought. Had an erratic issue once caused by a bad dist and started looking in all the wrong places before I got to it.

You said you checked around it, but did you check the inside?
Not sure whether or not you mentioned it.

IROC-J28

Mine is doing the exact same thing but it clears up and runs fine for like 30 sec in between. I unplugged the IAC and there was no change so automatically i took it out, cleaned it and put it back in and i thought i solved the problem but i didnt. itll start, run then the injectors dump gas and the thing runs like junk. it hisses REALLY LOUD at the throttle body. When its running ruogh it literally sounds like a top fuel dragster... black smoke everywhere

IROC-J28

i threw in a new cap, rotor, coil, wires, plugs and ignition control module. must admit its sounds alot better when its running clear but thats so few and far apart that it really dousnt matter. I didnt put in my e3 plugs yet because i didnt want to foul them out since its just dumpin gas into the TB. I got a cheap set of $1.99 Denso plugs in it now

IROC-J28

Jus came to the conclusion that im jus gonna rebuild the TB. take eveything apart, replace the TPS, all the gaskets, the pressure regulator set up, diaphragm, IAC, and clean everything. I think im just gonna reuse the injectors because they dont seem to be the problem. Ive got till July 26th to get this thing running a1 and im gonna start with the TB set up.

one92rs

iTrader: (5)

so was this ever repaired. if so what was wrong.

IROC-J28

no im waiting till i get back from Atlanta to start rebuilding the TB

IROC-J28

ok so i just got back home from atlanta... car has been sitting untouched, not started for about 10 days. I started it up today and its running great all of a sudden??? wtf??? the only prob i see now is the fan isnt coming on but now that i think about it, it hasnt came on since i pulled it out of storage, but other than that and the exhaust leak it seems ok, im gonna get this fan moving and put it on the highway to see if it acts up again.

IROC-J28

UPDATE: after changing literally everything (MAP, TPS, IAC, ESC, Ignition control mod, cap, rotor, coil, wires, plugs) I can get it started and after chugging around trying to teach itself how to idle for a few seconds it'll run fine for about 10-15 minutes then it just shuts down like someone turned the key off. No sputter, no knock, no drama at all, it just politely shuts off.... AND WONT START BACK UP!! after it shuts down theres spark out of the coil but the spark is white, not blue. It wont even start with starting fluid so i know its spark related. I put in another working coil and no change. Any Help or just another brain of ideas would be greatly appreciated.... THANX

IROC-J28

starting to lean towards a bad ecm

rusty vango

check your fuel pressure AND volume i think your frustration lies there

IROC-J28

Im getting 12-13psi and the injectors are working as they should... Im almost sure its a spark issue

xX89RSXx

iTrader: (1)

I had an ignition module act like that. When it cooled off it would start back up. $15 part, think parts store can test them.

IROC-J28

I thought that same thing so I bought another one.... testing the one i bought 2 weeks ago and the nnew one i just picked up today. Both test good but i thought i would put the new one in for the hell of it. No change.... So

IROC-J28

So I was checking the coil again... this time in the garage instead of in the sunlight.... BLUE AS ICE at the coil and every cylinder.... defiantly a fuel problem. I got it to start by un plugging one injector and holding the throttle all the way open. Started right up but that one injector was spittin out waaaay too much fuel. as soon as I plugged in the 2nd injector it jus quit instantly and if I go to turn the key again, each injector dumps so much gas into the TB that it floods almost intantly

IROC-J28

changed the coolant temp sensor (in manifold) (took an antifreeze bath btw) good news is it stays running, however it runs like &HIT. No SES codes... thinklin bout changing the fuel pressure regulator diaphragm and all that jazz... AND the fan wont come on and the thermostat is stuck closed

Arizona IROC

iTrader: (4)

The regulator was my problem. Just a tiny hole screwed everything up. To check it pull the vacuum hose off of it and see if there is any gas that comes out. (or a bad gas smell)
If so it needs to be replaced. (not a fun job)