How's it going today?

I have a 91 Camaro with a 3.1 Liter and for the life of me I cant figure out where a disconnected vacuum hose goes. All I know is that it was running fine until i disconnected the electronic EGR valve and now it wont even start.

If it sits for a while it will attempt to and then die instantaneously. So after searching underneath the hood for about a week I noticed i have a hose that isnt connected to anything. On the back of the plenum there are two ports. One has a T connection and the other is a single male outlet.

My question today is where in the hell does that single male outlet run to??? Its connected at the plenum but I have no idea where its supposed to go

My best guess is that it goes to the fuel pressure regulator. But i'm new at this so I dont have a clue as to where that is either.

Any help would be appreciated

-Thanks!

 

give me a minuet..ill look at mine and tell ya... i will answer in 15 minuets

 

ok look at your firewall on the passenger side.. im not positive what that is but its bolted to the top of the fire wall.. the wires that come out of the device that you want to plug the vacum line into goes to the egr.

 

I appreciate the info and whatever it is....well thats where it was supposed to be connected. Unfortunately that didnt solve the problem. Guess i'll have to start a new thread. I replaced my entire distributor assembly plus reset the timing to top dead center.

After i did that it ran and i reset the timing to 0 degrees. I was doing this all in the meantime because i broke both studs that held the EGR valve in place. After i connected the EGR valve when i was done my camaro stopped running. I checked all my vacuum hoses and all are fine. I patched the EGR tube (to my dismay it broke when i was moving it) that routes the gas back into the plenum.

Nothing i've tried works. I've just about had it with the damn car and even though i paid 650 for it and drove it home after i paid for it....i'm considering selling it unless i can find a decent mechanic who can make all the service engine codes stop, get it to run, and i can be done with this whole mess.

 

Base timing is 10* BTDC

 

That may be a possibility....but it ran smooth before and it just all of a sudden quit running after i drilled/tapped the studs for the EGR valve and then reattached it.

 

yea 10* is what you gotta do before looking at other things!
try setting the base timming to 10 degrees. then disconnect battery for a minuet then start the car and let it relearn what the car is doing...jsut let it idle for 5 min then drive it a little...

 

what code is it throwing... have you ever heard of useing a paper clip to see what code its throwing on the check engine light>>>>

 

Yeah its throwing a 46 code now.

Which i believe is the VATS system and that just doesnt make sense to me

 

Code 46 could also be the PS pressure switch circuit.

 

I'm just going by what the Haynes manual is telling me and thats what it said a 46 code is

 

yea 46 is the vats . what exactly does the car do??? Does it start??? or what....

 

I assume i installed the distributor improperly somehow. But i put it all back together and it started as well as ran. I moved my electronic egr valve out of the way in order to get to the #1 spark plug easier to set it at top dead center. When i moved the egr valve i broke both studs. So after i replaced both and put the valve back in place the car wouldnt run anymore. it attempts to start if it sits for a bit and will try to fire over but it wont idle or anything.

 

when you put the ignition control module back on the dizzy.. did you put that di-electric greese back on the bottom of the ICM?? Its just a thought.

Another thought is when the ICM gets hot they act funny if there not good. But run fine when the car sits for a long time.

 

it came pre-assembled on the distributor assembly that i purchased

 

well mabey your dizzy is just that far off that its not wanting to run....

can you hear your fuel pump prime itself when you turn the key on but only to turn the gauges and acc. stuff on..not turn the car over...

 

a code 46 vats should stop the injectors and not crank the motor... are you sure its 46.. thats the anti theft code

 

I just went out and checked it. It still have me a 46 code.

 

lol... well does it attemp to start?? or just keep on cranking away? if its just cranking away...check to see if the plugs spark!
I gotta get off the computer for a bit.. CHeck the spark!, and if its not sparking and the plugs are NOT wet. Then its the ICM. but try to get your timing back to 10* base

 

it attempts to start...i think it might be the fuel pump but I'll have to check that tomorrow because i'm fresh out of starting fluid :'(

 

Before checking your fuel pump check your fuel filter and fuel pressure.

 

Updates??? Any luck...

 

Well after resetting the timing to 10 and making sure the distributor assembly was in place properly....no luck.

So i moved on to phase 2....which was spraying starting fluid into my throttle body... and wouldnt you know it? the damn thing fired right over. Just goes to show you that even if you can hear your fuel pump engaging doesnt mean its enough to crank your engine over.

I hadnt had a chance to mess with the car in a while because i'd been working 5 consecutive days and was too tired after work to even want to deal with the headache of it. Plus i was working on putting a qualitex seat into my 86 chevy pick up which is proving to be way more dependable than my 91 camaro.

 

If you have a problem with the vats system it keeps the injectors from pulsing. The fuel pump will still run but the computer will not pulse the injectors. Does the security light come on and go off?

 

have you tryied to reset the ECU? Or use a different ignition key? The chip could be bad in the key your using. You didnt accidently disterb any wires arround the fuel rail when you replaced the dizzy.......

 

Before youo go do anything major I had the same problem. This is what was done to fix my car. You have to hook the car up to a computer to 0 out the timing and let the car reset itself and if that doesn't work just off to the left of the distributor is a small module that go bad and will not allow your car to start

 

Are you talking about the Ignition Control Module?

He hasent been on this post for awhile???? I wounder if it ever got fixed?

 

You're absolute right I haven't had a chance to post on this for a while. I just got into Texas a&m so I've been sorting through a mess of financial aid paperwork.

I'm at a loss of what to begin looking at. Camaro has been sitting for about 3 weeks now. All it does is crank and the distributor is absolutely in the right position. I hope that it's just some sensor. I have no codes any more because I disconnected the battery over night.

Like I said all it does is crank for ever and all eternity. It doesn't even attempt to start now. But I'm open to any and all suggestions...

 

Did you ever change the ignition control module?? I for got if you ever had it tested or not.

 

Yeah I replaced it whenever I changed out the distributor

 

did you take the plugs out and crank it over to see if it sparks?

 

Yeah I have spark and the fuel pressure is registering fine as well

 

are the plugs wet if you crank the motor and then take a plug out?
You try shoting a shot of gas in the TB when someone is cranking it just to see if it will want to start?
If you got fuel in there and spark then its gotta be timing or a wire somewhere off. or or not in place. Also a dirty injector/s....

 

The biggest thing that I can't figure out is that it was running find with an electronic timing code and then all of a sudden it just quit on me.

 

Umm, if you mean plug a scanner into the ALDL port, that will do nothing for setting the timing correctly.

Timing is set on these cars the old fashioned way, by twisting the dizzy and using a timing light.

If the VATS isn't working correctly, nothing else you do will fix the problem.

You can bypass the VATS system entirely by using a module that feeds a 50HZ square wave signal into the ECM itself, or reprogramming the the EPROM in the ECM for no VATS.

You can also install the correct value resistor in the harness below the column, if the VATS module itself is functioning correctly, but just not seeing the correct value from the key.

You can replace the key cylinder if that is the issue.

 

I posted this in another thread but it should work here.
It sounds like you have a VATS issue. The vats system keeps the injectors from pulsing and sometimes keeps the starter from engaging depending on how it failed and if someone has messed with your starter relay. From your post it looks like you have fuel pressure and you have spark so you need to check if your injectors are pulsing. Since your car has a vats code I'm going to say thats your problem but another problem with these cars is a shorted injector that will also mimic the same symtoms. Does your car have a security light in your insterment cluster? It should come on with the key on and go off after a few seconds if it stays on the car should not start. Did you check your fuel pressure at the rail?

 

Hello all! I apologize for how long it's taken me to get back to this thread. But as an update I think I've ruled out the fuel pump. I just checked it today and it's running at 44 psi. I also replaced my fuel filter because I thought it might have been clogged. Once again I restabbed by distributor at tdc. When I re-read this thread I saw someone say something about ten degrees. Does that mean advance it by ten? By turning the distributor counter clockwise? I'm still learning on this whole idea of fuel injection. I also do not have a VATS code anymore. I'm open to any and all ideas. Oh and the last thing I did today was rip off the EGR and plugged the hole it went into on the intake plenum.

Thanks in advance to anyone who replies!

 

First, the frequency signal is 30Hz, not 50... That started in around 1995 with Passkey III.

Second, OP, take a test light and connect the clip to either the battery positive terminal or the BAT post on the alternator. Disconnect the 6-wire connector from the front of the injector harness and probe the blue and green wires (in the engine harness half, not the injector half) with the test light as the engine is cranked. If the light doesn't flash, you probably still have a VATS issue or something else. If it does, disconnect the light from the 12V source and connect the clip to ground. Probe the pink wires with the ignition ON. The light should light on both as both are ignition power sources. If not, check the INJ fuses in the dash first. Also, check the injectors' resistance per bank by probing the blue and green wires against the pink ones (in the injector harness, not the engine harness) with a DMM. Should come out to about 4 ohms per bank. If 6 or more, you have a shorted injector and need to pull the upper plenum again to find out which one. Any single injector with a resistance less than 11.8 ohms needs to be replaced (GM spec as per the 1992 service manual). Worry about getting the engine running before you set the timing to 10* BTDC... Yes, it does run at TDC and even ATDC, but it doesn't run well.

If everything checks out, I wouldn't rule out a bad ECM, but you should make sure that the ECM is seeing reference pulses from the ignition module in the distributor first. Beg, borrow, or nab a scanner (or tuning cable) and hook it up to the ALDL to check to see that the ECM is seeing an RPM signal.

And, while you're at it, see if you can get a used service manual... They're on here occasionally and eBay often due to dealer closings. Follow that up by doing a dance around your burning Haynes manual .

 

From everything that I've checked this morning all the symptoms are pointing to the vats system once again. And wouldn't you know it that security light is on once again. I measured the ohm resistance on my key an got 2.37 which I believe is a number 8 key blank. I just bought a resistor online to wire in. When I looked under my dash I saw 2 wires leading into another 2 wires with a plug in between. I tried to measure the ohm rating leading to the module but it wasn't matching anything close to 2.37. It was wrapped in orange shearing and the two exitif wires were purple/white & black/white. I hope that's te right connection. I also think I may have a dead battery. Although it reads 12 volts I don't think it has enough cranking amps. This may be a dumb question but could this be the root of my security issue?

 

Battery voltage has nothing to do with the VATS module sending the proper output...

Read here to get an understanding of the system: https://www.thirdgen.org/vats_passkey_system

If your key is reading 2.37K ohms resistance, the car SHOULD be running. If you're not getting a reading at the bottom of the steering column (the lock cylinder side of the harness connector), you could have a problem in the wiring between the lock cylinder and the VATS harness connector. Check the resistance with the key in the lock and the lock connector disconnected from the dash harness first, and then check it again with the lock connector connected and the VATS module disconnected (same purple and black/white wires at the module as in the harness).

:edit: The article has a bit of bad info... If the VATS has disabled the fuel injection, the set code is 46, not 53.

 

Well I have no idea what I did but she lives once again. After letting in run for a while I'm back to the same 2 original codes that I started with

33: map sensor
42: electronic spark timing

The funny thing is that even without the egr connected it's still not throwing an egr code.
Any more tips guys? I also am in need of a plate to place on top of my exhaust manifold where the egr use to be.....if anybody knows where I can buy one I'd really appreciate it.

Thanks for all the help so far!!!

 

The EGR isn't going to throw a code until you're traveling down the road and the ECM gets to open each solenoid individually and check for the resulting change in manifold pressure. Or it may not throw the code for now because right now it's thinking it can't trust the MAP sensor.

If you're trying to set the ignition timing, the code 42 will set as the tan EST wire is disconnected.

The code 33 is MAP voltage high (low vacuum). Check to see that the green wire in the MAP connector (the 3-wire green one by the heater box assembly) isn't getting 5V with the sensor unplugged.