86 Vette Barely Starts
 

Ok,first off "HELLO EVERYBODY".I`m new to the forum and need a little help!I have an 86 Vette that tries to start,but won`t.It sometimes starts with barely an idle(really rough and lopes)buy dies after about 10 seconds.The car was sitting for about a month prior to this and at that time ran good with the exception that after it heated up the idle would go up and down.I thought this to be the fuel pressure regulator,but after hooking up a pressure gauge found it was not.Now my bigger problem is getting it to start and stay running.I changed out the cap and rotor,NO DIFFERENCE!I reset the IAC valvethen checked the TPS for the correct voltage setting,which was fine.Also installed a new O2 sensor,NO HELP!I`m thinking EGR,maybe Knock Sensor or Ignition Module?I will be checking for spark,but when I changed out the cap I used a coil from my other 87 Vette which does run.Again it did not make a difference.Any help would be greatly appreciated!I`m a good weekend mechanic who knows a little and learn as I go.

RE: 86 Vette Barely Starts
 

First, Welcome to the site. Glad to have ya. As for your Vette. Sounds like you've checked alot as I did. From your description of the symptoms it sounds like the same thing I had with my '87. It turned out to be the ECM in the Dist. whether it was worn out or the grease on the bottom side had dried out I'm not sure, but replacing it fixed the problem. I'm not sure of any way to test them other than replacing them. Unfortunately there are so many damn things it could be that the process of elimination is sometimes the only thing you can do. Good luck with it, Cheers

RE: 86 Vette Barely Starts
 

Hi and thanks for the welcome Blueshark.Yeah I`m going through the motions checking everything.Vacuum lines,electrical connectors,sensor settings and anything else I`m reading about.When you say the ECM in the distributor,you mean the Ignition Module.I found a couple online and for the price I`m going to order one and change it out.We`ll see where that gets me!Hopefully back on the road or should I say my Fiance back on the road(its her car).Meanwhile I will keep checking over everything and doing the test I can do.Any other thoughts you or anyone can offer I will gladly listen!

RE: 86 Vette Barely Starts
 

First, unplug the MAF and which puts it in backup mode. If the car starts and idles, it probably is the problem. Lots of history with MAF on tuned port engines.[8D]

RE: 86 Vette Barely Starts
 

Thanks Mech259,I`ll give it a try tomorrow.I am getting a code 34,but I put my MAF from my 87 on there and it still does the same thing.Not sure what that means,but I`ll try anything.Tried starting it again today and it had a small backfire through the throttle body.Any suggestions on this?I`ll let you how I make out!Thanks Again.Tom

RE: 86 Vette Barely Starts
 

How many miles on the car? Can you check ignition timing? Code 34 has to do with MAF. Your supply voltage to the sensor may be the problem, so try the test I suggested.

RE: 86 Vette Barely Starts
 

FIRST let me apologize for the lengthy post you are going to read!:).After erasing the code 34 from the ECM I gave the test you suggested(Mech259) and still no change.Any idears(ideas) as to my next move?I thought about timing,but how would the timing have got so far out just from sitting for about a month?Ok,I better tell you this,prior to this I changed out the throttle body.I used the TPS,IAC and its housing from my throttle body on the used replacement one.Reason for the change?The throttle was sticking and in doing some research I found that the cause for this was a warped throttle rod.After doing this everything was running and working fine except for a problem with the engine idling up and down after it heated up.This problem already existed,so it was not a result of throttle body change.Thought it was a bad fuel pressure regulator,but a simple test with a pressure gauge ruled this out,I THINK!Did however notice that when I disconnected the canister solenoid the motor did not idle up and down so bad anymore.At this point the car sat for about a month and that leads us to where we are now,A NON RUNNING CORVETTE!

RE: 86 Vette Barely Starts
 

Well, the next step would be to determine whether you are losing fire or injector pulse. If you have a noid light, you can check pulse by unplugging 1 injector and see if pulse goes away right before engine dies. Does the car stay running if you open the throttle and try to keep it running? Also, take a 2 - 3 ft piece of heater hose and try to listen around for a vacuum leak.

RE: 86 Vette Barely Starts
 

Went away for a few days so now I am back to the testing or maybe not.I don`t have a noid light,but I am working on getting one.The motor won`t start so checking forvacuum leaks is out for now.I did however pull 5 of the plugs and found a significant amount of water on all of them.Water in the GAS,but HOW?With some further investigation(checking the gas filler cap)I found the water drain hole was plugged up and there was water laying in the filler panel.I removed the gas cap and there was water inside the filler neck and it has some surface rust.I`m guessing with the drain clogged water pooled inside and went through the vents in the cap and in to the tank.Does this sound possible Mech259?I`m going to drain the tank and the rest of the system and see what I find.The worst part is we just got that heavy rain here in Jersey so if the water got into the tank before how much more just went in again!Any ideas on how to get the fuel out of the rails?

RE: 86 Vette Barely Starts
 

Get the fuel out of rails? How much gas is in the tank?

Disconnect the battery. Get a couple of oil pans ready, and a gas can. Disconnect the filter, pull the gas cap, disconnect the fuel lines at the intake. Empty each pan into the gas can while the second pan fills.

RE: 86 Vette Barely Starts
 

You can bypass the fuel pump relay and put a drain hose to your fuel pressure test port (remove schrader valve) , then run fuel into a drain pan to see if there is water.

RE: 86 Vette Barely Starts
 

Yeah I figured bypassing the fuel pump relay to pump the gas out would be the way to go,but was going to pull thefilter like CWB suggested.Mech259`s way sounds like it will get the fuel out of the rails as well as the rest of the lines and tank.I`m going to follow both of your procedures as I figure once the gas tank is empty the lines will still have some gas that will need to come out.This forum is excellent and your help is greatly appreciated.

RE: 86 Vette Barely Starts
 

Hi guys,pumped the gas out through the schrader valve and got about 5 gallons of what looked like skim milk.Going to pull the fuel filter and empty the lines out tomorrow.Gonna go with new plugs and filter,refuel her up and hope for a running vette!Let ya know tomorrow night.:D

RE: 86 Vette Barely Starts
 

Hope you don't have any trash stopping up the injectors. Good Luck! [8D]

RE: 86 Vette Barely Starts
 

Well got everything cleaned out,HOPEFULLY!Cars running .but not great.Think I need to change out the IAC valve.It idles up and down,and about 10-20 seconds after start up I can hear the air from the air cleaner going into the air ducts get louder(like a loud vacuum noise).I have read some similar forums with the same problem and they seem to all say the IAC or EGR.What do you guys think?I figure it can`t hurt to change the IAC first as theEGR is under the plenum.If I take that apart,I`m replacing the Fuel Pressure Regulator and EGR.Is there a test for the EGR that can be done?Also pulled some of the spark plugs and no sign of water.Oh and Mech259,I hope there is no trash in the injectors too!Guess if I pull the Plenum,I will either get the injectors cleaned or replace them.:eek:

RE: 86 Vette Barely Starts
 

Now that you're running, do some tests before replacing stuff.

Test the fuel pressure static (motor off), at idle with vacuum on FPR, at idle with vacuum off of FPR, and pedal down pressure (you gotta' tape the guage to the windshield to read pressure and make sure it's enriching at full throttle).

Then check for vacuum leaks:

RE: 86 Vette Barely Starts
 

I did the fuel pressure test and all was as it is suppose to be.I didn`t try the vacuum off the FPR so I will give that a try tomorrow.Checked all vacuum lines and they seem to be fine too.Checked PCV and thats ok(actually brand new),but made sure it was ok.I did think of doing the carb cleaner test,but gotta get the carb cleaner.I bought a new IAC,but haven`t installed it yet.Trying to get some work done on my boat,a few house projects and therapy for a recent back surgery limit my time as well as range of movement.Hope everybody is doing better than me!

RE: 86 Vette Barely Starts
 

Took a few days off due to my back.I put the new IAC on and started replacing some of the rubber vacuum lines.The old ones seem to be very dry and there is some noticable dry rot(cracking) in the lines.The motor is still running rough and the idle goes up and down at idle.Now there is a real bad bog at acceleration.Mostly on the start,but picks up and goes after a few seconds.Did the carb spray test and did not get any signs of a leak on the intake,vacuum lines or fuel related parts of the engine.Next I guess would be a test or replacement of the EGR Valve and if I do that I`m pulling the fuel pressure regulator to put in a new one.Can`t seem to find a new EGR valve solenoid.Any other ideas,ANYBODY?This car is driving me nuts![sm=wtf.gif].

RE: 86 Vette Barely Starts
 

You're loping idle is a vacuum leak.

RE: 86 Vette Barely Starts
 

Alright,I threw a brick on the gas pedal and got the car idle up to about a steady 1400 rpm.I then sprayed small amounts of carb spray along the intake,the top and bottom of the runners,the throttle body,all vacuum line connections and hoses and I`m sure other places that I thought to spray,but no change.I put on the new IAC(correctly as the book said to do)and the car seems to be running better with a very small amount of idle lope.I also reset the minimum idle speed and the TPS.Its still running a little rough,but has a major amount of bogging when hitting the peddle.It is fine if I bring the idle up slowly.Oh and now for some reason when putting the car into gear it goes in kinda hard,like the idle is too high,but its not!:eek:Any other things I should look at?I`m thinking the fuel injectors might have an issue due to the water in the gas.Going to try the EGR test next or maybe throw that brick through the window!

RE: 86 Vette Barely Starts
 

You probably need to clean the injectors like I suggested earlier due to the water contamination. Each injector has an inlet screen that can catch small particles and restrict fuel flow.