Hi Gang

An having problem with my 85, no run. Want to know if any one has a good manual for this year that they want to part with? if so let me know and we can talk about it. And if any one wants to help with my problem.

Take care............Gunny

 

hey gunny,

You can get a factory manual from :

http://www.helminc.com/ they gernerally run about 85 dollars, or go to your local auto parts place and get the chilton type manuals...

Also they are availablee through companies like :

http://www.zip-products.com/

Hope this helps,

Mo

 

Hi Mo

Thanks for the information. Helm has a complete for $81, you was close. How sharp are you on problems with a 85?

Take care...........Gunny

 

What kind of problems are you having? I once owned a 87 and a 89...

Mo

 

Hi Mo

Sorry I have been slow in getting back to you. I was just driving back from a place, and all of a sudden the car starts slowing down drastically, really running rough, and the gas mileage went to h---, like in half. I barely got it home. Now it will not run hardly at all, will not idle, or accelerate at all. I start it and it idles for a second then shuts down, like it is out of gas. I had about a half tank gas, got gas at the same place I always do. If it sits for a few days, and I start it it will run like norm for about 2 minutes then it shuts down right now.

All I have checked so far is the gas pressure at the rail, steady and holds 14 lbs. Before this happened it was running great like norm. No missing or any thing. I have kept it running with some ether shot into the air intake, long enough to check a few things.I have looked at all the wiring, nothing seems out of place there, the car has been well maintained.

What I was going to check next was the OXY sensor, cause when it does start after a few days of sitting idle, it seems to run just long enough till the sensor gets hot and starts feeding info to the computer.

I know this type of diag. is difficult at best, but give me your educated guess at what it could be. I really don't think of water being in the gas. I know its possible. This manual I have is not very good. Dont give you the check out values for the different componets, like the Ing. mod, etc. It really is difficult to saparate whether it is gas or ignition related. But being I have the pressure there, but there could be some thing sending a signal to the comp. telling it to shut down the injectors. It puts up a code 22, 34, 44.

Thanks and take care..... Gunny If you would rather e-mail me instead of posting it here, until later after we possibly figure it out and post the results. I am at fordvette@sbcglobal.net up here in San Jose.

 

you know it sounds like your maf sensor!

I had the exact same symptoms....

Simply unplug your MAF sensor, it will set a code 34.

It is the sesnor that is right in front of the throttle body, Large black plastic piece the plug is underneath.

Wht will happen is it will set a code but should run smooth again...

If this resolves the probelm then you should also replace the burn off relay as well.

Mo

 

Hi Mo

Thanks for the info. Well it so happens a friend of mine across the street had one of these sensors he had bought a while back. He was thinking it was this too just like you. He had similar problems with his 85. So I took mine off and put his on and it ran the same, crappy. I don't know which one of us that was more disappointed, him or me. It did not seem to change a thing. I even did it like say the dealership would do, erased all the codes, then tried it. He was so convinced this was the problem.

You mention this burn off relay, where and what is that. You might be calling it some thing other then what I call it.

I even talked to another friend of mine that use to have an older Vette, and has worked on them plenty. he first thought it was the sensor too. So this makes at least 4 minds thinking the same thing. The part we tried was brand new, he said he paid something like $160 for it. Did not turn out to be his problem some how so he never used it. The car has good Vacuum too, and you cannot hear any whistles, or things like that, from a vacuum leak.

So what is your next shot at this? My thinking still is on the OXY sensor. I don't know why. I once worked on a Miata, and it had similar symptoms, and it turned out to be the OXY sensor. My thinking cap is really getting a workout here. Too bad there is not a good manual that would give you some readings you could check things like this out, with out having to substitute parts.

Thanks and take care..........Gunny

 

HMMM... how about the coil the electronic pick up? Yes you could also try disconnecting the O2 and see what happens, I'll "meditate" on this a little more as well...

mo

 

Hi Mo

Yes I think that is where I am going to zero in on tomorrow. The sensor, and the module. Maybe I will have a little new info then. Some times it just does not make sense what can and does go wrong with these systems. These electronics are great when they work, but when they don't they can be some thing else. I really appreciate your help here.

Thanks and take care............Gunny

 

All I have checked so far is the gas pressure at the rail, steady and holds 14 lbs. Before this happened it was running great like norm. No missing or any thing. I have kept it running with some ether shot into the air intake, long enough to check a few things.I have looked at all the wiring, nothing seems out of place there, the car has been well maintained. ----------------------------------------------------------------------------------------------------------------------------------- Fuel pressure of 14# is way too low. With the car running it should be mid 30#s. I would look at replacing the filter and pump. Both are quick and easy to change.

 

Hi Spanky

Thanks for the info. I think where I was messing up was I was going by 1984 manual, (did not have a 85) Different injector system all together. It should have dawned on me that this 85 system should require more pressure. So I guess tomorrow I will be replacing the fuel filter first, and see what that does. I will be back letting every one know how it works out.

Thanks and take care............Gunny

 

Good call spanky,

For some reason I went brain dead thinking tht perhaps the 85's were still running a lower fuel pressure.... I know my 89 was running about 40...

Mo

 

Hi Mo & Spanky

Well I changed the fuel filter in the car, and it will start up and idle now, will not take the gas, but it will idle. It is still very rough though. I am going to pull the fuel pump tomorrow. I checked the fuel pressure again and it is still 12/14 lbs. And it will hold that pressure. The fuel pump does run, when ever I got it all connected up after replacing the fuel filter I could hear it running. So maybe tomorrow I will find out some more.

Thanks and take care...........Gunny

 

Hi Mo & Spanky

Can the pump be accessed through the tank filler door???

Take care...........Gunny

 

[QUOTE=fordvettesbc]Hi Mo & Spanky

Can the pump be accessed through the tank filler door???

Yes, it can. Remove the fuel filler door, the rubber filler neck housing, etc.

Before you do, test the output and pressure. You should see 34 to 39 psi and flow rate should be 1/2 pint or more in 15 seconds. This info is from the Helm manual for an '85, page 6C-4. You can run the fuel pump by applying battery voltage to terminal "G" of the ALCL.

Get the manual, best $$$ you can invest.

 

Hi Rcourtem

Thanks for the info, that is what I was thinking. Later years I think is a little more work involved. What is your take on the problem?

Thanks and take care............Gunny

 

You are going in the right direction. The fuel pump is really easy from the top. takes less than an hour. Clean off the area around the access hole first,to keep dirt out.

 

Ok I will keep every one informed as to the progress, so we can all learn from this possibly. Just because you drive a Vette, don't mean you have all the money in the world. And besides the pleasure you get from doing it yourself.

Thanks and take care.......Gunny

 

gunny,

Also besure you are getting the full 12 volts to the pump. It should be the gray wire.

Remove the four screw holding the door to the rear of the care, "carefully' pull up the rubber boot. remove the electrical connections and hoses, and as i recall it is about 4 screws. It is not difficult. The pump is attached to the fuel level sensor so take care pulling it throught the tank opening. As was mentioned clean around the opening and becareful not to rip the rubber gasket.

Mo

 

We have the same car, 1985, right?? It looks like a straightforward procedure, maybe an hour or less. You may need a new gasket or o-ring when you replace the filler assembly.