HELP! 90 Heads Reassembly - A/C brackets

[chevyaddict]

I did it!!! I put a fuel injected, computer controlled car engine completely back together and she is running! I did something REALLY dumb that I'm too embarrassed to share (especially after a feat such as this as I'm only used to working on older 60's and 70's cars). She is purring like a kitten. YAY!!! Thanks to everyone for their input and help... couldn't have done it without ya!!

 

[boomdriver]

I did it!!! I put a fuel injected, computer controlled car engine completely back together and she is running! I did something REALLY dumb that I'm too embarrassed to share (especially after a feat such as this as I'm only used to working on older 60's and 70's cars). She is purring like a kitten. YAY!!! Thanks to everyone for their input and help... couldn't have done it without ya!!

COOL !

good for you...

the really nice thing about trouble shooting is that you go thru every system on the car and by the time you figure out that you forgot to put gas in it, everything else is adjusted and in top shape !

mines been tuned "by proxie" more than once.

 

[chevyaddict]

Everything is great - no leaks or nothing. The only problem I'm having is a hard start when she is cold. I'm having to turn her over about three different times before she is firing up. Once warm - everything perfect. Running perfect. No codes.... is this just a need to drive her awhile and let the computer reset with everything since she sat dead for so long? Battery was dead the whole time too.... I did set the base timing at 6 degrees.... do I need to check it now that she has run a bit?

 

[boomdriver]

Everything is great - no leaks or nothing. The only problem I'm having is a hard start when she is cold. I'm having to turn her over about three different times before she is firing up. Once warm - everything perfect. Running perfect. No codes.... is this just a need to drive her awhile and let the computer reset with everything since she sat dead for so long? Battery was dead the whole time too.... I did set the base timing at 6 degrees.... do I need to check it now that she has run a bit?

The books says that the C4 ECM has a "run" memory that assist it in making faster, more accurate decisions based on past performance. So, yes, drive it a good 30 minutes before its performance stabilizes. If the base timing was set properly with the wire d/c, its probably ok. As far as the cold start and having to turn over several times before firing, mine does that too. Not 100% sure why....the cold start injector is operated by a direct link to the temp/time switch in the intake, but I pulled mine off and it did the same things. I know it has something to do with temps...just not sure where or what. It might be related to the oil pressure switch. I am thinking that IF there were a bad fuel relay, and the pump were running off the oil pressure switch power route, it might take those several crank revolutions to get a bump in pressure to operate that switch and supply power to the fuel pump....but thats just a theory at this point. Makes some sense because the only time the oil system is truely empty is when the motor is stone cold. Any other time there is some oil in the passages so the crank time is less when its warmed, for oil pressure to get to the switch...Sounds good anyway.
I know now to turn the key more slowly and give the fuel relay system a chance to work before getting the starter involved. That seems to help a little. But then again, once warmed even a bit, the motor lights off instantly.

I'd say drive it a bit...putting some easy miles on it...go back and look for loose bolts/nuts, then go for it !

Thats quite an acomplishment putting the accessory system back together after sitting for 2 yrs...If I tear something apart it has to be reassembled asap otherwise I'll forget what it was supposed to look like.!otfl

 

[JAKE]

.2. make sure both oil pressure switches are plugged in. One is for low pressure and will cut off the fuel pump if there is no oil pressure, the other sends the signal to the oil press gauge. The switch has 2 wires and should have power to one side all the time(key on). As long as this oil pressure switch is plugged in and working the fuel pump relay is not critical.

No, re: the highlighted area. There is no fuel pump cut off for low or no oil pressure. This gets passed around a lot, probably because it seems logical, but nope, our engines don't have that feature.

One is a sensor for the dashboard oil pressure gauge and the other is a backup for the fuel pump relay. Should the fuel pump RELAY fail, the fuel pump will still be energized once that sender sees around 4 psi of oil pressure. It's like a back-up to keep folks from being stranded.

If fact the L98s and the LT1/4s will run quite happily with ZERO oil pressure, but not for long. Both my 86 Vette and my 96 LT1 Vette engines ran normally with ZERO oil pressure.

The 86 was due to a defective FRAM oil filter. I've posted on that issue on several other Forums and is why I ALWAYS warn to stay clear of FRAM.

Here's how it happened: I changed the oil and filter on my 86 just as I'd done for over 40 years. Fired the engine and ZERO oil pressure. Shut down the engine immediately and checked down under but no leak, so I re-fired the engine. Still NO OIL PRESSURE. So I re-installed the old filter and BINGO! oil pressure returned to normal. I then drove back to O'Reilly's and exchanged the new FRAM filter for a ACDELCO (IIRC) and when I installed it all was well again.

The 96 LT1 was when the oil pump drive gear failed; ZERO OIL PRESSURE.

I thought this no/low oil pressure - fuel pump shut down claim had died out but I still see it pop up from time on other Forums as well. Wonder how it ever got started? Maybe some foreign car(s) have that feature??

Hope this helps.

Jake

 

[chevyaddict]

Way long time ago back when I was a youngin I worked at Autozone and used to always tell people not buy Fram oil filters because I had heard all the stories... this is a pretty bad one! Although as of late I've been using them. Maybe I should stop again!

After driving her all day yesterday she is starting up beautifully just as before this job so I think the computer just had to get itself readjusted. Its funny how cars have to "settle in" again when they have been sitting. She is making some interesting little noises and the radio is being difficult but I think this will all work out in a couple of days. I forgot just how awesome this car really is to drive!

And BTW, I can't believe I successfully reassembled this car after all that time either. That, frankly is the reason I kept putting it off -fear of not being able to get it back together. I completely forgot everything, didn't take notes, and not good pictures. But really most of this stuff goes back on only one way and thanks to those awesome A/C bracket photos it wasn't too bad! Believe it or not I didn't have ANY bolts left over either which almost always happens with a job this big!

 

[boomdriver]

No, re: the highlighted area. There is no fuel pump cut off for low or no oil pressure. This gets passed around a lot, probably because it seems logical, but nope, our engines don't have that feature.

One is a sensor for the dashboard oil pressure gauge and the other is a backup for the fuel pump relay. Should the fuel pump RELAY fail, the fuel pump will still be energized once that sender sees around 4 psi of oil pressure. It's like a back-up to keep folks from being stranded.

Jake

umm
respectively disagree...sort of.

sure, the intention may have been for fuel pump backup power, but when the power is running thru the oil pressure switch, with a failed fuel relay, the loss of oil pressure also means the loss of the fuel pump......

That may NOT be the design intent, but thats the way it works. Is this flawed engineering, or misunderstood intent?
Its possible that it was intended to have a dual purpose. There are many other places to get alternate power when/if a relay fails. Distributer pulse, flashers, anywhere that had a way to signal that the engine was on or turning over.

How is anyone supposed to know when their fuel relay is bad if the system uses something (the oil pressure) thats always there as an alternate path? Harder starting? Most people would'nt look at the relay until after they had eliminated many other things.

Makes me wonder if there was not some debate @ GM regarding the intention of this switch. With this switch, the relay is all but pointless. Without oil pressure, you really do not need fuel....in fact, you do not want fuel. So, why else would the designers use oil pressure to complete an alternate power route?

For grins tomorrow I am going to remove the fuel relay and see what happens.By the condition of the plug and last inch of wire it probably does not work anyway.. According to everyone (and the FSM drawing) the fuel pump will run fine by way of the oil pressure switch. Now, what happens if that switch is disconnected? I think the fuel pump will not run. Not if it has no way to get power.

regarding the Fram filter fear....I have experienced the same effect on start up with a new fram filter. This happens because fram uses a different filtering media and it takes a little longer to pass oil (cold oil) thru the low micron element.It took mine perhaps 3 seconds :ughfor pressure to appear. Frams not the 1st choice but nothing to be afraid of.
Having a background in hydraulics, I can tell you that ALL spin-on filters benefit from having at least some fluid in the filter before installing. This helps with saturation and reduces the time that the oil pump will waste filling the can instead of circulating. If its really a concern, pulling the distributer power lead and cranking for a few seconds will also help fill the filter. The ultimate answer is an oil accumalator. For $250 you can have oil pressure before the starter engages. With an est 80% of engine wear coming from dry/cold starts, thats a damn cheap investment. Problem is, where do you put one on a vette? ...they work alot like our fuel relay in priming the injectors prior to starter engaging.

This is a good arguement for products like Prolong or other additives that help protect against wear from dry starts,. that and the no cutting off fuel- fuel pump backup switch.

 

[vetteoz]

. With this switch, the relay is all but pointless.

True but
The relay allows the ECM to prime the rails key on, which when working correctly allow instant starts without cranking
My 12:1 383 will fire 1st time without even hearing the engine crank over

.
How is anyone supposed to know when their fuel relay is bad .... Most people would'nt look at the relay until after they had eliminated many other things.

If you venture to the other C4 Forums,
invariably the first question asked of anybody complaining of long crank / hard starts is
" are the rails being primed / can you hear pump run , key on? "
to indicate if the relay is working

 

[boomdriver]

True but
The relay allows the ECM to prime the rails key on, which when working correctly allow instant starts without cranking
My 12:1 383 will fire 1st time without even hearing the engine crank over


If you venture to the other C4 Forums,
invariably the first question asked of anybody complaining of long crank / hard starts is
" are the rails being primed / can you hear pump run , key on? "
to indicate if the relay is working

True, the relay permits that fast prime for the injectors...where the switch on mine takes 2-3 seconds of cranking to get that pressure spike to close the switch. Its hard on my motor too...Mines not stroked but its bored way over. I've got a new fuel relay & pigtail coming, and may look into a simple modifacation that will do things a little different.
but first, a small accumalator to solve all the oil/switch pressure problems...if I can find a place to mount one. The "can" is about the size of a roll of paper towels. Having oil pressure before the starter turns over....without a doubt, priceless !

 

[chevyaddict]

Code 32

Ok, so I've been driving her for about four days now. Running great except two things. First, twice now she has died and then when I try to restart she pops and backfires .... and that after about two tries she fires right up and is fine. I just put my second tank of gas in her. I honestly think this is just bad gas from sitting for over two years so I'm not too worried about that. Now that I put the second tank of gas in her I imagine that will stop. When I pulled her in today from this problem happening about 10 miles ago though the exhaust smells funny..... I'm wondering if I need to put some stuff in the tank to absorb water? Thoughts?

The second problem is an intermittent code 32 which is an "egr system" code. I put a new EGR on her since I had her apart but I'm wondering was it the wrong one? She just passed emissions with flying colors so..... do I do anything about this?

 

[boomdriver]

Ok, so I've been driving her for about four days now. Running great except two things. First, twice now she has died and then when I try to restart she pops and backfires .... and that after about two tries she fires right up and is fine. I just put my second tank of gas in her. I honestly think this is just bad gas from sitting for over two years so I'm not too worried about that. Now that I put the second tank of gas in her I imagine that will stop. When I pulled her in today from this problem happening about 10 miles ago though the exhaust smells funny..... I'm wondering if I need to put some stuff in the tank to absorb water? Thoughts?

The second problem is an intermittent code 32 which is an "egr system" code. I put a new EGR on her since I had her apart but I'm wondering was it the wrong one? She just passed emissions with flying colors so..... do I do anything about this?

I would take another look at the fuel pressure regarding the stalling then popping and spitting on restart. Low fuel pressure does exactly that...A clogged filter would not be a shock after sitting that long. it takes at least 20 PSI to run the engine and anything less will make the motor backfire and spit and burp. Low battery voltage does that too. Less than 10.5 volts.
Some SeaFoam would not hurt. Lucas makes a good fuel system cleaner, and so does DuraLube. Stay away from the store brands and the cheap stuff because its often just paint thinner, xylene, naptha, turprentine or alcohol. Marvel Mystery Oil is also good for cleaning a fuel system. Add to a tank of gas.

Check the fuel pressure first. Your new gauge should be pretty steady. If the needle bounces alot, or flickers more than a couple lbs at idle, thats a sign of a flow problem. 40-45 lbs steady is a good number,. A drop of maybe 5 psi then right back up to where it was whenever you rev the motor. The needle speaks volumes about how the fuel is flowing thru the system. The PSI number is one thing, but the behavior of the needle will tell you about the volume. The system should hold the pressure for at least 1/2 hr after shut down. A good system holds for hours.

The EGR code could be a vac line to the egr solenoid. That line is split with the fuel vapor recovery can, and connects to a fitting under the throttle body. The egr solenoid plug might be off.

The egr valve is easy enough to test.....get the vac line to the valve, and pull a vac (even sucking on the hose is enough) and use a mirror under the edge of the egr valve to watch to see if the valve diaphram moves. If the egr was stuck open, that too could cause the engine to die and a hard restart. Usually that will also make the performance sluggish or flat.