mtlgta

Hi , need advice I own a 89 GTA 350 it is all stock .Two or three times a month it will crank but not start after letting it sit for 6 to 10 hours it starts . I have taken it to several shops they checked fuel pump good ,injectors good ,coil good ,ignition coil good , ignition module good , spark plugs and wires good , battery ,alternator , starter good .It does this in the summer and winter any ideas why it does this ?
(Vats was bypassed)

Thanks in advance

86T/A_Ram_Air

my first question has to be how was vats bypassed? i had a similar problem on one of my cars, it wound up being a cranky fuel pump....most of the time it worked, and then it would stop.....and then one day it died.....its very possible there is a intermittant short in the pump itself. lets face it, GM fuel pumps, not very realiable

transam85dudeman

replace the coil , hot coil syndrome the coil is good for 9 minutes then dies, and doesn't start.. next test the tps make sure it isnt set too high in values or it wont start
(tells the computer flood or some stuff). then check the coolant sensor connector wires under the throttle body for shorts, and check the pickup coil resistance between 500-1500 ohms. Mine wouldn't start a while back, it turned out to be the ignition coil, it tested good, but after 88600 discharges it would get hot and fail. also if coolant sensor is bad or wire broken to it, i doubt it would start there also. My pickup coil (not the bulky coil with spark plug wire, but in the dizzy under the ignition control module) was testing good, however the reference point was off due to the internal magnet built into the pickup coil broke in 6 different spots. The pickup coil tells the computer the where the crankshaft is, and what cylinder when to pulse the injectors and spark via module. . just some places to start lookings nothing to extreme, im almost certain youll fix it.

-check the oil pressure switch it wont continue to have fuel power unless pressure. most likley the pickup coil or ignition.

irocuroc

the shop said injectors were good.. how did they check them. Most shops do not check them right. get a ohm meter and see what they read hot. If any are below 10 they are shorted and will shut the ecu down.

mtlgta

I thank you all for your replies , now I have a place to start .

I will keep you all posted , thanks again .

mtlgta

Hi guys, this weekend I was going to check everything you guys posted but a fellow co-worker said that i should get under the car with a piece of wood and whack the gas tank a few times and then try and start the car , if it starts its the fuel pump .
I just got home from work tried it and it started now I guess its the fuel pump . I don't have the experience to drop the diff and then remove the gas tank , would any one know were it's located so I can cut a hole from the inside of the car .

Thanks in advance .

rgarcia63

I posted a pic on reply #5 here. https://www.thirdgen.org/forums/tech...-question.html
If you need actual measurements do the following:
Measure the flat surface distance between the 2 stiffeners on your rear deck as shown in the picture. Left is rear of car.
Print the picture to whatever size you want measure the same flat surface.
Use proportional equation to determine actual size of cutout. Example: fractions 3/4=24/n, n=(24x4)/3, n=96/3, n=32
Car flat surface = 15in.
Picture (printed 8.5 x 11) flat surface = 3in.
Picture Cutout width = 2.6in.
Equation (15 x 2.6)/3=13 Actual cutout width = 13in.
Replace 2.6 with any picture measurement to convert to actual size.

Stephen

iTrader: (12)

86T/A_Ram_Air

ive never done that for fear of cutting into the fuel lines

mtlgta

Hi Guys , what brand of fuel pump should I buy ? I don't want to go cheap on this item ,I want to use a brand that is reliable .
Also is the sending unit part of the fuel pump should I change that also ?

Thanks again

Stephen

iTrader: (12)

Typically, the tank is pulled, the hole cut, the lines cut & that is pretty much the last time the tank has to be pulled, unless the tank itself has to be replaced/worked on.

rgarcia63

If you use a disc cutter it shouldn't be a problem.
All fuel lines will need to cut. The supply line will need a compression coupling the rest can be coupled with short hoses and clamps.
From the picture (if yours is the same) it looks like just the harness maybe in danger of being cut.
Cut the 1-1/2", 1-1/4", and 9/16" sides then lift enough to move harness out of the way as you cut.

rednekwizard

My 86' needs help, it keeps flooding itself out and won't start, would an adjustable fuel pressure regulator help or would it just be a waste of money.
I have done replaced the TPS and the spring and diaphragm in the regulator.

witnlyn

check your collant temp sensor, mine was bad and would flood like crazy.

transam85dudeman

adjust the tps

rednekwizard

I adjusted it everywhich direction it would go, but it still wont start, I'm going to picapart to get a pickup coil and coolant temp sensor, plus I'm ordering a 50,000 volt coil from summit, the one it has now barely lights up a spark tester.

mtlgta

Hi all , I need to replace my F/P went to GM they quoted me $185.00 for a stock ACDELCO unit .

Then I went to summit racing they have the ACDELCO F/P for $119.00 , is it the same pump ?

I have a 89 GTA 350

Thanks in advance .

transam85dudeman

i paid 163 too, its a bummer, then i learned about rockauto.com they have a/c delco fuel pump on closeout (whatever that means) for like 40 bucks, plus there coupon codes somewhere on this site in the message board to even take an addition 10% off. when you replace the pulsator thats located between the fuel pump itself and the hard-line, i recommend special high fuel pressure clamps(for an example of what these are, check you powersteeering pump return hose clamp, they come stock) and a neoprene hose (typically in the a/c delco box with the pump.. The first pic is the pulsator, the second pic is the crimped clamp, and the third pic is the tool to crimp the clamps. good luck, and for idea purposes only, i recommend ordering a free catalog from Paddox parts https://www.paddockparts.com/Paddock...treq&mscssid=&

Almo the Pirate

after running for a couple minutes, my car refuses to restart unless i let it sit for 5 or 10 minutes. do you think all that would apply to me too? anything else it might be?
ive checked the fuel pressure, its at 40 psi and doesnt drop when i shut if off so its not a leaky injector.

transam85dudeman

if you're asking me? If it cranks, make sure to check the Throttle positioning sensor first to determine its at 0.054volts with key to on position(if its set to high it wont start).. my personal experience with cranking and no start is check the resistance of pickup coil first, 500-1500ohms, (when i had a hot start problem i noticed my pickup coil's permanent magnet was shattered in pieces, throwing off the injector pulses and spark.) next check the coil, should measure good, because it doesn't fail until hot. (If you wanted to you can run the car till it wont start, then test the ignition coil.) I spent the cash only after i checked the ignition coil resistance and color of spark, after visually inspecting/testing resistance of the pickup-coil, had autozone test the Ignition module(requires special thermal grease to reinstall if its removed, 3 bucks), and the resistance of the coolant "sensor" voltage and resistance..also i checked for broken wires leading to the coolant sensor to. In the end, i replaced the ignition coil, and bam, Mexico power(autozone joke) it ran. But i was cautious at first so i didn't drive too far, in case it didnt work. Now its solid enough to see one of last Space Shuttle landings on the 21st.

mtlgta

Finally dropped the tank replaced fuel pump , it runs great .( thanks 86T/A_RAM_AIR)

I also changed the pick up coil . (wires , plugs , rotor , changed but they never changed the pick up coil ) Thanks TRANSAM 85 DUDEMAN .

(STEPHEN thank you for the pics but we went with dropping the tank )

The car cranking and not starting or cranking and starting after the 4th or fifth crank is now fixed .

Now the only issue I have is when I filled up the tank it was leaking from were the filler neck meets the tank is there a way to fix that with out dropping the tank again ?


Thanks In Advance

transam85dudeman

probably not, you might be able to get away with some of that fuel tank repair putty. it goes on soft and dries hard. its made for fuel tanks. i dont whats it called.. Or you can dropp the tank again and dump the fuel. theres this special liquid you put in the tank to kepp it from blowing up while you braze weld the area thats leaking

mtlgta

Has anyone used "J-B Weld" does it work ?

would it stop the leak I have coming from the filler neck ?

any advice greatly appreciated .

Gregzz4

Whoa there!!!!
Don't do that. I work in a Rad shop, and after all the fuel tanks we have worked on/heard about guys working on, I can tell you.....DO NOT PUT HEAT TO YOUR TANK until you are absolutely shure it is not going to ignite.
I am NOT trying to promote my industry. Just saying you need to be Very Careful.
Don't trust ANYTHING you can purchase. Nothing has been proven to make it safe enough to use a torch on a fuel tank.
Now, if you want to use a Hot Iron and try to solder it yourself, you need to learn to solder all around the connection as Lead runs like Mercury.
It can be done, although it's tricky, and you need to get both surfaces very clean and make sure they are 'tinned' before you proceed. That is that they have already accepted solder and then you can proceed to try to bond them together but if they are different thicknesses of metal then you will need to get the thicker of the two hotter first, watch the other get shinny with the lead you applied, and then apply the solder/lead to the surface, don't melt it with the torch, and you should know the rest.
If you don't, take it to a shop. Pull the Tank and have it Professionally done. Nothing like spending some money for some safety/security.

Gregzz4

[quote=mtlgta;4461665]Finally dropped the tank replaced fuel pump , it runs great .( thanks 86T/A_RAM_AIR)

I also changed the pick up coil . (wires , plugs , rotor , changed but they never changed the pick up coil ) Thanks TRANSAM 85 DUDEMAN .

(STEPHEN thank you for the pics but we went with dropping the tank )

The car cranking and not starting or cranking and starting after the 4th or fifth crank is now fixed .

Now the only issue I have is when I filled up the tank it was leaking from were the filler neck meets the tank is there a way to fix that with out dropping the tank again ?

Yes, there is JB Weld you can use, and the Fire Department uses something I can't recall from a company in Seattle to paste small leaks.

86T/A_Ram_Air

your very welcome, always a pleasure to help someone out

Chevy86 IROC-Z

iTrader: (17)

What!!!!!! How can your TPI flood if it's a F.I. system?

rednekwizard

No clue, but thats what it does and no one can figure it out, I pull the plugs and they are soaked in fuel and get fowled out about three or four weeks.
I've taken it to the shop and they charged me ninety dollars to tell me what I already know, Not a damn thing.
The only thing I can now do to correct it is to change the injectors and see if that fixes the problem.

Stephen

iTrader: (12)

I'd wonder if your plugs aren't firing like they should, if there is leftover fuel. I'd doubt that all 8 injectors would leak at the same time vs a dizzy not firing all 8 plugs.

rednekwizard

I also found out that the 350 TPI that I have in my Z came from an 86 corvette, Through trial and error I was trying to find a Mass Airflow sensor and finally crossed the numbers from the one in my car and it only comes back for the 86 corvette.

rednekwizard

Brand new distributer from CSK performance and accel module with new cap and rotor, and i had to go back to the stock autolite plugs.

rgarcia63

Temporarily pull there "Crank Fuse" which powers the cold start injector. If it stops flooding either the injector is leaking, or the cold start temp switch is bad.

That doesn't rules out leaking cylinder injectors, or faulty computer control.

witnlyn

collant temp sensor would make it think its subzero temp and add tons of fuel at start up.

rgarcia63

The coolant sensor needs to read less than 20°F and more than 210°F for the ECM to set a DTC, but no DTC doesn't mean the sensor is reading correctly it can still be faulty enough to dump extra fuel and not set a DTC. Gray smake out the tail pipe is indicative of a coolant sensor reading colder than normal.

ATX-Iroc

Put a fuel pressure gauge on it and see if it holds pressure after it primes. It should hold pressure for a long time, you shouldnt be able to see the needle move. If the pressure bleeds off fast you either have a leak or bad wiring so unplug the injectors and try again, if unplugging the injectors solves the problem look to the ecm or wires. I can help you if that turns out to be the problem.

rednekwizard

Would having the original camaro ECM with the vette motor be an issue?
Would it be a good idea to get a vette ECM from my local picapart, since I know that there is one 86 vette out there that matches my motor?

rednekwizard

The coolant temp sensor was an issue, it had a busted harness so I changed it to a new one but still having issues with it.

rgarcia63

Did you disconnect the battery for a few minutes to reset the ECM?

The Vette ECM may not be the same model of ECM you currently have, if not it may interchange, verify to be sure.