Ive bought a 91 rs camaro with a v6 in it. Well the guy i know real well put a new fuel pump in the car. He fired it up and it ran for 30 seconds then never hit again. I know its not ecmb fuse or anything like that or the injectors and so forth would have not worked for that 30 seconds. It may be a fuse to the pump or bad dirty filter. I need some body else to give me some info that is a graduate in the third gen world. I'm new ive never had one before.
I gave 300 for it and it is in awesome shape its unreal. But it may take a thousand to fix. He put the pump in the car when it didnt work he got agitated and pushed it back in the shop for it to sit until i came around. Have not picked it up yet. I will get it tomorrow. Cant wait. In my area there is not a single third gen anywhere they all got crushed or went for cash for clunkers.
If anybody can shed some light on this matter that would be awesome. Thanks

 

If the check engine light is coming on, the fuel pump fuse is fine (same fuse).

Did he think to check for fuel pressure at the rail? If not, he probably ought to. Could be the pressure line needs to be blown out as well as the in-line filter by the rear wheel replaced.

 

Sound like the problem I had. Bad injectors 3 of the tested user 10 ohm...

Check filter.... And fuel pressure

 

I'm gonna give. It a rest for a day and hit it sat. Injectors is my next place I'm going to look I'm gonna see if they are pulsing if so I know I've got power there. No telling way the rats ate up on it. The air bag blew out on it when I put a battery in it so I know I've got some problems.

 

make sure he didnt install a tbi fuel pump

 

Ok good fuel pressure. But the injectors are not opening mabie due to computer problem?
Any ideas If I take a spray bottle and feed it fuel to the intake it runs fine until I stop. So electrical from cap and ignition is fine. What's lets the injectors pulse where dose the signal come from go to and end. All fuses are good

 

Check for bad grounds or any broken wires in the harness.

 

Think I know what it may be the chipped key

 

The key disables ignition not injectors. It wouldnt crank at all.

 

Oh ok

 

ok could the computer in took a crap even though it will ran when i feed it fuel into the intake and it run fine while im feeding it. Every thing works on it so i dont know.

 

I've heard bad thing about the computer. I got one out of the junk yard. And mine still acted the same way.

 

W R O N G. The VATS disables the STARTER AND the injectors.

If you know how, pull the codes from the ECM. Check for a code 46. This signals a VATS issue.

Disconnect the fuel injector connector at the front of the engine and check the pink wires for 12V and, using a test light hooked to a 12V source, check for pulsed ground from the ECM when cranking on the blue and green wires. Also test the resistance of the fuel injectors while the harness is separated... Should be no more than 4 ohms per bank (11.8 per injector).

What do you mean it has good fuel pressure? If there isn't a minimum of 37 PSI, it's not GOOD fuel pressure.

 

i got to looking too>>>

System Operation
When the system is operating in normal mode, the VATS decoder reads the correct resistance during cranking. The module grounds the Start Enable Relay coil. When the start enable relay contacts close, voltage is allowed to the "S" terminal of the starter. The VATS module also sends an enable signal to the ECM. This signal allows the ECM to operate the fuel injectors during cranking. The SECURITY light will also illuminate for approximately five seconds, then turn off and remain off.

If an incorrect or no key resistance is read by the VATS decoder module, the module will shut down the start enable and ECM signal outputs for 4 minutes. The SECURITY light will flash during the cranking attempt, and will remain on during the 4-minute duration. Even if the correct resistance is read within that 4 minute duration, the VATS module will not operate the relay or signal the ECM..An error code.53 will also be set if the proper signal is not being received on CKT 229 by the ECM when the ignition is turned ON.


OK well i need more fuel then thanks for the info maverick the old owner is gonna bring me the shop manuals on it then that might give me a little more of a understanding on it.

 

Now i replaced the pump and ive got 51 psi that ought to be good.

 

Still nothing a few hit and misses but thats all it did. Maybe a stuck open injector then released? I am not sure.

 

51 PSI is a little higher than is usually seen. Make sure that when the engine finally runs that it gets down to 47 (the pressure regulator generally drops the base pressure by about 3-10 PSI when the engine is running, most commonly about 3-5 PSI). If not, the return line probably needs to be blown out.

In my experience with VATS, the engine does occasionally hiccup like one cylinder is momentarily getting fuel, even though the VATS has shut off the fuel injectors. Which is why you need to make sure the ECM isn't posting a code 46.

 

ok i cant get it started so i dont know the running pressure yet but when the pump kicks on the needle on the fuel pressure gauge goes up to the 50 mark. i took the old gas out of the tank it looked as if it was beer in there. didnt even smell like gas even old gas. but how do i check for codes?
OR where can i find a carb intake for that motor. i called a dealership on the key and the vat situation and they told me they could order me a key and program the computer to the new key. The key im trying to start it with is a copy not the one that came with the car so its got me wondering. Its got me confused i can walk all over the tbi set up in my truck and not have a prob. this is different ive never had to deal with multi port.

 

When i insert the key and turn the ignition the secure light comes one for a sec then goes off. Dose that mean its functioning normaly or will it allow it to crank and not supply power to injectors.

 

OK i Checked my codes and all i am getting is a constant 12 more than three times in a row fan comes on everything that you tube says. but 12 flashed about 6 times? Whats that

 

Code 12 means that the ECM isn't being told that the engine is cranking by the ignition module (ECM not receiving distributor reference pulses). Since you know the engine runs when being fed fuel manually, the next step is to make sure that the connection to the ECM from the distributor is secure, the 4-wire connector on the ignition module in the base of the distributor.

Since you have no code 46, you need to test the injector pulse from the ECM as I pointed out above. As well as that the injectors are receiving power and there aren't any that are shorted out internally.

Once that is done, try some fresh gas. Worse comes to worse, the injectors need to be replaced or cleaned, but most cleaning shops (that you send only the injectors to) recommend just out and out replacing the injectors due to bad design.

 

i founs A WIRE last night at 2 am hang on a sec its a 4 pin let me post pic.

 

nevermind cant figure that out eather

 

ok on the four pin at base of distributor should there be any power to them at all while key is on and not cranking im not getting no power to any of the wires and fuses are still good

 

ok well i had the icm tested its good and when i probe my ijectors i got power but no pusle. its still hiccuping. Stop i did it wrong I have pusle on blue and green wires on the injector harness. Now to check resistance on injectors

 

There isn't supposed to be any power on any of the ECM wires. The ignition module generates a signal over the purple wire with the engine cranking or running. The ECM sends a 5V signal over the tan wire with the engine running over 400 RPM.

Did you hook up the test light clip (the WIRE end of the test light, not the probe) to a BATTERY source when you checked for the injector pulse? If you left it hooked to ground, you won't get anything, because the ECM is grounding the wires and not providing power.

 

im using a test probe from mac that has a positve and a negitive lead and it shows a ground or a positive feed

 

it showed a negitive pulse on the green and blue wire

 

3.8 on one side and 3.9 on other

 

i guess now what i need to do is pull the injector wires off and ohm out each one and see where they sit

 

Ok injector ohms are all over the place 2 under 11.8 and then they go up to 14

 

I Need Help Diagnosing A Bad Fuel Pressure Regulator.

I Have A TPI Engine In My '90 Iroc-Z And It Has A Loss Of Power, Idles Crappy, & It Starts To Shake & Stall Out After Driving In Stop/Go Traffic After About 20 Minutes. After That I Have To Pull Over & Park It For About 45 Minutes Before It Will Stay Idling Again. I Pulled The Vaccum Hose Off Of My Fuel Pressure Regulator Today & The Hose Smells Like Gas, But I Did Not See Any Fuel Leaking From The Fuel Pressure Regulator While The Car Was Running. Would That Still Mean I Have A Bad Fuel Pressure Regulator, Or Is It Just A Possibility?


Also When The Car Is Running And I Pull The Hose From The Fuel Pressure Regulator It Idles At Around 750 RPM And The Idle Seems A Lot Smoother. When I Plug The Hose Back In Instantly It Starts Idling Really Rough At Around 500 RPM.

 

Try to make sure when you ohm those injectors out that it is some what near room tempeture. Also if there gapped far apart as you said. 11ohm-14ohms, and you tested them well, then they are junk.

 

The ones under 11.8 need to be replaced as per GM spec (11.8 is the minimum for the 3.1).

If you're showing a negative pulse on the injectors when the engine is cranked, the problem is probably the fuel injectors. You have spark and you have power and ground to the injectors but the injectors aren't working. Try replacing the 2 that are under GM minimums first. Put one of the new ones on each bank. The engine WILL run on one bank, but it WILL RUN LIKE GARBAGE.

 

im just gonna put a whole new set in it next week till then im gonna work on the interior. Thanks much for the Info guys.

 

ok i pulled the injectors out of the car its 20 degrees out side cold! but i brought them into the house wich is about 80 and let them sit for a hour. all the injectors Ohm out closer together now. The back two on the rail are still the lowest @ 10.1 and 11.0 the rest was from 12 -12.5 so they are close. Its hard to figure the cold would cause such a big change. I removed the injectors from the rail and looked inside the opening that goes in the rail and could only see the hole in one of them so they are full of crap.

 

Problem Solved i Cleaned up the injectors and put fuel rail and injectors down in a bucket of parts cleaner for two days to soak. Well installed the rail and injectors back in car within a few cranks the car fired right up. Thanks guys for all the info on what i may needed to to. The info that was given helped out a lot. Now for a new problem!

 

Well i said next week but i just now got my new set in and its 8 months since i said that. Well with the new injectors the car runs amazing. difference Night and Day. Lets just hope it stays that way I just could not figure out why it would foul plugs on certian cyl. every time you let it sit for a day or so. well tomorrow im gonna see what happens hopefully its cured.

 

There fowled as in socking wet or pitch black?

 

They was soaking wet. I would burn them off stick them in and go. Well I just it the key this morning and took right off

 

If there just soaked, then i would think that your injector is either sticking open(leaking by when the car is off) A fuel pressure guage would show if this is true or not.

Or you have some ittermitten spark issues on that cylinder.

 

True if it keeps doing it now ill check that. It crossed my mind to do that but I never took the pressure tester home with me from the shop. Now if its a spark issue I'm gonna be replacing the distributer and coil and wires Reminds me I need to dig that dis out of the bottom of my tool box.

 

i do believe that the injectors fixed my problem its been popping off great and never misses a bit.

 

Ok one more question on this whole subject. The car runs great idles great after fixing a few vacume leaks. But question is (my truck dose this sometimes too) first start of the day crank it about 5 to 6 times till it builds up fuel pressure for it to hit is that kinda normal. its a whole new fuel system now i would not think it would take it that long to prime back up. Just wondering if anybody else has the same thing happening