91 Camaro Rs 305 TBI

Well im in a bit of a dilemma and could really use some help.

Ive been trying to troubleshoot what has been causing my car to hesitate when i accelerate. If i stop at a stop sign and press down on the gas the car will jolt for a second then go.

Not only that but when i start the car sometimes it will just bog down and start trying to die unless i give it gas for a few seconds and maintain a steady RPM for a bit.


One thing Ive noticed is that when I pump gas and fill up the car, the car wont hesitate anymore at least for quite a bit. But i mean its not like im always running low on gas I try not to go under half a tank so i know its not a running out of fuel issue. (Although when i first got the car a few months ago, it would usually always be under half a tank of fuel so i don't know if this could have caused a fuel pump issue.)


Things ive tried so far/Things i found

-New fuel filter

-New IAC

-New 02 sensor (ran a OBD 1 scanner a while back gave me code 44 Lean Exhaust)

-New PCV (read the troubleshooting on Haynes manual suggesting a plugged pcv)

-changed spark plugs (ac delco)

-New distributor cap and rotor

-Haven't done spark plug wires yet but at this point im really doubting that's the issue.

-Fixed 3 vacuum leaks that i found (cracked hoses) Positive there is none left about 80% positive

Symptoms
-Car tries to die on start up
-Hesitation
-Hard starts (possible starter going out?)
-Dies while going into reverse
-Heard a grinding noise once when starting the car coming from the back


Im no expert only have basic knowledge of cars but im really trying to get in there and fix this myself along with a couple of friends that have been helping me out.

Questions

1) Is there anyway for me to check the fuel pump myself? or do something to test the pump?

2) Can i completely rule out the spark plug wires? Wouldn't i have backfires if these were the issue?

3) should i upgrade spark plugs to something better? any in particular recommended?

4) How much can i expect to be charged at a dealer for a diagnostic?

Thanks for taking the time to read this.

 

Id have to start by telling you to check your grounds. (Battery ground cable, etc.) This souns like it may be an issue with your starter solenoid grounding out ( may explain the sound coming from you car too..) If something's not grounded right or just loosens up it may cause your coil to heat up not work properly... I'd start with your grounds before jumping to fuel...

 

1. Unless I missed it, have you replaced your filter? It's easy to check the fuel pressure- replace your filter, and check the pressure. If that's not it, maybe you have an injector that's leaking/plugged. You can pick up a pressure gauge w/ the adapter for the schrader valve, test pressure KOEO, and KOER. Replace the fuse with a new one of the same amps that is good, check the relay (if there is one), and make sure that you are getting a full 12 volts at the pump with both KOEO and KOER.

2. Take a voltmeter and test the resistance of the wires. One easy way is to take a long screwdriver with a LOT of insulation on the handle and follow the wire from distributor cap to plug while the engine is running. If there's a leak, it will jump to the screwdriver. Check first in a dark garage with it running, and look for any 'lightning bolts' of it arcing to the block, heads, brackets, etc.

3. If your plugs haven't been replaced in a while, it won't hurt any. Delco's or Champions. Copper is good.

4. Plan on about $100/hour at the stealership....that's what they charge around here at least. Keep in mind, if it takes you 8 hours to do what would take them 4, that's still $50/hour your paying yourself.

What cap and rotor did you get? Try and always get a set with copper contacts- they conduct current more effeciently than the steel/aluminum kits.

 

Ahh i forgot to add the fuel filter on the list, ive actually already replaced my filter and im still having issues.I want to say the brand of the cap and rotor was duralast.

What would be an effective way to check for a leaking injector?

Im gonna check my fuse box today to test for any bad fuses. I dont own a voltmeter nor know anyone that does but ill probably check my local autozone. Il post an update soon.

 

I think my grounds are good, is there an effective way to test this? basically just tighten everything up right?

 

First and foremost, get a fuel pressure gauge. IIRC, Advance has decent ones for about $20.

You can pick up a good voltmeter for cheap at Vato-Zone or Advance, or (my recommendation) is get a good one for a few bucks more at Sears- mine does everything including read temp, which comes in handy more than you'd ever think. Just like sliced bread, I don't know how I got by before it.

When I had a CFI car, I just removed the air cleaner assembly, started, and looked at the spray patterns. If it doesn't look like a perfect triangular mist, it's clogging or wearing out.

http://www.google.com/images?um=1&hl...=&oq=&gs_rfai=

If your fuel pressure checks out fine and the spary pattern is bad, run some BG 22k through it (about $25/can) with a full tank of gas. After the 3rd tank, change your filter again. If it is still continuing, it might be time to replace the injector(s).

I haven't had a TBI setup for a while, but with the MPFI that I've had in the past, a leaking injector will cause that side/runner of the intake to be 'washed'- it will look pretty d*mn clean inside the intake and runners versus the non leaking side. If it's a FPR that's gone bad, typically all the fuel drains back to the tank, meaning you have to key on/off a few times to prime it (which is why it starts hard the first 1 or 2 trys).

 

Thanks hawk im gonna go ahead and look at the spray pattern on the injectors.(might even post up a video of what i found a bit later) It might just be the FPR because that's exactly what i have to do to start the car, and its worse on a cold start, about 3 cranks.

What would be the norm when it comes to fuel pressure?

How can i check the regulator? would the pressure reading tell me everything i need to know about the regulator?

 

Chilton says 9-13 PSI for TBI, 1-2.0 ohms resistance on the injectors.

A weak fuel pump can cause the same symptoms as a FPR allowing drainback- that's why you need to measure the fuel pressure . No point in spending money on an FPR if it's fine and the pump is the cause of the problems.

 

As far as checking your grounds yeah, also be sure while you're takin a quick peek that they aren't rusting or anything... Or if they're "floating" grounds that whatever the other ground wires lead to is ok.