91 camaro surging

Hello, I'm new here but anyhow have several projects but my 91 camaro RS is surging at idle and bogs down when trying to drive. I have changed out the fuel filter, cps- thottle senser, coolant senser- because my fan also wont come on unless my A/C is on, and cleaned my throttle body. This has a 305 tbi.
How can I check the fuel pressure on this tbi?

Any help appreciated...

the problem with your fan not coming on is the switch that's in the side of the engine block underneath the head on the right (passenger) side. as for your "surging" is the service engine soon light on? If not you might have a mis-fire.

the problem with your fan not coming on is the switch that's in the side of the engine block underneath the head on the right (passenger) side. as for your "surging" is the service engine soon light on? If not you might have a mis-fire.

Thanks for the speedy reply, the only thing I've seen on the passenger side is the knock senser at least thats what I read it was,., I ran the code and get a code 44 - lean exhuast . I've also have changed out the o2 sensor with no change.

Thats a cool camaro u got.

the knock sensor is on the front of the block, this sensor is on the side. Disconnect your negative battery cable for 10 minutes to clear the codes. when you re-connect it, see if it throw the code again. If not, start troubleshooting your ignition components.

both sensors are on the passenger side, but the cooling fan switch is closer to the back of the block (between the 6th and 8th cylinders) and a bit higher than the knock sensor.

yea, what he said...

yea, what he said...

Ok thanks, I'll look for the sensor again next time I have it up on the stands. I started putting on some new plugs and wires, and also have an Accel cap and rotor to put on.
I've unhook the battery before but the code comes back.

From Haynes Manual...

Code 44: Lean exhaust

Lean condition caused by malfunctioning carburetor/fuel injector, vacuum leak, low fuel pressure, etc.; poor electrical connection, open or short in circuit, defective MAP sensor; defective oxygen sensor, defective ECM.

be careful if you go to replacing that fan switch, it is directly linked into a coolant passage, so when it comes out coolant is going to start gushing out, i know, i took a shower in coolant when i did it. so if you dont drain the coolant first, make sure its not hot when you do it.


as far as the surging, its definatly related to the lean code, which may be clogged fuel injectors, i would get a can of BG 44k, or other fuel system cleaner, and run it through the tank and see if it helps any. to check the fuel pressure, youll need a fuel pressure guage, and fitting. find the black cap on the fuel rails, and unscrew it there should be a valve underneith that your fuel pressure guage should screw onto. then turn on the engine and read the fuel pressure, should be around 40-45 psi with the engine running.

also, im slightly leaning towards a faulty MAP sensor on this from prior experience with a similar problem. but dont put any money on that, its just a feeling.

also, im slightly leaning towards a faulty MAP sensor on this from prior experience with a similar problem. but dont put any money on that, its just a feeling.


Thanks for the input 89IROC&RS, would'nt I get a code for the map sensor though? As far as the fuel pressure I have a throttle body so I dont see any fitting, I was on thirdgen.org and they have a link to a tbi specialist that has some good info on tbi's, www.cfm-tech.com. They show how to check for fuel pressure on the tbi's.
Thanks for the shower tip, coolant sensor.

I may go ahead and replace my fuel reg. , but I'm going to check the pressure first.

Thanks

From Haynes Manual...

Code 44: Lean exhaust

Lean condition caused by malfunctioning carburetor/fuel injector, vacuum leak, low fuel pressure, etc.; poor electrical connection, open or short in circuit, defective MAP sensor; defective oxygen sensor, defective ECM.
werd

maybe thats where i read it............ ;)




but no i really did have a similar problem that was a map sensor, so just an idea.

my brother had same problem ,found to have a bad fuel pump

i would get a can of BG 44k
======================================WJFK....... 106.7.......... huh?

BG is a company that sells products for automotive applications. their 44k is a fuel system treatment that you pour into the tank. it removes varnishis, carbon deposits, and cleans injectors. ive used it in all of my families cars and also done the BG induction service, and they make a drastic difference. i did both to the IROC when i brought it home, and also did the throttle body service, (man the nasty black shit that came outta that thing was scurry) and thats one of the reasons i wound up parking her on the back lot fence that night. throttle responce was frickin sick. (in a good way)

If you step on the gas and it goes for a while hte nbogs down like you are tugging a buick then its probably a bad fuel pump. thats what my car had w/ bogging. It practically had a heart attack whne I turned on the A/C literally jumping around like a person just learning a tsickshift would drive. have a mechanic check the PSI of it if you can't do it yourself

If you step on the gas and it goes for a while hte nbogs down like you are tugging a buick then its probably a bad fuel pump. thats what my car had w/ bogging. It practically had a heart attack whne I turned on the A/C literally jumping around like a person just learning a tsickshift would drive. have a mechanic check the PSI of it if you can't do it yourself

I check the fuel psi, while running was 5 psi, I read it was supposed to be 9-13 psi. Their is 2 fuel lines going to the tbi, does it matter which one I use? Thinking maybe bad fuel regulator.

Thanks again for all the help!!

Warren

yes it matters, one is the input line that will be at full pressure, and the second line is the return line, after the pressure regulator and the fuel is under far less pressure.

the big line is the input line, the small line is the return line.

yes it matters, one is the input line that will be at full pressure, and the second line is the return line, after the pressure regulator and the fuel is under far less pressure.

the big line is the input line, the small line is the return line.

Ok thanks, there was 2 different size lines and the fuel psi gage only fit on the big line, just wanted to make sure, mmmm sounds like fuel pump now......

did you ever change the fuel filter????

did you ever change the fuel filter????


Ya I changed the fuel filter out, was trying all the simple stuff first.

ok couldnt remember

Ya I changed the fuel filter out, was trying all the simple stuff first.


UPDATE: Well I put a fuel reg. rebuild kit in and still have same problem, psi is still only 5-6 psi while running.

5-6 psi?! It should bel ike 40-50 psi! (Atleast that what it is for mye v-6 i would sasume it should be the same, )

5-6 psi?! It should bel ike 40-50 psi! (Atleast that what it is for mye v-6 i would sasume it should be the same, )


Well this is a throttle body, tbi. at www.cfm-tech.com thats what they say it should be 9-13. I think for a multiport its 40 -50. I guess I'll hook up my gage to my 88 chevy truck, it has a tbi also and see what it reads.