92 camaro 305 TBI fuel delivery problems
trace
I have spark. I've changed the fuel filter. I want to make sure it's the
fuel pump before going to all that work.
- would like to hear opinions/experience on cutting the trunk floor for
access to the fuel pump instead of dropping the tank.
- there's supposed to be a fuel pressure regulator that might be causing the
problem. where is it, what does it look like, and how to test it?
- which fuse protects the fuel pump? I don't see one in the fuse panel for
"FP" or similar.
- is there a fuel pump relay I can check? again, where/what/how?
can anyone here help me out?
thanks. Trace
Joseph Hitchcock
them while you try to start the car/truck. That will help you see if fuel
is even getting to the TBI.
Joe
"trace" <ttri...@spaminator.vvm.com> wrote in message
news:ECudndPcv_a...@vvm.com...
Anthony Fremont
> car won't start. see: http://groups.yahoo.com/group/camaro/message/5220
>
> I have spark. I've changed the fuel filter. I want to make sure it's the
> fuel pump before going to all that work.
>
> - would like to hear opinions/experience on cutting the trunk floor for
> access to the fuel pump instead of dropping the tank.
I've got a 90 IROC that I will probably do this on the next time I have to
change my pump. Your pump can usually be changed without doing the whole
compliment of stuff that the manual says. The tank can be lowered enough
to change the pump without taking the tank completely out or removing the
exhaust system.
> - there's supposed to be a fuel pressure regulator that might be causing
> the
> problem. where is it, what does it look like, and how to test it?
It's inside your air cleaner standing proudly on top of the TBI. When you
crank the engine, you should be able to see gas spraying out of the
injectors onto the butterfly. I would look there first. Next you need to
measure the fuel pressure there, it should be between 9 and 13 lbs. If
it's low (not zero but low), you might have a plugged line, inline filter,
pickup screen or even a bad pump.
> - which fuse protects the fuel pump? I don't see one in the fuse panel
> for "FP" or similar.
Based on a 90 TBI camaro:
The fuel pump AND ECM (computer) run off power supplied by an inline fuse
located behind the battery on the fender. Since you have spark, you
probably have a functioning ECM and consequently a good fuse.
The relay is sort of attached to the firewall just outside of the power
brake booster. IIRC, it's in a cluster of relays kinda sticking out
weirdly. (On page 6E2-A-2) The computer will generate a diagnostic code if
this relay isn't working right.
In the rear of the engine compartment on the passenger side up high is a
connector with one wire mounted so that it just sticks out into the air
kinda stupid like. It should be a RED wire. That's the fuel pump
test/primer connector. You put 12V to that and the pump will run. Make
sure you have the right connector before applying juice. BTW, buy a
factory service manual www.helminc.com They're full of juicy tidbits like
this.
> - is there a fuel pump relay I can check? again, where/what/how?
When you first turn the key on the fuel pump should run for two seconds then
turn off. Put your ear against the gas tank and have someone else turn the
key on, listen for it to run for the first two seconds and then stop. It
should do this each time the key is turned on. Don't crank the engine,
just turn the key to the ON position and listen for it running.
If it's not running when you turn the key on, apply 12V to the test
connector with key off. If it runs then, it's most likely a bad relay or a
bad connection to the relay. If it still doesn't run, it's either the pump
or a bad ground for the pump. Buy a manual, the diagnostic charts are
endless. Tell me what you find out, and we'll go from there.
> can anyone here help me out?
> thanks. Trace
--
michael brown
5:25pm up 18 days, 6:55, 2 users, load average: 1.18, 1.23, 1.18
trace
i've now verified power all the way back to the tank, but the pump's not
running. must be the pump afterall. :-\ hello 6 more hrs of work.
i do have another question: where do you check fuel pressure on a TBI? do
you have to disconnect the fuel line and put the guage inline? is there
something available like a tee with a schrader fitting that i could
permanently install under the hood?
~trace
Anthony Fremont
> thanks for the helpful replies.
>
> i've now verified power all the way back to the tank, but the pump's not
> running. must be the pump afterall. :-\ hello 6 more hrs of work.
Not so fast, make sure the ground return from the in-tank pump is good. If
it's open or is a high resistance to ground, you will get the same
symptoms. The pump needs a good ground return to complete the circuit.
Check the ground wire first, make sure that it's zero ohms in resistance
from the ground contact in the connector to the pump, and car body ground.
It's also allot easier than changing the pump first and then checking the
ground. ;-) The resistance from the fuel pump test connector (under the
hood) and the neg terminal of the battery should be something like 5 or 10
ohms (kinda WAGing it here, I don't remember what mine measured out to
exactly). It should be fairly low as the pump surely draws at least an amp
or two.
> i do have another question: where do you check fuel pressure on a TBI?
> do
> you have to disconnect the fuel line and put the guage inline? is there
> something available like a tee with a schrader fitting that i could
> permanently install under the hood?
I don't know about the throttle body systems, my car has a TPI system. ;-))
I don't know why you couldn't install a schrader valve if one is not
already present somewhere. In fact if you wanted, you could put in a
permanent fuel pressure gauge.
--
michael brown
2:32pm up 19 days, 4:02, 2 users, load average: 0.00, 0.00, 0.00
Tim Thompson
line to check pressure on TBI cars. I don't know of any kit to put a
valve on for checking the pressure.