Texasborn

Well, started out with a bad stumble. I pulled error code 22 from it? or whatever the TPS error is, I forgot. I tested it and it was bad. So I replaced it.

Next error code was 44. O2 Lean. Tested it and it tested bad. So I replaced it.

It still falls on it face. Injectors are flowing great. New fuel, Lucas injector cleaner, disassembled and cleaned injectors.

If you move the TPS by hand the injectors dumps fuel so I am perdy sure the fuel flow is good. But when you crack the throttle it dies or falls on its face/stumbles.

Every thing points to a lean condition. But everything seams to check out good.

I have a OTC MONITOR 2000 DIAGNOSTIC COMPUTER, if you remember it was a very high end tool for ODB I ECC's. And it says the car is now good to go. With no codes.

Any Ideas? Its getting close to winter and I would like to get it out and running before it gets cold.

Thanks in advance.

Chris

Midnight 85

You don't mention what year the car is and your profile is not filled out so I can only ask if you set the tps properly when you replaced it? some are adjustable while the newer ones are stationary but only you know what you have.

CFI-EFI

Tested what? Replaced what? From your description it DOES sound like it's lean. Have you checked the fuel pressure?

RACE ON!!!

Texasborn

My bad, '84 Corvette, bone stock.

Texasborn

Tested TPS, replaced TPS. Tested O2 sensor, replaced O2 sensor.

Cleared codes, no new codes are present.

Fuel pressure. No have not tested. Not sure how to do it, My test equipment is for newer FI cars. And would the fuel pressure change by its self?

Thanks!

Midnight 85

I know what CFI is going to say, "Get the Factory Service Manual". The FSM will show you all you need to know, meanwhile LISTEN to CFI he will steer you right.

0Paul Ruggeri

The fuel pressure should be about 12 psi. You need a gauge that goes in line with the fuel line since these cars don't have a test port. Some times the MAP sensors go bad without setting a code, so that could also be the problem.

Good Luck, Paul

redrose

FIRST check on ANY/ALL fuel injected engines is FUEL PRESSURE.

ALWAYS.
ALWAYS.
ALWAYS.

yeah, lots of other possibles, do FUEL PRESSURE check FIRST !!!!!!

many early tBi models do not have a test port, you will need to fab a test hook-up, fuel pump will max out at under 15 psi so ''common'' rubber hose/clamps/brass tee will do (for early tBi only, multi-port systems need ''exotic'' connectors)

rick lambert

The 84 is somewhat different than what I'm used to, but have you checked the voltage at the TPS at both positions? Closed and WOT?

Texasborn

So can I tap in any where past the fuel pump? Or do I need to cut the hard lines going into the injectors? Aslo I thought I saw a online how-to on this subject. Any ideas?

Texasborn

Yes voltages are right on the button, both WOT and idle.

CFI-EFI

If it couldn't change by itself, they wouldn't sell fuel pressure gauges. Pumps get tired, filters clog, rubber fuel lines deteriorate, etc. Yes, it can change by itself. I have been saved from bringing up the FSM, which is a must. The closer to the TBs you check the pressure, the more meaningful the results. I have permanently inserted a Schrader valve in a "tee" into the steel line between the TBs on my car. There are devices, special plumbing, for checking the fuel pressure on these cars. As a temporary, stop gap, you could tee into the fuel line forward of the fuel filter. The spec is 9 to 13 psi.

RACE ON!!!

Texasborn

Fuel pressure was around 8psi. I adjusted the regulator and the pressure never moved. I pulled the fuel pump and the strainer was toasted. I will replace it today, should fix the psi problem.

Is it possible to have too much PSI? Or is the fuel pump limited as far as PSI is concerned?

Thanks for all the help!!!!

CFI-EFI

You should test that pump before you waste money on a new one. It might just need a cheap strainer, and/or a fuel filter. As I said previously, the spec for the fuel pressure is 9 to 13 psi. How, why, would you have too much pressure? "Is the fuel pump limited as far as PSI is concerned?" You said you had "adjusted the regulator". Why would you think you might have too much pressure?

RACE ON!!!

Texasborn

Must not have been clear in my last post.

I said the strainer was toast/clogged. And I was wondering since I bumped up the regulator, when I replaced the strainer the pump may push too much pressure. And I also said I replaced the fuel filter. Thats when I check the fuel pump strainer for a clog.

Thanks for the reply!!!! Your help is appreciated.

redrose

at abt 6 psi, your engine will start and run, but poorly, esp while in open loop for first 2-3 min.

at abt 9 psi, the ecm will compensate in closed loop and driveability will be marginal, open loop still will have typ ''lean'' reacts, loss of performance may be noticeable.

over 13 psi, open loop will again be problematic with ''rich'' engine (modded engines may benefit from pressure above 13 psi)

your pump will ''deadhead'' at abt 15 psi when new, less with age...reduced internal flow near/at deadhead will cause excessive heat and destroy pump in seconds.

replace the rubber connector between the pump and adjacent steel tube inside fuel tank and recheck pressure before replacing pump.

in-tank pumps have a life expectancy of 100k miles or 10 yr., whichever comes first.

schrade

Fuel pressure should be around 43 PSI at idle; no vacuum.

Cancel; I just noticed CFI, not TPI...

CFI-EFI

No problem. Just recheck it. If it's too high, readjust the regulator. I used to do mine before and after smog tests, until I realized it didn't make any difference.

RACE ON!!!

Texasborn

DONE!! Fuel strainer was replaced and fuel pressure is at 13psi. All is well.

Thanks for ALL the help!!!!!!!!!!

CFI-EFI

I'm glad the hear you didn't waste a ton of money on unneeded parts.

RACE ON!!!