need help-'95 TBI chevy to 69Fj45

[fj40m4]

the engine runs poorly, hardly idles, running rich. could the computer be in limp mode? The O2 sensor is hooked up, still need to wire in the speed buffer and speed sensor.

we are using a '88 Toyota EFI pickup tank and fuel pump. The Chevy uses 12 PSI but what does the Toyota use for PSI and gallons per minute?

any info would be great, we are leaving for Moab in three days!!!!!!!!!!!!!!

[yoda]

What are you running...350?...factory harness?...computer(match engine?) I have info on systems at home.

[larryboy]

all those symptoms point to the egr.

[pismojim]

Yoda, on behalf of FJ40m4 and CRZR45, yes it's a 350, with matching wiring harness and tranny, a few more details:

previous thread

I'll be heading over to provide and moral support this afternoon. Will pass along any info.

Thanks,
Moab bound, tick tock, tick tock,....

[orangefj45]

hey there!
are you going to bring that rig to the 45 run? late august. northern CA.

how far from the exhaust manifold to exhaust pipe flange is your o2 sensor located. if it's too far downstream it will trip out the computer. i've seen it happen a few times.
also, if you have the factory harness you should have a scanner port on it. hook up a scanner and see what it comes up with.
keep us updated. should not be too dificult to figure out.

[RustyNailJustin]

I did my first TBI conversion a few years ago and I had simmlar problems... As someone else posted a few up get it hooked up to a scanner to find out if you have some sensors that are not working. One thing that I did was have a PROM chip burned that bypasses the VSS this made a huge difference also check your fuel preasure TBI requires 9-13 PSI I have a pump that does about 15 and works great. It took me some time of trouble shooting and changing things around to get it to run perfict. But now like a stripid ass ape!!! Good luck

[cruiserbrett]

The egr can cause that for sure... I would get a factory HELM manual b/c they have the troubleshooting steps you need. Get a check engine light and get it to give the codes. Not sure if the 95 is the same, but with a paperclip in the A and B terminals in the ALDL link mine will give two digit codes and the manual will give steps to follow to track down the problem. It is not in closed loop mode by the sounds of it so the O2 sensor will not be an input to the computer, only after the timer and the coolant temp criteria are met will it take input from the 02 and control fuel mixtures then. Is the computer original to the engine and harness? Did you pull them yourself??? If the computer is not original to the engine and the PROM has the wrong number of cylinder select it will go to limp mode, which might be for a four or six cylinder, really screwing with things.

Take a timing light and connect it as though you were going to check the timing. Aim it at the throttle body to check the spray pattern of the injectors... Should get a nice even pattern on both injectors.

I duked out an idle problem on my 305 TPI and it took two weeks and about $250 worth of diagnostic tools. Check the diy-efi.org archives, there is a TON of good info there. Turned out to be what I think was a bad ground on the ignition module... $0 fix, just removed it and cleaned it and reinstalled it....

-Brett

[EricFJ40]

Mine did basically the same thing you described when I first fired it up. I couldn't come up with anything, so I forced it to keep running until it hit it's normal operating temp, and the problem went away. I changed out the temp sensor (the one near the thermostat) and that fixed it. It was somehow telling the computer to dump way too much fuel when it was cold. Hope this helps.

[pismojim]

Update from the shed:

Things are looking mo betta notwithstanding a proper test drive. The pit drew, K&J, are now onto building bumpers and nerf bars. Tomorrow may be a free day, whoops it is tomorrow already.

It looks like a bum alternator had allowed the battery voltage drop below what the computer liked. Plus added an O2 sensor and the engine seems to be running well. I'm just the burrito gofer and tool fetcher, but I wanted to thank everyone for the help. Thanks.

Still planning to leave for Moab early Tuesday.