kirkm76

I just completed my L03 to l05 swap. I felt a little stumble from time to time and it just doesn't seem to run as smooth as it did. Checking the voltage on the 02 sensor (I have heard RTV fumes after a rebuild or reman install can kill them), I get .0-.1 for a couple minutes as I should, then it starts switching, like .1 to .5 ish (I don't rev it or anything, then after another few minute the voltage drops off to like .01 or nothing. Has anyone seen an O2 sensor die in this manner?

ShiftyCapone

iTrader: (7)

What injectors are you running and did you use a 350 knock sensor? Also, have you done any chip work? If you said no to any of the above you more than likely have fueling and chip issues.

Fast355

iTrader: (2)

The 0-.1 volt signal is normal for a cold 02 sensor. At 600* Farenheit the O2 sensor starts to wake-up and work. The voltage the sensor puts out at 14.7 air/fuel ratio is about .45 volts. With a rich mixture it puts out higher voltage about .9 volts. It sounds like your system is running lean. By chance are you still running the 305 injectors or prom chip?

kirkm76

Well, I am running the 350 knock sensor. I got a chip made from TBIChips.com that was supposed to work with the 305 injectors. I am also still running the ESC module from the 305. Anyhow, I am going to talk to the dude that burned the chip and see if it's calibrated for 350 injectors. I also have a chance to pick up a Caprice 9C1 computer cheap, but if I'm not mistaken they use the L98 Cam rather than the L03/05 Peanut cam, so that may cause trouble. I think it ran larger injectors than the standard L05 also. Maybe I'll get it and use it as an excuse to swap the cam too. I think the 9C1's were like 210 H.P. stock with gobs of torque, so that'll be fun and I am sure there is room for improvement in that. I had thought too about picking up a stock computer from a roadmaster and the injectors, but the 9c1 is a lot of extra power, so I am leaning towards it unless I can get this one to run with a simple injector swap.

Fast355

iTrader: (2)

K vin code truck 350 TBIs were 210 HP @ 3,800 and 310 ft/lbs @ 2,800 and usually came with 4 bolt mains and sometimes a roller cam.
Really the 9c1 TBI 350 really doesn't have any more power than your regular 350 TBI. It does however have the speed limiter removed and the prom is tuned slightly richer to give a little extra torque. The engine the I pulled from a 1992 van was the same as the 9c1 engine. They use the L-98 cam or the L03 cam depending on the year. Mine came with the 65 lb/hr injectors in the van TBI unit. Apparently they were stock because my computer had the BPW constant set at like 120 something instead of the 135 you would usually see on a 350.

kirkm76

I think I am going to do the datalog on it and see what's up. I just need to build the cable. I already have a crusty little 486 laptop that I am not scared to leave in the car. I figure with all the expertise floating around here I can get it tuned easily enough. It's only 20 bucks to have a new one burned, but I'll probably get the stuff and learn to do that too since my eventual plans call for a cam swap and vortec heads on it. I want it to run with stock LT1's eventually. The stock roadmaster L05 computer is like 180 hp, so I was wanting to stay away from that one. I am just going to do it myself though. I do want to dump the L03 injectors at my earliest chance, just needed to be cheap at the time, but like I said, the chip took those injectors into account, maybe the compromise just dosen't work so well though. Ah well, it does feel strong though, so I can live with it as I sort it out. I'm looking forward to learning to tune the EFI though...Then all my "You oughta' just put a carb on it" friends and the "TBI sucks crowd" will lay off.

kirkm76

Well, I tested further today. With the sensor not connected to the PCM it seems to settle around .7 volts. I figure this is about normal since if I recall open loop is a little rich. Then I go plugged it in and got my probe up in it to see what it did connected to the ECU. It fluctuated all the way from like .07 to over .8. Some things I saw on other websites indicated this to be normal, but it was a BMW site, however I figure the sensor works the same. What do you guys think? All I can figure is that if I am having O2 sensor related issues is maybe the sensor is sluggish due to the sealants in the reman motor.

ShiftyCapone

iTrader: (7)

I would start to datalog and look at that. I bet the 02 is not your problem. I would bet the house that you are having fueling and chip issues with the 305 injectors and stab in the dark prom.

Dewey316

In closed-loop the o2 sensor will 'swing' back and forth. That is the way it is designed to function.

edit..

I just re-read your first thread. I would agree, it sounds like the chip is the issue.

Dewey316

Cut your losses now. Use the $20 towards getting the equipment to do this yourself. You seem reasonably intelegent, and seem to have a handle on how modern fuel systems tend to work. I'm pretty sure you'll have no issues tuning this yourself. Read up on this stuff in the DIY board, and ask questions.

kirkm76

Yeah, I think you are right. We are going to make an ALDL cable at work today and I'll hook it up. I think you are right though. In open loop I would rev it and hold it steady and it would be lean according to the O2 voltage. I have a line on some 9c1 injectors and the prom. I hope to find for sure which cam it used and go from there.

90RS305

Threads Merged....