I've been working on a TPI swap in my jeep for awhile now, but can't seem to make any headway. If someone could push me in the right direction, I would be so grateful. This is getting discouraging.

It's a rebuilt 350 that I have swapped a 89 TPI to. Shorty headers with heated O2. I have the factory wiring harness with the AIR stuff gone and I'm running an ARAP bin with AUJL timing advance table.

I have moved the injector constant up and down but the INT and BLM always go up and max out like it's lean but it has to be rich cause I can barely stay in the shop with it at this time from fumes. I have two scans to post the first is with the constant at 28lbs. The injectors are 24lb SVO's I've tried everything from 17lb to 35lb. The base pulse width changes but the INT and BLM always max out.

The second scan is after I changed the number one MAF table. I was reading 10gm/sec so I went to 10 and the cell above it and the one below it I changed all three multiplied all three by 1.5. Anyway same thing INT and BLM both maxed out.

I'm sure I've left out some vital info, I'm just so frustrated at the moment. I've been day dreaming about my shop burning down to get insurance money to start over with. LOL. Thanks to anyone that feels like helping.

 

I'm no expert by far, still learning myself, but hopefully this might help. I have heard of the crappy NB O2 sensor getting 'confused' at extreme AFRs, where it is possible it can read VERY lean (BLM/INT maxing) when it is in fact VERY RICH. Have you tried pulling fuel OUT instead of putting more in? Be careful with this though, might help you narrow down the issue.

 

Well that was the principal I was operating on today. I checked my plugs and they were black, which supported the idea that it is running rich even though it thinks it's lean. I made sure my o2 sensor and the exhaust flange near it was tight so no exhaust leak.

At this point I started messing with the #1 MAF table. I reduced the values in the cells near what the MAF was showing at idle. Now the engine ran better, not good, but better and the fumes were noticeably better in my shop.

However, it still maxed out the INT and BLM. Also, my IAC counts seem low at 1-10. I think I've read that they should be in the 30's. So this has me thinking vacuum leak, so I break out my propane torch, with it unlit I stick it all over the intake area hoping for some sign. Never could tell anything. I took the air filter off and stuck the propane torch right in the MAF and still couldn't tell the propane was doing anything, the idle is erratic even if it is better, so I can't tell if the propane is having any effect.

So unless someone has a better idea I'll keep looking for vacuum leaks. It runs best when I first start it up, so tomorrow, I'll try the propane again when it's still cold.

Thanks.

 

Start by setting the system to run in open loop only. Do this by setting the min. enable temp for Closed Loop, to it's maximum (255 degrees C). This will allow you tune without the ECM trying to compensate.

This won't cure the reason that the ECM is thinking that you are lean, but would at least get you runniong decent and not rich, provided everything else is matched up.

FWIW, I've been running my Datsun in OL for a little over 2 years now. I'm also running the truck of a friend of mine in OL, and has been for about 3 years. So long as the tune is good, you will be running fine.

 

To find vacuum leaks, the best method I have found is using those colored smoke bombs that are sold around 4th of july as fireworks. Throw one into a water bottle, plumb a air-tight hose into the water bottle cap, plumb that into your intake manifold, and watch where the smoke comes out :0

 

Well, I put the MAF table back to stock and setting the cl enable out of reach kept the BLMs and INT at 128 as predicted with a decent running engine, good enough for me to go over it three times with starting fluid, I never found any sign of a vaccuum leak. I don't have any smoke bombs. HA.

Keeping it in open loop won't be a long term solution because it idles up and down. Like 450-850 rpm.

I did try one other thing. I set the BLM maximum to 110. Now this is the best the engine has run. I know there is something wrong to have to do this, but I was wondering what that might point to. With it locked to 110 it sounded like a normal stock motor, so nice. Until I gave it a blip of the throttle, then when it came back to idle it was back to searching 450-800rpm. But after like a minute it would calm back down and idle real good again.

During all this the IAC count never got over 12, most of the time it was 0. This still has me concerned, and tomorrow I plan to remove the IAC and check it's seat and reset it.

Thanks for the help and keep the ideas coming.

 

hey man did you by chance find anything on your problem i am having the same type of problem on my TPI swap in my truck. just curious maybe it can point me in the right direction

 

Welp, I was digging around in the TPI area to get the directions for minimum air and IAC setting. I came up with a post somewhere by Vader where he said that IAC counts don't really matter, so I quit worrying about mine being around 10 or so. Anyway after resetting IAC and minimum air, I decided to check some more basics, starting with timing. I checked it shortly after getting the engine going in the first place right after the TPI swap, and I know it was at 6 degrees. How it got off I have no idea. It was like 2 degrees retarded. Anyway, I reset the timing, and the reset IAC and minimum air again. After all that when I ran out of shop time, it was running the best so far. I haven't had any time to work on it this week, but hopefully soon since things are looking up.
Good luck with your swap, I know how frustrating they can be.

 

ya tell me about it. it does get discuraging sometimes. makes me want to rip it all out and do it over again. i did make some headway on my problems. mine started spitting and sputtering while crusin down the highway but i could never get it to act up when i had the computer on it. finally i tried the wiggle test on wires and bumped the relay for the mass airflow burnoff and it started doing it. turns out i had a bad relay. dont know if you are having any probblems like that but every once in a while my sensor reading would bump up to 26 at idle and cause it to throw more fuel in.