TPI = Mass Frusteration!

[Hossbaby50]

Are you getting ample fuel pressure? TPI needs something like 38 psi to function. If you have plenty of fuel pressure then I would start looking to see if the injectors are pulsing. If they pulse then I would look to make sure that the TPI knows it is trying to start. There is a wire that must be hooked to the starter that tells the ECM that the motor is trying to start.

Harley

 

[Russell]

I've never heard of a wire that goes to the starter before. I've got a wire that comes from the safety neutral switch. Its not like the engine isn't trying to start at all. There is just something messed up enough that the engine won't start, wether that be the spark way off, or not enough / too much fuel.

I know that all my injectors are pulsing, and I know that my dizzy is sending the spark down, its just that something isn't in sync, and I have no idea why.

 

[Russell]

Well, I can safely rule out ignition now. I installed the distributer from my 89 chevy half ton into the, which was running till the minute I pulled it. Put it into the 80, and suddenly it behaves like it should, however, the truck is either getting too much, or not enough fuel now. So, I'll need to do some more pressure testing, and try a new set of injectors, and maybe I can get the thing to run. If the fuel system checks out, then I think I'll probally wind up just hauling the stupid peice of crap off to the wrecking yard :P

Actually, probally not, I'll just dive into the wiring, and check it for like the 50th time.

 

[boxxerace]

I am not sure if you stated that you tested fuel pressure yet, but I had a situation where I thought I had electronic timing issues or something to do with spark.

Turns out I had a burst hose in the tank and I was getting low fuel pressure. It acted all funny and not in ways that indicated fuel problems.

I put a gauge on the fuel rail and sure enough, I had like 10 psi. Fixed the 10 cent hose and I was right back up to 40 psi with no problems.

Good luck man!

 

[BadDog]

I had the exact thing happen to me back when I first got the TBI. Geeze, I wasted a lot of time on that. The best advice I ever got on EFI was to get a guage, you simply can't do anything without it and pressure is the first thing you check ANY time you have something that is not just blatantly obvious...

 

[goldwing2000]

Did you ever check for vacuum leaks? I know you said you were going to about a jillion posts back but we never heard the result.

That was my first thought on post #1.

 

[Russell]

Wow, super old post

However, still very relevant, as the TPI still hasn't run yet.

I'm just completing the finishing touches on a speed density conversion, and hopefully in the next day or two I'll try to fire it up again.

There were a number of things that I've found in making a new harness, and converting to speed density. First was that the truck was running in failsoft mode, as the electric fan was running all the time. I'm 90% sure that is was running failsoft due to the MAF being dropped on its head a few times, and likely not working anymore. I also found a few wiring problems, and that my EGR solenoid was not correct for my application, and l was likely open all the time.

And yeah, next thing on my to buy list is a fuel pressure gauge

 

[mouse]

Any updates?

 

[dyeager535]

I saw a video of it running, so I know he is past that part.

 

[Russell]

Haha, cool! Just noticed the EFI forum now!

As Dorian mentioned, it does infact run now, but I still have one more timing related bug to hammer out, and then a whooooole lot of tuning.

I'm fairly confident that my problem is a bad knock sensor. Not only is it suppost to be used on a MAF setup with a `165 ECM, but it is also a cheap Napa repo.

Basically, I am getting a code 43, which is an ESC failure. When you first start the engine, the ECM immediately rockets the timing up in an internal ESC test. What it is listening for is the knock sensor to detect the pinging induced by the excessive timing. It detects this very quickly when the knock sensor is working, backing the timing off right away to keep the engine from being damaged.

However, in my case, it isn't getting any kind of response from the knock sensor, and after two attempts, it simply sets code 43, then limits the timing to what is specified in the prom, less any retarding factors that may be applied somewhere.

What this results in is very retarded timing that will allow the engine to run, and probally limp you home, but you won't be able to take off without backfiring through the exhaust, or with any real power.

I've confirmed the knock sensor's non-op status first by not getting any continuity in an ohm out attempt, and also by tapping on my pass side manifold with a hammer. The hammer should retard my timing to a significant degree with each hit, but doesn't.

Its been a definite uphill battle, but one system at a time, I am figuring things out. Since posting last, I also found that my fuel pressure was wayyyy low. Either it was a TBI pump that the ebay seller (sickening liar that guy...) tried to pass off as a TPI pump (gotta hand it to him, I didn't figure it out for almost a year and a half, LOL), or a badly worn out TPI pump. So, finally, my fuel pressure is good, air is good, and electrical appears to be good. Its just down to getting that timing (which has plauged me since day one, always had a code 43, MAF and MAP) working properly, then getting her tuned up

I'll keep you guys posted, and probally start a new topic devoted to tuning up a TPI as I figure it out, so other guys can reference sometime soon.