DavidB
1/2 ton status
I think it will idle around in 4lo but throttle or drive/reverse kill it. lack of VSS maybe?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
TBI Trouble
- Thread starter DavidB
- Start date
I think it will idle around in 4lo but throttle or drive/reverse kill it. lack of VSS maybe?
VSS has a huge bearing on idle for SOME ECM's. If you look at some posts in here for VSS, you'll see that many running the '747 ECM state that their setup doesn't care if it has VSS or not, while mine (which is TPI for the record) starts to have problems within miles of not getting VSS input.
Usually VSS is "turned off" in the PROM if its not going to be used, but Painless (a misnomer obviously) had/has simply had people ground the P/N switch to make the vehicle think it's always in park.
Usually VSS is "turned off" in the PROM if its not going to be used, but Painless (a misnomer obviously) had/has simply had people ground the P/N switch to make the vehicle think it's always in park.
Thunder
3/4 ton status
What kind of fuel pump? You need a pump specifically designed for FI. A pump designed for a carb that pulsates or varies fuel pressure will screw up the regulator.
Regulator in TBI needs a constant pressure to work right.
Regulator in TBI needs a constant pressure to work right.
DavidB
1/2 ton status
We've got a steady 11 psi. It didn't have a filter after it, so we installed a nice big one.
It ran like that for quite a while before the new engine, TB, etc.
It ran like that for quite a while before the new engine, TB, etc.
DavidB
1/2 ton status
The VSS is "off" according to the scanner.
bp71k5
3/4 ton status
11psi could be too low. My 350 Scott built needs 18to run right
DavidB
1/2 ton status
From what I've read, if it's a little low, it will hurt top end, but shouldn't just not run at all like that.
I'm not sure what he did, when he put the ground strap on, it smoothed out the surging in the idle but now it will only idle. He siad he disconnected all the different sensors and started reconnecting them one by one to see which one might be the issue, maybe something got fried in that process. If the TPS was poofed, wouldn't that do it?
bp71k5
3/4 ton status
I suppose, but whatever happened to the low vacuum problem?
DavidB
1/2 ton status
Had some vac leaks. I need to get over there and check it out but he and I are both busy. He called me Sat and was so discouraged he was talking about dumping the whole thing, which is pretty sad. We've put a lot of work and he's put a lot of $ into it.
