TBI 454 idle problem

[PlayingWithTBI]

I'm still waiting to be approved at gearheadefi

Did you start a thread in the Introductions forum there?

 

[Godholio]

Did you start a thread in the Introductions forum there?

Sure didn't. It still gives me the same message it did when I clicked the email link: "Your account has been activated but you are currently in the moderation queue to be added to the forum." I can't post even in the intro forum.






Planning to put together a cheap little smoke machine to hunt for any missed vacuum leaks. Was going to do it tonight, but the store is still closing early for covid (though the website doesn't show it).

 

[RawbDidIt]

Sure didn't. It still gives me the same message it did when I clicked the email link: "Your account has been activated but you are currently in the moderation queue to be added to the forum." I can't post even in the intro forum.






Planning to put together a cheap little smoke machine to hunt for any missed vacuum leaks. Was going to do it tonight, but the store is still closing early for covid (though the website doesn't show it).

You could build a smoke machine i suppose, or you could go buy some unscented incense. Is there a reason you don't just hook up a gage?

Sent from my SM-N976V using Tapatalk

 

[Godholio]

You could build a smoke machine i suppose, or you could go buy some unscented incense. Is there a reason you don't just hook up a gage?

Sent from my SM-N976V using Tapatalk

What gauge? A smoke machine makes locating a mystery leak a lot easier than waving incense around or spraying carb cleaner everywhere (which I've been doing) and will run me about $10, including $5 for a harbor freight soldering iron as a heat source.

 

[RawbDidIt]

What gauge? A smoke machine makes locating a mystery leak a lot easier than waving incense around or spraying carb cleaner everywhere (which I've been doing) and will run me about $10, including $5 for a harbor freight soldering iron as a heat source.

A vacuum gage

Sent from my SM-N976V using Tapatalk

 

[Godholio]

Mine needs a rebuild.

 

[Insert Quarter]

When I first bought mine it wouldn't idle without stalling. After adjusting the TPS, cleaning the IAC, plugs, wires, etc. the main culprit ended up being the EGR valve. That got it to idle well enough. Later, after driving it for a few days, I replaced the distributor pick up coil and that made it run a good bit smoother.

 

[LC2NLS6]

I had that issue, have to pull the fuel filter and put the pressure test guage there. I rented one from autozone. It's a PITA, but easier than replacing the fuel pump. I had to put a new pump in and ran perfect after that. I'm betting its the pump gone bad and low pressure.

 

[Godholio]

None of the local stores rent out a TBI fuel pressure tester or adapter. Nor do they have an EGR (nor does the junkyard) so that's on order.
The smoke test looked good except for the oil cap, which is not the problem (I would be PISSED lol).

 

[Godholio]

Well, being quarantined for covid exposure gave me an excuse to order some stuff. I cleaned out the EGR, it was surprisingly clean. Clean enough that I didn't bother installing the new one. Still waiting on the cable for datalogging. Bought an Actron CP7838 fuel pressure tester. This one includes the TBI adapter (and others) for only a few bucks more than the adapter alone. And here's where things get interesting.

Key on/engine off, the pump should prime for 2 seconds and build pressure. Mine didn't; no priming at all, I tried several times. When trying to start, fuel pressure took several seconds to build at all, it would start to catch around 8 psi, but would stall...never got higher than 10 doing this a few times, then I start getting into the pedal to keep it alive. When I finally got it running, it topped out at 20 psi. Spec is 26-32.

The failure to prime the pump suggests it's the relay, but the low pressure while running suggests the pump. I'm going to check the relay hopefully tomorrow, and look for a gnarly ground, but I'm not sure a bad relay explains 20 psi. Or that a bad pump explains the lack of priming.

Both?