Are TBI 350’s just this sluggish?

[stutaeng]

Single owner truck, Old man died kids and grandkids wanted to sell it, came with a stack of paperwork. I’ve got most of the receipts for oil changes dating back to 93, including all the miscellaneous things that he had fixed. It has been sitting since 2013 when the PO died.
I doubt it’s 305, but your right, it wouldn’t hurt to look.

Sounds like a nice truck then. That's useful information for us to know. It's nice when you can go back into the records and see what services/repairs have been performed on the vehicle. Some people take good care of vehicles; unfortunately, most everyone (like 95%, LOL) do not.

Sounds like a performance issue. It's likely related to it being sitting so long. Have you run though a full tank of fuel?

 

[BradHSo]

Another thought, these TBIs are fairly well known to have a bad coil and ICM. It appears when the coil shorts out or melts the insulation it can overheat the ICM and cause stumbling and/or surging. One trick is to spray water on the coil, not the wires, while idling and see if it stumbles. If so, you know the coil is bad but still don't know for sure the ICM is. Here's a picture of my Pertronix Flame Thrower after less than 2000 miles. Note the burn marks by the iron. My ICM went out about the same time causing surging at ~2200RPM while cruising in OD. I've found a lot of others here and on other sites experience the same issue. When replacing parts use quality ones like AC Delco, Delphi, etc.

You must be registered for see images attach

I’ll check this after work. Yea I’ve learned on my 97 c3500, to buy nothing but ACdelco.
Thanks!

 

[BradHSo]

Sounds like a nice truck then. That's useful information for us to know. It's nice when you can go back into the records and see what services/repairs have been performed on the vehicle. Some people take good care of vehicles; unfortunately, most everyone (like 95%, LOL) do not.

Sounds like a performance issue. It's likely related to it being sitting so long. Have you run though a full tank of fuel?

Yea that’s what made me jump on it, it’s hard to find any thing 27 years old that someone actually cared about it’s whole life. The only bad part is the windshield was left uncovered, and the dash looked like mulch chips. But I’ve fixed that.

Yup, I’ve been through about 4 tanks so far.

I’m borrowing the kit to check the pump pressure (at the filter) and I plan on replacing the filter while it’s out, I’m an aircraft mechanic by trade so I’m going to use my filter cutter and open it up and see what it looks like. Hopefully it’s not too rusty....

 

[98 Nitro]

How good does it run over 3000 rpms?
A 305 would not run any better over 3000 rpms than a 350 unless it is a 305 TPI. BTW-GM performance parts use to sell TPI heads as OTC HP upgrades for TBI engines, so check head casting numbers, that is if fuel pressure is ok and your timing/ignition all checks good.

 

[BradHSo]

Fuel pressure was 8-9 at idle cold and after it warmed up it dropped to a steady 7, my fuel filter was slapped fuel of black and red gunk. I unplugged the tan and black wire then checked the timing and holy crap was it retarded, it was so far to the right that it was off the timing marker. I re timed and changed the filter, I think I’m making progress as the truck feels a lot better and doesn’t hesitate off idle. Will be ordering a fuel pump next and changing the ICM and coil as I listened to PlayingwithTbi’s advice and misted it with water and it immediately ran like crap.
Thanks for everyone’s help!

 

[SUBURBAN5]

Fuel pressure was 8-9 at idle cold and after it warmed up it dropped to a steady 7, my fuel filter was slapped fuel of black and red gunk. I unplugged the tan and black wire then checked the timing and holy crap was it retarded, it was so far to the right that it was off the timing marker. I re timed and changed the filter, I think I’m making progress as the truck feels a lot better and doesn’t hesitate off idle. Will be ordering a fuel pump next and changing the ICM and coil as I listened to PlayingwithTbi’s advice and misted it with water and it immediately ran like crap.
Thanks for everyone’s help!

Awesome job. Lot of times its fuel lol. My vortec has some goofy moods. I'll have to figure out a way to up the fuel pressure. I'm hitting 55 at idle and wish it was at least 58... anyways I recommend rebuilding your tbi in time because that's important to be top notch lol. Also if you need anything there's a lot of tbi owners on here lol

 

[BradHSo]

Awesome job. Lot of times its fuel lol. My vortec has some goofy moods. I'll have to figure out a way to up the fuel pressure. I'm hitting 55 at idle and wish it was at least 58... anyways I recommend rebuilding your tbi in time because that's important to be top notch lol. Also if you need anything there's a lot of tbi owners on here lol

The next project I’ve got to tackle is the fuel injectors on my 97 454, don’t even want to think about it lol.

So far this forum seems awesome, coming from the Volvo world, this place is full of nice people lol

 

[SUBURBAN5]

Did the 454 have the same injectors as the 350?

 

[BradHSo]

Did the 454 have the same injectors as the 350?

I don’t believe so, but they are stricken with the common leak down problem, if it sits for a awhile it’ll just crank and crank and crank, then blow black smoke. Plus the MPGs took a turn for the worse around 6-8. It’s a pretty well know issue for the vortec 7400’s

 

[SUBURBAN5]

Do they use a similar spider injector?