Delayed hot start .....

[bugdewde]

'95 K2500 Burb
7.4L TBI
120k miles

Starts right up cold. No issues.
After it gets hot, it cranks for about 3-4 seconds before firing off, depending on heat.

I'm sure something is amiss, as this probably didn't happen when it was new (just bought it a couple months ago).
Doesn't seem to be an issue as it starts every time .... just concerned about starter wear.

Unsure what to look for? Never owned a TBI before.
Not showing a CEL (check engine light).
Coolant sensor?
-Ignition parts?
-Injector wear?

I recently installed an aftermarket muffler (no cat) and notice that upon decel it will backfire once when the decel vacuum transitions to coast/accel.
Assuming fuel is supposed to cut off completely during decel. Maybe fuel is being sucked into combustion chamber during decel (unburned) and it ignites when normal load of fuel is injected after decel.

Any thoughts ?

 

[PlayingWithTBI]

Get a good scanner to data log while cranking, you s/b able to see what's wrong.

Has anyone "tuned" or played with your PCM? DFCO (Decel Fuel Cut Off) can be adjusted and/or turned off altogether. I don't have DFCO enabled on mine it engine brakes too hard when it's on. It still doesn't backfire when I let off the gas, just coasts nicely.

 

[bugdewde]

I can datalog OBD1?

Unknown about any tuning or things like that. Just bought it a couple months back from a dealer in Phoenix, AZ.
Immediately drove it home 1800 miles to East TN. No issues encountered. 12.5 mpg on interstate (3.73 gears) @ 70 mph. All that lovely flat land makes for good mileage. East TN hills I get about 9-10 mpg. Lol.....

Bought it to tow my rally Miata (2100 lbs) and gear.

Just recently getting under the truck to inspect & diagnose some stuff.
Plenty oil under engine & on trans, as well as trans mount bolts missing (fixed today).
Trans fluid is going SOMEWHERE..... probably check transfer case to see if it's leaking into it.
New front suspension, steering & brake parts ordered/arrived. Awaiting buddy's shop time (lift).

 

[PlayingWithTBI]

I can datalog OBD1?

Yep, your 95 is an oddball, it has a 16 pin ALDL connector instead of the customary 12 pin on earlier TBIs. I'm using my laptop with TunerPro RT and these cables. I only have the 12 pin because of mine being an 88. Even the Snap On "bricks" can still do it.

http://aldlcable.com/aldl.asp

 

[bugdewde]

Yep, your 95 is an oddball, it has a 16 pin ALDL connector instead of the customary 12 pin on earlier TBIs. I'm using my laptop with TunerPro RT and these cables. I only have the 12 pin because of mine being an 88. Even the Snap On "bricks" can still do it.

http://aldlcable.com/aldl.asp

Hey TBI .....
I'm re-visiting this thread because I remembered you mentioning I can datalog OBD1 ..... I just bought a BAFX Bluetooth reader for my '06 GTO because my old OBD2 handheld scanner doesn't jive with the GTO's computer (CANBUS?).

I'm shopping for an app to access the info when my BAFX unit arrives.
Torque Pro app comes recommended from a GTO forum.... but I'm reading reviews saying it's not up to dste and there are better ones out now.

I recalled you use TunerPro on a laptop for your OBD1 ... and was wondering if you might be of assistance on recommending a phone app that might also log my OBD1 Suburban .... or do I have to have a program on a computer like your TunerPro?

Noob when it comes to this tech stuff.

 

[PlayingWithTBI]

and was wondering if you might be of assistance on recommending a phone app that might also log my OBD1 Suburban

Can't help you there. Before you pull the trigger check your ALDL connector to verify if it's a 12 pin or 16 pin connector.

 

[bugdewde]

Can't help you there. Before you pull the trigger check your ALDL connector to verify if it's a 12 pin or 16 pin connector.

Yeah, it's a 12-pin. Maybe an early '95?
Guess I need the cables & software like yours.

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