tbi surge - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chris989 · 01-04-2018, 06:36 PM

Hello all,

My tbi build has been better than expected but recently i have developed an issue where when decelerating my engine will surge. It feels almost like i am driving gas,brake,gas,brake.

I checked all the basics and did a little data logging and can not find anything. I thought it might be the 4l80 locking and unlocking but the MSD controller does not show any signs of it.

Has anyone ever come across this? I posted over at 3rd gen and gearheads but i did not get any responses.

Thanks,
Chris

andyh1956 · 01-07-2018, 01:16 AM

Sounds like your Idle Air Control Valve Pintle is not seating properly at closed throttle. Or MAYBE you EGR is fluttering due to malfunctioning vacuum controls. Plug it off & drive the truck to eliminate that part. Also disconnect the cruze cable & drive it.

chris989 · 01-07-2018, 12:59 PM

Quote:

Originally Posted by andyh1956

Sounds like your Idle Air Control Valve Pintle is not seating properly at closed throttle. Or MAYBE you EGR is fluttering due to malfunctioning vacuum controls. Plug it off & drive the truck to eliminate that part. Also disconnect the cruze cable & drive it.

I just did some data logging yesterday and conclude there is nothing in the TBI system that is causing it.

It has to be the stall converter locking and unlocking, I though it my be something with shift solenoids but i downshifted as i slowed from 60 - 0mph and it does it in every gear.

Morgsie · 01-07-2018, 01:57 PM

What ECU are you running? My TBI caprice use to surge and on deceleration aswell. Try and disable "Async" injection that's what solved my surging issue.

chris989 · 01-08-2018, 09:27 PM

Quote:

Originally Posted by Morgsie

What ECU are you running? My TBI caprice use to surge and on deceleration aswell. Try and disable "Async" injection that's what solved my surging issue.

i think i have the 7747, the data is on the computer in the shop.

I do not have any surge at idle or while cruising, It is smooth as can be. I will look into the async injection.

Talked to my transmission shop today and they feel it could be the controller and I am skeptical of it too. A few months ago it was giving me TPS errors and would not calibrate. MSD had me calibrate the system with the motor running. It would not calibrate with just the ignition on. I think i will have summit ship me a new one and test it.

01-04-2018, 06:36 PM	#1
chris989 Registered User Join Date: Dec 2011 Location: Boise, Idaho Posts: 583	tbi surge Hello all, My tbi build has been better than expected but recently i have developed an issue where when decelerating my engine will surge. It feels almost like i am driving gas,brake,gas,brake. I checked all the basics and did a little data logging and can not find anything. I thought it might be the 4l80 locking and unlocking but the MSD controller does not show any signs of it. Has anyone ever come across this? I posted over at 3rd gen and gearheads but i did not get any responses. Thanks, Chris

01-07-2018, 01:16 AM	#2
andyh1956 Registered User Join Date: Mar 2010 Location: thomastown mississippi Posts: 1,261	Re: tbi surge Sounds like your Idle Air Control Valve Pintle is not seating properly at closed throttle. Or MAYBE you EGR is fluttering due to malfunctioning vacuum controls. Plug it off & drive the truck to eliminate that part. Also disconnect the cruze cable & drive it.

01-07-2018, 01:57 PM	#4
Morgsie Registered User Join Date: Apr 2005 Location: BC, Canada Posts: 122	Re: tbi surge What ECU are you running? My TBI caprice use to surge and on deceleration aswell. Try and disable "Async" injection that's what solved my surging issue.



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