Violent Power Dropouts at Heavy Throttle

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Philip Parker
Posts: 8
Joined: Sat Aug 03, 2019 11:06 pm
Location: CO

Violent Power Dropouts at Heavy Throttle

Post by Philip Parker »

Just got done with the B35 swap into an 86 car with a getrag 265.

When the car gets warm and enters closed loop it will buck wildly under significant or full throttle - like it is dropping spark and then coming back on in a split second multiple times in a row.

Anyone ever encounter this?

Thanks

Philip
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RossDinan6
Posts: 295
Joined: Mon Jan 29, 2007 2:35 am
Location: SW FL, USA

Re: Violent Power Dropouts at Heavy Throttle

Post by RossDinan6 »

This is probably no help, but it sounds like something that occurred with my car many years ago (15ish).

My car is a Dinan turbo car and I was tracking it at the time. Under high load conditions the car would "buck" like it was turning on and off at a high rate. I did a bunch of troubleshooting at the time. Without a wideband at there was no way to tell for sure weather the issue was fuel or ignition. My thinking was it could be a problem with the Motronic, or the piggyback Dinantronics magic box.

Not wanting to grenade the engine and being modified, I decided at that time it was time for a stand alone system. That was an interesting and educational process.

Maybe trying a known good ECU is in order?

If you can come up with a way to monitor spark and fuel you may be able to narrow it down. Other than that, I got nuthin.
Ross
'84 633 Dinan turbo
marc79euro645
Posts: 56
Joined: Tue Feb 11, 2020 12:31 am
Location: pensacola

Re: Violent Power Dropouts at Heavy Throttle

Post by marc79euro645 »

It could be a lot of things. I think I would start by wiring a noid light (small led) in parallel with injector, and position it where you can see it and drive. The light should flicker with crank position sensor pulse. If it doesn't drop out when engine bucks, then I would suspect fuel pump, and drive with gauge visable.
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