91 - Sluggish at WOT - Then sideways when sec pump kicks in

[BigIke]

Hey Y'all,

I had alternator issues, the car made it back home 8hrs with some tricky driving to keep RPMs up, worst drive of my life, no AC in the rain and traffic, LOL. Installed new alternator in 1 hour, at night and that is good now!

Problem at hand... Been having issues when the car is hot, sometimes it will load up and die, then when i floor it, there is no power, then BOOM, car goes sideways. My secondaries are wired open with the supporting Haibeck tune, and i've got 106,000 miles on The Juan.

So i'm thinking that i might have a clogged fuel filter, and when the second pump comes online, the fuel demand is satisfied and i get a shot of nitrous feel when full power comes online. Seriously, the car will try to swap ends if the AC is off; before that, it won't get out of its own way...

I've also purchased two new fuel pumps, and when the hurricane passes, i've got a fuel filter on hand. Thinking that the filter might be clogged enough to where the single pump isn't enough.

What do y'all think?

[BigIke]

Replaced fuel filter - it was clogged, but my main problem is still present.

When I go WOT, there is black smoke and no power, when the rpms get up, something happens, maybe the second pump coming online... But full power comes online hard... It black smokes during this time to, but I've got a great time, without headers so it's a little fat.

No replies, so my effort to be precise, could have been to wordy or incoherent... Any help poor fa-voor? Lol

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[XfireZ51]

If u have deleted the secondaries, and a Haibeck calibration for that, the secondaries are ON beginning at Off Idle. So the secondary fuel pump is running from Off Idle.

[BigIke]

Originally Posted by XfireZ51

If u have deleted the secondaries, and a Haibeck calibration for that, the secondaries are ON beginning at Off Idle. So the secondary fuel pump is running from Off Idle.

O okay, I thought I'd read that the secondary pump didn't come online immediately...

I know that even The Car is cold both are online, during that time The Car runs great.

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[QB93Z]

You can get a fuel pressure gauge and tape it to the windshield and go for a test drive. It will answer your question about fuel pumps.


I suggest investigating the black smoke. That is not normal for a ZR-1. Check your spark plugs to see if one cylinder is ingesting oil.


I am not sure what you mean by "goes sideways". If you mean that the rear end tends to move to the right, you should investigate the drive train support called the C-Beam. Make sure the bolts at the transmission and at the differential are properly torqued. If the problem continues, you may want to install C-Beam plates.


Good luck,


Jim

[DRM500RUBYZR-1]

I know that even The Car is cold both are online, during that time The Car runs great


Just to confirm.
The car runs fine with no problem, even at WOT, until it "warms-up"?
Then the problem ALWAYS happens, once warm?
Also, please define warm, i.e. what coolant temp?
Black smoke when cold also, or just when hot?
Those answers might help narrow it down a bit.
Marty

[XfireZ51]

BigIke,

I have recently investigated a condition of black smoke when I would go deep into the accelerator also. Pulled my spark plugs and #7 was very "sooty".
Motor idled fine, seemed to accelerate ok, etc. Compression was good. 220psi.
Turns out I had a cracked top compression ring. In 4 places.
Not wanting to panic u but if u keep getting black smoke it may not be just the motor clearing itself out. As Jim notes, it isn't normal operation.

[BigIke]

Thanks for the replies guys!

1. When cold out runs perfect, from initial start-up, tell warm.
2. Somewhere around 140-160, it behind to act up.
3. When the second pump comes on, the tires break loss like I've spayed a 300hp shot of nitrous. Lol
4. The tune is super fat, it's a header tune with stock manifolds.
5. I'll replace the plugs.
6. The fuel mileage was really bad, got 17mpg on my last trip, I'm use to 23 on my trips to Louisiana for work. I go 7mph over the speed limit, everywhere on cruise control.
8. I'll buy plugs today and set the TPS at .54vdc with a true RMS VOM also.

Thanks again y'all! Jay

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[secondchance]

Just in case, check fuel pressure regulator hose for fuel. When my regulator failed, I was getting additional fuel sucked into the plenum especially in high vacuum condition.

[XfireZ51]

Originally Posted by BigIke

Thanks for the replies guys!

1. When cold out runs perfect, from initial start-up, tell warm.
2. Somewhere around 140-160, it behind to act up.
3. When the second pump comes on, the tires break loss like I've spayed a 300hp shot of nitrous. Lol
4. The tune is super fat, it's a header tune with stock manifolds.
5. I'll replace the plugs.
6. The fuel mileage was really bad, got 17mpg on my last trip, I'm use to 23 on my trips to Louisiana for work. I go 7mph over the speed limit, everywhere on cruise control.
8. I'll buy plugs today and set the TPS at .54vdc with a true RMS VOM also.

Thanks again y'all! Jay

Sent from my SM-G950U using ZR-1 Net Registry mobile app

1. 140-160F is where the engine management goes into closed loop.
2. The tune is probably NOT super fat. It may be richer although probably not at part throttle. Certainly not to the tune of 6mpg.
3. Let's see what the plugs look like.
4. And again, w secondary delete, ur second pump comes on at Off Idle, so ur sideways excursions shouldn't be due to the secondaries kicking in.