Secondary Issues! Need opinions

[executioner]

Just picked up a 93 that appears to have full power issues. When I turn the key and the green LED lights up, I didn't feel much difference. Checked for the secondary pump to run with the key on and got nothing. Checked power at the harness and thats good. I assume the pump is bad, but before dropping $200 on a new one I first put a vacuum pump on the line with the car running and wouldnt ya know, when I rev the car now it shoots up the RPM range much faster. Did I answer my own question? Can I bypass this system somehow? Thanks!

[Ccmano]

Just fixed a 91 with the same issues. Check the pump with direct 12v to the terminals to verify it’s the pump itself. Probably a bad pump. That said the system doesn’t need the pump to activate the secondary’s. Engine vacuum is enough. The pump is there to fill the gaps like when your on full throttle and engine vacuum disappears. The likely culprit is the check valve under the plenum, barring a major vacuum leak elsewhere under there.

Here’s a good write up. Not sure who wrote it.

The test of that Vacuum Check Valve is a simple test without removing the Plenum. Just disconnect the Plenum Vacuum line on the drivers side and hold thumb over end of disconnected line. With the Ignition Switch on the Vacuum Pump will keep cycling until you plug the end of that vacuum line fitting. The Vacuum Pump will then stop cycling indicating no Vacuum leaks unless of course you have additional Vacuum leaks in the Secondary Vacuum System. If disconnecting that Vacuum line results in the Vacuum Pump not Cycling without blocking with finger, the Vacuum Check Valve is operating correctly. The Plenum has to be removed to replace that check valve.

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[executioner]

Thanks for the input. I'll try that just to know for sure but I did a little more research and have decided to just eliminate the system entirely and purchase a Haibeck chip to keep the car in full power mode at all times. I really don't want to fiddle with a key every time and I never use a valet, so its useless in my opinion.

[Ccmano]

Thanks for the input. I'll try that just to know for sure but I did a little more research and have decided to just eliminate the system entirely and purchase a Haibeck chip to keep the car in full power mode at all times. I really don't want to fiddle with a key every time and I never use a valet, so its useless in my opinion.

That’s what I did. Works great! Haven’t looked back once.
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[executioner]

I'm wondering if I should replace the injectors while I have the plenum off. Being that its a 93 I wonder if they're still good. I know the 90-92 were the problem children, but still. Better than having to remove the plenum twice.

[Ccmano]

While I’m generally of the “if it ain’t broke don’t fix it” mind set, if money is not an issue, replacing 25yr old injectors while your in there is not a bad idea. Accel or FIC Lucas style injectors seem to be what everyone is doing. Did Accels on the last car and was very pleased.
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[executioner]

I'm usually of that mindset also but considering I just saved a ton of money when I bought the car I feel like I should tune it up nice and call it a day. I'll look into those injectors. Know of a good place to pick them up from? Thanks for all your help!

[Ccmano]

Accel 150821 injectors (Summit Racing) seems to be the go to item. I used them as well. FIC is also popular with excellent results.
http://www.jerrysgaskets.com/fuel-injector-set-16-90-95-13b2/

I’m currently running rebuilt Ford injectors (my car came with them) with no issues. Like these. This company has an excellent reputation with the LS1 guys.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F12 1088079341
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[Paul Workman]

While I’m generally of the “if it ain’t broke don’t fix it” mind set, if money is not an issue, replacing 25yr old injectors while your in there is not a bad idea. Accel or FIC Lucas style injectors seem to be what everyone is doing. Did Accels on the last car and was very pleased.
H
:cheers:

:thumbsup::thumbsup:

Parts that don't exist don't cost much & they NEVER FAIL!

IMO, deleting the secondaries completely was one of the best mods I did.