No full power

[efnfast]

So I've never really noticed a huge differance between normal power and full power. Seems 125 hp should be pretty seat of the pants. So tonight in 4th gear with power key off. 60-90mph in 7 seconds. Power key on, dash light on. 60-90 mph in 7 seconds. Have I not had full power since I bought this car last summer?????:mad: Second gear chirpies is about the best it will do.

[tccrab]

So I've never really noticed a huge differance between normal power and full power. Seems 125 hp should be pretty seat of the pants. So tonight in 4th gear with power key off. 60-90mph in 7 seconds. Power key on, dash light on. 60-90 mph in 7 seconds. Have I not had full power since I bought this car last summer?????:mad: Second gear chirpies is about the best it will do.

The difference should be night and day.
Depending on your tires and road conditions you should be able to do WAY more than 2nd gear chirpies.

Power Key "On"
Going into 2nd gear at WOT should cause serious clouds of no expense spared super premium Z rated tire smoke.
Hammering the throttle at about 30mph in second gear causes tire smoke with no clutch needed.
Car pulls HARD from 3000 all the way to 7500rpm (and beyond).

Power Key "Off"
Feels like something the wife could drive to the shopping mall in the rain.
Initial acceleration feels good but runs out of wind quickly around 5000rpm.


'Crabs

[efnfast]

Definatley no tire smoke in second gear. Ever. The good news is, the vette I love I think I'll love more once I get this straightned out. Any suggestions?

[tccrab]

Check to see if any ECM codes are stored.
Does your SES light come on and go off when you start the car?

'Crabs

[efnfast]

SES comes on before I engage the starter, but does not come on when I start the car

[mike100]

my car won't spin the tires in 2nd, but if it stops pulling at 5000 rpm, then you are only running on primary injectors.

I don't know of any other way to check outside of the scan tool which shows the sec on/off status.

91-up cars have the green 'full power' led next to the power key. that should illuminate.

[efnfast]

MY 90, has a full power display on the info panel. It doesn't seem to stop pulling at 5k. If the scan tool shows seconderies on, does that mean they are working?. Still going to dyno the car tomorrow. Guess that will tell all.

[mike100]

MY 90, has a full power display on the info panel. It doesn't seem to stop pulling at 5k. If the scan tool shows seconderies on, does that mean they are working?. Still going to dyno the car tomorrow. Guess that will tell all.

if there is a big vacuum leak, the dedicated sensor on the secondary vac line should report a failure as a check engine light. should, never happened to me so I can't step-by-step you through it.

The tech1 tool does have a function to temporarily switch to 16 injector operation for a moment or two for diagnostics, but I do not think it opens the secondary throttle ports.

sounds like yours is working. the engine should run strong from 4000 to 6500..power peaking at about 6k...

[efnfast]

Well, like I say, tomorrow I'll dyno it. 250 hp without, 375 with. I'll be sure to post. Should show a little over 300 at the rears?

[1990 quasar blue]

Most put down either side of 330. Mine only made 320/320.

[gbmidyear66]

I would first do a quick check that your secondarys are opening, and that you secondary Vac system is holding vacuum (i.e. - pump does not run steady with key on, engine off).

You can check secondary actuator operation by "backprobing" - I believe it is pin C17 (check your FSM) on the ECM you want to connect to ground (I use a saftey pin to backprobe the signal).

With the ignition on, looking through the plenum with a flashlight at the secondary linkage - you should see the actuators open when you ground C17

If the above is all good - you are 90% there

[Brad Sewell]

My 90 will spin the tires in 2nd but it is certainly not all hell breaks loose spinning. But my Michelins are not the Goodyear smoke machines either. That's not a knock on the Goodyears, my tires just don't smoke that much.

Under hard acceleration you should be able to feel the secondaries open around 3000. Post up the Dyno results. I think I'm going to get mine on the treadmill next week.

[Route 66]

I'am having the same problem. I replaced the injectors. I put it back togather, had a few problems. I had a trouble code LTPWS 34 code. I first thought that was the problem. After reading the mechanics repair manual I no longer think that the LTPWS has anything to do with the secondary power system.! I also got a SES falt code 22 because I had noved the TPS. Someone here told me how to set it where it should be, I did that and then cleared the falt code 22. Now I no longer have any falt codes from the SES. But I can't get the secondary power to work. I don't think the secondary power was working before I replaced the injectors. I new the secondary injectors were bad so I assumed that was why I didn't have secondary power. I have looked under the plenum at the actuators they do not open. The vacuum pump is working properly, I repaired what leaks
I had in the vacuum lines. I also checked the actuators while I had the plenum off they work ok. I don't have a Tech I or anytype of scan tool. I am at a loss as to what to look for. Your help would be greatly appreciated as always.

Thanks ...E

[gbmidyear66]

Did you run the checks I suggested below?

If the secondary vac system holds vacuum, but the actuators don't activate when you ground the ECM pin, then my guess is you might have a bad secondary solenoid....

[tomtom72]

If I remember correctly....I may not be, but I do think that there is no DTC for a failed secondary vacuum solenoid. I know that a TECH1 or 1A can test it, but the aftermarket scanners & software can't do that test.

You may want to look at DTC61 as a diagnostic flow chart to see if the secondary solenoid is the issue.
:cheers:
Tom

[efnfast]

I'll look into things when I get back from the dyno. http://performance-dyno.com/dynocam.html

I'm not sure which way I want this to go. I'd rather not have anything busted, but wouldn't it be cool to find 125 extra hp I never knew I had.

I dyno at 8:30 this morning, I'll post up results when I get back.

:cheers: Steve :flag:

[Paul Workman]

MY 90, has a full power display on the info panel. It doesn't seem to stop pulling at 5k. If the scan tool shows seconderies on, does that mean they are working?. Still going to dyno the car tomorrow. Guess that will tell all.

Oh, wow... Putting it on the dyno is ONE way of testing for secondary operation, but if it is just to verify their operation, I would rather use the money toward one of Marc's chips for secondaries delete, and just pull the bastards and never look back! I've yet to hear of anyone that has deleted them put them back, unless it was for NCRS or possibly emmissions requirements. AND, you might pick up a few extra ponies in the process, to boot!

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-1007.jpg

I'm a BIG fan of deleting the bastards; pros outweigh the cons (for me). I'm just sayin...

P.

[efnfast]

Paul, I was scheduled for the dyno anyway. I figured it would give me a good baseline before I start doing mods. Dyno'd at 311 RWHP.

[mike100]

That result sounds like the engine is down 10-15 hp from stock and my best guess is partial restriction in the catalytic converters. If you get 200+ psi on all 8 cylinders with a compression test, I would tend to think your engine is still fine. That's easy to check on the LT5.

[efnfast]

Mikeahundred, headers, no cats, and exhaust go on as soon as he headers come back from being ceramic coated. I'm going to do a Marc chip and intake soon after. Then I'll dyno again.

[mike100]

Then again (as reminded from another topic) you could have restriction on the other end if the intake bellows is collapsing..did your dyno guy mount and AFR to the exh pipe to see how rich it was running?

[efnfast]

I didn't see the air intake collapse, but was not paying close attention to it. It was running rich, he guessed I could gain 10 or so hp by leaning it out. Marcs chip will take care of that.

[1990 quasar blue]

Can you post the graph?

[efnfast]

Can you post the graph?
'fraid that's beyond my computer skills.

[efnfast]

Dyno'ed again yesterday. Since the last time, I've done ceramic coated OBX headers, OBX exhaust, a Marc chip and Marc's intake hoops.

The last run in March netted 311 SAE adjusted wheel hp. It was a perfect spring day, and the actual number was 325 hp. SAE adjusted me down to 311.

Yesterday was a perfectly horrible day. Too hot, too humid, pressure too low. I was hoping for 340 rwhp. SAE adjusted was........353 rwhp.:cheers:-Steve:dancing

[ghlkal]

SAE adjusted was........353 rwhp.

Awesome - 353 at the wheels must feel good.

Steve, how was the AFR on the dyno run? Did Marc's chip keep things in range with your mods?

[ZZZZZR1]

Steve

Congrats!!!!!!!

Great power improvement.

How does the permagrin feel?????

:cheers:

David

[efnfast]

ghlkal, the afr looks to be about 12.5, a little leaner than it was on the first run. That's what Marc wanted because I have no cats.

Dave, the permagrin is always big. It must be better in the drivers seat than the passengers seat. After a bit my wifes small grin turns into more of a frown. As if to say, "do you always have to mash the pedal to the floor?". -Steve:dancing