90 - Running out of breath at 5000 - No Codes

[rhipsher]

Don! Three words. Secondary vacuum solenoid.

[dondon]

Originally Posted by scottfab

Jonathan, here is way to operate the secondaries with the plenum in place. This will allow you to test them and actually see them pull in without rolling down the highway.

I agree with all in this article except the assertion that 1 sec cycle time on the pump is ok. It states that that having a longer cycle time does not affect the engine power. While this is correct, to leave a system with this amount of leakage is just asking for the pump to cycle itself into oblivion. I'd investigate and fix a vacuum system that cycled 10 sec or less. So anyway, try this and actuate the secondaries several times. If they seem to pull in on both sides, clear any codes then go for a drive and see. If it drops out again look to see what codes are set again and we can go from there.


http://www.zr1specialist.com/HAT%20W...0Operation.pdf

Hi Scott

Thanks for the info. FYI - car feels as though it starts quicker with new fuel pumps.

I've already run that test with success and it holds the actuators open as long as I want them to be open (was shorting the circuit on the front suspension arms). Pump runs while actuators are moving then shuts off again immediately and never turns on until the actuators are energized again.

These are the vacuum tests I previously ran:

Passenger side connector to the pump (by the oil filter), if I vacuum test it holds in both directions. If I pull the cylinder 3/5 vacuum pipe, it holds going down, but going into the plenum(metal side), I cannot get vacuum to hold.
Vacuum test Map sensor by the battery / ECM, the pipe does not hold vacuum, but the Map sensor does.
Vacuum test MAP sensor behind plenum, vacuum holds on the sensor, but does not hold going back into the plenum.

Don't think any of the above is a problem but in the interests of full information.

I think I'm going to try something ODD prior to pulling the plenum off again (its on the outer edge of my comfort level). Add vacuum to the sensor under the ECM, and pinch the pipe off when its in the range that Franke Specified, and then block the spider vein that would run to the sensor. My expectation is that and I am probably wrong... the sensor will be within range, the ECM will activate the secondaries and the pump will provide all vacuum necessary. If it runs well then I think the problem is somewhere in the spider vein headed to the sensor, but then again maybe not. This is not my area of expertise.

Thanks for the continued help
Jonathan

[scottfab]

Originally Posted by dondon

Hi Scott

... snip...
I think I'm going to try something ODD prior to pulling the plenum off again (its on the outer edge of my comfort level). Add vacuum to the sensor under the ECM, and pinch the pipe off when its in the range that Franke Specified, and then block the spider vein that would run to the sensor. My expectation is that and I am probably wrong... the sensor will be within range, the ECM will activate the secondaries and the pump will provide all vacuum necessary. If it runs well then I think the problem is somewhere in the spider vein headed to the sensor, but then again maybe not. This is not my area of expertise.

Thanks for the continued help
Jonathan

You will be an expert at the end of it all.
Can you confirm. No codes are set AND the loss of power is always at 5000rpm? (each and every attempt?)

[dondon]

Originally Posted by scottfab

You will be an expert at the end of it all.
Can you confirm. No codes are set AND the loss of power is always at 5000rpm? (each and every attempt?)

I tried the

Add vacuum to the sensor under the ECM, and pinch the pipe off when its in the range that Franke Specified, and then block the spider vein that would run to the sensor. My expectation is that and I am probably wrong... the sensor will be within range, the ECM will activate the secondaries and the pump will provide all vacuum necessary.

Surprise surprise - I was wrong . So it immediately set a HARD Code 61, the ECM clearly is smart enough to know I was messing with it.

Anyway, I reset the code, hooked up the plumbing as it was before and. went for a ride. Car ran as before, with same symptoms. The code 61 is intermittent... meaning the code gets stored, it does not have the hard stop at 3000 rpm as you see when the service engine soon light is on.

So maybe I need to setup a video... the car accellerates, and it feels brisk, probably within a second it feels less brisk but continues accelerating to 4000 with some force from 4000 to 5000 acceleration is slow and at 5000 I run out of patience and shift (usually I'm in 1st and 2nd gear), as I'm in the city.

Easiest way to get the code 61 stored is to get on the the highway in a high gear at low speed and mash the accelerator.

http://www.zr1specialist.com/HAT%20W...0Operation.pdf

- what does this test eliminate any items from the suspect list
- actuators [yes / no]
- solenoid [yes / no]
- reservoir tank [yes / no]
- front portion of vacuum system pipes [yes / no]
- check valve near solenoid [yes / no]

My gut feel says and the secondary vacuum number is the big clue, does anyone know perhaps if it stays at 0 kpa like mine does, and at which point that changes. ie does it change when the secondary pump charges the system or some other time. All I can think is something under the GD plenum is preventing Vac from getting to the Vacuum sensor under the ECM... there may be other issues as I recently replaced the solenoid, reservoir tank and spider hoses... so who knows.

There is so much info on this forum about the code 61, you would swear I was deaf to something or overlooked something.

[Franke]

Looks like you've replaced almost everything in the secondary's operation and your tests on the "plumbing" seem ok. Do you have a spare ECM?

[John Boothby]

Originally Posted by rhipsher

Don! Three words. Secondary vacuum solenoid.

I rebuilt my entire secondary vac system with brand new parts and after about 1 month one of the actuators went bad as well as the secondary solenoid. These were new items. I replaced the actuator with the old one, which was still good, and installed a new solenoid, and all has been fine since then.

I will bet that when you find the problem, it will be something simple.

[rhipsher]

There is another thing you should check. There are two check valves. One up front and one in back. The one in back is for cruise control which does not affect the secondaries. But the one that's up front can. It should only allow flow in one direction. So disconnect it and blow through both ports. If you can blow through both ports then there is some dirt inside of it causing the little BB ball to remain stuck. Just run some soap and water through it and blow it out with some compressed air. Then test it again.

[dondon]

Originally Posted by rhipsher

There is another thing you should check. There are two check valves. One up front and one in back. The one in back is for cruise control which does not affect the secondaries. But the one that's up front can. It should only allow flow in one direction. So disconnect it and blow through both ports. If you can blow through both ports then there is some dirt inside of it causing the little BB ball to remain stuck. Just run some soap and water through it and blow it out with some compressed air. Then test it again.

Is this something I can do with plenum in place?

To be specific I'm trying to test :

The check valve located to the left of the tag in this picture.

Any way to do this with plenum in place? It will add about a weeks lead time in order to get gaskets etc to do this job.

Thanks for input.

[rhipsher]

Originally Posted by dondon

Is this something I can do with plenum in place?

To be specific I'm trying to test :

The check valve located to the left of the tag in this picture.

Any way to do this with plenum in place? It will add about a weeks lead time in order to get gaskets etc to do this job.

Thanks for input.

No!

[rhipsher]

I assume your gaskets are original. Otherwise I just cut my own Felpro gaskets and reuse them. But my setup is a bit different then yours. I have finolic spacers sandwiched between the plenum and IH which blocks coolant from making it into the plenum. So I would just order the stock gaskets from Jerry.