:driving: Turbo Boost Gauge readings

[nvno1]

Originally Posted by Flooder

Sure you will, just not very much. You can still make your BOV vent when in neutral.

matter of fact it did...my boost gauage hopped up to nearly 5psi. it was pretty cool to see.

[nvno1]

OkAy SOoooo...like my Hg rading are low..i got video coverage of the issue, no dvd player on the wk pc and dont have internet access else where right now. so what i decided to do is block everything off with block off plates, get another BAC, change all the remaining hoses, upper to lower intake gasket and check the fuel injectors. from the information you guys have given me the Hgs are to low. i am sure that it HAS to be a vac leak somewhere. oil pressure good, not getting hot, no bubbling at the rad, no sweet smell out exhast, and hard to start unless i play with the trottle.

[Flooder]

"The HG's are too low"? WTF. lol.

[RETed]

Originally Posted by nvno1

from the information you guys have given me the Hgs are to low. i am sure that it HAS to be a vac leak somewhere. oil pressure good, not getting hot, no bubbling at the rad, no sweet smell out exhast, and hard to start unless i play with the trottle.

I doubt that's the case.
I put money it's something else.

Other causes that can "fool" your boost gauge to show improper vacuum while driving:

* ignition problems
* fuel delivery problems
* misfire
* hurt motor


-Ted

[NoDOHC]

Have you compression checked this engine yet?

[nvno1]

Originally Posted by Flooder

"The HG's are too low"? WTF. lol.

Flooder, i have the feeling that you are under the impression that i know a ton about Rx7s or perhaps you were just bored. please feel free to provide useful information as to why what i stated was so funny.

From what i read and am lead to believe is that, if you have a VAC Leak ur car will not idle correctly. The internal pressure would be off thus causing the Hgs to not be at lets say -10hg min (on 85psi per rotor(front/rear) @1000rpms. I have good fuel pressure, set the timing to TDS and cas aligmnt as per FSM, good plugs, good A/F meter and no flooding. I have used two 1/2 cans of starter fluid to try and locate a vac leak and nothing have surfaced.

The troubleshooting help that I've recieved, mostly everyone is stating that it is mostlikely a vac leak. When i posted the ? as to what Hgs read under idle there was no response from you in that regards and the information that i got really has me believing this is the issue. please coorect me if im wrong.

[nvno1]

Originally Posted by RETed

I doubt that's the case.
I put money it's something else.

Other causes that can "fool" your boost gauge to show improper vacuum while driving:

* ignition problems
* fuel delivery problems
* misfire
* hurt motor


-Ted

Ted i'm not driving;(, I got strong spark, getting good signal from the cas, plugs are good, coils seem good, good clear fuel flow, 85psi on front and rear and it doesnt backfire.

[nvno1]

Originally Posted by NoDOHC

Have you compression checked this engine yet?

yep, 85psi on front and rear before warm up.

[NoDOHC]

I would go and get a real vacuum gauge and put it on the car. Connect it to the port that comes out of the side on the manifold right next to the split between upper and lower manifolds.

I am inclined to mistrust your stock vacuum gauge.

If the vacuum gauge is reading identical to your boost gauge, you almost have to be running on 1 rotor or it should rev up really fast.

[nvno1]

Originally Posted by NoDOHC

I would go and get a real vacuum gauge and put it on the car. Connect it to the port that comes out of the side on the manifold right next to the split between upper and lower manifolds.

I am inclined to mistrust your stock vacuum gauge.

If the vacuum gauge is reading identical to your boost gauge, you almost have to be running on 1 rotor or it should rev up really fast.

Thanks NoDOHC, the gauage is aftermarket and i am starting to believe it might be operating on one rotor(fuel injector not pulsing). The reason i state this is because the car is hard to start(unless i play with the pedal) in addition to several turns of the key. When it does start it sometimes sort of stutters then rev good but the rpms drop then hop back up, then drop, then hops up again. This shit is getting on my nerves!!! When the car warms up at idle its does the same thing...hops from 1000 to bout 1600-1800 then back down to 1000.

What freaking me out is that the compression is 85psi front and rear, fuel pressure is good, no flooding, oil pressure good, plugs clean, oil clean, af meter reading good, once running revs up quick when i hold the pedal however the rpms will drop then come back to where it was previously.

This car is a common swap:
84 gslse, 87 TII(s4) complete pass harness(nothing was cut) still connected to the motor,drivers harness made and continu test done(ends tested), walbro pump, stock ecu, 87 TII tranny(still shopping for driveshaft).

[Rx-7fetish]

Originally Posted by nvno1

When it does start it sometimes sort of stutters then rev good but the rpms drop then hop back up, then drop, then hops up again. This shit is getting on my nerves!!! When the car warms up at idle its does the same thing...hops from 1000 to bout 1600-1800 then back down to 1000.

Sounds like tps to me, have you checked it besides poking it with your finger, mainly the test lights or volt meter?

Originally Posted by nvno1

What freaking me out is that the compression is 85psi front and rear, fuel pressure is good, no flooding, oil pressure good, plugs clean, oil clean, af meter reading good, once running revs up quick when i hold the pedal however the rpms will drop then come back to where it was previously.

Sounds like your afm is going bad or there is an intake leak after it. I had the same symptoms on both my 10th ann and an 87 gxl, the 10th ann had an intake leak between the afm and the turbo, and the afm was going bad on the gxl.

[NoDOHC]

Hopping is common around that speed, the stock ECU advances the timing quite a bit at 1200 rpm. Try adjusting the idle down to 750 rpm. It could be the TPS, but it is not uncommon for a properly tuned car to hunt if the idle speed is set too high.

[nvno1]

Originally Posted by Rx-7fetish

Sounds like tps to me, have you checked it besides poking it with your finger, mainly the test lights or volt meter?

Sounds like your afm is going bad or there is an intake leak after it. I had the same symptoms on both my 10th ann and an 87 gxl, the 10th ann had an intake leak between the afm and the turbo, and the afm was going bad on the gxl.

Thanks for the response without the doggish dialog...i have check the TPS w/lights and a meter. when i press the TPS in all the way the motor heads to redline quick i mean fast dude.( love the TII motor bwoy)

we checked the afm per FSM and it fine according to the FSM..I plan on blocking off everything and triple checking the hoses. going to be replacing all vac lines that remain and the gasket for the Upper to Lower. can it test okay and still be bad?

[nvno1]

Originally Posted by NoDOHC

Hopping is common around that speed, the stock ECU advances the timing quite a bit at 1200 rpm. Try adjusting the idle down to 750 rpm. It could be the TPS, but it is not uncommon for a properly tuned car to hunt if the idle speed is set too high.

...NoDOHC thanks for your feedback always a pleasure to hear from you....the BAC is bad i believe, the plunger is not moving...just tested it..the BAC was not plugged in either at the time and i tried it plugged up and not plugged up same rpm hunting...waiting to get the block off plates and gaskets now.

[NoDOHC]

If the idle is above 750 and the engine is warm, the BAC should be shut. If you unplugged it and the pulsation didn't go away, I doubt that it is the issue. The stock ECU has a 'hole' in the timing map to make the engine idle down while getting excessive air and fuel (5 degrees ATDC). If I program a similar hole into my Haltech, it will do the same oscillations if I set the idle too high. Seriously, try adjusting the idle down to 750 with the check jumper connected and then see what it idles like.

This still doesn't explain why the engine is running at such low vacuum. You said that it revs very quickly from idle if you floor it?

Are you sure that the timing is correct?

By press the TPS in all the way, you mean floor the gas, right? Pressing in the TPS without moving the pedal shouldn't make the engine rev to the redline.