fuel pressure/egr vsv question

[Bri7man]

So I have a fuel pressure vsv on my car measuring 54 ohms, I have an egr vsv on my car measuring 54 ohms also. Max tsrm spec is 50 ohms. My car is stumbling to its death in neutral after high boost.

I have 2 other fuel pressure vsv's reading 0 ohms(no good), and an egr 7mge vsv that reads 35 ohms.

Can I interchange egr and fuel pressure vsv's?
Can I interchange 7mge and 7mgte vsv's?

It's just an on/off switch inside right?

 

[jetjock]

They're three-way solenoids. Neither of them can be responsible for your symptom.

 

[Bri7man]

Oh that's just wonderful.. *sigh* I really need an award for the amt of stress I'm suppressing right now.


Alright, so what symptoms does an out of spec egr and fuel pressure vsv display?

 

[Kai]

Jetjock - surely if the VSV for Fuel Pressure isn't working at all, or correctly, this is going to cause problems, no?

 

[jetjock]

In theory I don't see how Kai. There's no failure mode of either VSV that would cause his symptom, at least as I understand it. Feel free to offer an alternate hypothesis in case I'm overlooking something.

 

[Kai]

Have a look at FI-73 in the TSRM - fuel pressure with vacuum connected is 23-30 psi, without it, it's 33-40 psi. The VSV switches the vacuum on and off to the regulator. If the fuel pressure isn't switching as it should, you're surely going to end up with poor spray from the injectors, causing his problem?

 

[jetjock]

I'm familiar with how it works. Perhaps the OP should clarify exactly what his symptom is.

And stop calling me Shirley

 

[Bri7man]

Sure. Well after letting off from boost and shifting into neutral the rpm's will stumble below 500 and the car will continue to fight off death unless I give it tap from the throttle, it will usually die if it begins to stumble and I don't catch it within 3 seconds. This doesn't always happen, but more often that not, as in let's just say I'm actively monitoring rpm's between shifts and in neutral. I've swapped in 3 different tps's and just changed in another afm, the problem still exists, I cleaned my iscv check valve, my cps is at a max resistance at 180 ohms(issue?), and 3 of the iscv's that I acquired are within spec and i took them apart and wd40'd the bearings, none were stuck.

 

[jetjock]

That's how I read it. Problem occurs after boost, not during. Which brings me back to post # 2.

Edit: You could just hook the FPR directly to the manifold (thus bypassing the VSV) and see what happens. Not much will change me thinks...

 

[GrimJack]

Have a look at FI-73 in the TSRM - fuel pressure with vacuum connected is 23-30 psi, without it, it's 33-40 psi. The VSV switches the vacuum on and off to the regulator. If the fuel pressure isn't switching as it should, you're surely going to end up with poor spray from the injectors, causing his problem?

Well, if nothing else it's really easy to test, just bypass the VSV and run vacuum constantly to the FPR. If the stumble leaves - which I hate to say it, but I must admit is unlikely - then this is the culprit.

The thing is, if this were the problem, it should run poorly at idle all the time, not just when letting off the throttle after boost.

 

[Bri7man]

I'll try that, I just measured VF and TE1 on the diagnostic block and got a reading of 1.06V, from what I understand which is very little, that it is quite low?
I'll try to bypass the vsv, but I'm honestly scared to test it, if I don't catch the rpm and it dies it seems like a 50% chance it will start up again without having to wait an hour to go by. I guess I'll try it on my own street.

 

[JStoked]

What kinda of bov are you running?

 

[JStoked]

What kinda of bov are you running?

 

[Bri7man]

I'm running a stock bov, I cleaned it thoroughly with gas and ran it with white vinigar through the dishwasher. It's recirculated.

So that last voltage reading was wrong, because I had swapped in my other tps, which changed the timing to around 7btdc, so I adjusted the timing to 10 and now the reading is 3.5V, the opposite side of the spectrum.

I bypassed the fuel pressure vsv vac lines with it still plugged, nothing new happened, started up and idled the same as it did with the vac lines connected to it. About go take it out around the block.

 

[3p141592654]

I'm getting confused about the voltages. Is the 3.5V the Vf voltage (referenced to E1 and not TE1), or something else? Anyway, a Vf of 1V or 3.5V is okay, certainly not the cause of your problem.

A stumble after boost typically would be a leak of metered air, especially if this stumble only occurs when you go to positive boost, and not with light throttle and no boost. However, your comment seems to imply that you cannot start the car for an hour after this happens.... that's a big puzzle, and changes the game some!!

 

[Bri7man]

Sorry I was sleep deprived and tired when I posted, I mixed up the terminals, it was VF and E1.

 

[Bri7man]

It seems like vapor lock or flooded cyl's, or if those 2 are the same thing..?

Not sure. But anyways I do know I'm in for some trouble and a call to my insurance company for a tow if the car doesn't fire on the first key turn attempt following death after boosting. After that I can continue cranking for as long as I want and it wont start. It needs a minimum of 20 mins sitting(if lucky) and maximum, an hour, and it'll barely start and the rpm's will stumble around 300-400, tap the throttle, and it's alive again. And will shut off and start normally.

The frequency of the car not starting again after engine death following boost for example has been 2 times in the past 5 situations.

Edit,

I should make it clear that my cps was adjusted although the wire resistances are 180-183, max tsrm spec is 180ohms.

 

[thevork]

Problem found already?
Maybe it's an open door but poor idle after boost is most likely a boost-leak. Can you pressure-test the intake from just after the AFM to the throttle body ?

I've had similar problems and after pressurizing the intake system I could easily tell where the boost leak was.
Also, if your Vf signal was way off (around 1.0?) and reading correct after swapping out your TPS then the TPS was not set correctly or it was fubar.

And maybe I missed it, but did you check your codes?

 

[Bri7man]

I fixed the idle but i still need to do a boost leak test, hopefully I can tomorrow. oh yes very fond with codes, all clear. BTDC was way rich after switching TPS so it was like LESS FUEL LESS FUEL, I set to 10 and I got 3.5V