Stuttering and stalling under boost after fmic, built head with 272's, o2 housing

[96gstdsm]

Got my car back and now when under boost it stutters a bit. It will also stall out when I come to a stop sometimes. Sometimes it will idle fine, other times it will start dropping and then shooting up to like 1500 then back down to 300 etc till it dies out.
When I got to really get on it a bit and it gets into boost it will hesitate and stutter first then get into boost and be ok. Just pretty much the initial getting into boost that stutters bad.
I think the idle is set around 800 or so. Seems to switch depending on how long it has been on so hard to really say. Kinda switches between 750 and 1000 when not dying out.
Would untuned cams do this? I also have some skunk 2 adjustable cam gears zero'd out.
My car did not have any idle problems after I got a 6 bolt block put in with a 190 pump rewired. I then brought it back for the rebuilt 7 bolt head with bc 272's, o2 housing, front mount, and a 3" downpipe and it has been happening since then. I have been monitoring everything with ecu+ so I can datalog if that would help finding out what is wrong.

Any suggestions would be great.

 

[bling5tatus]

C'mon man, boost leak test is #1 with a problem like this. I think the moderators should make a sticky saying BOOST LEAK TEST FIRST BEFORE POSTING... then if you have to post, post results of boost leak test stating that there was none... AND the problem you're still having.

 

[96gstdsm]

C'mon man, boost leak test is #1 with a problem like this. I think the moderators should make a sticky saying BOOST LEAK TEST FIRST BEFORE POSTING... then if you have to post, post results of boost leak test stating that there was none... AND the problem you're still having.

Thanks but yeah I have boost leak tested already twice. There was a very small boost leak by the throttle body, but nothing serious at all. Would not think a small one like that would effect the car that much. Also would not think it would only occasionally make my car stall out or stutter.
I am also getting a p1105 which is the fuel pressure solenoid. Just came up though after driving a couple hundred miles already with idle problems and stalling and stuttering. So would not think that is the problem either

 

[bling5tatus]

ISC motor? Check to make sure that is moving smoothly with throttle position... you can also test it with a multimeter.

 

[90gst_sean]

Make sure you boost leak test well past your max psi ran on the street; you could have a leaky inner cooler.

Its not a Ebay special is it?

 

[96gstdsm]

ISC motor? Do you have a logger, can you verify that it didn't coincidentally die at the same time you got a new fmic?

I have ecu+ which has a data logger also. What would I check with that? Seems very unlikely that it would just go out when I got a new fmic installed. IS there something I can check for to see if it got messed up by the installer? I don't really trust the guy at all who did all the work so anything he touched I think can be messed up. Something with the wiring could be the problem.
I have a 6 bolt block so I got a 1g CAS the green top one. With my ecu+ I have the input and output setting set at 90-94 instead of 9094 input and 95-96 for the output like it is supposed to be. The only way it seems to work pretty well is with it set at both 90-94 settings. I will get a ton of misfire codes if I put it to 95-96 for both. Could that mess something else up even even though it seems to work best for preventing the misfire code.

 

[96gstdsm]

Make sure you boost leak test well past your max psi ran on the street; you could have a leaky inner cooler.

Its not a Ebay special is it?

I got the ssac one. That one has been proven so I don't want to hear the "you get what you pay for crap" Cause in some cases that is not true, this intercooler being an example.

 

[RedTurboEclipse]

You try something simple and changing your spark plugs and wires?

Do a log of the run where it hesitates. It might help us distinguish the cause of your problems.

90gst_sean-- sorry buddy ebay intercoolers are pretty much proven to be good.

 

[bling5tatus]

Well ISC's are known to go bad just from age. Also, even if you have adjustable cam gears, if they're zero'd out they should be exactly like stock cam gears (someone correct me if I'm mistaken)... so I don't think that would be an issue here either.

I would check the isc, because it allows more or less air to bypass the throttle plate depending on what the car's doing, and when that thing messes up and starts doing other stuff that it's not supposed to it causes a lot of problems, including stumbling, bad idle, etc. I would check that, and anything else any of the more wise ones here have to say too.

 

[96gstdsm]

Well ISC's are known to go bad just from age. Also, even if you have adjustable cam gears, if they're zero'd out they should be exactly like stock cam gears (someone correct me if I'm mistaken)... so I don't think that would be an issue here either.

I would check the isc, because it allows more or less air to bypass the throttle plate depending on what the car's doing, and when that thing messes up and starts doing other stuff that it's not supposed to it causes a lot of problems, including stumbling, bad idle, etc. I would check that, and anything else any of the more wise ones here have to say too.

Yeah that is what I figure the most likely culprit is so I'll take a look at that tomorrow. Want to get this thing in the best shape I can before I bring it in to get dyno tuned. Every extra little thing I know will cost me more money, and thats one thing I'm sick of spending right now. Just finished getting ripped off with shotty work and spent a total including labor of like 9 grand into this car.

 

[RedTurboEclipse]

test your ISC:

http://dmtalon.v8eaters.com/ISC.html

 

[96gstdsm]

You try something simple and changing your spark plugs and wires?

Do a log of the run where it hesitates. It might help us distinguish the cause of your problems.

90gst_sean-- sorry buddy ebay intercoolers are pretty much proven to be good.

The plugs are brand new. Checked them and they looked clean, no signs of running lean or rich. Possibly slightly rich but nothing that would cause stuttering I don't believe. Plugs are fairly new also. Everything worked fine until I had to bring my car back to the shop that installed my 6 bolt since they didn't resurface the head(told them to and they denied it, lucky me hah) anyways. Besides burning coolant the car drove fine. No stuttering or anything. Using the same wires as then so they should be good. New plugs. Something along the lines got changed somehow and I don't know what.
I will test the isc, any way it could have something to do with the bigger cams and adjustable cam gears?
When I step on it I see about 28 degrees of timing, is that too high?

Also as I stated before I got a CEL P1105 fuel pressure solenoid. Could that cause this?

 

[92 GSR-4]

Based on what you've said, and as long as there isn't a boost leak:

1) Boost leak anyway.

2) Check the TPS, maybe the plug came off when installing the FMIC.

3) Try resetting the idle via grounding out the terminals.

Good Luck!

 

[oldman]

Also as I stated before I got a CEL P1105 fuel pressure solenoid. Could that cause this?

Yes.

 

[96gstdsm]

Yes.

What could I do to check what is wrong with it? How do I fix it? If the vacuum lines were removed from it that would cause this? The guy who did all the stuff on my car, removed all the vacuum lines for some reason without telling me, don't remember if he also took the one on the fuel pressure solenoid if I am thinking of the correct thing. It is the little knob thing you can turn by the driver side firewall and has a vacuum line that runs to be the valve cover area correct?

 

[oldman]

Find the stock FPR at the very end (driver side) of the fuel rail, follow the vacuum line attached to it and tell me where it goes to.

 

[96gstdsm]

Find the stock FPR at the very end (driver side) of the fuel rail, follow the vacuum line attached to it and tell me where it goes to.

OK there is no vacuum line going anywhere there anymore. The solenoid has been removed I guess. Also I found this connection not connected to anything. I know it was prior to bringing it to this dsm shop.
So if it is not connected can it cause this? I thought it was already disconnected last time before the bad head gasket but I could be wrong. My car didn't seem to have any stuttering problems then.
Here are some pics to make sure that this is in fact the missing fuel pressure solenoid. Also some pics of the plug that is not connected to anything.

http://i123.photobucket.com/albums/o281/ryangreene555/badwiring003.jpg

http://i123.photobucket.com/albums/o281/ryangreene555/badwiring002.jpg

http://i123.photobucket.com/albums/o281/ryangreene555/badwiring001.jpg

The first two are the connection I don't know what it is the last is the connection where I think the fuel pressure solenoid used to be.
Sorry for them being blurry was dark out there so couldn't really focus.
The first two pics are right behind the fuel rail if it is hard to tell.

MOD EDIT: PICS TOO LARGE. CONVERTED TO URL'S.

 

[oldman]

The first plug looks to be AC compressor, is it removed?

Second plug is for FPS, this is why you're throwing the code, you can remove the vacuum lines but you must leave it plugged in. That said, the code is not the cause of your problem.

 

[96gstdsm]

The first plug looks to be AC compressor, is it removed?

Second plug is for FPS, this is why you're throwing the code, you can remove the vacuum lines but you must leave it plugged in. That said, the code is not the cause of your problem.

Hmm don't know why he would remove the plug for the AC compressor. It hasn't been working prior to going there in the first place, but that plug was never loose. Is there any reason why he would unplug it?
The compressor is still there, but I have never had it working since I have owned the car about a year.

So would you say having that out of the way the best bet would be the isc or the tps?
Could the mas plug cause this? If a boost leak popped up again for some reason at the throttle body, would it have to be a real big leak to cause this? Cause there was a very slight one there, but would not think it would be enough to cause anything like this.

 

[oldman]

I'm not 100% sure it's for the AC, why don't you reach down there and check.

TPS and ISC, you have a logger, do you know how to check them?

Boost leak, how much pressure were you able to maintain on the boost gauge during your boost leak test? What was the compressor regulator (assuming you were using an air compressor) set to? How long did it take to bleed down to zero after you remove the air source?

 

[96gstdsm]

I'm not 100% sure it's for the AC, why don't you reach down there and check.

TPS and ISC, you have a logger, do you know how to check them?

Boost leak, how much pressure were you able to maintain on the boost gauge during your boost leak test? What was the compressor regulator (assuming you were using an air compressor) set to? How long did it take to bleed down to zero after you remove the air source?

Couldn't really see anything as it was real dark out there so will check again tomorrow. I do have a logger but I do no know how to test that.
Can they all show info on that?
I see on the list in my logger that it shows tps, I don't see anything for the isc though. What volts do I check for with the tps?

 

[oldman]

I have never used a 2G logger but on 1G mmcd or dsmlink (1 or 2G), you can log both TPS and ISC.

With TPS, you want .62volts for 2G at idle (closed throttle) and 5 volts (give or take) at WOT, you also want to slowly go through the entire throttle range and make sure the TPS works in a smooth motion.

ISC ranges from 0 - 120, at idle after the car is in operating temperature, your ISC should settle at around 30, putting any load, like turning your steering wheel, will cause the ISC to open more to compensate so you should see the number increase. All of this is to maintain an idle of 750 which bring us to another issue. If you're not idling at 750, this usually means your BISS has been turned out to far and your ISC has maxed out its adjustment range, if this is the case, you will find your ISC stuck at 0 during idle.

Any reason why you skipped boost leak test questions?

 

[96gstdsm]

I will re do the boost leak test. That was done by the installer guy and said he tested twice and was only one very small leak by the throttle body. I will test again myself hopefully tomorrow.
As for the idle, when I went to pick it up it died right away, so he turned the idle up a bit. Thats why it was raised. He seems to love to just try some sort of an easy crappy fix for everything he screws up. So I am just assuming lots of little things are screwed up.

 

[oldman]

I will re do the boost leak test. That was done by the installer guy and said he tested twice and was only one very small leak by the throttle body. I will test again myself hopefully tomorrow.
As for the idle, when I went to pick it up it died right away, so he turned the idle up a bit. Thats why it was raised. He seems to love to just try some sort of an easy crappy fix for everything he screws up. So I am just assuming lots of little things are screwed up.

Yep, you can't just go and turn the BISS without grounding out the ISC, he has probably also turned it too much so the ISC can't bring idle down to 750 anymore while stuck at zero. I'm also willing to bet that you have some nasty boost leaks waiting to be discovered.

 

[96gstdsm]

Yep, you can't just go and turn the BISS without grounding out the ISC, he has probably also turned it too much so the ISC can't bring idle down to 750 anymore while stuck at zero. I'm also willing to bet that you have some nasty boost leaks waiting to be discovered.

Yeah could be. So I should turn it the other way to correct that or no?
Also is talking about your experiences with a dsm shop good or bad allowed on here?

On another note would low oil pressure according to the stock gauge most likely mean a bad oil pump? The oil pressure is much lower than it was on my old engine. The 6 bolt engine I got now the oil pressure during idle is around the bottom line, maybe a little bit higher, and then when driving gets up to around the middle line. Haven't had time yet to hook up my oil pressure gauge so just wondering how horrible the stock gauge is and what numbers at those points could mean.