White Spark plugs a low vacuum at idle

[blackrosenova40]

i have a 1990 Gsx and I only pull 7 inches of vacuum and my spark plugs are pure white.

My Eclipse will not go past 3800-4000 rpm , it feels like a brick wall, I wont dare go past it , feels like I will kill the engine

I did a compression check the read as follows

#1 152
#2 154
#3 162
#4 164

My car currently has 13300 miles on it and it has been checked for vacuum leaks and there are none. It idles smoothly but low vacuum which I find odd.

I just replaced the fuel filter and when I took of the top hose on the filter there was barely pressure, in fact it just kinda dribbled.

Could my fuel pump be bad? I dont know what else could be wrong, perhaps my computer is malfunctioning. Please help i cant figure it out.

Thanks in advance -Chad

Ps: My valve timing and ignition timing are right on also.

 

[FastGS-T]

I think you need to do an EXTENSIVE boost leak test. With soapy water, the whole 9. The whole brick wall feeling is fuel cut, usually caused by boost leaks and/or over boosting. It happens because the ECU is seeing too much air. White sparkplugs usually mean a sudden large increase in temperature right? You may be running massively lean from over boosting.. What does your boost gauge read?

 

[bojanglesracing]

yea same here white means your lean. and your are hitting fuel cut. and like he said you probley have a boost leak.

 

[blackrosenova40]

Sorry , I should clarify , I had it tested , I brought it into a local shop in town and got it tested for 40$ and there were none.

I thnk they used a smoke machine or something.

 

[FastGS-T]

Well the fact that it is still happening is back up to rule #1. Never let a shop do your work.

goto www.vfaq.com and search on doing a boost leak test. There are tons of threads on here about it also.

What is your mod list? Do a soapy water boost leak test and see what you find. Trust us it's worth it and very important.

 

[ddavisaf]

The smoke tests aren't always as accurate. Reason being is they don't pump the smoke through at 20 psi like we do when we test our intake tracks.
Like everyone said... boost leak test it at 20 psi.
http://www.vfaq.com/mods/ICtester.html

 

[blackrosenova40]

Well I tested my intake and it held 25 pounds of air, so I dont know what do to.

 

[Dream On]

Did it hold it for 30 seconds? And this may be a stupid question, but do you have a boost gauge or are you relying on your vacuum from the stock boost gauge?

 

[oldman]

Did it hold it for 30 seconds? And this may be a stupid question, but do you have a boost gauge or are you relying on your vacuum from the stock boost gauge?

number 7 makes this highly probable.

 

[jhines]

You say that it reads 7" at idle, once you have checked for the leaks, it might not be a bad idea to check the EGR. It could have some issues causing that loss of vacuum. Not all too familiar with that system though. Also, the PCV could cause that power loss, but it would not cause that "brick wall" or the fuel to barely drip out. But you definitely need to do a very thorough leak test and post the results you find. Then maybe we can al go from there with some more ideas.
-Hines

 

[blackrosenova40]

I am taking a reading from the stock boost gauge. I am recieving an aftermarket Autometer gauge tommorow.

It reads exactly at 7 at idle, and when I decelarate it reads more of course, what I dont know.

Yes it held for more than 30 seconds, and I already have blocked off my egr thinking that was the problem.

Its really wierd my car idles perfectly.

What I mean by brick wall affect , its as though it is really really runnin lean at about 3800-4000.

My next course of action is check fuel pressure.

 

[oldman]

I am taking a reading from the stock boost gauge. I am recieving an aftermarket Autometer gauge tommorow.

It reads exactly at 7 at idle, and when I decelarate it reads more of course, what I dont know.

First off, the stock boost gauge does not measure real pressure. Secondly, Isn't -7inHG as low as the gauge go?

 

[blackrosenova40]

It can go a little past 7 inches

 

[oldman]

Get the autometer on tomorrow first.

 

[blackrosenova40]

Will do

 

[Ultimatedsm]

Several things can cause that: (Good to get that gauge for the boost leak test and in general).

1. Bad plugs and wires
2. Boost leak
3. Coil pack/Transistor
4. Bad MAF
5. Leaky caps on those 1g ECU's

Check these one by one and I know you will find the problem. Trust me its one of these. I had a similar problem as you and it turned out to be a bad MAF, the pain in the ass part was that the car drove fine but once boost hit, the car would hit a brick wall. I checked all those parts I listed (I checked the MAF last and didn't check the 2g ECU). So I was like what the hell is going on, I hold 20 psi for 30 seconds, my plugs are fine and gapped correctly, wires are brand new, coil-pack and transistor was swapped (Friend had spares) and I was just like what the &%*#(&$*)@#&$*)#(@&$*(# is going on. Then it turned out to be the MAF, stupid thing. Anyway sorry to bore you with my MAF story, just check out everything thoroughly or I have to hurt you.....just kidding. Good luck with the car and again I know its one of these for sure.

 

[GVR4592]

Nobody has pointed out the fact that the stock boost gauge doesn't read in in/hg, it reads in psi. So if it sits at -7 PSI that is not that bad. That would be roughly 14 in/hg at 32 degrees farenheit. As for the diagnosis:

Several things can cause that: (Good to get that gauge for the boost leak test and in general).

1. Bad plugs and wires
2. Boost leak
3. Coil pack/Transistor
4. Bad MAF
5. Leaky caps on those 1g ECU's

Check these one by one and I know you will find the problem. Trust me its one of these. I had a similar problem as you and it turned out to be a bad MAF, the pain in the ass part was that the car drove fine but once boost hit, the car would hit a brick wall. I checked all those parts I listed (I checked the MAF last and didn't check the 2g ECU). So I was like what the hell is going on, I hold 20 psi for 30 seconds, my plugs are fine and gapped correctly, wires are brand new, coil-pack and transistor was swapped (Friend had spares) and I was just like what the &%*#(&$*)@#&$*)#(@&$*(# is going on. Then it turned out to be the MAF, stupid thing. Anyway sorry to bore you with my MAF story, just check out everything thoroughly or I have to hurt you.....just kidding. Good luck with the car and again I know its one of these for sure.

That is exactly what I would do.

 

[Defiant]

Make sure your vacuum isn't collapsing the sensor line to the gauge- unless you're referring to the stock "boost" gauge, which means nothing. As for the plugs, reading a cut from plugs out of an injected engine is dicey at best. Make sure yours are fresh, BPR6ES gapped at .028".

 

[blackrosenova40]

Thanks for the help everyone

 

[blackrosenova40]

Well I installed my vaccum/boost gauge and I read 17.5 cold and about 19.5 warm from just idling.

What should be my next step?

 

[jhines]

Well you have no vacuum leak then, have you looked at your fuel pressure. You said that you were running extremely LEAN and that your plugs are very white. When you go into the 3800-4000 range, does the MIL come on, or is it on all the time, or does nothing happen. It could be an air monitor or something. Not sure, what all have you checked exactly?
-Hines

 

[blackrosenova40]

I have replaced with new wires, blocked off egr , checked compression, checked valve timing, ignition timing, fuel filter is new.

 

[oldman]

I have replaced with new wires, blocked off egr , checked compression, checked valve timing, ignition timing, fuel filter is new.

Assuming everything was done right including the boost leak test, I suggest investing in a logger so you can see whether the maf is sending wrong signals or you're not delivering enough fuel. Ultimatedsm's post above summed it up pretty well.

 

[blackrosenova40]

Woohoo I even pull 20 inches of vacuum after a good 20 minute drive

My car will seem to run lean at 3800-4000 whether I take it slow to 4000 without boost or fast to 4000 with boost.

That seems to me like it would be coilpack/transistor

 

[blackrosenova40]

New update on what may be wrong, if I push in the clutch cruising at 3500 or higher in 3rd gear or higher, the engine will go down to idle speed then die.

Does that help with what may be wrong?