Newbie with a few probably simple questions

[odormat000]

I am brand new to the whole DSM thing and just bought a 91 Laser RS Turbo. I am very young and dumb when it comes to cars but am willing to learn if you just be patient with me.

Four things wrong

1. When driving I start to smell a lot of gas and see a few puddles below the fuel injectors under the intake manifold. Does gas often leak from the fuel rail or could it be coming from somewhere else?

2. There is a hissing noise under the hood at idle and I can't exactly tell where it is coming from. Like air escaping from somewhere or something. Any ideas? That's supposed to be bad right?

3. While in 1st and 2nd gear if i try to give it some gas it just spudders a little and I have to wait for it to get to 4,000 RPM's before i can give it real gas.

4. It idles rough as in the car is kind of shakes a little and it's kind of on and off.

Any advice will help a lot. Feel free to answer all or just one. THANKS! -Matt

 

[ilikespeeding]

1. You're probably looking at an o ring from the fuel rail fittings. Get a 14 or 16 gauge wire and connect it from the positive battery cable to the fuel test connector on the firewall. A simple search will show you where that is. Do this with your car off and look for a leak around the fuel rail.

2. You probably have a vacuum leak. Try pinching off vacuum lines with a needle nose plier to see if you can figure out if it's a vacuum leak or not. I'd check the PCV hose first.

3. & 4. You might want to take a look at spark plugs. See if they're dirty and check the gapping.

 

[absolute_DSM]

1. Injector seals.

2. Do a boost leak test.

3. Make sure youre running NGK BR6 spark plugs gapped to .028".

4. Check your idle. Does it surge? Start here - Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[odormat000]

Thanks you guys

I was thinking it was the injector seals just wasn't sure.

There might be a hose somewhere that got disconnected or something from the guy I bought the car from so i'll have to take a closer look around as for why I hear the hissing noise. I don't know if it would be a boost leak though. Is there any vacuum or pressure in the intercooler piping while the car is idling?

and as for the bad idle idk if it would be the spark plugs because the guy i bought the car from told me that he just changed the spark plugs. they weren't the NGK ones but another brand and who knows maybe they weren't even the right kind so i guess that may be one of the problems I will have to get the ones you recommended and then see if that helps. Thanks!

 

[absolute_DSM]

Get NGKs and dont look back. There all multiple cars that I know that run perfect on the "stock" set of spark plugs, but when people try to get all fancy and buy "performance" platinum dual tipped spark plugs for $7.50 a piece, the car runs like crap. Just like the SL1 I just worked on....

Boost leak=vacuum leak.

 

[odormat000]

Thanks for the tips Eric, I'll go and test it out. tomorrow i'm going to make a homemade boost leak test adapter to use with my air tank and i'll see how that tests out. with my luck i'll find many leaks.

 

[odormat000]

Also the idle doesn't surge it's just rough and it shakes a little. Do you think it could be because of the spark plugs?

 

[My1GLaser]

The idle issue is because of the leaks In My Honest Opinion (IMHO). When your car is leaking air at idle you are pulling air into the motor from all those leaks. The ECU doesn't know about the extra air right away because it expects the amount of air that pulled thru the Mass Airflow Sensor (MAS) to be the amount going into the motor.

So the injectors spray the amount of fuel to keep the Air Fuel Ratio (AFR) at 14.7:1 (stoich). But the air from these leaks are bypassing the ECU sensors and the mixture in the combustion chamber is wrong. The ECU has to figure it out with a feedback system.

It gets feedback from the O2 sensor and this is called "closed loop" mode. The ECU uses something called fuel trims to keep the ratio correct. You can read here for a thorough explanation. Basically, the Short Term Fuel Trim cycles rapidly to keep the AFR in line. It can pull as much as -12.5% from the normal fuel amount or add +12.5% to the normal fuel amount.

Normal fuel trim action is expected (a few %). That is what gets the O2 sensor voltage to cycle, but with alot of leaks the trims will be all over the place (possibly all the way from -12.5 to +12.5) trying to keep it stoich. The ECU will have the Idle Speed Controller all the way in so it doesn't bypass any air around the throttle plate and it won't be able to help steady the idle with normal movement. So you end up with crap for an idle with all that excessive adjusting going on, and it happens rapidly which causes the sputtering and chugging. Ask me how I know about crappy idle issues. This problem also affects part-throttle low rpm acceleration as well.

It could be plugs too, but they won't help much if all those leaks are still there.

Not to mention that the ECU also adjusts ignition timing to help control idle, which can add to the problem...especially if your base timing isn't at 5*.

I wanted to go into detail as much as I could since you want to learn. DSM idle issues are common, so understanding what is going on at idle makes troubleshooting much easier. Check out this site often. http://vfaq.com/index-main.html It is one of the best out there for DSMs. Good luck.

 

[odormat000]

Thanks that helped.

I noticed the hissing leak was coming from the injector/fuel rail and eci injection intake area. Not sure exactly where in there but when i put my hand over more towards the middle it gets quieter. Hopefully if i fix that leak then everything will fall together. if not then looks like i've got some troubles in my future. I plan on taking out my intercooler and cleaning it out and replacing hoses and what not. I wanna get it up to 100% before I do any modding. I am a ways away from that. I also need a boost gauge and a turbo timer.

 

[absolute_DSM]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[odormat000]

Alright those are a lot of steps so i'll find time this weekend. also where do you guys buy your NGK's from? anyone wanna hook me up with a link to some cheap ones and tell me exactly which ones to buy. i'm only gonna run stock boost for now so i don't need any performance ones.

 

[2gdanny]

I would recommend ngk's cold plugs, ill look for the part number off mine if I have a chance tomorrow. And im sure any auto parts would have some for you.
I would also recommend you getting some plug wires if you are still running stockers, remove the fuel rail + injectors and replace all the seals just to insure my self. And after do a boost leaked test.

Keep us posted

 

[odormat000]

Well I know there is like the 6, 7, 8, or 9 for the NGK's and 6 is for stock and 7 is one point colder, ect. Also are the seals for fuel rails and fuel injectors pretty much universal like a local parts store should have them no problem?

 

[2gdanny]

I use 6's i will prob be going into getting colder and yeah pepboys/ outozone or any auto parts showld have ngk's and injectors seals or just go to your mitsu delar and get a fuel rail and injector seals, be ready to pay top doller at a delar.

 

[kenamond]

A few things to add.

Get the NGK BPR6ES plugs from NAPA ($2/ea). Ignore anyone telling you differently.

There are obviously two ends to an injector. The fuel rail end is sealed by o-rings. If they leak, you get fuel leaking out. Sounds like you might have this problem. The other end seals to the head in the intake port, and this is called an injector seal or insulator. They are rubber, but over time they get hard like plastic and stop sealing well. When the insulators leak, you get air. At idle, the intake ports see vaccuum, so the air is getting sucked in past the insulator. Under boost, the air leaks out. Either is a leak that needs to be fixed. The boost leak test (BLT) will help you find all of the leaks. Fixing boost leaks can make a huge difference in how well your motor runs. Night and day in many cases.

At full throttle, the ECU stops using the front O2 sensor. That's open loop mode. The ECU goes on blind faith that the airflow it measured in the MAS/MAF is correct and injects fuel based on that information. If you have a boost leak, it doesn't correct for it. Air leaks out somewhere, but it doesn't know, and ends up injecting too much fuel. If the leak is bad, the car runs even richer at wide open throttle when it's in open-loop mode.

Injector insulators can be purchased online for about $20 for a set of 4. I got my o-rings from a mitsu dealership for $20. Search for DSM injector seals and o-rings. The insulators/seals look like thick black washers (not like o-rings).

So go do that BLT, fix *everything*, replace the plugs (gap them yourself to 0.028"), and then see how the car runs.

 

[2gdanny]

+1 what he said.

 

[helman14]

X2 ,people here in this site help alot i had a problem with my laser and they helped me in every way

 

[odormat000]

I think BPR7ES is slightly cooler than the BPR6ES

Right but what will that do to my car if i'm only running stock boost right now?

 

[My1GLaser]

They won't run right in a stock car. The 6 gets hot enough to "self-clean" deposits and stuff from it. A colder plug will end up fouling in a stock motor over time, because it won't get hot enough to remove those deposits.

In a heavily modded car the 6s wouldn't lose enough heat between each spark and the combustion chamber would get hotter and hotter leading to knock. And when you run higher boost the cylinder pressure increases and it gets hotter in the CC. (P=VT) Then you need a set of plugs that run cooler so you don't pre-ignite as easily.

 

[odormat000]

well put it all makes a lot more sense now. so when i start running around 16 pounds or a little more of boost go a degree colder?

 

[kenamond]

well put it all makes a lot more sense now. so when i start running around 16 pounds or a little more of boost go a degree colder?

Maybe 17psi. I imagine there's a grey area where both 6s and 7s will work. But for now, you want 6s. Don't forget to gap them to 0.028" yourself (never assume they are correctly "pre-gapped").

 

[redyute1]

explained that so good even my wife would understand, have you ever been a teacher j/k

 

[odormat000]

YES!!!! I just fixed all four problems. I took a closer look and the bottom seal on the left inside injector wasn't put on right so I took off the fuel rail then adjusted it and put it back together. now my car runs so much better. better idle, no spudder, no gas, nothing is wrong with it. before my turbo wouldn't do anything because as soon as i got out of vacuum and starting hitting some PSI it would just leak out of my injector but now it's like my car just cut down 4 seconds on it's quarter mile. as if it were seriously that bad before

 

[odormat000]

one more question just so I know. Why do i need to gap them to .028 if stock is .032? how does this affect how they work? What is the advantage?

 

[My1GLaser]

There are a few reasons for a specific gap. (I am sure there are more that I don't know)

Normally there is a range for the gap. IIRC it is .028-.032 for our car. If you set it to .028 then when the electrode erodes over time you will still be in the range.

A smaller gap is less likely to blow out under high boost.

A smaller gap runs cooler than a larger gap. The resistance in the air space on a large gap requires more power to jump the gap and the spark is hotter. (You should see the spark jump 1.5" when testing plug wires...its like a bolt of lightning.) Anything that runs hotter in our motor increases the chance of preignition & detonation, which can destroy a motor.