SPRAYED 01

iTrader: (22)

So i just pulled the car out of storage friday night. The car runs good around town but when i get into any boost it starts popping and misfiring. Even on the highway at 75mph with the converter locked,i give it 1/8 throttle and build up maybe 1-3psi and it starts jerking and misfiring badly.

Plugs are gapped at.025,the wires are new msds,timing is 18 degrees total. At first i thought it was the 4 month old gas,so i burned through that tank and filled up with 4 gallons of 100 and the rest 93octance with no change.

Any idea?

Alex

BLOWNBLUEZ06

iTrader: (17)

Most every time I have had this problem, it has been spark related. Pull those MSD wires and put a meter on them. I have them on my car and hate them. They will go bad from pulling them off carefully one time. If you're not having a problem with a miss when out of boost, I doubt this is your problem though. I just know that cylinder pressure puts the spark out. Do you have any logging software? It would help to see what your computer sees. Air leaking past the MAF, bad coil/s, low voltage getting to fuel pump or coils due to weak alternator or weak grounding possibly from corrosion, lean pop from clogged fuel filter or weak pump, partially clogged catalytic converters ( which I would doubt since you're turbo charged I wouldn't expect it to build boost), thrust bearings out in the turbo enough to cause the compressor to hit the housing, something stuck in the intake side of the turbo.

I have seen or personally dealt with each of these problems.

Start with the simple stuff for obvious reasons.

Let us know what you find.

85mudblazin

iTrader: (7)

Do you have a fuel pressure gauge?? Might just be a clogged fuel filter from sitting so long.

SPRAYED 01

iTrader: (22)

I have a wideband and a fuel psi gauge in the car. A/f is 11.4 and the pressure is about 70psi. Brand new lonnies dual intank setup. The fuel pumps and spark plugs wires have about 50miles on them. I put them friday night before i even started the car. I guess i could have a coil issue. How can i check these coils?

Jimmy P

iTrader: (177)

I had a similar problem. Turned out to be a bad 02 sensor. It would be fine under normal driving and idle, but as soon as boost was building up it would sputter and misfire real bad.

SPRAYED 01

iTrader: (22)

Thats interesting,the 02s dont have over 3k on them. I wonder if i disconnected them if it would go to a default setting just for test purposes.

speedracer5532

iTrader: (8)

I have the same problem with my engine. I just got my LSX 427 running and around 3K to 3.5K rpms it would sputter and misfire bad. I am running my car in open loop so I know it isn't an O2 sensor problem. I am going to try a set of square truck coils to see what that does. What is weird is that I never had this problem last year with my 402 and basically the same setup.

SPRAYED 01

iTrader: (22)

If i disconnect the 02s will the car just default to open loop

koji777

iTrader: (3)

How do you check the coils?

SPRAYED 01

iTrader: (22)

I just drove the car and with a cold engine it didnt misfire. Im thinking maybe because it was in open loop. Also car has developed a slight surging at low speeds that isnt there in open loop either. I tried to disconnect my coolant sensor to put it in open loop and the car wouldnt start with it disconnected. Can i just disconnect my frt o2s?

Gabbiani

iTrader: (20)

I had a plug wire do the same thing. Ran fine at any rpm out of boost.
I know you don't need another person saying ignition, but sometimes you can check these things 10 times and on the 11th you find it.

SPRAYED 01

iTrader: (22)

Im going to pull them all off anyway just to check. I know the msds are not the best but they were the only ones if found with a universal set for ls1. I need to make custom length ones for the turbo kit im running.

speedracer5532

iTrader: (8)

If you check the resistance on a plug wire what should it be?

SPRAYED 01

iTrader: (22)

Im thinking it should be about 20-30 ohms on an msd. But sometimes the resistance can be okay but if its arching through the insulation it could still cause a problem.

On a side note i put the car in open loop and it still pops alittle. Im thinking some kind of ignition problem. It also is only building about 11lbs where before it would do 14lbs.

kidcamaro98

iTrader: (8)

Boost leak...

SPRAYED 01

iTrader: (22)

I checked for boost leaks and couldnt find any. Even if there was a leak would that cause the car to misfire alot. I could see loosing alot of power but not misfiring

ddnspider

iTrader: (26)

a boost leak after turbo isnt going to cause massive misfiring....but if you have a hole in the hotside that will cause big issues.

SPRAYED 01

iTrader: (22)

So basically a hole in the exhaust to the turbo?

Pro Stock John

iTrader: (34)

I've had two sets of plugs wires on my Formula in 8 years, that's rarely the problem. I like the idea of fouled 02's, vacuum leak, or something.

ddnspider

iTrader: (26)

correct.a hole or leak in the hotside with cause it to be all over the place.