Popping problem. - Bad ground?

[kenny]

Car pops @ WOT.

Fuel pressure is fine. I've swapped everything spark related with known good parts.

Nothing obviously hitting (positive cable on downpipe, or anything like that).

Twice the car has lost power to the ECM (Direct Scan readings all go to zero for 2-4 frames). Once after it lost power, it threw a code 42. The other time, nothing.

Direct Scan shows voltage at 12.8-13.3 when at idle and ~13.8 @ WOT (seems kind of low, car has a Red's volt booster).

Once it threw five codes as soon as I started it (24, 25, 32, 34, 42).

Sound like a bad ground? Bad hot wire to the ignition module?

Need to get this taken care of as I'm trying to sell the car, but don't want to sell it not running like it should. Thanks in advance.

 

[turbo2nr]

run a new feed wire to Ecm, try a different ecm. Make a better ground for motor, and/or Ecm.

???

 

[Whitettype86]

There normous things that can cause popping and it sucks when it happens. What plugs do u run and whats the gap on the plugs? What boost level are u running?

 

[kenny]

Originally posted by Whitettype86
There normous things that can cause popping and it sucks when it happens. What plugs do u run and whats the gap on the plugs? What boost level are u running?

CR42TS's, .032.

20+

Plugs are fine.

 

[whitehot84]

Check the hot wire very carefully to see if it's shorting to the downpipe. Comon problem.

 

[kenny]

Originally posted by whitehot84
Check the hot wire very carefully to see if it's shorting to the downpipe. Comon problem.

One of the first things I checked. Looks normal.

That was covered in my first post.

 

[kenny]

ttt

 

[kenny]

nothing?

 

[John Larkin]

I recall this happening to me once. Seems like it was a DirectScan fart. It happens. Unplug DS, reset ECM and see what happens when you drive car without DS plugged in. The connector for DS can go in too far and do weird things.

 

[kenny]

Does it without Direct Scan.

Does it with a different ECM, different chip, etc. etc.

Has to be a wire somewhere.

 

[turbo2nr]

I love Turbo Regals, but none of this crap happens with Subarus. I have had a few, and they are so easy to tune. Nothing ever like this happens! You can change everything that bolts on to motor, and it will tune itself, up to 25%+/- fuel correction. It has an awsome wide band built in. Just put parts on and go. No breakdowns! It will compensate for any missing sensors! I have recently bought a 10,000 mile GN, and already had many problems. These cars need a towtruck to follow you everywhere, and a trunk full of spare parts. I forgot how easy these cars get all out of wack. But the work is worth it. Keep 'em running! Don't give up!

 

[kenny]

Originally posted by turbo2nr
I love Turbo Regals, but none of this crap happens with Subarus. I have had a few, and they are so easy to tune. Nothing ever like this happens! You can change everything that bolts on to motor, and it will tune itself, up to 25%+/- fuel correction. It has an awsome wide band built in. Just put parts on and go. No breakdowns! It will compensate for any missing sensors! I have recently bought a 10,000 mile GN, and already had many problems. These cars need a towtruck to follow you everywhere, and a trunk full of spare parts. I forgot how easy these cars get all out of wack. But the work is worth it. Keep 'em running! Don't give up!

Thanks for the insight! That helped me fix the problem at hand! Car runs great now!

 

[turbo2nr]

Sorry i could not help, but I have seen about 20 popping threads in my first week here. I have had a couple of cars (GN) that pop. There is an endless amout of reasons why. Do some searching. There is no way our simple computer can tell us why, just start checking everything. Thats all you can do!

 

[kenny]

ttt

 

[six is enough]

Does it pop in all gears or only in 3rd. You might try lowering your fuel pressure to see if this helps. Look at your crank sensor, clean it with brake cleaner to remove any oil that may have collected. Also try lowering boost to see if the problem goes away. I had a bad pop in third leaned it out with the translator plus and the pop went away. Good luck!

 

[turbo2nr]

You have a voltage problem. Check line from the alternator to rest of car, and check for a good ground for alt.. you are loosing voltage, when you put a big drain on the charging system. Have you swapped alt. recently? I had a turbo Rivieria do this, and i found that someone had spliced a wire that came from alt. . It corroded over time, and drove me nutz! I finally found it, after tryng a different ECM, sensors, etc>

Anothe time I had this problem on a GN was when I jammed some wires into the fuse block to get some power for my guage lights, I picked the ign/ecm fuse to tap in. Car ran fine except when I floored it over 10psi, POP, POP. I was fast to catch that one. I have been to track rental days many times with GNs. There is always 1out of every 5 GNs that pop. These cars have so many ways to cause this, but it is usually voltage/ign related.

Good luck! Look at wires from every angle. Look for signs of people tampering with systems. You will find your problem there.

Scott

 

[kenny]

Originally posted by six is enough
Does it pop in all gears or only in 3rd. You might try lowering your fuel pressure to see if this helps. Look at your crank sensor, clean it with brake cleaner to remove any oil that may have collected. Also try lowering boost to see if the problem goes away. I had a bad pop in third leaned it out with the translator plus and the pop went away. Good luck!

Not the fuel pressure.

I know for sure from racing it and having a wide band on it that where it's at is perfect.

Problem does go away with lower boost, seems to occur above 15-17.

Originally posted by turbo2nr
You have a voltage problem. Check line from the alternator to rest of car, and check for a good ground for alt.. you are loosing voltage, when you put a big drain on the charging system. Have you swapped alt. recently? I had a turbo Rivieria do this, and i found that someone had spliced a wire that came from alt. . It corroded over time, and drove me nutz! I finally found it, after tryng a different ECM, sensors, etc>

Anothe time I had this problem on a GN was when I jammed some wires into the fuse block to get some power for my guage lights, I picked the ign/ecm fuse to tap in. Car ran fine except when I floored it over 10psi, POP, POP. I was fast to catch that one. I have been to track rental days many times with GNs. There is always 1out of every 5 GNs that pop. These cars have so many ways to cause this, but it is usually voltage/ign related.

Good luck! Look at wires from every angle. Look for signs of people tampering with systems. You will find your problem there.

Scott

I have had the alt. off, as I bought a new one, and looking at the wire it seems to be fine. I'm waiting on a multimeter to see what the voltage is like at the alt.

Driving me nuts is an understatement.

 

[turbo2nr]

I think you have the wrong alt! Get a pro to check. I have seen one in the right case with the wrong diodes. You have to have the special TR, 130amp alt. That is your problem. Car will run fine untill you get on it. I have seen this a couple of times. Find a auto electronics specialist. You can't use just a multimeter.

Your welcome,
Scott

 

[Sleeper-6]

Kenny, Is it possable that you have two different problems? Maybe the popping is something not related to the ECM issue? It's possable you have a plug wire that's crapping out under a heavy load. Same for the plugs, It's possable they're fine under normal driving but not up to the task under boost.
You could try bypassing the volt booster, it does not sound like it's working properly. I'm getting about 14 volts at WOT with out one. Maybe it's causing an intermitent short that's screwing you all up.

Hey Turbo2nr, Just how old are the Subarus you're working on? I think we're doing pretty good considering these cars were built almost 20 years ago. I ran over 4000 miles on the Power Tour and never opened my toolbox.

 

[turbo2nr]

I love Buicks! I have an 85 Rivieria T-type, looks like new. And have had a few GNs. My current Gn has about 10,000 miles. They need special love and care, but I do wish the stock computer was a little more up to date, but Oh well. I have had a few WRXs. My current one has a built motor with JE forged piston, Crower rods, ARP head studs, Cometic high boost gaskets, A few different Garrett turbos(the real ones with full ball bearings and a water cooled center), I spray methanol, no2, and have an up graded drivetrain with a one piece aluminum drive shaft rated at 800hp, Bigger rear diff unit, Bigger axels and CV joints, eight point cage, etc. It has been over 130mph in the 1320'. Not bad for a little 2.0 liter @3100#.

This guy said he had replaced his alternator recently, I would look there, but everything on a Buick can cause popping, except the rear view mirror.

Scott