vettepacecar

when i hit the nitrous it pops in the intake and blows the MAF.
I have a 150 shot, the timing is retarted 8 degrees, have all new cap,rotor,wires,& plugs
Should i get an MSD,Anyone ever have this problem

FU

That's most likely fuel leanout. Be very careful with leanout.

SPD DMN

Try a smaller hot until you get the problem resolved or it may get to be a bigger problem. Try working the way up from 50. Does it only do it on a 150 shot?

dwaltz

My '92 did exactly what you're describing until we put on an MSD unit, then it worked perfectly. Also, have you checked your fuel pressure? I don't know the specs required, but we added a second electric fuel pump to insure that a lean situation didn't occur.
BTW, when I refer to "we" I mean my mechanic and my checkbook, so I really don't have a lot of personal tech knowledge, just know it's been working perfectly for almost 5 years now!

vettepacecar

i ve been using the 150 jets for a while so something has changed,im still running the stock pump and regulator, the maf's are getting expensive,or if i could bypass the maf that would be great

FU

Changed your fuel filter lately ??

vettepacecar

Fuel filter is 2 months old,this problem just started 2 weeks ago
Ive put the car on the scanner and all sensor are fine, i was running a 300 hp set up May , ive been using the plate setup for about 2 months

Dr. Doom

Does sound like detonation. Are you using the same grade/brand of fuel? Have you installed a Hobbs switch(which will cut nitrous flow if fuel pressure drops below a certain #)? Have you checked the fuel solenoid on the N2O system(clogged, working)? Don't know what kind of plate system you have, but you should be able to go up in jet size for the fuel if everything else checks out(I also agree about going down on N2O shot size as well). The stock pump and regulator should be able to handle a 150 hp shot as long as they are in proper working order. I suggest getting a fuel pressure gauge. This will eliminate much of the guess work. It may also save you from buying a lot of unecessary parts that you don't really need. As far as an MSD.....it wouldn't be a bad idea to have one(helps in the upper rpm ranges), but I don't think this will solve the problem.

Jim Martley2

Foolish question but, what brand of spark plugs are you running? I have had problems with Champion plugs over the years (no flame intended to die hard Champion users ) and I swear by Autolite plugs now. Just a thought !!!

88L98

if you ran previously with no problems, id start by checking fuel pressure at WOT with the gauge taped to the windshield. test with just the vacuum line removed from the fuel pressure regulator does not give the same reading if your pump is starting to go out. it sounds like your lean to me. i wouldnt hit your nos any more cause you could ruin a head gasket or worse running lean. do you have an o2 sensor gauge?

sloan

I do not have direct knowledge with a Corvette application of nitrous. However, I have raced plate systems in carbed applications and these tips helped me.

1. Try retarding the timing to 12 degrees
2. Use the highest octane fuel you can buy with additive (fuel is reformulated in summer months)
3. Use plugs a step colder than stock
4. Use no more gap than .040 regardless of ignition system
5. VERY IMPORTANT Nitrous detonation does not sound like metallic pinging rather low thunder. If you hear and you hear it it will barely be audible.
6. Inspect plugs after every run

I hope this helps a little.

MVR 155

Have you checked the plugs since this problem has started?? When you read the plugs after using the nitrous do they look lean? What gap are you running on the plugs and what heat range?

Without having the above info I will still take a stab at this. If everything was OK before I would rule out needing an MSD. I would guess that you have a lack of fuel somewhere or insufficient octane in the fuel you are using. Your pump could be starting to fail. You may have burned an electrode or two off of your plugs which is causing a massive miss under load with the Nitrous.

In my opinion you should have the following if your gonna be spraying a 150 shot.

1. Bigger in tank pump or helper pump
2. 1 heat range colder spark plugs (non Platinum)
3. Plugs gapped at .035-.040
4. MSD ignition with some kind of timing contol (manual or solenoid activated). I would then set your timing at the distributor at what you would normally have it at for maximum HP when you are running the car N/A and then you can either dial out some timing on your own from inside the car with the MSD or have it hooked up to an automatic retard that activates when the solenoids are powered.

I am currently using a 6A box with a manual timing control (**** mounted inside the car) I just ordered a Digital 6 MSD box that has the automatic timing control built in.