Did nitrous kill my motor? - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

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post #1 of 10 (permalink) Old Nov 13th, 00, 02:33 PM Thread Starter
Join Date: May 2000
Posts: 67

I just finished installing a NOS Superpowershot System on my 383. A little background on the motor..

It is a completely new 383. Scat crank, pink rods, TRW forged psitons, ARP Studs on everything, everything balanced (internally and externally). I used the complete Edelbrock package including aluminum heads, cam, 750 cfm carb, water pump, etc.

I have an msd box with an hei and mallory pro coil.

My new fuel system uses a Holley Blue Pump, with 6an braided line, into a Moroso Fuel Block into two seperate Holley Regulators (one for carb set at 5psi and one for nitrous set at 7psi).

The nitrous system uses a throttle switch to activate the nitrous. I also have the purge valve, bottle heater, and remote opener.

I took the car (1969 Camaro) out today for the first time. Ran it around town and warmed it up and everything ran well. Got it out on a deserted stretch of road, activated the nitrous system and began to get on the car in first gear.

I floored the pedal once I was over 3000 rpm and the nitrous kicked in. It immediately spun the tires, the shift light went off (5000rpm) so I let off and shifted into second.

Again, I worked the rpms up to around 2500-3000 and then romped on the gas to activate the nitrous. The car ran awesome. I was very impressed.

I shifted into third before I ever saw the shift light, drove another 100 feet or so and the car went dead!

I smelled gas and thought it might be flooded. I let it sit for about 5-10 minutes and then tried to restart it. The car would start with the pedal pushed all the way down, but it runs really rough and only at WOT.

I had the car towed home and pulled the valve covers. Everything looks fine-nothing broken, bent, or off center and all the roller rockers move when you crank the car over. There is no clanking or clunking either.

My next move is too pull the plugs and take a look....but I am a little baffled.


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post #2 of 10 (permalink) Old Nov 13th, 00, 03:00 PM
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Location: McKinney, Tx
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A completely new motor, never even fired? You just ran it for a short period of time, then hit it with the nitrous? Have you ever heard of a break-in period? Did you break in the cam? I think you may have answered your own question, but I'm no expert. Sounds like you're going to have to do some major investigation. Hope you didn't blow it up. Good luck......KZ

John D. Smith
69' SS/396
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post #3 of 10 (permalink) Old Nov 13th, 00, 03:09 PM
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It sure sounds like it's flooding although I'm not sure the car would shut off under full throttle.

Did you try to re-start the engine without the air cleaner on? You should be able to see it flooding out the vent tubes or boosters. It's easy to get some debris in the fuel lines when hooking up a new fuel system.

How much horsepower were you running the nitrous at? Anything over 150 h.p. or so I would recommend a separate fuel system (pump, lines, etc.) for the nitrous. Also cut back the timing some as per NOS's recommendations.

Anyway, it sounds like it's flooding to me, especially since the fuel system and lines are new. Double-check the fuel pressure also.

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post #4 of 10 (permalink) Old Nov 13th, 00, 03:23 PM Thread Starter
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Sorry I wasn't very clear. I used all brand new parts in the motor and very carefully broke it in for the frist 3500 miles. The motor now has about 4000 miles on it.

After talking to a couple of people, I believe it is flooding. I think some junk from the new hoses, perhaps a piece of hose or braided remnant, got into the carb. I have a Fram filter before the pump, but nothing after.

In retrospect, I should have pumped some gas thru the lines and put another filter in before the carb. I believe I'll be pulling the carb off tomorrow.

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post #5 of 10 (permalink) Old Nov 14th, 00, 02:43 AM
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Do yourself a huge favor. Buy two 5psi (or so) Hobbs switches and put one in each regulator. Then cut the wire coming off the NOS throttle switch (the one that goes to the solinoids)and connect it through these new switches. I know its a fuzzy picture, but I can email you a quick drawing if you wish.

Once installed, if either regualtor drops below 5 psi, the NOS will shut off.

BTW, make sure the NOS fuel solinoid is not hung open and leaking fuel into the engine. I have seen this happen when people use teflon tape.


1992 Firebird 355/Six Speed
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
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post #6 of 10 (permalink) Old Nov 14th, 00, 06:54 AM
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No offense but did you let the engine break in first?If not next time let it!Ive seen the same thing once-what happened was the engine wasnt broke in and he completely flattened the lobes.The spring pressures are to great at first, so let it have time to adjust before playing-you play you pay they say.
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post #7 of 10 (permalink) Old Nov 14th, 00, 06:57 AM
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sorry a little late didnt see your second response. Yes it sounds like it is flooded,i always had the same problem with my 750.
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post #8 of 10 (permalink) Old Nov 14th, 00, 08:27 AM
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Check the fuel solenoid on your nitrous kit also. I have seen them dribble fuel into the intake before because of trash not letting it fully seal.

67 RS/SS 350 700R4
69 SS clone unfinished
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post #9 of 10 (permalink) Old Nov 14th, 00, 10:17 AM
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Take the Mallory pro coil out of the system, use either the MSD coil in the HEI or the stock one will work for now too. MSD says in the instructions not to use that coil. Could be part of the problem. Also like said, check solenoid, carb, fuel systems and add another if running the 150 up> Galen

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post #10 of 10 (permalink) Old Nov 14th, 00, 11:25 AM Thread Starter
Join Date: May 2000
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Thanks for the advice Galen, but the Mallory Pro Coil is on the list of acceptable coils that came with my MSD6 box and the car runs great with it--never had a problem and I've been using it for a year now (I used it on the old 350 before I put in the 383)

Thanks again to everyone for the help..I'll let you know what I discover in the next few days.

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