dizwiz24

Ive got some problems here.

I just got done installing an NX nitrous system and my engine idles very rough, stumbles, misses, has lost low-end TQ, etc. It runs this way whether the nitrous is turned on or off. I should also add the 50 hp shot I added feels like nothing. I dont notice it. The car is slower than it was before nitrous.
I have all the safeguards too (3000-5800 rpm window switch, WOT switch, Digital-6 timing retard, etc.)

My question is...whatare the symptoms/causes of an engine jumping timing (like the timing chain jumped the gear a tooth or so)....

Any ideas? I have a vented optispark that is about 1.5 years old.

I will hook the scan tool up tomorrow.

NOT-MEE

i worked with nos alot growing up i used to live in cypress ca home of n.o.s.
it sounds like a vacum leak timing chain jumping a tooth would have a wired effect also but ck the easy stuff first.

Netnarc2

I had a timing belt jump on a Pinto and we couldn't get the timing right after that. We ended up having to remove the distributor and re-inserting it. Things just got worse after that. If your timing chain jumped it should show up when you try to time the engine. That's all I can tell ya. Well actually, we re-installed the timing belt one tooth off, but it should be the same effect as if it had jumped.


[Modified by Netnarc2, 6:39 AM 5/20/2003]

CorvetteZ51Racer

I've seen timing belts jump a tooth, but I have never seen a timing chain on a pushrod motor jump a tooth...hell, I had ~5* of slop in my old chain when I tore down the old motor to rebuild, and nothing had jumped. Though I agree to check the easy stuff first, I would include a compression test in that...if it's a dry nitrous system and you were already running fairly high compression, you may have hurt the bottom end. But, as was mentioned before, check the easy things first.

dizwiz24

THen mine probably didnt do that then (if they ever do).

PurpleC4

dizwiz. You didn't say what year. I know that it is an LT1 because of the refernce to the OptiSpark. Have you checked for Codes? Don't jump to the "off the wall" stuff until you check the basics. If your Vette is 94 or later.... it could be a MAF problem.
~ Stan

65Z01

Look first to whatever you touched during the NOS installation.

A vacuum gauge will tell you if manifold vac is off.

Of course a scan tool will show up what the ECM sees and maybe the problem.

98NYFINESTVETTE

Does it back fire on a load or on deceleration?

MyZ51

Usually a timing gear will jump a tooth when engine is shut down. The crank wants to keep turning from reciprocating weight wanting to keep turning, and the camshaft wanting to stop because of the resistance of the valve springs, the cam stops, and crank turns, and the loose chain lets it jump a tooth.

You can check for valve timing with a simple vacuum test, if it's off a tooth, your vacuum will be low by 4 or 5 inches.