i posted a while back...
car is cam only...wet kit walbrough 255, and a mallory 685

ran out at the track, bottle pressure near 900...pulling 4 degrees, and its braking up (pops mayb 3 time in first, 10 in 2nd, and 15 in 3rd), we put in the 125 fuel pill with the 100 shot and its still breaking up but sounds to be better...everytime i pulled more timing my times slowed by 3-5 hundreths...

HSW said put new plugs in it with .30 gap, so i did(and put contact greese on the plug ends...

last night i went out and decited to spray...bottle pressure was low becasue its cold but not too bad about 800...
im pulling 4 degrees from a roll with 100 pills in and its breaking up, louder and worse than before...changed it to 5 degrees and its stil breaking up, decide to stay in it for a second and its stil breakin up(about 3 seconds) and BOOOM big pop, shoved it in neutral quick, engine idles down ran fine, im thinking now that was caused by blowing out the spark and the fuel building in the exhaust which ignited and exploded.....so i think im not gettin a great spark, car run like a bat outa hell on motor...(msd coil, brand new opti, think my new stock wires arent enough, they were great for motor but i guess i need to get some wires anyways???
if so what are you guys using and where did you get them, any input accepted
thanks

 

If its breaking up, not missing, its probably fuel related. Check your FP when you do this.

 

yeah check the FP like HardcoreRM said, but check it when you are spraying.

but if you do decide to get wires get the Taylor wires from thunder, either over the valve cover ones or just the standard ones.

do u have a stock knock sensor in the car? if its a lt1 try putting a lt4 knock senser in it. the computer might be detecting knock and pulling extra timing than what you already pulled and that might be why it is doing that.

Note: my car was doing the same thing, i never could figure out what was wrong or why it was doing that so i pulled off and didnt want to destroy anything, needless to say i blew the skirting off the pistons when i pulled the motor apart and to this day i cant figure out why it was doing that. if i had to guess its in the tune.

good luck.

 

lt4 knock sensor and cesensatised through tuning...fuel pressure was checked, not on spray but checked was 42 wtih vac line on and 47 while off, it has a walbrough pumpo, figured it would be ok, and a new filter

 

Check your fuel pressure with the car under load, with spray. That's the only way to tell if you have enough pressure.

Have you pulled the plugs? What to do they look like after a pass with all the breaking up?

 

i know i have told u this before, but i will try agian.
( i am spraying a 150, but i did the same test with 75 jets)
if i retard the timing through the mallory it will pop, the more timing i pull out the more it pops. so i have been running it with stock timing and it runs like a raped ape.
i say lower ur jets to maybe a 50 or smallest that u have, leave it at stock timing and see if it pops. if it dont slowly increase the shot with stock timing and see what happens.
this will at minimum rule something out.
FYI ,( u probably already know but ) a 50 shot on stock timing wont hurt anything.

 

im tuned...i cant run any shot without pulling timing, i checked tonite the timing, took the ground off the noids and hit the wot switch with the motor sitting at 3k, i could hear it bog down, its oblivously pulling timing, that was set at (pulling 8 degrees)

if that was true i can run it while pulling timing without the n20 on and it should still pop correct?



injuneer, i will check it under a load asap, the gauge i had is a no bleed off gauge so i only got on reading, i bled it off and it showed 42 and 47, perfect like they should be, how can i test it while spraying? i would need to buy another t or something? and i have pulled the plugs they appear to be completely black on the ground strap, the timing i was told looks good 3/4 up the barb, they did seem to have a little gas on them also.
http://i21.photobucket.com/albums/b2...MVC-003F-1.jpg
http://i21.photobucket.com/albums/b2...8/MVC-002F.jpg
http://i21.photobucket.com/albums/b2...8/MVC-001F.jpg
i sprayed, then killed it and coasted into my driveway...pulled them about 2 hours later and this is what they look like....this is a 100 shot pulling 4 degrees with a walbrough 255 intank pump and a hotwire kit...

 

i am not sure how u have your timing wire wired in, but if u have it to the noids, then i dont think it will work like u saying. maybe u have it wired wrong, if u unhooked it from the noids and it still retarded the timing. so somehow it is getting the signal. where is that coming from?
i am not sure how you would go about that.

isnt ur tune adding timing?

 

i took the ground off the noids sothey couldent ahve a complete circuit...while the 12v was still going to them, and the retard signal wire....

also meant to ask, might be the poor mans way to check, but if i leave the 100 n20 pill in and do a 150 fuel pill, it should clear up quite a bit if not completely, that should tell me if its outa fuel?

 

If you do that you'll be adding an excessive amount of fuel in relation to nitrous.

Matt

 

yea, im not going to, ive got a dyno at work, and i think theyre goana work me in late tomaro, well mess with it and figure it out, get it dialed in, mayb i can go get a 6.90 before the season is ove, i wish i had of got my 150 n20 pill! (not mad)

 

Like he said, it will run alot richer. However, it would be more reliable to use a fuel pressure gauge. Any garage should have one. Get them to test your pressure while you give it a WOT run. Or buy one, their cheap enough. I think you can get one for around $25 ? I forget, its been so long. Harbor Frieght has them REAL cheap btw.