89 Firebird Turbo 3500 Build

[Mars]

I was having an ign issue a couple weeks ago. I bit the bullet, and got new plugs, wires and MSD coils. fixed. The plugs and wires were pretty old and the coils were also 15+ years old, so nice to have new goodies on there.

I put on a new (used) Pass side axle in tonight, i think 90% of the shimmy is gone.

[ericjon262]

Wow I never would have thought about the crank sensor failing like that. Do they actually commonly fail that way?

Will on PFF had one go on his N* in a similar manner.

it's also very capable of cutting ignition if it fails...

[caffeine]

The crank sensor does come within a 1/2" of the exhaust manifold so it is actually a likely candidate.

[caffeine]

Wow I never would have thought about the crank sensor failing like that. Do they actually commonly fail that way?

[ericjon262]

Well I just sourced a 4.11 LSD centre section for the 9" so hopefully that rear end will be in there for the next race.

OTOH the misfire is still there it turns out; it just migrated to higher RPMs. So that 13.8 @ 107 I was also short shifting.

Anyone know what can cause a high RPM misfire? It's not the coil pack or plugs as both have been changed out. I'm really not sure what to check next. AFRs are steady until it misfires and I'm pretty sure it's spark since it backfires out the exhaust when it happens.

crank position sensor

[caffeine]

Well I just sourced a 4.11 LSD centre section for the 9" so hopefully that rear end will be in there for the next race.

OTOH the misfire is still there it turns out; it just migrated to higher RPMs. So that 13.8 @ 107 I was also short shifting.

Anyone know what can cause a high RPM misfire? It's not the coil pack or plugs as both have been changed out. I'm really not sure what to check next. AFRs are steady until it misfires and I'm pretty sure it's spark since it backfires out the exhaust when it happens.

[ForcedFirebird]

2.5 60' and 107, the car is making good power.

Mars, that's the problem with the Borg-Warner 9 bolt. They are pretty stout, but parts are hard to get. Put the same one as you did in my bird.

[Mars]

Ahh one of those weekends.

I also had issues. ran a best of 11.55 on 6 psi and didn't want to go any higher boost because of a HORRIBLE shimmy / vibration over 100MPH. I checked the car out and can't really figure it out. I think maybe my slicks (that I bought used) are screwed up. Should have a new set of MH racemaster drags for the next race anyways. I also found one of my front wheel bearings kinda loose. Might have been causing it.

Might have twisted an axle too ( no one makes 9 bolt axles of course)..

So, yeah, all the power in the world is no good with a bad vibration like that..

Keep at it man, you'll get it going fast.

[caffeine]

My car wasn't the only with issues either, so my friends and I pretty much spent the whole weekend fixing cars lol.

[caffeine]

Well, had a bunch of problems at the track. First, that 3.73 rear end turned out to have different style housing ends than all other 10-bolts I've seen, so I couldn't swap my brakes over. I decided to go with the 3.23 rear end.

On the way to the track, the clutch master cylinder rod bent, so that had to be removed and bent back before I could race.

On Saturday, the car was misfiring badly all day under boost, tried coils and plugs but that didn't change anything. Then I found that the positive battery cable terminal had broken, so that was replaced. I'm not sure if the battery cable was the issue or if resetting the ECM fixed the problem, but the misfire was gone for Sunday.

Sunday there was only 1 time trial left before eliminations so I made the most of it, but then a) the boost controller wasn't working, and b) the 2-step rev limiter stopped building more than 5 psi, so I bogged off the line. That was the best run at 13.8 @ 107 MPH and a 2.5 sec 60-ft.

I was eliminated in the 1st round of eliminations but its just as well because it rained after that anyway and the races were cancelled.

Needless to say I'm pretty bummed about the weekend but ill try to make it at least once to Mission on the mainland before the season is over.

[ericjon262]

Im running the 1/4 this weekend too. I will text you if I hit 10s.

we better see one of you hit 10's before the summer is gone!

[34blazer]

Im running the 1/4 this weekend too. I will text you if I hit 10s.

Dont forget the video camera...LOL

[Mars]

Im running the 1/4 this weekend too. I will text you if I hit 10s.

[caffeine]

Tomorrow I'm picking up a 3.73 open rear end (10-bolt) for $120 and then on Thursday we're gonna weld up the centre section haha. Friday leave for the races.

[robertisaar]

gears that wouldn't cruise at 70MPH at less than 1500RPM would help.