TheExaminer

I had an L98 about 20 years ago, and one thing I always loved about it was that when you turned the key, it fired up faster than any other engine I've ever had. I mean it started immediately, almost without even turning over--almost like an electric motor. I traded that car for a Camaro with an LT1, and it always turned over a couple times before firing, didn't sound as cool. The car I have now is an L98, sometimes it fires up like my old car, and sometimes it turns over a couple tims first. So: 1. Why was my old L98 different from my LT1? And 2: Why does THIS L98 do one thing one time, and another thing another time? Doesn't seem to be any rhyme or reason to it, just does one thing then another. Why?

NowhereFast

I'm also curious about this. My LB9 would do the same thing, sometimes fire up instantly, other times not.

TheExaminer

I wonder if it has something to do with the FI setup? IDK. One time it fired up super fast when I got done charging the battery, so maybe it's electrical. But then this morning after sitting all night it fired up fast. I went to church, and when I started it after driving it, it turned over a couple times. Go figure...

-=Z28=-

iTrader: (3)

Could be a number of things. Timing, spark, something in your ignition, compression, could be a weak starter....ect

TheExaminer

Yeah, but it's so haphazard, no pattern. That makes me look at electrical, maybe you're right about the ignition or starter. Tough to say. But the thing is, no other FI motor I've ever had has NOT turned over a couple times first, even when new or low mileage. So what made the L98 different that it fired up so fast?

novaderrik

i'll take a guess and say that it's because the old TPI engines were batch fire: the ecm just fired half of the injectors for each revolution of the distributor. there was no crank sensor involved, it just knew to fire half now and half later..

the LT1 was sequential, which means that it fired each injector in the order that the cylinders fire so it needed to see the signal from the crank sensor a couple of times to tell it when to start the injector sequence and when to fire them.

dmccain

iTrader: (2)

25 yrs or so give or take may have something to do with it

TheExaminer

Makes sense, great answer. I guess that also explains why my 4th gen Camaro 3.8 and 07 Mustang 4.0 acts differently than an L98. So, do you think the distributor may be getting worn out? Or maybe the icm? Because sometimes it fires normally, sometimes it acts like an LT1. I guess Autozone can test an icm? May see if I can pull mine and do that. Couldn't hurt I guess.

Rob's 92 gta

My car would do the same. What I found on mine was fuel pressure. The pressure would bleed down over night. The old regulator didn't bleed down overnight before it went bad it would start maybe a half a turn or so and start. If i would spin the engine immediately it would turn until pressure came up.(maybe a turn or two). When I wait for the the pump to prime with the key on(till I heard it stop) hit the starter and would start instantly. Could be something like mine on yours also.

TheExaminer

Ok, I'll try priming the pump and see what happens. I'm not sure that's it though, or if it IS, mine is bleeding down a lot quicker than over night, because it will fire up real quick sometimes after sitting for days, then turn over 1-2 times a couple minutes later if I restart it. But the FPR is an interesting idea. I'm about due for one anyway because there is a slight fuel smell in the FPR vacuum line, and a clicking type noise coming from the FPR. But the priming idea might tell me. I may be priming the pump sometimes and sometimes not without even knowing it. Never even gave it any thought. Great tip, thx!

TheExaminer

Just for k&g I went out just now and let it prime for a sec first. SWOOOSH! Fired right up. I bet you're right, I bet you're exactly right. I'll try it that way from now on and see what happens til I replace the FPR.