Have 94 LT1 from Buick roadmaster in 48 Chev have had it running but can not get it to start. Checked ignition as per manual and have spark at plugs but weak. Have
40lbs fuel pressure and plugs are wet when I pulled them. Have had injectors cleaned and checked and new ignition module. Turns over good and have strong battery.
Have it running but cannot get it to start??? BTW - you speak funny.
Is the ignition from the '94 or from the '48? I'd expect the '94, but.... Also, are the cap, rotor and wires fairly new?
The ignition is from the 94 LT1 Buick and I have had the engine running before and it seemed ok but when I went to start it after it set for a week it will not start. The only thing that I have replaced is the ignation module.
Just a thought at this point... have you checked that the ignition module is getting full battery voltage (maybe 11 volts while cranking)? The old ignition systems used a ballast resistor in series with the ignition coil hot side when running, and bypassed it when the ignition switch was turned to "start." If something has left the ballast resistor in the circuit it could be trouble like this.
Mike
Does it have the "Opti-Spark" system"? If so, beg, borrow or ....beg again....to borrow a known good one. They are quite troublesome. s
run and would > there be a wiring issue. The wiring is a Painless harness for the 94 LT1 and it did start and run when I first got the car together.
That sounds pretty bad. Check the voltage across the battery when cranking to be sure (although I'd think you'd notice 10 volts cranking) and then find out where the voltage drop is coming from. More than maybe .3 volts drop points to something wrong. Once the engine fires the voltage will rise enough to ensure it continues. Anyway, if the battery is good the wiring is certainly my prime suspect.
I've dealt with a few engines that wouldn't start because of bad batteries. It can be a problem to diagnose, because just how much voltage sag is allowable when cranking is not a science. A friend's seventy-something Chevy truck with a large block V8 wouldn't even crank, and still wouldn't when jumped. We changed the starter and still no-go! Replacing the battery fixed it. Hmm.
Mike
Hi, je. Trying inexpensive guesses, why don't you take a look at the plugs, as they may tell a story. To check proper operation of injectors: If plugs are obviously too wet after attempting a start, then something is amiss, either a no-fire situation, or a too-much-fuel situation. To determine which, use a "noid light" to test whether injectors (one at a time with 1 noid light) are firing to control opening of injectors. A constant light while cranking could indicate a constantly-opened injector condition--this would show wet plugs. A no-light (plugs would be dry) indicates electrical problem before the injector & shows the injector(s) are not opening at all--no fuel to combustion chamber which would result in dry plugs. If it pulsates, AND fuel pressure is within specs, then you'd expect a no-fire condition. Again, this is an inexpensive guess-test for too little or too much fuel caused by improper operation of injectors. If PAINLESS provided an aldl circuit, nothing would be better than a scan of the system thru the outlet. HTH, s
I checked the injectors and they seem to be ok I ran thru the checks again and do not have any spark at the plugs now. The book tell me that when I do not get voltage from the B terminal at the control module when I crank that this is either in the module or the optispark unit. This is the only test that is not like the book says and I put on a new Ignition control module and get the same results. So far I have new ignition control module, plugs, battery and had the injectors cleaned and checked by a fuel injection company. I checked and cleaned all the plug and coil wires and they look new and the wiring harness and conections are new. I feel the optispark unit may be the problem and want to know if there is a way to have them checked off the car. I may be able to borrow one to try but do not have it now. I get 10.5 volts when I crank at the coil and module also the voltage at the battery drops to 10.5 when cranking. I have 12 volts with the ignition on and not cranking.
Sorry, I dunno how to check them either--note I asked you about it on
1st reply (below). But they are noted for giving trouble. The 95 and up (I think that was the year) had a somewhat improved design. Another shortcoming here is I don't know if a later model can be substituted. I really need to learn more, as I have an LT1 in my 86 S10 Blazer. Never any problems in 4 years--sits for 2 months and fires right up as fast as any car I've ever seen. No, I didn't build it; I bo't it this way. s
Finally got the engine to fire with some help from a mechanic friend and a borrowed part. The new ignation control module was bad replaced it with another and it fired right up. I sure learned a lot from tracking down this problem and not to assume a part is good because it is new. Runs fine now so can get the rest of the car together.
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