one injector that is shorted to ground would cause a no start on the L98. not sure about yours. I would ohm them if you have not done so. forget about water in gas. I never thought it was fuel because it should start for a few seconds with very little fuel. your issue is still NO START.

as Daniel said, check for injector pulse, not sure how to do on the lt1. on l98, you use a noid light or suitable test light to check a harness connector while cranking to get a blinking light.

it will run/start with one or more injectors not firing, I would think. my 91 will. if it were not flooded.

 

Thanks guys. I'll try an analog voltmeter and look for a brief swing of the needle, that should work, I'd imagine...... my digital VM is too southern.

I have the factory manuals and have used them over the years, I just never was fond of how they're arraged, or at least not indexed as well as I'd have liked, I seem to spend more time looking for a section than I do reading it!!

 

The 93 is a batch fire injector setup. There are 4 injectors (2 sets) in parallel. Theoretically, if one shorted hard (zero ohms) to ground, it could kill the drive (pulse) for the whole batch of 4. But I think that would be the exception to the rule and a small possibility.

I don’t know if a meter could react fast enough to show a pulse from an injector which is one reason a noid light is used. But would I would do is with the key to only ON, measure every wire on every injector. They should all (16 wires) measure 12 volts as voltage is applied to them but the ECM is not completing the ground return path. If there is no voltage on them (fuse?) or, one wire is 12 volts and the other is low (zero volts) the ECM is at fault.

But before going off the deep end, I would make sure there is SUFFICIENT spark at the plugs. Should be able to draw a 1/2 inch white spark. That may be why you it's not trying to start.

 

This is truly mind-boggling. I pulled a connector off one injector, hooked up an analog voltmeter to it and had son crank the car. Yep, pulses for sure.

I pulled off the rubber conduit between air filter and throttle body, had him crank the engine, and sprayed a stream of ether (starting fluid) right into the manifold, holding butterflies open. NOTHING.

Last nite in dark I pulled #5 plug wire off and put a spare plug in it and leaned it against the exh manifold. Crank motor and yes, spark visible. Had also done same thing on cyl 4 a couple days in the past.

WTF??? First thought is timing chain is broken. Opened oil filler, crank motor and YES, the lifter is moving up and down.

I'm at a loss to explain it, unless somehow the spark timing is altered, I mean, if theres spark and ether and the valves are moving, there's got to be something gonna burn. All I can figure is spark timing is altered, but how , why ?? I'm at a total loss.

Only other possibility I can think of is that the engine is flooded. I propose to pull the fuse (fuses) for the injectors, then just crank the motor a while with the butterflies open..... shouldn't that clear the system of excess fuel / ether that might be present ?

I put in a new ignition coil 2 weeks ago, just cuz the one in there was the original one and its 20 years later.

The car was running fine when last parked into the garage, arrgh

As an aside, three buzzards are circling above

 

Pulled the wire off between the coil and the opti. Put another coil wire on the coil, with a spark plug in the other end and set it against the block, son cranked the motor. Whole bunch of sparks, plug was gapped to 0.085. arrgh


BTW, no DTC's in the CCM

 

There are two fuses for the injectors- I'd be checking both of them since you have spark.
See if you can "borrow" a set of noid lights (yea thats what they are called) and check each injector electrical plug if the fuses are good.

 

The only 2 injector fuses are in passenger side at the end of the dash, two 10 amp fuses, both good. Are there any others ?

I pulled the big fuses behind the battery yesterday, cleaned all the contacts blew the thing out with comp. air.

I just finished ohm testing the injectors, all are in the 15.2-15.4 ohm range.

 

maybe the chip in my key is not good, I'll try using a spare.

what else shuts off the injector circuit ? like a TPS not connected ?
MAP sensor, etc..... is there any one sensor that if its off, fuel won't be delivered ? THANKS TO ALL !!!1 especially DUB, I wasn't ignoring your advice

 

but its not the injectors, I just rednecked it with a long flex-neck funnel, spread 100 ml of gas right into the middle of the manifold, thru the butterflies, nuthin. Yet, has spark at coil and at the business end of two randomly-selected plug wires, #4, #5.

Back to theory that spark timing is off .

Question: The damper doesn't have a timing mark, but it does have an arrow. Can I put some white-out correction fluid mark on the damper at the TDC mark where the cast-in timing arrow points, hook up conventional timing light to wire #1 and see that mark at same approx location as on my other 350 chev, when the motor is not running but only being cranked over ?

 

Did you ever measure the fuel pressure with the fuel gauge you borrowed?

A noid light will confirm injector drive. It should be checked with the injector connected and you should check it in both banks.

Always go back to what you touched. You can connect and hang the old coil in place. The main connector and coil wire will all reach and that way you can eliminate the coil.

If the timing chain broke, the cam would not be turning or the opti which drives the ECM to develop the injector pulses and spark.

Sorry to be a stickler.

 

fuel pressure 41 and holds
injector harness has pulses
spark present at business end of spark plug wires

its the shiitt fuel, I was running 87 oct in the cold weather. ORI increases wi ext. temp., there's an SAE chart out there

 

I worked as chemist a decade, Lubrizol, fuel science, motor oil additive packages. I know watered down gas when I see it. Take a sample of the crap that's in my tank, blend with xylene or toluene to add to aromatic content and watch indices of refraction mix, that fuel from gas station is so polar it ain't funny , I can smell the EtOH in it and its got to be way too much, they probably sent E-15 by "mistake". Who would care ? The auto mechanics won't care, just more work $$ for them, just like the lawyers when new "laws" are passed. As the country goes down, they sell crap fuel to keep everybody working, fixing all the broke stuff, here's a link for ya

 

if the key chip was part of this problem you would not be cranking and would have no injector pulse.

if you have a signal on the meter or test light, blinking, the circuit is not "shut off." you should check one harness per side.

unplug the MAF and see the reaction. then connect it up and unplug TPS. this is per my FSM, not a WAG.

what did the plugs look like? rich or normal?

again, the immediate issue is "not firing," which may not be fuel contamination, unless it were a homogenous mixture. it could be rich because of a CTS, for example. that should set a code. the "clear flood" should allow it to start if not run.

 

Thanks Joe Paco, I'll go check for pulse on the left side, I only checked the right previously.

I have the FSM too, what page you on ? I didn't realize there is an MAF on this one, I thought it was the other one, speed-density is it ? I'm going to go get some fresh fuel, I cranked it over after pulling a couple plugs and replacing them after cleaning them, it fired a couple bumps, its just that it sucks getting to the left bank, arrgh, that's what I get for buying cheap fuel

 

mine has the MAP, IAT -intake/manifold ambient temp. I assume yours has one or the other and the idea is the same -unplug one and see reaction, then the other. nothing to lose.

I would be very surprised if fuel was so bad as to cause no fire -missing, shudder, coughing, maybe. especially if it was "fine" one day, bad the next.

 

Drained the tank by siphoning. Put some 93 octane in. Crank her up... a few wanna be puffs. If only I could drain the rails , I could rule out bad fuel from before. I remain optimistic though , she hasn't puffed this much before I changed what was in her tank. If I knew a way to recirculate whats in the rail vs just letting it **** out during cranking.....

what a long thread, you all are great for helping, I'm the same way with stuff I know, I shared lots in the past so don't think there's no Karma here BTW, my 67 K20 fired right up when I needed a ride, the MSD 8365 distributor is a badass piece of work, that 5000lb hunk hauls butt

 

I'm pretty sure the LT1s still had a bypass type fuel regulator. If you have a "return" fuel line, then this is your setup. Assuming that's true, just turning on the ignition will flush out all the fuel in the rails. If you really want to be sure all the old fuel is out of the rails then turn the ignition on and off a few times.

 

Thanks for that tip. Late yesterday I siphoned the fuel tank dry and added 5 gals of fresh 93 octane. Tried starting it and got a few ignitions, like she was wanting to start, closest thing she done near starting yet, but battery was nearing the end so I hung it up and put the charger on it. We'll see in a few hours what today brings

 

Chris, save that gas for your Toyota!

when I can explain how gas goes bad overnight, I will believe. but some sensors seem to go bad at any time. far as I know, the l98 needs inputs from MAF or MAP, CTS, TPS, IAT, and signal from the rotating distributor before it will start. the lt1 is similar I think.

the chart A-3 in my book, "cranks but won't run," mentions contaminated fuel in cold weather, plus several pages of other possibilities, most of them already mentioned in this thread.

joe

 

You may have made the same mistake I did when my INJ 2 fuse blew.
The INJ 1 fuse is a higher amp rating than the INJ 2 fuse. I don't have my FSM handy and the car is at the shop. The INJ 1 fuse is 20 or 30 amp if I can recall.

When my INJ 2 fuse blew I checked the one below it - of course it was OK. When I checked the correct fuse it was blown.

As an aside, the engine would start and run with the INJ 2 fuse blown, just wouldn't run well

If you are getting pulses on both sides it may not be the fuse

And the 93 is like my 92 - MAP only, no MAF.