Starting problems

[Highway Man]

Well, I've read about other people having problems and now I guess its my turn. I have had my 92 lt1 for about three weeks and it has started everytime and ran beautifully until today. I went out and started it right up and it was running just fine and because the rear window was fogged up I turned the rear window defogger on for the first time. While I was getting out a cd for some music the car just died. It had ran for several minutes. I waited awhile and tried to start the car again with no success. It turns over just fine-it just won't start. I unhooked the negative cable on the battery for a few minutes to see if that would jar something loose but that didn't work either. Before I tried to start the car the second time I made sure everything was turned off so there wouldn't be any extra drain on the battery. I have lights and all kinds of power it just won't start. The only modification I have done is to install a high flow air system to the car and I am wondering if I have set of some kind of sensor issue. Any and all feedback would be greatly appreciated. ;help

 

[ex-x-fire]

3 tools you need for your c4 if you plan on figuring out no starts.
1 a fuel pressure tester. Should hold psi after engine is off.
2 a noid light. This tests for injector pulse.
3 a spark tester. Hooks to a ignition wire to see if you have spark.
#2 you can get by with a test light if you have to. #3 you could get by with a screw driver close to ground (but not touching) in a pinch.

 

[boomdriver]

Well, I've read about other people having problems and now I guess its my turn. I have had my 92 lt1 for about three weeks and it has started everytime and ran beautifully until today. I went out and started it right up and it was running just fine and because the rear window was fogged up I turned the rear window defogger on for the first time. While I was getting out a cd for some music the car just died. It had ran for several minutes. I waited awhile and tried to start the car again with no success. It turns over just fine-it just won't start. I unhooked the negative cable on the battery for a few minutes to see if that would jar something loose but that didn't work either. Before I tried to start the car the second time I made sure everything was turned off so there wouldn't be any extra drain on the battery. I have lights and all kinds of power it just won't start. The only modification I have done is to install a high flow air system to the car and I am wondering if I have set of some kind of sensor issue. Any and all feedback would be greatly appreciated. ;help

Plugged fuel filter inline, under passenger side door hinge on frame rail.

Low/shaky pressure readings will confirm this outstanding diagnosisotfl:eyerole

Until you get a gauge to test, turn the key on for 5 seconds then off.

Now go find the fuel test port on the fuel rail. Its covered by a small black cap that screws off. Get a nail or something to push the valve button to see IF there is any fuel pressure.
Good news will spray all over.

Bad news...it barely leaks out even when you hold the valve open/down. No spray, buy a filter and maybe a pump.

 

[Highway Man]

Thanks

Thanks a bunch guys! I really appreciate the feedback. If there is anyone else out there with any suggestions I am all ears. I am kind of surprised though that the security system wasn't mentioned. I have read where some people had a lot of problems with that, but hey I am going to check out these fuel issues first!

 

[John Robinson]

There are three things an engine needs to run

1. Fuel
2. Air
3. Spark

As others have said check for these three things and one of them will be missing.

Check for any codes that might lead you to the area that is in trouble.

If you don't have one get a Field Service Manual (FSM)

On the spark side of the three things needed to make an engine run you might check to be sure you have all the sensors plugged in tightly on the Throttle body and the rubber connection to the air cleaner. While you are lookiing at them spray the contacts with a contact cleaner (Corrosion on the contacts can be a problem)

A quick check to see if you have a fuel problem is to spray some carb cleaner in the throttle body while having someone turn over the engine to see if it trys to fire. If it does you may have answeared the question about spark becasue any fire at all would need spark. It goes without saying that if the engine starts even momentarily you need to think about a new fuel pump, filtler, fuel pump pickup filter or a preassure regulator. As for the preassure regulator pull the vacuum hose off and see if there is fuel in the vacuum hose. If there is you have a bad fuel rail regulator.

Oh and you might also want to check all the fuses. The ones in the fuse panel and the ones next to the battery.

And one last thing to check (I am not kidding) do you have pleanty of gas. Don't trust the gauge if it is showing only a couple of bars.

Good luck and let us know what you find out. This would be good excersize to work off a Thanksgiving meal so you will be ready for a double helping of pie

 

[Highway Man]

Keep it coming

I am appreciating all the feedback! I like to look at the little things first and then work my way in but, I am open to any and all suggestions. I have a feeling that when I find it is going to be some small thing but I will let you all know so someone else can benefit from my experience. We have a busy day today being Thanksgiving and I probably won't get a chance to look at it today but tomorrow I will be under the hood. As for the pie when I get my black beauty going I may just eat the whole pie!!! :L I hope everyone has a really good Thanksgiving and thanks again.

 

[Highway Man]

The battle is joined

I am in the process of solving my no start problem on my 92 lt1. I checked all fuses and they are all okay. Next I checked fuel pressure by holding in the fuel pressure relief valve as boomdriver suggested and I have a trickle instead of a spray so I suspect it is either the fuel filter, fuel pump, or both. It is off to the auto parts store in search of a fuel pressure gauge. Hopefully it will be only the filter-fingers crossed.

 

[Highway Man]

stumped

Well, after hooking up a fuel pressure tester and priming the engine I have 44 lbs. of pressure. I didn't think to test it while cranking it over but what I did do was spray carb cleaner in the intake while a person helping me cranked it over with no results. The car never hit a lick. Unless I am missing something that would rule out fuel filter and pump problems so, it appears that I may have a fire issue instead. The car did one odd thing though. While I was testing my fuel pressure the heater came on. It was after I had previously started the car and turned my rear window defogger on that the car died. I checked my fuses and they are all okay so I am looking at my next move. :confused

 

[vetteoz]

was spray carb cleaner in the intake while a person helping me cranked it over with no results. The car never hit a lick.

No spark
Start checking
http://www.underhoodservice.com/Article/40002/diagnosing_gm_lt1_v8_engines.aspx

How many miles?
Has the Opti ever been replaced?

 

[Highway Man]

present condition

The car has a little over 121,000 miles and to my knowledge the opti has never been replaced-I am the third owner. This could very well be the dreaded opti failure that this model is notorious for. ad Well, if it proves to be so I have a new water pump, thermostat, and hoses lined up so if I have to replace the opti I am going to go ahead and get the whole thing while I have it apart. I have no experience with an opti so could someone tell me if there is a way to test this thing to determine if it is bad or not rather than roll the dice by replacing it and hope all turns out well? Also could someone suggest a good opti replacement? I do know that the spark plugs and plug wires have been replaced so I don't think I have a problem there and the odds of them all going bad at once is pretty slim. Even with a couple of bad cylinders I would think that it would still try to hit. :W Thanks vetteoz for that site on the underhood service-an interesting read. The only mod I have made to the car is the installation of a K&N air filter and I opened up the air box to allow more air in but I wouldn't thing this would keep the car from starting? I will get the car going its just the process of finding the problem and getting it taken care of. Thanks everybody-keep it coming!

 

[vetteoz]

I will get the car going its just the process of finding the problem and getting it taken care of.

Sorry
posted wrong link :eyerole

How to diagnose LT1 No Start cond here
Lt1 No Start Diagnostic - Mainstreamtopics - Your General Forum

 

[Highway Man]

Good stuff

Sorry
posted wrong link :eyerole

How to diagnose LT1 No Start cond here
Lt1 No Start Diagnostic - Mainstreamtopics - Your General Forum

That's good stuff vetteoz-thanks a bunch man!

 

[vetteoz]

That's good stuff vetteoz-thanks a bunch man!

One of the best

Print the page out and file it somewhere for future use.
Or copy it into a Word doc and save on your computer

Online links can disappear at anytime which can be very annoying when you have bookmarked the answer but the site no longer exists

 

[CharlesBrown]

Cold start...won't run

Solved this problem on my '88. Replaced cold start valve, fuel pump and filter. Starts fine runs great, idles better too. Did I mention the $750 mechanics bill?

 

[Schrade]

Well, after hooking up a fuel pressure tester and priming the engine I have 44 lbs. of pressure. I didn't think to test it while cranking it over but what I did do was spray carb cleaner in the intake while a person helping me cranked it over with no results. The car never hit a lick. Unless I am missing something that would rule out fuel filter and pump problems so, it appears that I may have a fire issue instead. The car did one odd thing though. While I was testing my fuel pressure the heater came on. It was after I had previously started the car and turned my rear window defogger on that the car died. I checked my fuses and they are all okay so I am looking at my next move. :confused

You have not completed static FP tests. You have also to do dynamic tests, since it starts and cuts off.

Resume static FP tests by noting how long pressure holds. Post back after doing that...

Solved this problem on my '88. Replaced cold start valve, fuel pump and filter. Starts fine runs great, idles better too. Did I mention the $750 mechanics bill?

Were static and dynamic pressure tests done before this? I guess it doesn't matter too much, if it fixed the problem, but if the tests were not done, and this fixed the problem, you should have bought a lotto ticket YUP!

Another cause of slow bleed down is a stuck or shorted injector. this will usually cause a hard start and can be very damaging to the motor since fuel is filling that cylinder when ever there is pressure in the lines.

This is MOSTLY wrong. An open injector pintle can let pressure off immediately. Jon showed that in one of his vids, and it sure surprised me how fast, especially when the spray pattern was good between pulses.

 

[Highway Man]

Good posts and humor

Thanks to all! These are good posts and I appreciate the humor-we might as well have a little fun out of this. I'm not sweating bullets over this. I'll get it fixed its just a matter of finding the problem and addressing it. I have had trouble with other cars I have owned and none of them has put me in the grave-at least not yet!:L

 

[Highway Man]

Problem solved?

Well, I'm not totally sure this will solve my no-start problem as sometimes there can be more than one issue to address but hopefully this is all it will turn out to be and that is a bad coil wire. I got some contact cleaner and went to cleaning contacts and I noticed that the spark plug wires that the previous owner installed didn't look the same as the coil wire so I began to wonder. I said to myself self why don't you pull that coil wire and see if you have any continuity in it? So that is what I did and I get zero continuity. I took it to my local auto parts store and had them recheck it as they have a better tester than I do and they got a little reading but nowhere it should have been. I don't know just what kind of reading I should be getting but I would think that it would read off the scale. Any feedback? Could it really be that simple? I certainly hope so but I won't know for sure until Tuesday when my new coil wire comes in. I think while I'm at it I may well invest in a good quality set of new plug wires.

 

[LLC5]

Well, I'm not totally sure this will solve my no-start problem as sometimes there can be more than one issue to address but hopefully this is all it will turn out to be and that is a bad coil wire. I got some contact cleaner and went to cleaning contacts and I noticed that the spark plug wires that the previous owner installed didn't look the same as the coil wire so I began to wonder. I said to myself self why don't you pull that coil wire and see if you have any continuity in it? So that is what I did and I get zero continuity. I took it to my local auto parts store and had them recheck it as they have a better tester than I do and they got a little reading but nowhere it should have been. I don't know just what kind of reading I should be getting but I would think that it would read off the scale. Any feedback? Could it really be that simple? I certainly hope so but I won't know for sure until Tuesday when my new coil wire comes in. I think while I'm at it I may well invest in a good quality set of new plug wires.

Sure, it could be that simple. Hopefully it is.

Be sure to check the contacts in the coil and cap very carefully for corrosion or burn marks. Good luck with it.

 

[vetteoz]

runs great, idles better too.

Probably long overdue preventive maintenance

Cold start injector has no effect on engine running ; is only in operation while cranking ( cold engine )
CSI doesn't apply in OP's case because LT1 doesn't have one

 

[vetteoz]

I said to myself self why don't you pull that coil wire and see if you have any continuity in it? Any feedback? Could it really be that simple?

Got a old coil lead and spark plug to try direct off the coil to see if you have spark?
If so you know your wire(s) are dodgy

I don't know just what kind of reading I should be getting but I would think that it would read off the scale.

Varies by type and brand
http://www.tpub.com/basae/48.htm
http://www.aa1car.com/library/spark_plug_wires.htm