Help NO fire

**70 camaro** · 01-19-2006, 10:22 PM

99 z28 Ls1
Was starting fine. Now seems to have no spark.
Somebody said crank sensor,that has been checked/replaced.Seem to have power going to it but nothing. The car has 72,000 miles on it and I don't know what to check next. I am new to this site and also new to all this computer controlled stuff.
The car cranks fine, has gas ,can hear the pump run but just will not spark.
Any

body have ANY ideas , and I mean ANY please would love to hear them.

**02z28ls1** · 01-20-2006, 01:41 AM

When you say it has no spark and has fuel pressure how did you check that? Don't assume any of this stuff-you have to check it-you need around 50-60 psi at the fuel rails.Just hearing the pump run doesn't mean it's getting the fuel pressure.

**70 camaro** · 01-20-2006, 10:02 AM

Well I checked the spark by pulling out a plug and having somebody crank it over ( plug grounded and in the plug wire). I found out today that that isn't the best way to check , guess they have a tool that takes place of the plug.
As far as fuel pressure ,true I don't know the psi but the plug had fresh fuel on it and after a while of cranking could smell some fuel.
Is there a company that sells a fuel pressure gauge that can be mounted on or by the fuel rails inline style ?

**02z28ls1** · 01-20-2006, 04:56 PM

There are fairly inexpensive fuel pressure gauges that screw into the shrader valve on the fuel rail from a parts store-and I have a spark checker that resembles a spark plug but has a clip to clip it to a ground (from a parts jobber).You don't want that voltage running through you from these late model cars-it can knock you on your ass-maybe kill you.My point was to not assume this stuff but find out how much pressure is there.If you have a scanner or can get one you need to scan for trouble codes.

**70 camaro** · 01-20-2006, 07:24 PM

Thanks, I will look into both the scanner ,gauge and plug tool.
If you have any other ideas I would greatly appreciate your thougths.
Can you recommend a place that can modify the computer. I will not be needing any of the smog , abs , airbag, etc. AFTER I fix this problem.
THANKS , AGAIN

99PontTA · 01-21-2006, 03:27 PM

check the connections at the PCM under the hood.I doubt its a fuel problem because the plugs are wet and you don't have spark.I need to do some reading up on the squence of events to tell you exactly what needs to happen to have spark,but i think spark is enabled BEFORE fuel...so you may have a toasted PCM.The reason i say this is normal start up squence would be pcm sees crank sensor output,cam sensor output,then sees fast enough rpm,s then enables spark then fuel...something along these lines.I have a complete LS1 diagnostic cd someplacece in this mess,if i can find it i'll look it up and post the info.

**toneloc60** · 01-23-2006, 05:07 AM

I doubt it's a crank sensor if you've got fuel. Reason being, it wouldn't pulse the injectors if it didn't know where the engine was in the firing order.

What do you mean it was "starting fine?" What about "running fine?"

Is this an engine swap? A retro fit?

If all you were doing was starting it, why? Were you working on this thing for other reasons?

I'm not trying to put you on trial. I'm just trying to paint a picture so people have the best chance at figuring this thing out for you.

**70 camaro** · 01-24-2006, 01:14 AM

Yes to many of your questions. All I was doing was starting it.The car isn't done yet. It was an engine swap.
I didn't go into that because I tell people what I was doing and they kinda freak out.
I took everything out of a 99 z28 and put it all into a 1970 camaro.
I mean everything ! SO the complete wire harness was just plug and play. (motor,trans,colum,dash,brake booster,master,console,gauges,heater,a/c,seats, and I could go on and on and on.
But all plugs etc. had not been changed or modified so I was trying to take those questions out of the equation.
Today after putting a gauge on the fuel rail,checking spark (with a tool as per suggestions) and after checking for power to the coils I was just about to check to see if the coil packs were getting a pulse signal the damn thing started. ? Don't know why it just did.
I want to thank all who gave me suggestions it was very helpful in learning about this new stuff.
I also hope you all understand that the type of body that this setup is in didn't change my base question. THANKS AGAIN.

**02z28ls1** · 01-24-2006, 09:37 AM

Well I hope it's fixed and stays that way.It doesn't make a difference what body it's put in as long as nothing else is changed-I think people were a little confused by some of the comments you made about deleting some things off the computer and the way you had the vehicle described seemed to change from one post to the other.Anyway it's all good in the neighborhood!