Question about fuel pressure

[Yenkohead]

How long should I expect to wait before I get fuel to the plugs on an engine that has been sitting for awhile while I installed it? I have been trying to get this thing started and don't want to continue turning it over if it could cause some damage. I hear the fuel pump when switching the ignition to "ON". I checked the shrader valve and have fuel to that point. I pulled a plug and it has no gas on the electrode.

Should I keep trying to turn it over? I haven't verified spark yet, but unless I have fuel it's kind of moot I think (plus it takes a second set of eyes, which I don't have at the moment).

Thanks,
Greg

PS Yes, there is gas in the tank. :|

[RamAir95TA]

The plugs will stay dry until the fuel injectors open (via the PCM receiving the low resolution pulse from the optical sensor in the optispark). The pressure built up in the rails will simply return to the tank if the injectors do not open.

[SexyTransAm]

Will it do anything if ya hit it with a little starting fluid?

Sent from my SAMSUNG-SGH-I547 using Tapatalk 4

[Yenkohead]

The plugs will stay dry until the fuel injectors open (via the PCM receiving the low resolution pulse from the optical sensor in the optispark). The pressure built up in the rails will simply return to the tank if the injectors do not open.


Hmmm. Does this point to the optispark as the source of the problem then? This may partially explain why I couldn't start the previous engine (before it overheated) and dumped fluid into the some of the cylinders....................wait, strike that, I used the opti that came with the replacement engine.............whew! Anyway, I'm going to go out now and pull some codes with this handy dandy code scanner I bought for times such as this. I'll see what pops up. I never used one of these..............should be interesting. :face_shocked:

Thanks for that info!

Greg

[Ghettogmc23]

Possibly a blown fuse?

[Yenkohead]

Will it do anything if ya hit it with a little starting fluid?

Sent from my SAMSUNG-SGH-I547 using Tapatalk 4


You know I tried that twice without result or change. As I stated to RamAir95TA I am going to try out this code scanner (Mac Tools ET1005A). Maybe I can figger something out before I damage the engine I just spent weeks and weeks to get to this point.

Thanks,
Greg

[Yenkohead]

Possibly a blown fuse?

I like your thinking. I will check that even before the code scanner thing. Wouldn't that be nice for a change to be something as simple as a fuse............

Thanks,
Greg

[Fastbird]

When you're cranking the motor and all is well, the injectors are firing. If there's a VATS issue, the pump will be disabled, so you'll get some injector fire but the pressure will quickly bleed down. If you're diagnosing a no-start condition, start with the most obvious thing, is there a check engine light on? Check the codes. If not, check your three factors: Fuel, Spark, Air.

For what it's worth, you shouldn't be able to wash down the cylinders of a relatively stockish motor with extended cranking, so you shouldn't have to worry there. Once you know whether or not you've got fuel you can move on to diagnosing the spark and quit cranking it repeatedly.

[Yenkohead]

When you're cranking the motor and all is well, the injectors are firing. If there's a VATS issue, the pump will be disabled, so you'll get some injector fire but the pressure will quickly bleed down. If you're diagnosing a no-start condition, start with the most obvious thing, is there a check engine light on? Check the codes. If not, check your three factors: Fuel, Spark, Air.

For what it's worth, you shouldn't be able to wash down the cylinders of a relatively stockish motor with extended cranking, so you shouldn't have to worry there. Once you know whether or not you've got fuel you can move on to diagnosing the spark and quit cranking it repeatedly.

I tried to check the codes last night but ran into two issues. First, the code scanner I bought on Ebay (ET1005A) requires a software ID that I don't have so I couldn't utilize the computer software at that point (I was sitting in the car until 2am playing with this). Second, I suspect that because I have a '94 with OBD1 (12 pin connector) I may be out of luck. The scanner says that it will scan some GM OBD1 but when I attach the ALDL cable and try to read codes it states that I need to first connect the cable.............when it IS connected. It appears to recognize that I have a '94 LT1 Camaro but that's about it. When I try to use the ScanningSuite software I can only input the Manufacturer, Make, and type of vehicle (car or truck), but for the model there is nothing to choose. I guess I will have to look up how to get the codes with the paper clip at this point. I may also try to contact MacTools or the SW maker to see if I can get a software ID.
Sheesh! If it's not one thing it's another. :)

Thanks for your help!
Greg

[Blackbird96WS6]

The paperclip method worked great on my wife's Vette for pulling codes (thanks to MeanTA for showing me). I'm not sure if the pins are the same for the Vette and your setup, but I had to bridge pins 4 and 12 to pull the codes on it. Scroll all the way to the bottom to see the diagram for a 94-96 connector:

http://www.corvettephotographs.com/c4vettes/codes.htm

[Injuneer]

The MAC tools ET1005A is an OBD-2 scan tool. It isn't going to work on your 94 (OBD-1). The only codes it would pull from a pre-96 GM OBD-1 would be the Pxxxx format codes that are used in the 94/95 Corvette (sometimes referred to as OBD-1.5).

Paper clip does not work after 1993 on the F-Body LT1. Only for Corvette. The 94 F-Body connector is still the 12-pin OBD-1 connector, not the 16-pin connector shown at the bottom of the linked document.

[Blackbird96WS6]

Ah, darn. Thank you for pointing that out, Injuneer.

[Fastbird]

I tried to check the codes last night but ran into two issues. First, the code scanner I bought on Ebay (ET1005A) requires a software ID that I don't have so I couldn't utilize the computer software at that point (I was sitting in the car until 2am playing with this). Second, I suspect that because I have a '94 with OBD1 (12 pin connector) I may be out of luck. The scanner says that it will scan some GM OBD1 but when I attach the ALDL cable and try to read codes it states that I need to first connect the cable.............when it IS connected. It appears to recognize that I have a '94 LT1 Camaro but that's about it. When I try to use the ScanningSuite software I can only input the Manufacturer, Make, and type of vehicle (car or truck), but for the model there is nothing to choose. I guess I will have to look up how to get the codes with the paper clip at this point. I may also try to contact MacTools or the SW maker to see if I can get a software ID.
Sheesh! If it's not one thing it's another. :)

Thanks for your help!
Greg

Ouch. It's getting harder and harder to find an OBDI specific scanner anymore. Your best bet with minimal investment would be to pick up a cheap OBDI ALDL cable and download TTS Datamaster to your laptop. You get 20 free logs with it and IIRC you CAN verify what codes are present (someone PLEASE correct me if I"m wrong, it's been years since I've used Datamaster). Otherwise, you'd probably need to find a shop with something like a Snap On Solus or Verus scanner or the Mac/Matco equivalent.

[Injuneer]

Yes, that's still the case for DataMaster. There's a box that indicate "DTC OK" of there are no codes, and turns red when there is a code. You click on it, and the codes show up in a little grid, and turn red if they are set. There is a skimpy description of each that you get when you click on the red box, but you would be better off using the LT1-specific code list from Shoebox.

I would recommend looking at the new software from GaryDoug (who has joined this site). It will do OBD-I PCM, ABS and SRS. There is a link to the free download on the site somewhere. And he offers guidance on cable selection and computer operating systems. I know where the links are on Firebird Nation, but you have to be a member to do downloads. I think BobDec has post the links here?????

[95Zbuild]

Can also use free scan for codes.
I would use a squirt of gas in the throttle body, if all that checks out for codes.

94 C4, A4 with 3200 stall. 95 Z28 cc305 cam, 2600 stall, LT headers 1.6RR

[Injuneer]

FreeScan appears to be no longer "free". It's handled by a different site, and there may be a charge of some sort. Andy Whitaker directs you to ecufix.com but I can't find FreeScan on that site any more. I saw it once and I thought they were charging 10 Euro's for it.

Does anyone have a valid link to the FreeScan download?

[Yenkohead]

Thanks for all the replies. I am out of town this week so I am unable to proceed with any diagnosis. I think I downloaded FreeScan awhile back. I'll check shortly. I'll try to update when I get a chance to work on the car again.

Greg