Engine won't start after work done...... Please help!

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ExoticLSC

Registered
Hey guys I just did a bunch of work to my 96 LSC and now it will not run. I dropped the k member to install a 1 3/8" front sway bar, installed a remote mount tranny and engine oil filter, tranny cooler, all new front suspension; uppers, lowers, struts, all bushings, re-pinned the tranny harness for a '98 tranny install with PI converter, HD driveshaft, 4:10 gears, 1 3/8" rear sway bar, big brakes front/rear, cobra hub swap, and a walbro 255lph pump assembly from my '95. Most of the parts came from my '95 that was totalled. I'm thinking I might have broken a wire or connector somewhere when I dropped the k-member or when I raised the front of the engine to help get the new tranny in. I checked the crank position sensor, harness and plug and I haven't noticed any issues. The car cranks over fine but will not fire. I did notice that the fuel pump is running whenever the ignition is on even with the engine stopped, which I believe did not occur before. Please help!

Thanks,

-Joe Michael
 
ExoticLSC said:
Hey guys I just did a bunch of work to my 96 LSC and now it will not run. I dropped the k member to install a 1 3/8" front sway bar, installed a remote mount tranny and engine oil filter, tranny cooler, all new front suspension; uppers, lowers, struts, all bushings, re-pinned the tranny harness for a '98 tranny install with PI converter, HD driveshaft, 4:10 gears, 1 3/8" rear sway bar, big brakes front/rear, cobra hub swap, and a walbro 255lph pump assembly from my '95. Most of the parts came from my '95 that was totalled. I'm thinking I might have broken a wire or connector somewhere when I dropped the k-member or when I raised the front of the engine to help get the new tranny in. I checked the crank position sensor, harness and plug and I haven't noticed any issues. The car cranks over fine but will not fire. I did notice that the fuel pump is running whenever the ignition is on even with the engine stopped, which I believe did not occur before. Please help!

Thanks,

-Joe Michael
Click to expand...

Just a thought...could the repinned connector be related?

The fuel pump is supposed to turn on for a couple seconds when the key is turned on without starting...I don't think it is supposed to stay on without a running engine, but I may be wrong.
 
logres said:
The fuel pump is supposed to turn on for a couple seconds when the key is turned on without starting...I don't think it is supposed to stay on without a running engine, but I may be wrong.
Click to expand...

No, you're right. The fuel pump is not supposed to stay running without the engine running. I would start the troubleshooting from there.

Having said that, remember Fuel, Air and Spark.

Check that you have fuel pressure and that all the injectors are firing. The cam sensor controls injector 'timing', so check that as well.

Check that there are no anomalies in the air induction system. MAF, IACV, throttle body, etc...

Finally, check for spark at all cylinders. Remember the crank sensor and ignition control module work with the PCM to control spark.
 
Today I confirmed spark and fuel pressure (38 psi at the rail). However, it seems as if the injectors are not firing. The plugs did not have any fuel or even the smell of gasoline after several start attempts. I sprayed a bit of starter fluid into the intake tube (after the MAF) and cranked the engine, it started to run. What is the best way to check if/why the injectors are not firing? Also, at the end of the day the fuel pump stopped running. I used the complete fuel pump/float assembly from my '95, could that have caused an issue? :(

Thanks for the guidance,

-Joe Michael
 
At least it seems you've narrowed it to a fuel issue. Random thoughts...

Check ECM fuse and relay. Check for 12VDC at the injectors (red wire) with key in start or run.

Check TPS signal (Idle = 0.99VDC / WOT at near 5VDC will signal the PCM to turn off injectors)?

Backup and check cam sensor and harness.

All that is moot though if you've lost the fuel pump. :(
 
As far as the fuel lines go, they are different sizes at the tank connections so those are not reversed but definitely a good thought. I am getting 12v+ at the injectors during crank. ECM is getting power, but I was unable to check TPS signal. The fuel pump works intermittently.

***So check this out!..... I had my '97 PCM sitting around and decided to plug it in to the '96. I know, I know.... I know that they are not supposed to be compatible but when I cranked the engine, it actually ran though only for a few seconds. I assume that this is due to the PCM looking or the PATS chip code and not receiving it and shutting down. I'm thinking that the VCRM might be ok and that the original PCM is not working properly. I didn't get the original PCM to fire at all without starter fluid. If I look for a replacement PCM, do I need to find one with the same flash code as the original?

Let me know what you guys think. Thanks!
 
I just oredered a replacement PCM. I should be receiving it Monday, I'll let you guys know how it works out.

-Joe Michael
 
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