Cranks but no Start-- SOLVED

[intimdatr]

I think Laser swapped the plugs before he sold it to me. I'll check with him to be sure. The wires look fairly new (for whatever that's worth).

I saw the post about the flooding issues and it's definitely on my list of possibilities. With what's going on, it seems like the most feasible given his description and the symptoms. I say that because it only seems to do it after a 20 (or so) minute heat soak. The part that I think is against that theory though, is that you'd think it would have a hard time starting when it was cold too (the fuel would still be sitting in there).

I'm open to all suggestions though. You guys know more about this car than I do.

In the meantime, I'll take a look at the grounding strap. I did take a dremel brush to the mounting hardware of the DIS when I had it apart, to remove all the rust etc. from the screws. I'll do the same to the grounding strap and see if there's any difference.

Thanks all.

The wires looking new doesnt usually mean to much. Mine looked new and were pretty worn out.

If it was sitting for any period of time the gas would evaporate out of the cylinders. (their a seal but not air tight).

good place to start is with the grounds on this car (has TONS of important ones) many of these grounds can and will make the crap start and run like crap if they arent hooked up or clean.

 

[rubydist]

2 things from the video:

1. when you first try to start the car, you have to hold the key to crank more than 1.5 seconds. These engines are finicky, and will easily flood, especially when warm. If you try to start it, and it fails, you nearly always end up with a flooded condition. If it needs to crank 4-5 seconds to start, then for heaven's sake, crank it 5 seconds.

2. it exhibits typical symptoms of a lack of fuel pressure at crank. This can be due to injectors leaking fuel into the cylinders, or the fuel pump check valve leaking pressure back into the tank.

If you re-read post 11, you will see that I instructed you to turn the key to on for a few seconds, then off, then on again for a few seconds, and to repeat this several times. This is WITHOUT cranking. This will ensure that fuel pressure is built up. The next time you drive it and have a hot-restart condition, do the key on/off thing and tell us how that worked out.

 

[Noobz347]

2 things from the video:

1. when you first try to start the car, you have to hold the key to crank more than 1.5 seconds. These engines are finicky, and will easily flood, especially when warm. If you try to start it, and it fails, you nearly always end up with a flooded condition. If it needs to crank 4-5 seconds to start, then for heaven's sake, crank it 5 seconds.

2. it exhibits typical symptoms of a lack of fuel pressure at crank. This can be due to injectors leaking fuel into the cylinders, or the fuel pump check valve leaking pressure back into the tank.

If you re-read post 11, you will see that I instructed you to turn the key to on for a few seconds, then off, then on again for a few seconds, and to repeat this several times. This is WITHOUT cranking. This will ensure that fuel pressure is built up. The next time you drive it and have a hot-restart condition, do the key on/off thing and tell us how that worked out.

1. I was releasing the ign switch when it stumbled and acted like it was going to start.

2. When I get it to do it again. I'm going to run a jumper to the test connection and let the pump run for 15 seconds or so before trying to start it. If it cranks right up, then I'll know that something is screwy with the fuel system.

Thanks!

 

[Noobz347]

Today's Findings (or lack thereof):


When I got home from work today, I shut it down and waited 15 minutes. Sure enough, it cranks but wont start. So I pop the hood and install a jumper wire to the fuel test port

So the pump is now running continuously and I can hear the pump tone change as pressure builds and I can also hear fuel hissing through the regulator after a short time. So it's primed and ready. Still no start.

I pull the jumper wire and wire it in with one of the bottom screws of the DIS module then directly to ground. Still no start.

I try turning the ignition switch on and off 10 times. Still no start.

A short time later, it fires, stumbles, then acts right as rain again. Remember... the hood has been up this whole time and everything has been cooling (it's roughly 68* degrees with a steady wind today).

The wife needs to go to the bank so we take the SHO to the bank, sit at the drive through for a while and get it good and heat soaked again. When I get home, I shut it down and restart it. No problem. I shut it down again and wait one minute. Starts right back up. I shut it down again and wait two minutes. It starts right up again. I set my timer and wait 15 minutes with the hood closed. Sure it enough... It cranks but doesn't start. I try cycling the ign key again. 10 times. No start. I repeat this process 3 times in a row. Still no start.

I popped the hood, pulled the 3 plugs in the front. None of them smell like fuel and with a flashlight, I can see the top of the pistons. At least these three appear dray as a bone.

On a side note:

I assume the pic below is the IAC. Should that open port be attached to anything or is it supposed to remain open?

Thoughts? Thanks again, to the folks that are trying to help me out with this.

 

[Shovert]

Mine which is a 94. There is a plastic cap on it. Unsure if it is open to atmosphere or a solid cap.

 

[pjtoledo]

as the choices are either no fuel, or no spark at the right time, try some 'ol school diagnostics. mark your crank pulley and slap a timing light on it to verify the spark. have any starting fluid? squirt some of it, or gas into the intake thru a tube or something. just don't over do it.

The CCRM supplies constant power to all the injectors all the time, then the PCM individually grounds each injector to complete the circuit and fire them one at a time. during the dead time check for 12v at the injectors. one side of the injector should always read 12v,( key is on) the other side will read 12v when the injector is not firing, and less than 1 v, probably 0 as the injector fires. try icing, or putting a fan directly on the CCRM to see if that changes the cool time noticibly.


Perry

 

[pjtoledo]

do you have a mechanics stethoscope??? you can hear the injectors tick as they fire.


Perry

 

[Noobz347]

as the choices are either no fuel, or no spark at the right time, try some 'ol school diagnostics. mark your crank pulley and slap a timing light on it to verify the spark. have any starting fluid? squirt some of it, or gas into the intake thru a tube or something. just don't over do it.

The CCRM supplies constant power to all the injectors all the time, then the PCM individually grounds each injector to complete the circuit and fire them one at a time. during the dead time check for 12v at the injectors. one side of the injector should always read 12v,( key is on) the other side will read 12v when the injector is not firing, and less than 1 v, probably 0 as the injector fires. try icing, or putting a fan directly on the CCRM to see if that changes the cool time noticibly.


Perry

What is the location of the CCRM? Do you have a pic of one? I'm not well versed on all the SHO innards at all.

 

[pjtoledo]

What is the location of the CCRM? Do you have a pic of one? I'm not well versed on all the SHO innards at all.

its that square box on top of the hot radiator, wires attached. has the relays that run AC, injectors, fuel pump, and fan.

 

[Noobz347]

its that square box on top of the hot radiator, wires attached. has the relays that run AC, injectors, fuel pump, and fan.

This it?

 

[pjtoledo]

yep, get the right version if thats indeed it

 

[Noobz347]

I'll try the stuff that you posted and if this ends up being the culprit then at least they're available.

Thanks.

 

[rubydist]

the little port on the iac is vented to atmosphere - normally there is a cap on it to keep the dirt out, but it just vents to atmosphere, so you are okay there.

the fact that the plugs are dry after all your latest experimenting suggests that you are not getting fuel in this situation. you said you jumpered the pump and it runs and you can hear fuel going through the pressure regulator.

now, there are several possibilities:
1. the fuel pressure regulator sticks open when hot, no fuel pressure.
2. the fuel pump makes little pressure
3. the pcm is not telling the injectors to fire.

you can test for 1 or 2 by jumpering the fuel pump so it runs, and then putting a pressure gauge on the schrader valve on the fuel rail to test for fuel pressure. in fact, you should test it with the ignition and fuel pump off too, so you know if it bleeds down.

number 3 is more difficult - you should check all the engine grounds, to make sure you have good connections on all of those (SHO motors are notorious for not running or not running right due to bad engine grounds) but if those are all good, then I think I would swap in a known good pcm to see if that solves the problem.

btw, if you can hear the fuel pump run for a few seconds each time you turn on the key, then the ccrm is doing its job telling the pump to run, so that is not likely to be your issue.

 

[Noobz347]

1. I would think that if this were the problem then I should be seeing symptoms when the car is running and not just when it's been turned off and sitting for a while?

2. These I will have to look for. I also want to put a trouble light on the injector wires and see if they're at least pulsing when this happens.

3. Yep... I can hear it run when I rotate the ignition switch on and off.

The whole thing is very strange. Car can be heat soaked from running and restart immediately but quits starting after 15 or so minutes. Strange thing.

I'll get a fuel pressure gauge on it as soon as I can to see and/or eliminate that as an issue along with trying the engine starter fluid suggestion above. If it's not getting fuel for some reason, that should tell the tale.

 

[Noobz347]

Nothing really new to report today. I set my timer for 15 minutes after shutdown and verified that it was doing it again.

I installed the jumper into the test connector to make the fuel pump run constant.

I iced down the fuel regulator(s), CCRM, and whatever that little box is that hangs off the rear of the intake until they were cool/cold to the touch.

I also ran a jumper cable from the negative battery terminal to the ground strap location on the back of the intake.

None of that seemed to make a difference. After what seemed to be the normal amount of time with the hood open, the FN thing started back up like it always does.

I'm not sure if I broke it or if it was already broken but the spark plug wire for the driver side, rear cylinder snapped at the elbow where it goes into the coil block.

So new wires all around... I can't wait to do that job. What ass hat designed all the spaghetti on this damned thing anyway?

 

[itwonder]

Check again and see if you are getting a strong spark during the no start condition. If so, hold it WOT, open the lid of the air box, and give it a spray of starting fluid right into the air intake tube. It should at least fire then. This will help isolate ignition or fuel.

 

[pjtoledo]

Check again and see if you are getting a strong spark during the no start condition. If so, hold it WOT, open the lid of the air box, and give it a spray of starting fluid right into the air intake tube. It should at least fire then. This will help isolate ignition or fuel.

getting starting fluid on the hot element of the mass air flow sensor may not be a good idea. anybody know how hot those are?

 

[itwonder]

getting starting fluid on the hot element of the mass air flow sensor may not be a good idea. anybody know how hot those are?

You can unplug the MAF; it is not needed for this test.


BTW, hate to just toss stuff out until you have a chance to test, but FWIW, if your DIS seems to be running excessively hot, that may be pointing to a failing ignition coil. Might be worth swapping it out; you can pick one up cheap at a JY.

 

[Noobz347]

Gents....


Today it reached 82* ambient and the thing actually stalled on me twice while stopped (once at a light and the other behind a school bus) it ran great so long as I was moving.

So... I got it home and ran codes right away. Here's what I got:

519c
542c
556c

and I got a 55c once but was not able to duplicate that code (may have just been a stray).

With the other issues and symptoms I've described, I figure it might help to pinpoint. On a side note, today was the first day I've driven it since my last post because I JUST received the spark plug wires and replaced (so far) just the one that was damaged.

I have an idea of what I think I should do next but wanted to hear from you guys and see we're on the same page.


Thanks!

 

[rubydist]

519 = psps circuit open
542 = fuel pump secondary circuit failure
556 = fuel pump primary circuit failure

519 will only affect ps boost, so is not impacting your current issue

542 happens if engine stalls and can mostly be ignored

556 however suggests that ccrm is bad, fuel pump is bad, or wiring on fuel pump circuit is bad. start there.