Needs some troubleshooting help from Saturn Gurus

DavidD · 11-22-2004, 03:42 PM

Hello folks, just found this forum!

I could really use some troubleshooting help on my wife's Saturn from some of you Saturn experts around here.

The car is a 97 SC2 DOHC manual tranny

A little history so you can see where I have been with this car already.

The car was running fine until one day it started rattling and knocking real bad. I was pretty sure it was about to throw a rod so we decided to rebuild the engine (I am an ex ASE Cert Tech from many years ago). We got it out and disassembled and sure enough, it had spun a bearing on the #4 cylinder and was about to throw a rod. Did some damage to the piston as well. Anyway, quite a bit of money later and a bunch of new parts, we have the engine back in the car.

Problem is, I can't get it to start. Well, almost. I have gotten it to finally start a couple of times. I have to completely floor the accelerator before it even acts like it wants to try to start, and if I keep that up long enough, sometimes, it eventually will start. Once started it runs fantastic and idles fine, so I know nothing went wrong internally on the rebuild.

Thus far, I have checked out and/or replaced the following:

Fuel system:

Check fuel pressure on the schrader valve. You can turn the key on and hear the fuel pump for a couple of seconds. It doesn't read any pressure up front though until you start cranking and then rises to about 45 psi and holds that until you stop cranking. Fuel filter has been replaced. According to the manual, for that year it calls for 46-94 psi, so it's on the lower end.

There is definitely fuel getting into the combustion chambers as the plugs are getting wet.

Engine Electrical:

On the overhaul we put in Bosch Plantinum +4's in there. I have since read these are bad for Saturn and put in regular Delco's correctly gapped to .040 (they didn't have the NGKs).

Checked the resistance on the plug wires which averaged about 3000 ohms which is well below the listed 12,000 ohm tolerance. Also triple checked the firing order which is correct. Pulled the plug wires individually on the plugs and each one sparks to ground. Also pulled adjacent plug wires on the coil packs and the towers spark strong to each other. Checked each coil pack secondary resistance at about 8000 which is on the lower end of the specs the book shows at 8000-15000 ohms.

Next I went to the crankshaft position sensor. Pulled it out and check the resistance at 800 ohms which is dead center of the listed 700-900 ohms. Went ahead and replaced it anyway since it was cheap and the new one also checked at 800 ohms.

Have checked all the vacuum lines, sensor wiring etc about a million times and don't see anything that seems wrong.

The SES light is not flashing indicating any set codes either. Voltages all check ok at the coil pack plug. Checked the injector connectors with a noid light and it's flashing on all 4 when cranking.

I am at a loss now because I can't figure out why it doesn't want to start, when to me everything is saying that it SHOULD start. Perhaps I am just so frustrated with it that I am missing something obvious, I don't know, but I could really use some help. Thanks VERY MUCH in advance!

Anony00GT · 11-23-2004, 02:04 AM

You're flooding the engine out on initial startup. Flooring the accelerator puts most fuel-injected cars (including Saturns) into flood recovery mode, shuts off the injectors for the initial cranking to discharge the excess fuel.

Why is this happening? Probably an issue with the coolant temp sensor, located on the side of the cylinder head. Check the wiring connector carefully, and replace it if you see ANY corrosion. Also, replace the sensor itself, it's only a couple bucks at your local auto parts store. I have used many of these sensors from NAPA, on various Saturns, with no problems at all, however some people say that you can get a brass one from your Saturn dealer. Seeing as how the NAPA one is plastic, you might want to check that out.

**Ssicarman** · 11-23-2004, 02:53 AM

Welcome to the Board.

Coolant temp sensor is the place to start for the starting problem when you need to press the throttle to the floor to get it going. Do a search of the board for ECT, coolant sensor, PCM coolant sensor and you will come up with a wealth of information.

I suspect that you have a weak fuel pump as well which MAY
(do the coolant sensor first) be contributing to the problem a bit. You should get fuel pressure on the initial pump prime. The 97 MY does have a fuel pump that can loose its prime on extended sitting (overnight). The fuel pressure spec that ou have is out a good bit on the high end. Without actually checking the spec you likley should have 38 to 48 PSI (??)

DavidD · 11-23-2004, 10:23 AM

Thanks guys. We actually did replace the coolant sensor on the engine rebuild. The old one was cracked. The replacement was from Autozone (a wells brand I think?). I will check over the pigtail connecting to it.

I have also been a little suspicious of the fuel pressure. I am not really sure which spec to go by here. The Haynes manual lists a number of them.

Fuel Pressure at idle MPFI 91-97
vacuum hose attached to regulator 31-36 psi
vacuum hose removed from regulator 37-45 psi

Fuel system Pressure decay (max after 5 min)
MPFI 91-97 6 psi

Fuel pump pressure 91-97 46 to 94 psi
Fuel pump pressure decay max 6 psi

I was using that last one to go by there which puts it in the low end. There is NO pressure when you just turn the key on and you here the pump priming, at least not up front. The pressure only goes up when you begin cranking and then only to around 45 psi. It reaches this I would say after about 2-3 seconds of cranking. I haven't been able to get it started again to check the running pressure since I got the gauge.

I though it might be flooding to, which made sense with what Anony00Gt said, but then in my mind if the pressure is low or not quick enough, that seems to contradict itself. Or am I completely off here?

I will check the wiring on the coolant temp sensor and also check the resistance on it as well. My problem with getting Saturn parts is that I have to order them out of Amarillo, TX which is about 150 miles from me. I absolutely refuse to deal with the Lubbock dealership in any way.

**Ssicarman** · 11-24-2004, 03:24 AM

1998 fuel pressure for DOHC engines is 40 to 55 PSI. The 1997 should be the same.

DavidD · 11-24-2004, 03:35 AM

On the fuel pressure, should this be pressured up with just the key on for the couple of seconds or so the pump runs when you turn the key on? Or is it normal that the pressure stay at zero til the cranking begins?

**Ssicarman** · 11-24-2004, 03:43 AM

The system should be pressurized to the normal operating pressure during the 2-3 second prime run. Seeing as yours does not seem to I still suspect a fuel pump losing to much pressure while sitting. How long does it take for the pressure to drop away?
You likely have two problems though if once you have fuel pressure and the engine still does not want to start unless you press the gas pedal down. If you can get pressure by cranking the engine I might try to fix the not wanting to start without touching the gas pedal problem first.

DavidD · 11-24-2004, 04:11 AM

Yeah the pressure doesn't come up on the gauge at all until cranking begins, but it comes up quickly then. As soon as cranking stops it falls off pretty fast though.

I didn't get a chance to look at the temp sensor/pigtail today, we are having some bad weather.

And your right, the only times I have been able to get it to crank whatsoever is when I have it floored and then that is with a LOT of cranking. So much so I actually burned out one starter already.

**Ssicarman** · 11-24-2004, 05:29 AM

May be time to check out the pressure regulator valve. Hard to do with out the right line blockers but see if the pressure holds when the return line is blocked off.

DO NOT PINCH ANY OF THE PLASTIC FUEL LINES.

If the pressure drops when the return line is blocked off the your pressure problem is in the pump end of things.

DavidD · 12-04-2004, 02:31 AM

Well, I ordered a brand new ECTS and the connector pigtail for it from Saturn and it came in today. Weather is finally nice enough, so I am going to get back out there tomorrow and get this in and hope to God this fixes it.

Beyond that, my next thought is to drop the tank and have a look fuel pump, see if that little sock on the intake is messed up etc.

I did crimp the rubber return line with a pair of vise grips when I was cranking it before, the pressure on cranking did not change with or without it crimped. I was trying to see if the pressure regulator was sending the fuel back through the return lines.

At this point, it makes sense to me that fuel is getting in the chambers, we have spark, and the WOT clearout makes sense of why it's nearly starting on WOT. So that leads me to think the ECTS is sending bad signals like you guys say, or the computer is fubar (although I don't know why as it was working fine before the engine spun a bearing).

Any more thoughts from you guys before I get out under the hood again tomorrow and get this ECTS in?