1991 Saturn SL2 Engine will not start

When u replaced the computer did u have it programed?if so try holding the gas pedal all the way to floor while ur cranking it if it starts keep holding the ur foot to the floor see if it clear out some.let me know what u find.

This car did something similar about a year ago and thats when I replaced ignition module and the computer, both from a salvage yard. module did nothing but when I plugged the computer in it fired up and ran for a year. I bought another computer last week used and it has a manufactured sticker on it from Saturn...I plugged it in and still will not run. I never had either one programmed as they are from exact same car, year, tranny, etc.
Last years problem the engine never wanted to "fire" but this time it seems to fire once and then stall. My mechanic friend thinks it could be a ground issue but needs the wiring diagram for the car. Any other thoughts?

i thought u replaced the computer with a brand new one thats why i asked if u reprogramed it.have u checked to see how much fuel pressure it has with a fuel pressure gauge?i also suggested u try holding the gas pedal all the way to floor while ur cranking it if it starts keep holding ur foot to the floor see if it clears out some.did u try that yet?i posted a diagram of where the coolant temp sensor is also its the second one down with two wires going to it.they go bad cause no starts flooding when trying start over heating surging bucking all kinds of stuff.u could try replacing that there only like 10 becareful u will loose coolant if u replace it make sure u get a brass tipped one the plastic tipped ones crack.also check the connector they get corroded and turn green.if its corroded then u will have to replace the connector.let me know what u find.

Thanks for the diagram. I will forward this to my mechanic friend and we will try this asap. I have tried the gas pedal to the floor trick but it would not start. Hopefully we can try this stuff this weekend. Ill keep you posted. Thanks again.

Saturntech9,

Hello. My friend checked the fuel pressure and the temps and everything checked out ok. Any suggestions on what direction to move next? Salvage yard? Ha! Please advise.

Thanks again,
Leroy9

What was the fuel pressure u found when u checked it?what did u find with the bottom coolant temp sensor did u see if it read within 10 degrees on the computer from what the temp was at the bottle that's what spec is?did u replace it?was the connector corroded like green?this is the bottom one with two wires th only one iam concerned about for starting.get a niod light plug it into each injector connector crank it see if the light flashes.check the compression of each cylinder.then check the cam timming.if u need any directions or diagrams on how to do any of this let me know.I need to know what u found in detail when I ask u to do something because Iam not there to see what happened or what results u found.did u try holding ur gas pedal to the floor to see if it started?let me know.

Hi.
The coolant temp is within 2 degrees of the IAT. We tried to start it with pedal to the floor a few different times. Fuel pressure was in the low 40's.
My mechanic seems to think that its an injector pulse issue. Upon first crank when you first hit the key it fires right away and then immediately just goes back to cranking over and not firing.
If its not an injector pulsing issue hes seems to think its ground related. Would you have any diagrams showing the grounds?
Any thoughts on what else it could be? Ill pass your last message onto my mechanic and get back to you.

Thanks for all your help!

if u think its the injector pluse i posted the injector circuit tests tells u how to test the injector pluse circuit just get a gm multi port noid light that will fit the saturns.we can atleast rule out the injector pluse or find that it is the lack of the pluse.let me know what u find.

I did not want you to think that I fell off the planet. My mechanic is super busy and put my car on the back burner since I have another car. He works on friends cars on the side that are not in a hurry.
I was wondering if my current issue has anything relation to me pouring fuel injection cleaner into my gas tank a week before it decided to no longer start? Wasn't sure if the fuel filter could need changed or whatever else?

Thanks

[quote:f4eb0a57e3="leroy9"]I did not want you to think that I fell off the planet. My mechanic is super busy and put my car on the back burner since I have another car. He works on friends cars on the side that are not in a hurry.
I was wondering if my current issue has anything relation to me pouring fuel injection cleaner into my gas tank a week before it decided to no longer start? Wasn't sure if the fuel filter could need changed or whatever else?

Thanks[/quote:f4eb0a57e3]
i dont think its related to ur fuel cleaner.its hard to say if ur fuel filter being clogged though usually when they clog they still run but they run poorly.u should change it every 30,000 miles for maintance.ur coolant temp sensor reading within 2 degrees within ur iat is good for now but not a good way to test it.the best way to test it is when ur car is running letting it warm up and make sure ur computer reads within 10 degrees of ur coolant temp untill the fan comes on.but thats not a opion untill u get it runnung.so u have spark how did u test for it?the best way is to take off two wires off the coil packs right next to each and and have someone crank it over see if it sparks from tower to tower.then put them back on and take the other two off and test those to make sure both coils are working.also have u checked to see if the wires are on correctly?iam posting a spark plug wire diagram dont pay attenion to the firing order that will confuse u.u will see the engine block with the cylinder numbers labeled thats drawn as ur looking at the engine from under the hood.now the little drawing attached to the engine thats ur coils and u can see there labeled 4 1 2 3 thats the cylinder numbers they match up basicially connect the dots from ur coils to ur spark plugs.see if all that is correct.if thats all good then we will have to wait for the noid light test see if they falsh while ur trying to start the vechile and none of them stay on constant or the engine will flood.then ur compression test and checking cam timming.let me know what u find.

Im back from vacation and still at the same situation with the Saturn. Injectors shoot one shot of fuel on first engine crank, fires, spits and sputters, and then just cranks over.
My mechanic tried all of your thoughts and seems to think that we need a ground diagram and a computer wiring diagram. Any idea where I could get that information?

Thanks

[quote:acc1fad0a8="leroy9"]Im back from vacation and still at the same situation with the Saturn. Injectors shoot one shot of fuel on first engine crank, fires, spits and sputters, and then just cranks over.
My mechanic tried all of your thoughts and seems to think that we need a ground diagram and a computer wiring diagram. Any idea where I could get that information?

Thanks[/quote:acc1fad0a8]
Your mechanic is tired of my thought's lol that's fine with me.I emailed you a wire diagram for your pcm to your personal email.Good luck to you and your mechanic.

We are definitely not tired of you thoughts and/or suggestions as we are completely out of ideas on our end as we have tried everything that we could think of as well as your suggestions. We are stumped...He has been a mechanic for about 20 years and usually is a pretty good trouble shooter. I replied to your email with the diagrams. I tired to enlarge them so that they were easier to read but it made matters worse. Is there anything else we can try so I can get the car on the road again? I would have junked it by now but I just dropped a lot of new parts into it and its still in decent shape and has been reliable up until this point.

Larry

If you have spark and your injector pluse's when you try to start it then a bad ground to pcm doesn't make sense.Have you tried to read the code's in the pcm if you can then the ground's good.Give that a try and see if there is any code's if there is give the number's of them to me.Also i asked if you would check the compression if you did what were the reading's for each cylinder?I also asked you to check the cam timming did you if so was every thing lined up correctly?If you spray carb in the throttle body will the engine start and run for a few second's?Let me know.

Louie,

I forwarded your questions from the last email to Dan, my mechanic, and as soon as I get a reply Ill let you know. Cant wait to get that car on the road again.

Thanks for your patience.

Larry

Hello. I wanted to inform you as to what was going on with the 91 Saturn. I purchased Saturn manuals 1991-1994 and my mechanic tested ground wires associated with the ECM and everything checked out alright.
He did however notice the the ECM harness connector ends were corroded/worn so I located a salvage yard that is going to cut them out and send to me. We are hoping this corrects the problem.

We have everything component the car needs to run except the injectors are not spraying gas.

Thanks,

Larry

The corroded ecm connector make's sense for the no start make sure the ecm connectors on the computer aren't corroded as well.If the connector replacement doesn't work let me know and we will go from there.

I soldered the newer ECM wire by wire to ensure I matched up each wire correctly and plugged in each of the three ECM's I purchased and no go. 90 minutes of soldering in an awkward position with no reward. The engine did fire a few times for about 3 seconds and then quit. I could smell gas after it cranked a little while and I could hear the sending unit/fuel pump turn on when I turned the key.
My starter is now acting up I assume from the stress it has been put under from excessive no starts. My mechanic is going back to the flow charts in the manual on Saturday. We are completely out of options and I have about $500 invested so I hate to quit now.
Any other suggestions?

Thanks for everything thus far.

Larry

What year and model car ecm's were you using?Also do you have injector pulse now sound's like you do if you smell gas.

My car is a 1991 SL2 1.9 DOHC Auto and the two ECMs I purchased were supposed to be out of the same year 1991 and have DOHC and auto transmission. Is there a possibility that I was sold the wrong ECM? The 2nd ECM worked for about a year after plugging it in and turning the key.
I have injector pulse upon hitting the key at first but after a second it stops and the engine just cranks. We plan to trouble shoot more on Saturday and fix the starter as well. I feel obligated to fix the car at the point in the game.
I guess what this boils down to is...what would cause the injectors to not pulse. My friend said that if we had fuel, the car would run.

Thanks for all your help!
Larry

So the two pcm's your saying you just didn't change your confusing me now.So the one in there now has been in there for a year now?if that is the case then i would say it's the right one.What pulse's the injector's is the pcm it pulse's the ground to the injector.It shpuld pulse more then once.If you prime the car with carb spray will it run for a few second's?

The original PCM went bad a few years ago and from I can tell it was the original. I replaced it with PCM #2 in April of 2009 and I bought it from a salvage yard it was supposed to be from the same year and DOHC 1.9 auto.
PCM #2 I plugged it in and the car fired up and ran fine for a year. April 2010 the car just quit running while driving down the road. It quit a few different times of the course of a few weeks. I would let it sit for a day of so and then it would sometimes start. The last time it quit it has never started again.

I purchased PCM #3 from a salvage yard as well and hoped that it would just plug in and fire up like last time. The car has not ran since PCM #2 quit.
I still have all three PCM's and have tried all three but the car will not run.

I will have Dan prime the car to see if it will indeed run.

Larry

Let me know if it start's then we will know if it's lack of fuel.Also find out what your fuel pressure is and check for spark.

Hello,

Well Dan somehow rigged up an external fuel supply to and the car ran. While it was running he checked most of the vitals and everything checked out as if it would while running. If he took the fuel away and tried to let it fuel itself, if would not run. The fuel pressure was around 40 psi. There is an issue with the injectors and Dan wanted me to email you to see if you had any suggestions. He was maybe going to take a look at the injectors to see what was going on there.

Thanks

So did he run a pressure canister with gasoline instead of using the fuel pump?If so and it ran good then you have a problem with your fuel pump supply and not your injector's.

Dan had gas in plastic bottle and the gas was sucked through PCV hose. The injectors were not spraying any fuel and we have 40 psi fuel pressure at the rail. The car will run great if given fuel but when you remove the secondary fuel supply and try to run on its own, it will not start.
We did not have pressurized fuel, we let it draw in though the PCV hose instead of through the fuel rail.

Dan seems to think that for some reason the injectors are not pulsing so what do you think the problem is?

Thanks

I wouldn't add fuel thru the pcv hose if you have 40 psi at the rail i would check check and see if with the key in the run position engine off if you have power to all the pink and black wire's to the injector's.Then with the car cranking if you have a flashing ground to the dark blue wire's to the injector's..Use a bulb test light to check this like i told you.

I have power at the pink and black wires at the injectors, power on both sides of the connectors (to the injectors). I do not have flash at the dark blue wires while its cranking.

When you unplug the connectors at the injectors the pink/black have power and the blue wire has power. While cranking the dark blue wires are constant power and not pulsing. Should that wires be pulsing a ground signal to control the injector?

The computer or whatever is not working is not controlling the ground side of the injector.

What are the odds that I would have three faulty PCM's currently. Could it be possible and how can I test to see if that is the case? Should I consider buying another PCM to see if it would start?

We plugged a scan tool in and I think the only code that came up was 44 or 45 lean fuel mixture code.

Thanks

There's your problem the dark blue wire's shouldn't have power it should be the ground control from the pcm.Here's what i would do unplug all the pcm connector's and see if you still have power to the dark blue wire's to the injector's.If you lose the power then plug the connector's back into the pcm and see if the power come's back.Let me know what you find.

I was talking to a Saturn salvage yard and asked about my problem and they mentioned that it could be a fuse issue. I am in the process of checking all of the fuses in the entire car and also disconnecting the aftermarket car stereo. They said that sometimes aftermarket audio is to much for Saturn's causing circuit overload. Does that make sense to you?

That doesn't make sense because it would blow the fuse from what i have seen if the radio over loaded something.Also the radio is hooked into the body harness and the injector's are part of the engine harness.The radio goes thru the inside fuse box and the injector's goes thru the under hood fuse box.Try this check the dark blue wire's and make sure they still have power with the key on.Then unplug the injector fuse and see if the power goes away to the dark blue wire's.

I am going to work on it tomorrow and will test the blue wire for power with and without the fuse. If I still have power in the dark blue wire, what is my problem? Bad PCM? If the power goes away what would be my next move?

Thanks

If you still have power with the fuse out i would unplug the computer and see if the power goes away.If the power goes away without the fuse i would see where the power wire to the injector is shorting into the ground wire from the computer.