Resolved 1G Losing power, rough idle, hard starting. AGAIN 😞

[Gracer]

One week ago we fixed my hard starting issue by replacing the fuel pump and the wiring.
Now in the last couple of days it's been hard starting again. I'm getting adequate fuel pressure. I replaced the coolant temp sensor as well.

Then earlier tonight at work the car took several attempts to start and when it did crank over it idled really rough like a misfire until it warmed up all the way to temperature. Hours later when driving home from work right before I pulled into the garage the car started to surge and act funny and it seemed as if any accessories I turned on would make the car stumble and dim the lights. I turned the car off and check the battery voltage right away and it was only 11.80 volts. A couple minutes later I checked and we were up to 12 volts and slowly rising.

It's late at night and I have my newborn coming over in the morning but I'm suspecting that it must be the alternator. However this is a DSM and I know you guys might know some things I don't know about these cars. Would a failing alternator cause all of these symptoms?

First it was hard starting again. Then it was rough idle until warm. And now it's losing power when turning on accessories such as radio and fans and bright lights all seem to affect the car even when driving. I made one more attempt to turn the car over after I stopped and it started but it sounded like a weak battery of course because it barely had but 12.00 volts going to it.

Should I pull the alternator off and have it tested at a nearby auto store? If it checks out good, what other possible things could it be?

 

[We're on Boost]

It does sound like a bad alternator.

 

[CrackedDSM]

Bad alternator or bad Alt wiring. If it runs low enough on voltage it will run like an asthmatic porcupine missing a leg or two. Too low and it won’t run at all.


With the engine running voltage should be at least in the 13’s. Caressing 14’s gently and lovingly.

 

[Gracer]

It does sound like a bad alternator.

Bad alternator or bad Alt wiring. If it runs low enough on voltage it will run like an asthmatic porcupine missing a leg or two. Too low and it won’t run at all.

With the engine running voltage should be at least in the 13’s. Caressing 14’s gently and lovingly.

All right thanks again for that info! I'll go test it tomorrow. If it's bad I'll see if I have an extra one laying around, I don't think I do.

I just realized my 1G doesn't have a voltage meter gauge in the car like my Stealth did, which was nice, because I saw the voltage dropping when the alternator was crapping out. So I should get at least a 90 AMP yeah? The car is wired up for an aftermarket audio system I once had in there. Will the 90 amp alternator be enough?

Damn these cars really are a money pit huh at least there's no monthly payment

 

[Gracer]

Just replaced fuel filter. Fuel pump/wiring, CTS, alternator.

So my car just made it home from work late Friday night and was having symptoms of a failing alternator.

Car wouldn't start... battery(s) are good and holding 12.5-12.7 volts. After 4-5 starting attempts the battery would drain down below 12V and tire out.

Had alternator(s) tested at two different auto parts stores and both were bad.

Replaced with NEW 90 amp alternator and same NO START!

getting fuel pressure to rail immediately when turning key.

Car felt like it had a stumble/misfire shortly before the alternator went.

Could it be an ignition issue now?

Pretty sure my plugs are good as I just checked them a week ago and made sure they're gapped to .028.

Coil pack? , wires, ECU, PTU IDFK anymore but I'm going to go test the coil pack and I think I have a spare...

Compression was checked and good.

Any other ideas please chime in and help!!!

 

[CrackedDSM]

Pull the ECU and check the ISC driver. It's the little block looking things next to the capacitors on the board. They're either green or black, can't remember.

Easiest way to test if you have spark is just pull a plug wire and ground it on something while you crank it.


My gut is telling me either the ISC driver in the ECU took it out, or something like a bad PTU/wiring again. Also, check all of your fuses including the big ones in the fuse panel in the engine bay and on the battery terminal itself. Probably something stupid like too much current from a dying alt that popped a fuse.

 

[Gracer]

Pull the ECU and check the ISC driver. It's the little block looking things next to the capacitors on the board. They're either green or black, can't remember.

Easiest way to test if you have spark is just pull a plug wire and ground it on something while you crank it.


My gut is telling me either the ISC driver in the ECU took it out, or something like a bad PTU/wiring again. Also, check all of your fuses including the big ones in the fuse panel in the engine bay and on the battery terminal itself. Probably something stupid like too much current from a dying alt that popped a fuse.

Ok
I just check for spark and I only saw one of them igniting. I just pulled one boot at a time and turned the key in the dark garage. I layed the open end down near the valve cover.
So I swapped out the coil pack and still no start.
I did check all the fuses under the hood including the three off the positive battery post. All fuses good.

I'll pull the ECU tomorrow and check
Also. Is the PTU right there by the coil pack?

 

[CrackedDSM]

Ok
I just check for spark and I only saw one of them igniting. I just pulled one boot at a time and turned the key in the dark garage. I layed the open end down near the valve cover.
So I swapped out the coil pack and still no start.
I did check all the fuses under the hood including the three off the positive battery post. All fuses good.

I'll pull the ECU tomorrow and check
Also. Is the PTU right there by the coil pack?

Yep. PTU is a square looking thing, if it's in the OEM spot it should be mounted right nearby the coilpack. Weird how only one plug is firing.

 

[Gracer]

Yep. PTU is a square looking thing, if it's in the OEM spot it should be mounted right nearby the coilpack. Weird how only one plug is firing.

Yeah I thought that was weird too....
Maybe I can do a better check by putting a plug in the end of it.

Also, I was trying to read resistance on the coils and I was getting 001 ohm ?
I suck at the electronics aspect

 

[CrackedDSM]

It's worth an ask as to how old the wires are. I wonder if you moved the one wire that's sparking to another cylinder, does the spark follow it, or does it disappear?

Definitely worth testing with a plug in the end of the wire. Also: I've seen people test PTUs and they pass, but still are the problem.

 

[Gracer]

It's worth an ask as to how old the wires are. I wonder if you moved the one wire that's sparking to another cylinder, does the spark follow it, or does it disappear?

Definitely worth testing with a plug in the end of the wire. Also: I've seen people test PTUs and they pass, but still are the problem.

My plug wires are about 10 to 12 years old but I only have maybe 1,500 miles on them.
The car sat for like a decade for the most part.
I have had it up and running for 6 months until the last two weeks I've had all these issues.
I have NGK 7 mm blue plugs and ngk6 plugs.

 

[DSMPT]

Replaced with NEW 90 amp alternator and same NO START!

The alternator itself wouldn't directly be a cause of no-start issue as long as if the battery is healthy and charged.

getting fuel pressure to rail immediately when turning key.

How did you know about that? Did you check it with a pressure gauge? You won't see the fuel pressure until you start cranking.
Some people sometimes say "Confirmed, it has fuel" by just seeing some fuel in the fuel rail, but it doesn't guaranty that the fuel pressure is sufficient to start the engine.

Car felt like it had a stumble/misfire shortly before the alternator went.

Could it be an ignition issue now?

Could be several things. Could be ignition, could be valve timing, could be fuel related or some sensor started to fail etc.

The engine should fire up if it has fuel, spark in the right timing and compression. You need to make sure about those things one by one to narrow down the issue.
I remember that in your previous no-start thread, you could re-started the engine by playing fuel pump wiring or so. So if I were you, I would suspect some fuel related issue first and would start from there.

 

[dwb]

DSMs cook alternators for breakfast and eat them for lunch. But always good to double check your belt, fuses, wiring, grounds, and battery terminals first. Sure, get it tested, but almost guaranteed to fail (unless the problem lies with the car).
I personally run a "lifetime" reman 90a alternator. Some stores will show only the 65 or 75 amp versions. Ask for an early 90's Galant VR4 alternator in this case to receive the 90amp. I also prefer to deal with local stores when it comes to lifetime warranties. That way when it inevitably dies again, you aren't on the hook for shipping.

 

[Gracer]

I have a fuel pressure gauge on my AFPR and when I turn the key it instantly jumps to 45psi and then down just a little bit after cranking. That wasn't happening before I replaced the Wally pump and wiring I wasn't getting fuel pressure so I think I've fixed that issue at least.

 

[Gracer]

What about a crank position sensor? The one way down by the crank. I'll have to check codes again.

 

[Gracer]

I personally run a "lifetime" reman 90a alternator. Some stores will show only the 65 or 75 amp versions. Ask for an early 90's Galant VR4 alternator in this case to receive the 90amp.

Yeah that's what I did I went and got a remanufactured 90 amp alternator from a Galant. It's in the car now

 

[DSMPT]

I have a fuel pressure gauge on my AFPR and when I turn the key it instantly jumps to 45psi and then down just a little bit after cranking.

What do you mean by "turn the key it"? If you meant that you get the fuel pressure to 45 psi when you start cranking, then yes you have the fuel pressure. But if you meant that you get the fuel pressure when turning the key to ON position without cranking, then you most likely have some problem in the circuit.

What about a crank position sensor? The one way down by the crank. I'll have to check codes again.

If your car is 1g, you don't have the crank angle sensor on the front case by the crankshaft unless you modified.

You should upload pics and videos as much as you can. That would help us a lot to see the situation better.

 

[Gracer]

What do you mean by "turn the key it"? If you meant that you get the fuel pressure to 45 psi when you start cranking, then yes you have the fuel pressure. But if you meant that you get the fuel pressure when turning the key to ON position without cranking, then you most likely have some problem in the circuit.


If your car is 1g, you don't have the crank angle sensor on the front case by the crankshaft unless you modified.

You should upload pics and videos as much as you can. That would help us a lot to see the situation better.

Yeah it's a 1GB and I do have the CAS on top. I was thinking there was a separate crank sensor down below but yeah you're right not on mine. I meant I see fuel pressure when cranking and then hear the fuel pump

 

[CrackedDSM]

How’d it do swapping wires to a different coil?

 

[Gracer]

How’d it do swapping wires to a different coil?

I took a day off from the car.
I'll check tonight when I get home.
I'll make sure battery is good and charged and test each plug wire individually and try them on both coil packs. Also, I still have to pull the ECU/ECM... the (computer)
I'm going to be pissed at myself if it's just a wiring issue

 

[Gracer]

Pull the ECU and check the ISC driver. It's the little block looking things next to the capacitors on the board. They're either green or black, can't remember.

Easiest way to test if you have spark is just pull a plug wire and ground it on something while you crank it.


My gut is telling me either the ISC driver in the ECU took it out, or something like a bad PTU/wiring again. Also, check all of your fuses including the big ones in the fuse panel in the engine bay and on the battery terminal itself. Probably something stupid like too much current from a dying alt that popped a fuse.

Ok I'm coming back to you CrackedDSM
I have now checked plugs = good at o.28
Plug wires = #1 - 3.65 K OHMS
#2 - 4.98 k ohms
#3 - 6.17 k ohms
#4 - 5.63 k ohms
ECU = good nothing leaking and CEL turns off
Coil packs = IDK... one pack measured .001 .001 & .001 k ohms. the back up pack reads .000 .000 .000 k ohms I'm assuming the .001 pack is probably better? The Haynes says it should read very low resistance but doesn't really specify.
Voltage at battery 12.25V (been sitting out in the cold, 1 yrs old batt.) / 13.5V with bat. charge
Voltage at Alternator is also 13.5V
Voltage at fuel pump relay 13.21V
TPS = .739 K OHMS
CTS = forgot to check....
PTU = 47.2 k ohms cylinders 1/4
47.2 k ohms cylinders 2/3
* resistance goes to zero when voltage applied using 1.5V battery per Haynes manual *
If I did the test right it seems as if the PTU is junk?!?
Also, appears that my replacement engine is a 91 judging by the PTU. I just know I bought a used 6 bolt block/head for my 92. My ECU is out of a 91 GS-t if I recall....

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[Gracer]

It was the alternator the entire time as first suspected by me and several others.
So f*** O'Reilly's remanufactured junk alternators!!!!!
I ended up putting a DSM 75 amp alt. on that they said tested bad and now the car is up and running again. I traded in my 90 amp DSM alternator I had in the car because it most definitely had crapped out as these issues began. With their alternator my car barely turned over and the battery voltage was 11.8V and so I suspected it must be another bad alternator and sure enough my old 75amp one is holding steady at 14.6V

 

[CrackedDSM]

It was the alternator the entire time as first suspected by me and several others.
So f*** O'Reilly's remanufactured junk alternators!!!!!
I ended up putting a DSM 75 amp alt. on that they said tested bad and now the car is up and running again. I traded in my 90 amp DSM alternator I had in the car because it most definitely had crapped out as these issues began. With their alternator my car barely turned over and the battery voltage was 11.8V and so I suspected it must be another bad alternator and sure enough my old 75amp one is holding steady at 14.6V

Damn. For what it's worth my rockauto 90amp alternator does great holding voltage and hasn't crapped out yet.

 

[Gracer]

Damn. For what it's worth my rockauto 90amp alternator does great holding voltage and hasn't crapped out yet.

Good to know. I was going to get one from Rock Auto, but I didn't want to wait a few days for shipping. I should have waited. I'm going to get me a 90amp from RA. What was the brand name Cracked, do you recall? most I saw on there were 65amp and 75amp. I'll have to look again.

 

[CrackedDSM]

Good to know. I was going to get one from Rock Auto, but I didn't want to wait a few days for shipping. I should have waited. I'm going to get me a 90amp from RA. What was the brand name Cracked, do you recall? most I saw on there were 65amp and 75amp. I'll have to look again.

Yep! It was the BBB industries. https://www.rockauto.com/en/moreinfo.php?pk=1295621&cc=1103072&pt=2412&jsn=17

The one I got was a closeout for like $110 after shipping with no core required. It's a little more expensive now. Still, works great for me!


Edit: Their reman alternator has a mitsubishi symbol on the back, but so does the "new" one they offer. Mine didn't come stamped with a mitsu logo so don't bank on that.