ECU, fuel, or something else problem... Please help!
02-27-2007, 08:20 AM
#1
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ECU, fuel, or something else problem... Please help!
Ok, had the car running fine all this time, was very low on gas last night, left it in the garage, in the evening filled it up a little.
Today in the morning, started my 98SE 5spd., both fans turned on as if the engine was hot, Check Engine light came on and the idle was jumping up and down between 900-600. When I give it gas, it looks like it take a second to think about it, then jerks off and speeds up.
When I floor it, it revs to 3000 on the dot, no more, then falls to about 2500 and up and down. It stalled on me on the road when I took it for a drive, then had a hard time starting. Seems now it starts fine, but still won't go beyond 3000rpm.
I checked all fuses, temp sensor... filled it up with best gas and gas cleaner... still doing it, can not rev passed 3000.
Tried to diagnose the issue, no ECU codes come up, and can't communicate with the ECU itself....
Any suggestions would be helpful before I take it to a dealer.
Thanks to all
Today in the morning, started my 98SE 5spd., both fans turned on as if the engine was hot, Check Engine light came on and the idle was jumping up and down between 900-600. When I give it gas, it looks like it take a second to think about it, then jerks off and speeds up.
When I floor it, it revs to 3000 on the dot, no more, then falls to about 2500 and up and down. It stalled on me on the road when I took it for a drive, then had a hard time starting. Seems now it starts fine, but still won't go beyond 3000rpm.
I checked all fuses, temp sensor... filled it up with best gas and gas cleaner... still doing it, can not rev passed 3000.
Tried to diagnose the issue, no ECU codes come up, and can't communicate with the ECU itself....
Any suggestions would be helpful before I take it to a dealer.
Thanks to all
02-27-2007, 09:11 AM
#2
Check engine light and no codes? Cant communicate directly? no OBDII port? the rev stopping at 3000 could be a few things including the car being in safety mode (the usual cause slips my mind right now). Did you try the screw method to get the codes? Does Canadian Tire charge to scan?
02-27-2007, 09:16 AM
#3
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hooked up a module to OBDII port, said it couldn't communicate with car.
what's a safety mode? didn't know there is one on the car.
Yeah tried the manual screw method, didn't work... nothing came up, just stayed lit as was. I'm gonna try again, maybe I did it wrong.
Would a car keep running with a faulty or not working ECU?
what's a safety mode? didn't know there is one on the car.
Yeah tried the manual screw method, didn't work... nothing came up, just stayed lit as was. I'm gonna try again, maybe I did it wrong.
Would a car keep running with a faulty or not working ECU?
02-27-2007, 09:22 AM
#4
Yeah there is a safety mode. I was reading one section of the FSM and I came across it. Cant remember what part though It could still run depending on how bad the ECU is, and based on what you have described, that sounds like it is the problem. Unfortunately I dont think there is any way to be sure short of taking it out and getting it tested or replacing it with a borrowed one. I could be wrong.
02-27-2007, 09:33 AM
#5
Just looked it up again. It is caled "Fail-Safe Mode". It has to do with a malfunctioning MAF Sensor. I doubt highly that this is your problem though since you are experiencing a bunch of other problems with it. The fans and no communication makes me think the ECU is the problem. First thing you should try is removing and resecuring the harness.
02-27-2007, 11:40 AM
#6
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well, found the problem after getting someone at Nissan to analyzie it for me.
the ECU is fried, how, no idea. All the wiring is good, the ECU itself is gone.
So, now I'm faced with a task of finding an ECU, dealer said it may be up to $1000 from them. Is the 5spd and auto ECU same, assuming all specs are identical?
the ECU is fried, how, no idea. All the wiring is good, the ECU itself is gone.
So, now I'm faced with a task of finding an ECU, dealer said it may be up to $1000 from them. Is the 5spd and auto ECU same, assuming all specs are identical?
02-27-2007, 02:34 PM
#9
I have a friend parting out an I30. I will see if he can get out the ECU. only problem I can think of with using an auto ECU is getting tranny codes. Hopefully that is all done through the tranny computer only.
02-27-2007, 04:16 PM
#11
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I call 
on the fried ECU. That just doesn't happen.
Check the ECTS again, if it's within spec (table in Haynes manual) then I'd look v-e-r-y closely at the MAF sensor. Make sure your looking at the correct coolant temp sensor, there are two of them.
The symptom of not going over 3000 RPMs is directly in relation to a failing MAF sensor.
Do you have auto climate control? If it's above freezing and your set to AUTO, the compressor will be running and so will your cooling fans.
on the fried ECU. That just doesn't happen.Check the ECTS again, if it's within spec (table in Haynes manual) then I'd look v-e-r-y closely at the MAF sensor. Make sure your looking at the correct coolant temp sensor, there are two of them.
The symptom of not going over 3000 RPMs is directly in relation to a failing MAF sensor.
Do you have auto climate control? If it's above freezing and your set to AUTO, the compressor will be running and so will your cooling fans.
02-27-2007, 04:30 PM
#12
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on some other thread I posted, there was a trable someone posted there with the symptoms for "safe mode running" and they are 100% in line with what I have, due to a malfunctioning or failed ECU.
I don't have the ECU cover, and it's snowing as hell in Toronto last few days, maybe water got into it from my boots somehow, very well could have.
I don't have the ECU cover, and it's snowing as hell in Toronto last few days, maybe water got into it from my boots somehow, very well could have.
02-27-2007, 09:53 PM
#13
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Join Date: Dec 2006
Posts: 20
check for plugged fuel filter
Originally Posted by Riot^
Ok, had the car running fine all this time, was very low on gas last night, left it in the garage, in the evening filled it up a little.
Today in the morning, started my 98SE 5spd., both fans turned on as if the engine was hot, Check Engine light came on and the idle was jumping up and down between 900-600. When I give it gas, it looks like it take a second to think about it, then jerks off and speeds up.
When I floor it, it revs to 3000 on the dot, no more, then falls to about 2500 and up and down. It stalled on me on the road when I took it for a drive, then had a hard time starting. Seems now it starts fine, but still won't go beyond 3000rpm.
I checked all fuses, temp sensor... filled it up with best gas and gas cleaner... still doing it, can not rev passed 3000.
Tried to diagnose the issue, no ECU codes come up, and can't communicate with the ECU itself....
Any suggestions would be helpful before I take it to a dealer.
Thanks to all
Today in the morning, started my 98SE 5spd., both fans turned on as if the engine was hot, Check Engine light came on and the idle was jumping up and down between 900-600. When I give it gas, it looks like it take a second to think about it, then jerks off and speeds up.
When I floor it, it revs to 3000 on the dot, no more, then falls to about 2500 and up and down. It stalled on me on the road when I took it for a drive, then had a hard time starting. Seems now it starts fine, but still won't go beyond 3000rpm.
I checked all fuses, temp sensor... filled it up with best gas and gas cleaner... still doing it, can not rev passed 3000.
Tried to diagnose the issue, no ECU codes come up, and can't communicate with the ECU itself....
Any suggestions would be helpful before I take it to a dealer.
Thanks to all
02-28-2007, 03:56 AM
#15
Originally Posted by fanaticrockford
It's probably the coolant temp sensor. Just change the part it's under $20 at any parts store.
02-28-2007, 05:39 AM
#16
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plugged fuel filter would still read the ECU.
When module was attached to the ECU, it was unreadable, but all the connectors and harnesses to ECU were good when tested.
What are some good aftermarket ECUs I can look into?
When module was attached to the ECU, it was unreadable, but all the connectors and harnesses to ECU were good when tested.
What are some good aftermarket ECUs I can look into?
02-28-2007, 12:10 PM
#18
Originally Posted by 2da mizzax
Now how would the ECTS cause the ECM to be unreadable? ECTS is nto the anwer to everything.
Or
What would make the ecu fry from being parked over night?
He parked the car and it was fine the next time he started it there was a problem.
The ects makes a lot more sense. The cold from sitting overnight killed it. The ecu is in safe mode not allowing the car to rev becasue it thinks the car is overheating and thats why the fans are turning on right away.
Also has the coolant level been checked?
02-28-2007, 12:38 PM
#20
Originally Posted by 2da mizzax
An unreadable ECU IS a problem!
What i would do is replace the ects and make sure the coolant is full. Then check to see if it would rev and check for codes or to see if it's readable. If it's not then unhook the battery to reset the ecu then check to see if it's readable yet.
02-28-2007, 12:38 PM
#21
Originally Posted by njmaxseltd
I call on the fried ECU. That just doesn't happen.
Check the ECTS again, if it's within spec (table in Haynes manual) then I'd look v-e-r-y closely at the MAF sensor. Make sure your looking at the correct coolant temp sensor, there are two of them.
The symptom of not going over 3000 RPMs is directly in relation to a failing MAF sensor.
Do you have auto climate control? If it's above freezing and your set to AUTO, the compressor will be running and so will your cooling fans.
on the fried ECU. That just doesn't happen.Check the ECTS again, if it's within spec (table in Haynes manual) then I'd look v-e-r-y closely at the MAF sensor. Make sure your looking at the correct coolant temp sensor, there are two of them.
The symptom of not going over 3000 RPMs is directly in relation to a failing MAF sensor.
Do you have auto climate control? If it's above freezing and your set to AUTO, the compressor will be running and so will your cooling fans.
Secondly, I'll post this again like i did in his other thread.
According to this the IACV is controlled under certain limitations. That would explain the screwy idle bouncing up and down.
BTW, this also happened to meximax. It's not common, but it's possible. Hence this entry in the fail-safe chart.
Not to mention not being able to communicate with the ECU manually or VIA the Consult II. The ECU is dead.
02-28-2007, 02:23 PM
#22
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Thanks to all for posting.
the wiring is good, it was checked and seems to be working.
What I'm gonna do is unhook the ECU, see maybe somehow the connection is lose, if that fails, I think I'm going to try to hook up a 97 ECU on a 98, same models cars. Don't see how it may be a huge problem.
the wiring is good, it was checked and seems to be working.
What I'm gonna do is unhook the ECU, see maybe somehow the connection is lose, if that fails, I think I'm going to try to hook up a 97 ECU on a 98, same models cars. Don't see how it may be a huge problem.
02-28-2007, 08:52 PM
#24
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that ECU is a pain in the A$$ to take out.
Never got to it, screws way too far down there, couldn't reach them.
Unhooked the cables, unhooked the battery, reattached, still dead...
I think I'm going for the 97ECU on my 98.
Never got to it, screws way too far down there, couldn't reach them.
Unhooked the cables, unhooked the battery, reattached, still dead...
I think I'm going for the 97ECU on my 98.
02-28-2007, 09:13 PM
#25
Originally Posted by Riot^
that ECU is a pain in the A$$ to take out.
Never got to it, screws way too far down there, couldn't reach them.
Unhooked the cables, unhooked the battery, reattached, still dead...
I think I'm going for the 97ECU on my 98.
Never got to it, screws way too far down there, couldn't reach them.
Unhooked the cables, unhooked the battery, reattached, still dead...
I think I'm going for the 97ECU on my 98.
Also i forgot how long the battery had to be disconected to reset the ecu. Anybody else know?
03-01-2007, 03:56 AM
#29
Hey if you need an ecu, i actually happen to have a 98 auto ecu that is laying around it's a US model so don't know if that will throw a check engine light for you or not. If interested let me know.
edit oops just saw you have a 5 speed so it won't matter, no nevermind!
edit oops just saw you have a 5 speed so it won't matter, no nevermind!
03-01-2007, 07:04 AM
#30
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A sensor on the car that is sent reference voltage is shorted to ground affecting the ECU globally.
This is why it is running on a limp algorithm and why you cannot communicate with the ecu.
Eventually the power circuit will give up trying to push more current than it was designed for.
This is why it is running on a limp algorithm and why you cannot communicate with the ecu.
Eventually the power circuit will give up trying to push more current than it was designed for.
03-01-2007, 09:27 AM
#31
Originally Posted by HowlerMonkey
A sensor on the car that is sent reference voltage is shorted to ground affecting the ECU globally.
03-01-2007, 08:37 PM
#33
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Originally Posted by HowlerMonkey
A sensor on the car that is sent reference voltage is shorted to ground affecting the ECU globally.
This is why it is running on a limp algorithm and why you cannot communicate with the ecu.
Eventually the power circuit will give up trying to push more current than it was designed for.
This is why it is running on a limp algorithm and why you cannot communicate with the ecu.
Eventually the power circuit will give up trying to push more current than it was designed for.
so you think it's not the ECU that's fried?
what's your suggestion?
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