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Discussion Starter #1
Hi new here and I have a problem.

I did a search but turned up no help so I was hopping someone could help me solve this problem. To keep this short here is what I know for sure right now, the problem is that the computer will not send a grounding signal to the fuel pump relay or the main relay located in the same box. I am familiar with how most EFI pump systems work and I have quite a bit of mechanical experience but this has me stumped. I can (using a jumper) ground the wire coming from the computer (with the computer disconnected) at the fuel pump signal location on the computer connector and the fuel pump will run just fine. I know the circuit is good from the computer out to the relays and from the relays back to the pump and I have checked every ground location I can find but still no luck. I tried replacing the computer with a known good one but still the same problem, it scans OK and shows no trouble codes. There is no signal ever, not at first when turning the key on or while cranking- any ideas about this?


BTW I also checked the timing belt.
 

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that is a good method. there are two of them that go bad on 1g sportages it is the main relay and the fuel pump relay. i think one is yellow and the other is right next to it. some times it helps just by switching the two aroung and if that fixes it just replace them they usually go out together but i may not be the case for you and also the computer is not case sensitive so his test would work. alot of kia diagnostics include testing with a known good computer
 

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Tex

OK -- thanks for the correction... sorry about that, I was just going by my experience with Ford PCM's.

I'm not too swift when it comes to the electrical stuff, but I was just wondering if Kia's have those "fuel cutoff/shutoff switches" -- they're like little circuit breakers that pop out during harsh impacts... I had one pop out when I hit a really bad pot hole one time.

Harry
 

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Discussion Starter #5
Fellows thanks for the replies

The relays are not the problem because if I manually ground them by using a jumper from ground to the proper socket in the computer connector (in effect doing what the computer is supposed to be doing) then the pump will run just fine. Also when I hook a DVOM to the signal wire at the relay and turn the key on there is no ground signal so I know the problem is that the computer does not send the signal to the relay but I still for the life of me can not figure out why not. The fuel cutoff or inertia switch was a thought but I can not find one on this thing nor is there any mention of it in the owners manual. Most systems have this switch but it is located after the computer signal and thus would not cause this problem HOWEVER I can see where it could be set up that way if this switch does indeed exist so possibly that could be the problem? Any idea where/if this switch would be?


BTW it's a 2001, can't believe I forgot to mention that in my first post.
 

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i would just follow the ground wire from the pump to the computer. right now im not sure of a cut off switch,im leaning more towards a short or bad connection somewere
 

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99 Kia Elan 1.8L
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i would just follow the ground wire from the pump to the computer. right now im not sure of a cut off switch,im leaning more towards a short or bad connection somewere
The ground from the pump doesn't go to the ECU (computer).

Fellows thanks for the replies

The relays are not the problem because if I manually ground them by using a jumper from ground to the proper socket in the computer connector (in effect doing what the computer is supposed to be doing) then the pump will run just fine. Also when I hook a DVOM to the signal wire at the relay and turn the key on there is no ground signal so I know the problem is that the computer does not send the signal to the relay but I still for the life of me can not figure out why not. The fuel cutoff or inertia switch was a thought but I can not find one on this thing nor is there any mention of it in the owners manual. Most systems have this switch but it is located after the computer signal and thus would not cause this problem HOWEVER I can see where it could be set up that way if this switch does indeed exist so possibly that could be the problem? Any idea where/if this switch would be?


BTW it's a 2001, can't believe I forgot to mention that in my first post.
You're on the right track - the EGI and FP relay coils need to be energised (grounded) by the ECU to get the FP to run - maybe one of the Sportage owners can identify if and where the 'collision fuel shut-off switch' is located, but in the meantime why not take a look in the 'Shop' and 'ETM' section on the KiaTech web site.
 

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If the main relay isn't working right, it can cause this too. Mine was only sending about 6 volts most of the time to the circuits it controls, instead of 12 volts. I could turn the fuel pump on with the DTC, but it still wouldn't start until I replaced the main relay.
 

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Discussion Starter #9
I am about at wits end on this thing, I have replaced the ECM with no improvement in my problem and no trouble codes are coming up. I have back probed all the wires to the ECM and nothing appears to be shorted and the ECM appears to be working except for not sending the fuel pump relay signal. I can isolate the signal wire from the ECM to the fuel pump relay and then manually ground the relay with a jumper to ground and the pump will run just fine, in effect I am doing what the ECM is supposed to do to make the pump run. In this condition the engine will start but it will not idle and shakes violently below about 1500 RPM or so. I have thoroughly checked the TPS, the ignition coils, the MAF sensor is clean and checks OK and the plugs are not fouled. The problem is that as bad as this thing is running the computer gives a clean scan result and says that all is well! Without any trouble codes there is not much to go on except guess work and unfortunately the online shop manual at the KIA web site is so sketchy it is of next to no help. What I would REALLY like to find is a check procedure for the MAF and cam position sensor, what I need is the resistance values for a pin check on these items while disconnected and a test procedure with them connected and in a key on condition. Without the codes there is nothing to do but test each component individually but every text I find requires the specific trouble code (in this case non-existent) in order to establish a test procedure.
 

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99 Kia Elan 1.8L
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You sure have a tricky one there.

The ECU should power up the pump immediatly the Ignition switch is turned on, and hold power to the pump for about 30~60 seconds and if in that time the ECU does not get pulses confirming rotation of the engine the power from the fuel pump will be cut - if engine rotation is sensed then the pump will be kept on.
If this initial pump priming cycle does not work, then it's unlikely to work when cranking the engine.

Just to make 100% sure that it's not a wire problem, why not connect a test lamp to a good B+ and the other end to the ECU fuel pump connection.

As I say, this is a tricky one, seing that you've done everything expcted for this problem.
 

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Simple IAC and MAF tests

Radkins

With engine off and key out -- IAC OHMmeter test:

FYI: use a decent VOM... my $20 one gave bad results, while my $75 one gave good results

http://www.kia-forums.com/attachmen...-hope-doesnt-turn-out-bad-iac-valve-1-jpg.jpg

http://www.kia-forums.com/attachmen...-hope-doesnt-turn-out-bad-iac-valve-2-jpg.jpg

The MAF is a pretty simple device in that pin #4 (closest to the driver's side fender as I recall) will vary its output voltage according to the speed of the engine and the air flowing through the breather tube... so just stick a voltmeter btwn pin #4 and ground and see if it increases its output voltage as the speed of the engine is increased... if so, then it's probably OK.

Harry
 

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Discussion Starter #12
I am SURE the computer, which has been changed and no improvement, is not sending the signal to the fuel pump relay, no question about that but I can not understand why not. The wire from the computer is OK because I can use a jumper and manually ground this wire and the main relay ground (computer disconnected) at the computer connector on the harness and the pump will run just fine plus a check with a DVOM shows zero resistance in this wire from that point to the FP relay socket. The computer is receiving power and seems to be powering up and will scan but it shows a clean scan with zero trouble codes.
 

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I seem to remember someone having a similar problem they tracked down to a bad ground connection under the rear seat? Harry, do you remember this, or am I going nuts?
 

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Chicago

I do recall that general scenario, but the details escape me at the moment.

Radkins seems to know a lot more about electrical/wiring stuff than I do, so about all I can contribute is overall logic.

My sense at this point is that about the only thing that can be an issue is either the connection of that wire to the ECU (this is apparently the "output path" of the ECU to the FP), or a problem with one of the (?) "input" paths to the ECU that enable/trigger the outputting of the signal to the FP, given that the alternate ECU made no diff and therefore the assumption is that the ECU itself is OK.

Harry
 

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Discussion Starter #15 (Edited)
Chicago

I do recall that general scenario, but the details escape me at the moment.

My sense at this point is that about the only thing that can be an issue is either the connection of that wire to the ECU (this is apparently the "output path" of the ECU to the FP),Harry

BINGO!, Thank you very much!!!

I had determined the ECU was good as was the wire from the ECU but the one thing I had never checked was the ECU connector socket itself to the main relay (actually the wire /socket connection was bad). When I was grounding this wire I was probing it from outside the ECU connector so even though it was good up to that point it was not making a proper connection to the pin. Until I read what you said there I had just about given up and was going to by-pass the ECU with another relay connected to the ignition switch to control the fuel pump but this fixes the problem, the fuel pump problem anyway!


NOW! That I have the darn thing running I have the other problem that was not there before this fuel pump fiasco, when the engine is cold (even on a hot day) it is extremely hard to start and once it does it runs really rough and will not idle. The longer it runs the smoother it gets until after about 45 seconds to a minute it is running normally. It has full power, runs just fine and will start normally until it has time to cool off then the same problem starts all over again. It is running fine long before the water temperature starts to climb so I am thinking I can rule out the ECT, maybe anyway. The fuel pressure does not drop off while it sits and from the smell it seems to be over-rich during the start. After all the probing of the sensors during the fuel pump problem I probably fouled one of them but again the scanner is not showing any trouble codes so again I am at a loss.



Thanks again for the tip to solving that very perplexing problem, I figured it would be something simple but until it becomes known it is anything but simple!
 
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