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Discussion Starter #1
Hi all I am starting to work on a fuel pump problem on a 93 9000. The problem appears to be electrical and I am having trouble with the wiring diagram I have. I cannot distinguish on the diagram between the box of relays under the hood on the driver’s side or the ones above the glove box. They both appear to be related to the fuel supply system. Is there a site where I can find a clearer wiring diagram? In addition, it looks like the trouble might be in ECU because it looks like the wiring passes through there also. It looks like ECU unplugs easily. However, I have never replaced one before and was wondering if there are any special considerations to make.

Thanks in advance

Steve
 

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the fuel pump relay is behind the fuse box in the passenger compartment. The plastic thing that all the relays plug into has its own little map. Replace this part first because its cheap.

My fuel pump relay would only allow the car to start if i banged on it, but once the car started it would stay running
 

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Discussion Starter #3
Hi Boon 94 and thanks for your note. I discovered those awhile back above the glove when I was working on my 89 9000. The guy I bought the 93 9000 from replaced the ones under the hood on the drivers side. I think it is a main relay and pump relay. He did not know about the ones above the glove box. He gave up on fixing the car and I bought it. I found a pump in a small town out side where I live and I am going to go get it tomorrow. My plan is to replace the relay like you suggested replace the fuel pump and filter then try and start it. I only paid 350.00 for the car, so I do not mind putting some money into it. I am kinda doing the project for the challenge. Anyways, one guy I talked to suggested that the problem (it) was probably the ECU or perhaps the crankshaft sensor and that they can shut off the fuel delivery also. The junkyard wants 60.00 for the ECU with no guaranties (sold as is) do you think it could be that? Any opinion is appreciated.



Steve
 

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You need to be specific with the problems of the car? What is it? Does it not start or not stay running?

A fuel pump problem is easy to diagnose. Without the key in ignition, jumper fuse 14 to fuse 22. Fuse 12 is the hazard light. It is always hot. Fuse 22 is power to the fuel pump, hot only in run. By supplying power to the fuel pump from the battery, you'll hear the fuel pump motor turn in the trunk area.
 

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I woudnt expect the ECU as that doesnt seem to have many problems, however the crank position sensor can also cause the car not to start. Have to checked to see if there is any pressure in the fuel line?
 

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Discussion Starter #6
Thanks Yaofeng for your note. The vehicle is a 1993 9000 no turbo. The problem is no fuel and presently the vehicle has no fuel pump in it. I purchased the vehicle as a basket case after it had broken down on the previous owner when he was driving it. My understanding is there was some smoke that came out of the relay box under the hood on the driver’s side, and he assumed the problem was a fuel pump, so he pulled the old pump and broke that one pulling it out then he bought a new one for 500.00 and that did not fix the problem. He then kept the new one and sold me the car without a pump because he was so frustrated.

I pulled the slack out of the wires in the relay box under the hood and did notice a small black wire that had burned. However, this is the only wire I can see that is burned. One thing I did notice was when I put the battery of the car and put that on my charger (unhooked form the car) the charger acted funny; it started to charge the battery, but after a few minutes the amp meter on the charger starting flickering to negative amps like it was shorting out. I thinking that the battery might have shorted out internally and caused the problem at the main relay because if the short came from that source it would not have been fuse protected. Do you think that is possible? Any opinions are much appreciated.



steve
 

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A completely drained battery on a trickle charger will have the amp meter swing back and forth until the battery has established some charge. At least this is the experience I had with an old trickle charger. It may not happen on others.

At this point you can only hook everything up and try to start it. This is the only way to find out if and where something is wrong. And that includes a severe short somewhere. Anything else will be speculation.
 

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Discussion Starter #8
Thanks for your replay Yaofeng and Boon 94. Just got back from the junkyard and bought a fuel pump for 60.00 and it looks good. They offer no guaranties through. Anyways, I am going with your advice tomorrow and hooking things up and seeing what happens. Wish me luck and say a prayer. I will hook that battery up and keep an eye on it to see if it starts to charge.

Steve
 

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Discussion Starter #9 (Edited)
Hi all I am still trying to start the 93 9000. Anyways, I put a fuel pump in and at first it did not work then I did what was suggested by yaofeng and ran the jumper wire from 22 to 14 in the fuse box and the pump started to hum. I assume that this means it is working. At this point, my question is does this also mean that the fuel pump relay is also good? The sad part is the car will not start. My next question is could the problem be the DI? Would a bad DI shut off the fuel? Somewhere in this system something has shut off the fuel, I think. Perhaps a bad relay, perhaps a short in the wiring, I do not know. I heard that the ECU and Crank sensor could shut off the fuel, and I heard that the fuel modulator and map sensor could also shut off the fuel. I am not sure what a map sensor or fuel modulator even looks like or even if this vehicle has them. My books seem to be incomplete. In addition, I checked for compression by pulling a spark plug and using a compression gauge only on one cylinder, and the compression was at 130. So I figured the timing chain is not broken. Then after I did that, I read in one of my books not to crank the engine with the DI disconnected. I did not crank it long, so I hope I did not hurt anything. One more question please. How do I check for spark in an engine with a DI? Any opinions on what to do next are greatly appreciated.

Steve
 

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SP53, with the DI properly fitted crank the car over then go and listen under the hood you will hear a buzzing noise as the DI runs the "clean plugs" cycle.. It does this if the engine fails to start. Alternatively you can do it with the DI out but you need to make sure all the plugs are in (the DI) and well grounded to avoid damaging the DI.

I would do as someone else has already suggested and unbolt a fuel line or pull and injector to check that its getting some fuel, how long did you run the pump for? maybe it takes a while to get the fuel into the injectors if its all drained out?

Good Luck.
 

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Discussion Starter #11
Thanks for you notes Tooky and Norman I wish I would have talk to you guys sooner because it looks like I might have ruined the DI. They must be pretty sensitive because I only spun the motor briefly just to check the compression on one cylinder and I suppose it could have been bad all the time. What I did was put a known good one on the broken vehicle and put the unknown on the good vehicle. The good vehicle would not start until I put the good one back on it. The crappy thing is the bad vehicle did not start with the good one on it. It looks like I have a double problem. Perhaps the crank sensor is also bad on the broken vehicle. In addition, there is a year’s difference between the cars; one is 92 and the other a 93, but they look the same. And the bad DI looked like it had gotten hot at the tips where they go over the plugs.

Steve
 

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Discussion Starter #12
Thanks Tooky you made a good point. I only ran the pump for about 10 seconds because I did not want to run it long until I learned more about any other potential problems. My first fear was that I had hotwired the pump and was afraid I might have over ridden some other system, but now I think after reading and learning from members I will be a little more aggressive on the repair. I think today I will pull one of fuel line ends loose and put some gas up to the top and pull the wings and have a look at the sensor. However, there is one thing I could try without getting too dirty or overly involved and that is swap out the ECU with the 92 and see if that does anything. What do you think?

Steve
 
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