Does anyone have Fuel pump wiring diagram

[iroczinoz]

Fuel pump wiring diagram 10.2v at fuel pump connector bad? good?

I think i might have a problem with the fuel pump or the circuit. Does anyone have a wiring diagram so I can check everything out and make sure all the wires are good.

Also the Oil pressure switch does anyone know how to check this if it is faulty?

Last night the car died and took 30 mins to start up again. This only happened after 2 mins of driving so I am kind of ruling out the CAS.

When it did happen and I shorted out the ALDL to bring up the codes the FAN did not come on like it usually does. But once the car started and got it back home. I shorted out the ALDL again and the FAN came on.

Looks like some electrical issue or something but it is strange.

The car did not have any codes except for 31 the immobiliser circuit but I am not sure what is up with that. Since It starts if I press the unlock button if the car does not get started within 1 minute after opening.

The car is a 1994 VR 6cyl auto.

 

[kopper69]

I wouldnt rule out the CAS. Im not saying that it is the problem, just dont rule it out yet. CAS will do lots of funny things and very well could cause the car to stall after 2 mins.

Clear the codes by removing the 20A engine fuse near the battery for 10 seconds. Not much you can do except to wait for problem to reoccur or get worse. There is nothing more difficult than trying to diagnose a problem that doesnt exist. Hopefully when it next occurs, it will throw you an error code.

Fuel pumps normally have trouble starting. Once they are running, they are normally pretty good. I would check the connection on the side of the DFI module (under the coil packs). It is screwed on. Just undo the bolt, take it off and give it a clean with contact cleaner or similar. Redo it nice and tight.

Check that the contacts on the key and the ignition barrel are clean and make a nice connection.

 

[iroczinoz]

I'll check that out!

The car also has a slight miss when idling where you can hear it miss. It is very faint but you can notice it. It is not at set intervals but often it will miss say every 30 seconds.

Anyway to test the Oil pressure unit?

 

[ephect]

id say you have a vacuum leak some where, which is generally the cause of rough idle

check all hoses around the throttle body and follow them making sure they're all connected fine n not loose.. if everything looks fine n ur still experiencing rough idle, spray CRC on the hoses and if u have a vacuum leak the revs will increase becoz its sucked in the CRC, then u know u have a problem

also if the leads havent been changed, they can cause all sorts of problems also

i dont think the above info (my post) will help with ur car stalling

 

[iroczinoz]

I checked everything today wires hoses and they all look good. I will try the CRC and see what happens.

A few issues I found today. I bought a new fuel pump and fuel filter. I decided to just change the fuel filter to see what happens. I got the bugger out and found it pretty restrictive to blow air through so I thought I might be lucky with an easy fix.

The fuel pump I did not install as I am not 100% sure it is at fault at the moment. The other thing I did today was test the Volts at the fuel pump connector that plugs into the fuel pump assembly.

With key in the ON position it had 10.2 volts. Now I thought it would have had the battery volatge on it. Should it have the battery voltage on it or is 10.2 volts fine? My battery volts were 12.7.

I tried changing over the relays to try another one and the same thing 10.2 came up.

Now can somone please let me know if I have a wiring problem here or the volts are perfectly normal please.

Another strange noice that comes and goes is a loud cracking noise from the motor. Last time it happened was in January. Today it done the same thing for a while. But after a few restarts it went away. The noise is like a realy loud ticking noise. Like injectors ticking but this noise is about 100x louder. It is pretty mysterious as it comes and goes. Any ideas? The most noticeable where it was coming from was right around the throttle cable lever.

Does anyone have a test procedure for the fuel pump and wiring for a VR I could really put it to some good use.

thanks Mike

 

[kopper69]

Gregorys has a test procedure for the fuel pump circuit, but as I said above, it is only going to be of any use to you if the car isnt starting. If everything is working fine, you can do the entire test procedure 1000 times, you will never find anything.

Fuel pump is a pain to do. I would return it and get your $ back. Fuel filter should be restrictive to blow air thorough. Its hard to determine the condition of the filter, because it is encapsulated. You could try cutting it open, but as you cut it, all the metal filings go in the filter and you cant really get a good idea. You have changed it now and so can rule it out.

Voltage sounds ok, I will jump under my car quick and just see what my reading is. It goes through oil switch etc, so its bound to loose a little bit of voltage by the time it gets to the pump.

 

[iroczinoz]

Yeah I hear ya. The fuel filter that I pulled out was really restrictive to blow air through like I mean you really had to blow pretty damn hard to get air through the other end. The new one was pretty easy to blow through so I think it was a good move to change it.

I will not install the fuel pump and see a week. But like you say I think the fuel pump is fine that is why I did not change it. The mechanic I went to see said the fuel pump and quoted me $200. I said to myself damn this is just hope for the best and lets change parts when we don't even know 50% sure that the fuel pump is at fault.

So I decided to do it myself and start from the simple things. The clicking sound might be a VAC leak? But the funny thing is that the car is not doing it anymore.

I also cleaned the CAS terminal yesterday with some WD40 too and it does go much better. The idle seems smoother too. Maybe the problem is fixed hope so but I don't want to speak too soon

 

[kopper69]

ok iroczinoz. Just to make sure we are both checking the same thing. Power to the fuel pump is via a white round connector about say 10cm long. It is sealed so there is no way of backprobing the connector. To measure the voltage, i disconnected the white connector, put my probes on the two wires and turned the key just before the start, when the engine would normally prime. The voltage on the pump was the voltage on the battery. Priming only lasted about 2 seconds, so the reading wasnt completly stable.

This method disconnects the fuel pump. When you did your test, did you pierce the wires, so that the fuel pump was still connected? If so, it would explain why the voltage dropped to 10.x volts, instead of battery voltage.

 

[iroczinoz]

Hmm. The connector we tested was not round but square shape black. We also unplugged it and put the probes inside of it. Maybe the connector I should be checking is a different one?

 

[kopper69]

The connector that you checked was only the sender for the fuel gauge. Not associated with the fuel pump.