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240 Fuel Pump relay

88745ti

88745ti

New member
Joined
May 19, 2005
Location
St. Lucie County, FL
I need some help with a no-start condition on the wife's 91 240. I have spark at the coil, pump not turning on with ignition, fuses good. Jumper wired fuses 3&4 in tank pump turns on. So relay is bad right? White relay clipped onto the ecm under passenger side dash correct?

One thing that has me stumped however, is even when the fuses are jumpered the car still won't start. Is this because the other pump is not turning on or do I have other issues besides the relay? The in-tank pump was replaced about 6 months ago or so.
 
Yes, the other pump is not turning on. You are supposed to jumper from fuse 4 to fuse 6. That will make both pumps run bypassing the relay. You can also use a test light and see if it turns on the relay when cranking. You put the test light from terminal 87 and ground. I think it's the yellow/red wire IIRC.

If the relay isn't turning on and a replacement won't turn on. Then it also could be the ecu isn't getting the engine speed signal or the ecu itself is bad.
 
Also check to see if there are any stored ODB1 codes:
http://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

Dont recall off the top of my head if if '91 still had it, but if so, check the blade fuse holder in the engine compartment in front of the left strut tower, inspect this holder and fuse for any corrosion as this supplies power to the fuel pump relay.

It's also easy to pop the cover off the fuel pump relay, plug it back in and observe. One of the two internal relays should close when you switch on the ignition, the other should too but only for a moment when you first turn on the ignition; this second relay should close while cranking. If one or more is not closing, try holding them closed while cranking; if it starts, the relay is bad.

Failed solder joints on the relay's circuit board are a common failure point, best to check them and re-flow any that are suspicious (or just do all of them).
 
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Update:

Jumpered 4&6 pump(s) turns on still no start. Yes there is fuel in the tank lol. There is no blade fuse holder on the shock tower. I tried to pull codes but got nothing....no light flashes whatsoever. I assume there is an ecu relay somewhere?

I should also mention I am troubleshooting this with NO tools...ALL of mine are back in Hampton in my work truck :( I don't even have a test light. And we had a foot of snow this weekend. And the 240 is our only source of transportation atm. Sigh.

Sooo. Seems ECU related, no?

Edit: pulled code 113 out of it just now....apparently the wife and i had our signals crossed on when the ignition should be on and off :oops:
 
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1-1-3 code won't prevent the car from starting. Crank Position Sensor might be faulty, you can check it with the diagnostics.

From brickboard:
Turn the ignition ON to KPII and install the cable into socket 6 for ignition-related tests.
Press the button two times for >1 and <3 seconds each. The LED lamp should flash rapidly.
Remove the ignition coil center lead and crank the starter motor; the engine will not start but it will turn over. The LED should go out, then flash 1-4-1 for the RPM sensor. If no code is flashed and the lamp keeps flashing, the RPM sensor is faulty. Reinstall the coil lead and turn the ignition key ON to KPII.
Click to expand...
 
Thanks, just spent some time reading over that. I will run some more tests tomorrow. If the crank angle sensor were faulty would I still get spark?
 
That's what I thought.....I have plenty of spark. Hmmm. Any other reasons that I would still have a no start with the pump relay bypassed...and the relay was clearly not energizing on it's own. Possible the relay and the external pump died at the same time? There is a lot of snow buildup so it's hard to tell if the external pump is coming on with the bypass.

Other than pulling codes is there a way to test the ecu itself?
 
The way to test the ECU itself it to try another one.

Try starting with the MAF sensor unplugged, if it starts and runs, the MAF is bad, a common failure mode.

Next I would unplug the injectors and spray some starting fluid into the air box cover. The car should be eager to start, and if so you know that the ignition and valve timing (timing belt) are good to go, and the issue is most likely fuel related. If not, open the oil filler cap and make sure the cam shaft turns with the engine.
 
Next I'd pull all of the injector connectors at the same time and test between the harness connector terminals and the intake manifold (ground)(ignition on), the forward terminal supplies 12V+ to the injector. Make sure the ground points at the fuel rail bolts are in good order. Pull the main connector off the fuel and ignition computers and inspect for any signs of corrosion. If everything looks good, and the fuel pump relay is not suspect or is fully bypassed (both internal relays bypassed), timing belt marks have been verified, then I would consider the fuel ECU is very likely defective.
 
Had a similar 'no start' issue with my 83 245(lh, not kjet)...

My #12 fuse was corroded....looked fine, pulled it, hit it with some emery paper, hit the fuse block with the emery paper, turned the key and the car starts and runs like a top.........

Worth a shot???? I had spark, and had jumpered my fuel pumps as well with no luck, till a fellow here that goes by cleanflametrap turned me on the the #12 fuse 'fix'................
--carlos
 
Well I'll be damned..

Fuse 12 trick worked! I didn't even clean the contacts (didn't have any emery cloth on hand) I just pulled all of the fuses and re-seated them and she fired right up. Go figure. I have a bad habit of over-thinking things....I guess this was a case in-point. Oh well I'm just glad it was something simple this time. Thanks to everyone for the help, especially Carlos.

Anybody coming across this in a search, remember do the simple stuff first...might save you a few days of aggravation lol.
 
Praise goes to 'cleanflametrap' on this list, a.k.a. Art benstein..........

I was just the messenger, and lucky recipient of his advice as well ...

Glad it worked for ya 88745ti !!!!!
--carlos
 
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