924Board.org

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

Son and I wanted a car to renovate and found a running '87 924S, on the way home from purchase it died..previous owner said it sounded like what happened to him recently and is why he changed fuel pump.

I can not hear the pump when trying to start, expect a "whine" of sorts, get more of a slight clunk, but that might be due to the engine turning over..

Measured roughly 10V at the pump, but it's a digital meter and may not have gotten to 12V because didn't let it crank long enough..

Previous Owner did not change fuel filter when changing pump...don't think he took great care of it ... rat turds and Burr oak leaves stuffed in air filter..

sprayed starter spray in intake and it tried to catch, so pretty sure it's a fuel issue..

Had heard fuel tank "liner" (??) deteriorates and causes problems, but see no reference to this in any postings -- anybody know anything about this?

Also, seems weird that the filter would be the problem if the new pump got it working for a brief 10 mile drive till it died..

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

Doubt if it is your fuel pump. You can hear the fuel pump run by bridging the two far left fuses in your very upper fuse rail under the dash. At this point if you are convinced it is a fuel issue you need to check your fuel pressure at the rail. Be warned that there are common issues with the flywheel position and speed sensors, fuel pressure regulator and DME relay.

That said, the very tiniest particles can jamb the impeller on the 944 fuel pump. There is supposed to be an in tank filter to prevent dirt from reaching the fuel pump but they have often failed by the time 20+ years goes by. When I install a new fuel pump I useually put a clear inline fuel filter between the tank and pump. You would be surprised all the crap that collects in it.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

Thanks Joe-- not sure why you doubt the pump - I did try to listen for it when my son cranked, and could not hear it..that's why I suspect it again, but I will try shorting the terminals...read about that in a diff post of yours...and about your in-line filter, which is a really good idea - questions:

1) does extra filter need to be anything other than big?
2) what's the fuel line ID/OD coming from the tank to the pump, and beyond...(probably wouldn't hurt to replace eventually).
3) where are terminals 30 & 87b - repair manual says to pull fuse, de-pressurize, short those terminals and crank to hear?

Previous owner did put a new tank on about '02 or '03..but maybe not the filter..

thanks again

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

The quickest way to see if your fuel pump is functional is to bridge the two left fuses in your upper fuse block (the fuse block that faces the floor). The terminals you mention are under the dme relay. You can go that route if you want but my way is simpler and takes 5 seconds. You don't have to crank the car to do this test, you dont even have to have the keys in the car. All you are doing is tapping 12v from the very far left fuse and delivering it to the fuel pump circuit which is the second from left fuse. The only thing more direct is crawling under the car and clipping jumper wires from a battery to the fuel pump itself which is not as quick or easy.

If foreign matter has made its way into the new fuel pump you may be able to hear a very faint "thunk" at the moment you apply the jumper as the impeller hits what ever is jambing it. (ask me how i know) The correct noise is a very pronounced hummm.

A pre pump fuel filter you can use is the fram G3, available at most walmart stores for a few bucks. I have run this filter on different cars for several years with no problems. It will certainly flow enough fuel.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

JoeC - that's got to be what happened...I can feel and do hear a slight "clunk"...when it's cranking...but I'll give your method a shot, and will also apply and external 12V across it..for s***s and giggles...because I'll be right at the pump then. ..

hope that's it, and I'll keep you posted..may get some time on it manana..

thanks much..

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

ok big mistake - I bought a G3 fuel filter, but the fuel hose and filter inlet are diff. size - no way to join them..didn't realize till I after cut the line...

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

something is a miss then in this 924S...the hose from the tank is 13mm..
the hose that comes w/ the G3 will not fit over the inlet to the pump ..the inner diameter of the hose from the tank is larger than the G3 inlet...stll tried to tightend the high pressure hose clamp over it thinking that it would be okay, but couldn't tighten it down enough...

will try to resolve today

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

Here are a couple of shots of the fram filter on a 944. On this car I never even cut the original fuel line, I just added the filter and a zip tie and done.

A surprising amount of crap has collected in only a few hundred miles. After 27 years who knows what has made its way into the tank.

_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

Thanks again - my issue might all be due to having improperly sized high pressure hose clamps...I took a small piece of the hose and put it on the Fram filter and using a good clamp like you have in the pics...the seal appears to be tight..

I plan to replace the pump, outlet filter and install the new inlet filter...I strained some of the gas I drained...actually banged on the tank some with a rubber mallet ,added about 2 quarts to the tank and tried shaking it and emptied some dirty fuel..looks like stuff in your filter, but not as much

what about getting the fuel tank treated..cold boiled(?) ...ever done that to an old tank?

Thanks

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

Just be glad it isnt like this

This car was stored in a barn for 20 years and when I started it the fuel was so contaminated with this goo that when the engine cooled after runhning it all the intake valves stuck open (no BS) and I had to pull the head and drive the valves out and clean them off. I am guessing the fuel was contaminated but what with I dont know. I had a few parts cars at the time so I just swapped the fuel tank.

http://www.924board.org/viewtopic.php?t=32578&start=0

_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold

philk · Joined: 05 Apr 2012 Posts: 33 Location: Austin, TX

okay - got it all fixed and running...decided to use the fram filter after all so I can see crap in the gas..nothing yet ...helps to have the correct clamps..I put it in line with the pump and tank, but used the existing hose..the coating on the hose from the tank is cracked ...almost changed it out, but will wait on that for a little while..

on to the next issue..
thanks