87' 930 turbo start up problem

[Chapterdiep]

Hello All,

Read all the post at the forum but still not 100% get it
when trying to solve my turbo problem.

Car did not start because I did not hear the two fuel pumps run when
turn on ignition key.

I did the following steps:

Step-1:
Jumped Yellow Relay pin 30 and 87a - I heard the two fuel pumps run then
The car started no problem and run.

Step-2:
shut down the car replaced the jumper wire paperclip with the Yellow
Relay back to the car.
Turn on igniton key. I did not heard sound of the two fuel
Pump run. However, continues to turn the key to start, the
car start up fine and run. I kept it run about 5-10mins at idle with
the car is park. everything is working normal. Then I shut the car down.
Yellow replay still in the car.

Step-3:
I come back next day after the Step-2 with the Yellow Relay
in the car overnight. I try to start the car with igniton at on only position without
crank up the car. I did not hear two fuel pump run. So I crank up the car anyway.
Engine will not start as expected.

So then I repeated Step-2. Engine start up and run normal.

At this point, I can not rule out the Yellow Relay yet if it's a bad acting unit.
I haven't check out the Airflow Sensor Contact to see if it's bad or the Fuel Mixture
Knob was adjusted too much out that caused the Airflow Sensor Contact to
Not energize the Yellow Relay to active the two fuel pump. Without logic diagram
of the fuel system, I can not troubleshoot. I have look at the Fuel diagram from the
people posting here but it's not really the logic schematic of how the fuel system
Working on this car. Anyhow, I hope someone here can help figure out
How the Airflow Sensor Contact tie into the fuel circuit with the Yellow Relay logics.

Greatly appreciated!

[Jeff NJ]

The fuel pumps are not supposed to run unless the car is running. They do not run when the ignition is in the "on" position, but the car is not running. When you turn it to "on" you will hear a quick pulse of the fuel pumps, (I assume priming the csv??), but that is it.

I used to have the same symptom where the fuel pumps run when ignition was in the "on" position, and the reason was the yellow relay was failing. I took it apart and numerous contact solders were broken and they made contact sometimes.

I bet yours is the similar. Pull it apart and see what it looks like. I think you were on to something when you jumpered it and it worked.

This is what it SHOULDN'T look like. The black bottom has the 5 pins that are supposed to be soldered to the smaller board and you can see that all of them were broken. I repaired all 5 and purchased a new one and kept this repaired one as a backup.

[Chapterdiep]

Thanks Jeff for the write up and the photos.
I will dis-assemble the Yellow Relay tonight.
I remember when I had the 88' turbo. The Yellow Relay
went bad I have to pay it only $75.00 buck and now
The best price I can find is at Pelican Parts for $116.76 else where
Is $180-$2XX.00. Incredible they are getting so expensive.

I still don't know WHY the Yellow Relay work after
I took it out, PaperClip jump pin-30 / pin-87a, then put it back--->
It works. So weird! I thought there is another path in the fuel
logic related with the Airflow Sensor Meter / Airflow Sensor Contact.

Anyway, I will tear up that Yellow Relay apart tonight and order a new spare Yellow Relay.

[Jeff NJ]

Intermittent contact inside the relay from moving it around can cause it to work sometimes and not other times... pull it apart and take pics. Good luck!

[Chapterdiep]

Will do when I get home tonight.
Thank you Jeff

[mark houghton]

I echo Jeff's diagnosis. Bad yellow relay, or perhaps just poor connections in the socket and pins. You can spread the pins open a bit to get a tighter fit when inserted in the socket. Hose some brake cleaner into the socket to make sure it's at clean as you can get it. Wouldn't it be nice if that's the simple solution?
Have you taken the time to read our sticky on "car won't start"? There is a wealth of information there, very educational if for nothing else.

[Chapterdiep]

So I took the Yellow Relay apart tonight and look under
the microscope saw those solder joints on the legs were cracked.
I resolder them back. I will test start the engine tomorrow.
Hope it's the smoking gun. Thanks Jeff for taking me there!









Resolder all the joints and install the Yellow Relay back to the car for
Overnight. I will start the engine first thing tomorrow.

[Jeff NJ]

First do what Mark said and clean the posts and spread them just a bit with a razor, then put it back and put the key to the On position. If the pumps run for more than a split second, it isn't right. If not, progress! Then start it tomorrow.

Good luck!

[Chapterdiep]

I actually did used the thin knife spread all those of legs before
I put it back to the car.

How long I suppose to hear the fuel pumps run? 5sec?

Thanks

[Jeff NJ]

more like 1 second.

[T77911S]

solder joints did not look good
.
not related to your problem but since you have the skills, do the same thing with the speed relay under the seat. the solder joints go bad on it too. if I don't see any bad ones I usually just hit all the joints anyway.

if the relay was your problem you are lucky it started after putting it back in, actually unlucky. itd better if something just breaks instead of work sometimes and not work.

if this does not fix your issue, look at the CSV. could be you are running the pumps and putting just enough fuel in to start it. note, even though the sensor plate is closed, its possible for fuel to still leak out of the injectors with the pumps on either due to leaky injectors, FD issues or just a tad rich.

hope the relay was all it was.
you can also remove the connector on the rear of the AFM to "test" the yel relay. pumps should run with key.


good work jeff.
as jeff said, pumps run about 1-2 seconds.

[Chapterdiep]

The car started right up this morning.
Ran parking for 15mins. Everything looks good.

Will do a few more engine start-up overnight to see if the problem
Is totally gone.

Thank you Jeff and everyone for helping me.

[Jeff NJ]

Nice!

[mark houghton]

...and the correct car color!!!

[Chapterdiep]

Thank you Gents.

[jsveb]

Originally Posted by mark houghton

...and the correct car color!!!

Except for the fact that it isn't black
-------

Great to hear the car is running again.

[Chapterdiep]

Thanks Jsper,

Start up the engine again this morning and
It starts right up without problem.
I think the Yellow Relay was the problem.

[16Volt]

Congrats - and welcome to the PNW 930 group (if the car stayed here after Park Place).

[Chapterdiep]

Well, the car has issue start after a short drive this morning.
I have to use the paperclip to jump the Yellow Replay to start
The car. After the car started with Paperclip, I shut the engine down
Then put the Yellow Relay back. The car started then I drove home.

It seems to me that the Yellow Relay currently in the car is too old
And Things may have gone bad inside the unit.
Although I have fixed those legs cracked on the PCB with good soldered.
....Going to buy a new Yellow Relay today.

[T77911S]

next time it will not start remove the connector on the back of the AFM and turn the key on and see if the pumps run, then try to start it. if it starts, its not the relay.

check the connectors in the socket,. one may be spread open too much and not making good contact