darknezz7

I carry a new relay always with me and yes I tried swapping it with a few.

I'll try grounding 85 see what it does.

I'll check the ecu connector, but my guess is its the unit its self.

djgrayxj

Note from DJ
DF my thought exactly; except if it were my 88XJ and I tested and found that I had a ground problem; I take my oil dipstick grounding location apart and clean it again even though I had done this before.
This is the location that the ECU receives its grounds from (Bad Grounds make Bad Coffee; Bad Electronic Grounds Make Confused Electronic).

darknezz7

Yeah I already did this just a week ago, did not help.
Just got to get the ecu out and check the connector to it.

DFlintstone

The renix ECU has been called "aircraft grade". Serious puter trouble here. Micros., Intel, and HP are all clamping down on XP OS's out there and it's working! Thinking of trying Lenux....I'll disappear if I finally fix this to death...

Crusier, or maybe someone else can tell you which pin on the ECU grounds that. I can't access my files. My bet is it's the wire or a connection, (did it run grounding the pig-tail?), and not the dipstick ground. (although checking that again could not hurt.

djgrayxj

Note from DJ to OP
Clarification Needed Please!
1. Key OFF Fuel Pump Relay removed; battery voltage to Cavity #30 Yes or No
2. Key ON Fuel Pump Relay removed; battery voltage to Cavity #86 Yes or No
3. Yes or No removed; approximately 2FT Fine stranded wire(I used #22 wire you don’ want to expand that socket which will cause a bad connection with just the relay installed.) one end of which was striped and fanned out flat and inserted into Cavity #85 Yes or No
4. Fuel Pump Relay was replaced back into its socket Yes or No
5. Key ON Fuel Pump Relay replaced did you touch the other end of the wire in #3 to a good ground Yes or No
6. What happened? Nothing? Relay Clicked but fuel pump did not run? Or relay clicked and fuel pump ran?

djgrayxj

Note from DJ
This is a view of the Fuel Pump Relay Socket as you will see it when the relay is removed and you are standing looking over the passenger side fender


What we are trying to recreate by artificially grounding. Cavity #85 is the ground signal from the ECU which Energize the relay coil which will then close the movable contact which will the close the contact between #30 and 87 this is how the fuel pump is activated.

67 GMC

Great post DJ. The voltage readings at the various pin positions (with the jumpers removed!) would be helpful.

The OP wrote no +12V on 30 but is a big sign there's something wrong elsewhere. It's hard to tell if the jumper is on or off when he wrote that. 86 should have +12V when the key is on during the 3s prime.

It wouldn't hurt to check voltage of CPS while cranking to see if it's within spec.

I wouldn't swap ECUs without making sure there's no electrical shorts.

djgrayxj

Note from DJ

OP Quote from his Post #1 “I quickly figured out it would stay running if I help the key in the crank position. Not having my volt meter or cell service I fumbled around with a jumper for awhile until I jumped the fuel pump at the relay.

Well it runs but now when my key is on but not started the pumps always on. Got me home at least”.

67 I have ruled out the CPS at this time because OP states it will start and run until he releases the key and ignition switch reverts back to the run sequence but the fuel pump stops.

Renix fuel pump electrical problems are such a challenge to trouble shoot because the fuel pump is powered up many different ways.
1. Key on prime sequence pump running.
2. Key on awaiting start signal fuel pump is not running.
3. Key to start position fuel pump running.
4. Engine starts key returns to run position fuel pump running.
5. Then at wide open throttle the fuel pump receives power from yet another different path.

I’m advise OP in ways to trouble sequence #4 because of his description of the problem.

darknezz7

1. No, only if measuring at the + batt is there 12v, like its grounded
2. yes
3. yes
4. yes
5. yes
6. The relay clicks but pump does not run.

Remember that with the relay in the fuel pump does even not prime when first switched to key ON

There is no voltage at all with key off, is #1 my problem, no power to the relay?

So I am back to:
Relay out
Jumped 86 to 87
When key ON, pump is on full time
With this I also have power on 30 with key ON
Took my boat out with it like this and it seems to run just fine

A few more notes:
I had continuity from 30 and 87 to the - batt
But also had it from 30, 87, 87A and 86 to the + batt

With the engine running I do not get continuity from 85 to - or +, but it does read about 2v when going to the + batt

Thanks DJ, decipher away

DFlintstone

OK, I was a little off. "No, only if measuring at the + batt is there 12v, like its grounded"

A grounded hot wire is called a "short" , (short for short circuit). There things would get hot and hopefully blow a fuse, fusible link, or trip a circuit breaker.

Anyway you might have hit on it. 30 should always be hot I think, (have around 12 V0lts), from one of the 5 or so fusible links coming off the big post on the START relay.

I'd clean all the connections on the BIG starter relay, then check again for voltage at the #30 socket.

I don't get it how #30 would become hot, juicing 87 with the relay out. Relay in, yes, your jumper is juicing it through the functioning relay.

darknezz7

Ok so if I can confirm pin 30 is supposed to always have power then that would be my problem. I'll trace the wire.

DFlintstone

Sitting here cold and wet my 90 has bat voltage at the 30 socket, Ign. off. (see pic attached.)

darknezz7

Thank you! love this place, really pissed I cant login to my other account anymore...

So would it be a horrible idea to just cut that wire and run a fused one to the battery? If so what amp?

DFlintstone

Maybe first clean the terminals on the starter relay. Check that fan of five or so fused links feeding your system that comes off that big stud. Feel the wires inside the insulation and see if they seem OK. Usually you will regret hacking wires and getting creative. You might put your meter or a test light on 30 and poke around, jiggle things. Maybe you can find the "open". (short for open circuit). (Opposite of a short)

djgrayxj

Note from DJ
Photo of Starter Relay with Fuse Links


I think we are starting to zone in on the problem with your statement that you had no voltage to #30.
I believe #30 was powered by one of the Orange Fuse Links.
I will try and provide more information tomorrow.