Painless Efi Harness Doesn't Include Relays & The Relays Required Are Discontinued

[sircrunch]

I posted this over at foureyedpride too but, i know someone here probably has encountered this problem............got my painless harness in the mail and started putting it in. there is a place for two relays on this harness which are not included. they are for the EEC and fuel pump. In the instructions it gives a list of parts that you must provide yourself (like the A9L computer, and different sensors and such) and for these relays it gives HELLA part number 87452 for both.

So I called several parts stores and they all didnt have a listing for it. I started getting concerned. So I called painless. The guy scrambled around a while and I held on for about 15 minutes, finally came back and said I'll have to call you back. Well, in the meantime I call HELLA. The guy there said that part has been discontinued. It was a "dual 8710 40 amp with DIODE" and they dont make one like that with a diode anymore, but instead with a resistor. So he told me to ask Painless if a diode is required or if a resistor is ok.

Painless called me back and the guy was kind of airheaded sounding and was real huffy and impatient my judgement tells me that he'd say anything to get me off the phone. He told me get this relay: painless 80130. I dont trust this information.

Nevertheless, this relay retails for 17 bucks at autozone . 17 bucks X2 is 34.00 for relays that SHOULD HAVE, in my opinion, been included in this kit. I called painless back and got another guy for a second opinion, he said he has two relays he'd send me for free but he would never confirm to me that they are diode style.

Anyone know what relay i really need? is diode really that important?

 

[MikeH686]

Which kit is this?

 

[MikeH686]

Is this tje painless perfect ems kit?

 

[sircrunch]

its the 5.0 EFI engine harness part number 60510

 

[MikeH686]

So its the "conversion" kit ok thanks for letting me lnow cus im about to buy one from them idk if im gonna get the conversion kit or their perfect ems harness was this harness difficult in anyway?

 

[HISSIN50]

Can you not just add a flyback diode to the relay socket yourself?

 

[jrichker]

I will post a diagram that shows the addition of an external diode to a relay. It is a little rough, but you will get the idea.

OOPS! orginal drawing had the didoe backwards. Here's the corrected one...

 

[MikeH686]

So that diode is there to prevent the fan from pulling to many amps?

 

[HISSIN50]

So that diode is there to prevent the fan from pulling to many amps?

The diode does not do that.
His fan installation document happens to have info about installing a diode on a relay, which was why he included it. Different application, same principle.

 

[MikeH686]

Then what is the purpose of the diode im confused on that

 

[HISSIN50]

Then what is the purpose of the diode im confused on that

It mitigates inductance. You could think of it like a one-way valve that prevents backfeed.

 

[MikeH686]

Ok so any induced voltage will go through that so the fans wont run due to induced voltage correct or am i out in left field

 

[jrichker]

Using a diode as a dampener in automotive circuits:

Theory of operation:
The diode acts as a surge absorber or one way gate. Anytime you turn the power off an inductive load (coil, motor, solenoid, etc) the collapse of the magnetic field creates a voltage spike of opposite polarity to the voltage applied. The positive wire sees a negative spike and the negative wire sees a positive spike. The diode is wired backwards so that it does not conduct during normal forward operation. When the magnetic field collapses, the diode sees the reverse polarity spike and clamps it. This prevents the spike from possibly damaging the rest of the electronics in the car.A properly functioning diode will measure very high resistance or open circuit in one direction. Reverse the meter leads and it will measure a lower resistance.

 

[ratio411]

I know it's a bit late... but I'll post this for any future readers that might be considering a Painless harness....

Go with the RJM harness!

RJM includes all the relays and is honest to goodness a painless install.
Used one myself... and it was cheaper than Painless.

 

[MikeH686]

my only concern with the rjm harness is that im performing a wire tuck and i need a harness that is a bit lengthened, this is the advantage of the painless kit is that they offer the extra long kit, I have tried reaching out to rjm by both phone and email to see if they can customize a kit for me that is about 2 foot longer on the wire leads. Does anyone know of a member here that works for rjm?

 

[RacEoHolic330]

EDIT: I confused RJM with Ron Francis for some reason. I don't have the RJM kit, but I have one from Ron Francis. Sorry about that.

 

[ratio411]

Yeah, we used the "Universal" 5.0 kit, and we had to shorten the wires to put the PCM under the center console.

 

[MikeH686]

Ok so if yall had to shorten it i should be alright thank god