Electrical help! (1 Viewer)

[SmokingRocks]

I’m in an EMT Class right now so I can’t guve you all the details but if you search you will find this info.

1) you can Hotwire the fuel pump by bypassing the fpr and jumping two of the terminals at that connector. Can’t remember which ones. Do this and attempt to start the car. It should run fine.

2). You can pull your fuel return line off the fuel pressure regulator stick a hose on it and put the other end in a bottle. Crank over and see if you are getting fuel.

This test can be done by just hotwiring thw fuel pump. If desired.

Any check engine codes? Even if the light isn’t on there may be a code stored.

I agree this smells like a fuel problem, but let’s verify and check each box before we jump ahead and potentially miss something.

 

[Alan Jones]

I tried hot-wiring the FPR with no luck. I will have to wait to check the pressure regulator for fuel tomorrow, it's dark and cold here. Any thoughts as to what would cause the electrical surge with dash light fun, blown headlights, and now no start? If the fuel pump had problems on the road, possible cause?

 

[clx16]

You mentioned

Newer battery, newer starter, and alternator.

... I am guessing they are second hand or rebuilt? I haven't experienced a battery surge, but a regulator going bad in the alternator could surge I guess and maybe fry your headlights and fuel pump. If that were the case then my thoughts are voltage spike not amps.

 

[SmokingRocks]

Pull codes. Voltage surge could have damaged your ecu

 

[SmokingRocks]

Also are you sure you jumped the FPR connector correctly? Do you have a factory service manual?

Here is the engine control section from my FSM, I've noted on the pages what you should do and how to do it. I can't find my 96 FSM right now so keep in mind that the file I am sharing is from my 93. There were changes from 94 to 95 when they transitioned from OBD1 to OBD2. Most of the circuitry and system flow remains the same however. (Someone jump in if I'm mistaken)

Open this up look it over and test with a multi meter, report your findings back here.

engcon.pdf

 

[Alan Jones]

Alright Mr. Rocks, I am going to tackle this in the morning. I have looked over the diagrams you attached and am a bit lost. You have the EFI main relay circled. Is that where to jump the FPR? I had read somewhere that you remove the FPR and jump two of the leads there...

 

[SmokingRocks]

yes I have arrows pointing to the EFI relay and the Diagnostic Port on the following page. If you trace the arrow down to the bottom of the page you will see I added some text boxes in there to tell you what to do.

Let me know if you need more help.

 

[Alan Jones]

I can say that the EFI relay connector has 12v on pin 2 and 12v switched on pin 4.

 

[Alan Jones]

I can say that the EFI relay connector has 12v on pin 2 and 12v switched on pin 4.

 

[Alan Jones]

I am going to dig in to the data link connector again. There was no wire connected at the Fp location but the wire should be there,

 

[SmokingRocks]

@Alan Jones

Here is a link to the 1996 Factory Service Manual, down load it, save it to you're ipad, iphone, clouds, flash drive, burn it on a CD, print a hard copy, give a copy to your neighbor for safe keeping... you get the idea. This is your bible.

 

[SmokingRocks]

@Alan Jones

Here is the 1996 Electrical Wiring Diagram Supplement... This is like the New Testament of the above mentioned bible. Make a copy and hide it under your bed in addition to saving it to all the devices and neighbors as listed above.

Start looking into page 50 (after you start to understand what you are looking at, if you arent sure what you are looking at you can give me a call and I'll walk you through it, PM me for my number)

 

[SmokingRocks]

Page 65 shows the Fuel Pump Relay, notice the numbers at the wires where they meet up at the FPR rectangle, those corespond to the pin on the connector shown below.

12v should be present at terminal 5 when the ignition is in ON and START

If 12v isnt present at pin 5 then there is an issue at the circuit open relay or the EFI relay. Now there may be 12v there but for how long... So you hotwire the fuel pump by putting a test lead on the battery + and plug the other end into terminal 3 of the FPR connector. This will in theory turn the pump on full blast. So try starting the engine now and see what happens.

 

[Alan Jones]

Perhaps a bit closer. No 12v a pin 5. Jumped fuel pump and I can hear the fuel rail pressurize. When I crank it still runs for a few seconds and dies. Where is the circuit open relay and how do I test there?

And thanks in advance for your help!

 

[Alan Jones]

So far, EFI relay, FPR relay, Circuit open relay, fuel pump all working fine. 12 v coming to each relay. Still cranks and runs for a few seconds and dies. I can stay on the throttle and keep it running for only a moment or so. How do I test the MAF sensor? No leaks in air intake as I replaced that with high performance silicone a year or so ago. I get spark or it wouldn't run at all and certainly wouldn't run under throttle.

 

[Alan Jones]

MAF hits specs on ohms b/w THA and E2, 12v, ground, and voltage fluctuation between VG and E2 when you blow on it. I am going to pick up new cap, rotor and wires as they are overdue, but not sure that will help. Any advice would help...

 

[Alan Jones]

According to the electrical diagrams, could the file pressure regulator cause all of this?

 

[blkprj80]

If you disconnect and plug the vacuum line from the FPR, it might provide you a clue as to which way to go. I think it puts vacuum on the regulator to reduce fuel pressure, but I could be backwards on that.

 

[Alan Jones]

One more though, fuel was low when all of this happened. Would that lean toward fuel sock? Constantly reading every possible thread out there.

 

[blkprj80]

If you pull that inspection panel for the fuel pump, you could measure the voltage, while running. Then, you're one step closer to the fuel sock, if you need to go there.

A double failure is rare, although electrical surges kill a lot of stuff. I'd still question your alternator. Tell the rebuilder what happened, and kindly ask him if he thinks a bad alternator could surge.