3FE - No CEL and no +12V @ B+

Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
It is time to beat another dead horse. Anyone with me? I hear its all the rage these days. Well, anyway, like the title says, I have been battling this problem for a while. I just cant seem to nail down what is causing it. It starting after I completed a head gasket job/desmog a few weeks ago. The truck ran fine before the work (other than oil and water mixing and so on). I put all the pieces back, went to fire it up and nothing. The starter and motor turns but no fuel, spark... No cel or 12v to the B+ terminal. Ive tried John Helds instructions, checked fuses, jumped this, jumped that, and now Im stumped. I feel that I ve exhausted all of my knowledge of wiring and electronics. Getting to the just plain frustrated point that wants to pull it all and drop a v8 in it......but I like the stupid little 3fe and would like to get her going again. Someone please help, I promise to report back and say what the problem was if I get it running. Unlike some threads, its like reading a good book then to find out that someone ripped out the last few pages. You never know who the killer was...Thanks, guys and gals.

Keith
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
Fusible links, although crusty and need of replacement, seem to be still intact. I have 12v down stream of the links. I have tried jumping pins 2 & 4 on the relay. Doesn't really seem to do anything. Still don't get 12v at B+. Today I got .38v at the B+ terminal with the key on. All fuses seem to be good inside and under the hood. I get 12v to the main fuse box under the hood. I even pulled and opened the ecu the other day to visually inspected it, one thread here should actual burned components. I saw no obvious signs of damage. Any one know how many grounds there are? 4? 1 @ firewall to head, 1 @ coil to head, 1 @ fuel rail area by intake manifold, and 1 on intake manifold by cold start injector tie in. Correct, did I miss any? Please keep the thoughts coming.

Thanks,

Keith
 
Joined
May 22, 2016
Messages
1,319
Location
Southport NC
Same thing happened to me 2 weeks ago! After changing fuseable links..... still nothing! Ended up being my relay in the box under the hood! Pulled one out from drivers kick panel box, and put it under the hood and BINGO!!!
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
Which relay did you use? I tried the top left one I believe. It was the same part number as the one under the hood. Nothing changed. Hopefully I didn't use one that was needed for it to run. Rob Peter to pay Paul sorta thing. Where do the fusible links actually go? I know at least one goes to the fuse box.
 
Joined
May 22, 2016
Messages
1,319
Location
Southport NC
If the majority of your electronics work then I would say the links are ok. Check your radio, blower fan, lights, lighter, basically make sure everything works. (Except your cel!)
Someone sent me a diagram of the relays behind the kick panel, if I can find it I'll post it here! (I tried 1 relay, didn't work, had to try another!) the relays behind the kick panel control- lights, heater, ac, defrost, and 1 more I can't remember! Nothing to stop it from starting, I think I pulled the defrost one, then following day I went and taped the toyos at pik n pull!
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
Ok, I will try a different relay tomorrow after work. I believe everything inside still works. I didn't have any blown fuses or anything when I was checking the other day. I'll check again and report back.
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
I have been following these instructions....http://www.sdsysdesign.com/tlc/images/Strife/3FE EFI Diag.pdf......I think I have 12v everywhere except to B+(diagnostic port). After re reading this, I am thinking that I may have an issue between the efi fuse and pin 8 (B+). I have 12v at the fuse, but didn't follow this wire out to B+. I will try a different efi relay first to see if that changes anything before I go chasing wires.....again.

Keith
 
Joined
Mar 24, 2009
Messages
2,162
Location
Mesa, AZ
 
I would start with replacing the fusi le links and efi relay in general noth are fairly inexpensive from there its possible that the wiring in the engine wiring harness itself broke during the headgasket replacement just went through this a coupke months ago every time iwould pick up the truck from the shop it would die about 50 miles down the road due to a broken wire in wiring harness thw wires are over 25 years old so its a possibility
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
I will check the wiring when i get a chance.

List of things tried or checked.

- have 12v at fuse box
- have 12v to efi fuse
- fusible links seem to be intact
- no cell with key on
,- no 12v to B+
,- put 12v to fuel pump pin, pump works
- checked fuses, all seem to be intact and carry voltage
- jumped efi relay pin 2&4. No change
- swapped efi relay with one at ds kick panel, no change, but will try a different relay tonight
- desmogged and have all smog junk electronics unplugged and vac lines capped.
I have power to the starter. It and the motor turns, I can see the fan turn when cranking. However it does only sound like its just the starter turning. Not sure y that is tho. Any more thoughts?

Thanks
Keith
 

inkpot

SILVER Star
Joined
Jan 30, 2003
Messages
13,597
Location
All over Arizona
 
 
 
If the fusable links are tattered just replace them. Not expensive! If several strands of the wires are frayed then it will not carry full power even though it meters out at full voltage.
 
Joined
Dec 8, 2006
Messages
8,834
Location
New Jersey
 
 
New OEM fusible links are $12. Why give this a second thought?

Try unplugging the AFM connection. If the 2 phillips screws on the AFM housing were removed and the internal circuit board was moved, then there is likely a fractured wire. This can prevent the ECU from entering the "ready" state and energizing the EFI relay.

I would make sure that each pin of the EFI relay socket is good. Here is a diagram of the pinout along with the OEM wire colors. Make sure you're getting a good ground on pin 1 (brn). The pin 2 (red/yel)+12 comes from the EFI fuse and should always be present. Pin 3 (red) is the logic signal from the ECU that energizes the relay coil and it should read around +12 or so with the key in the ON position.

You will not get +12 at the diagnostic port until the EFI relay is closed.

Relay Block Fender.jpg
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
Great, thanks for the diagram. I am going to order a new fusible link and relay this week. Good pm even if mine seem to still work. I tried unplugging the AFM a couple times with no change. Upon reassembly of the motor, I did use brake cleaner to spray out any gunk that was inside the AFM/tube section. However, I did not disassemble the AFM and did not remove the 2 screws. Just opened the flap a bit to blow the gunk out. Could that have damaged the AFM somehow? Is there a way to bypass the AFM for testing purposes. I've read horror stories of people opening it up and screwing it up.
 
Joined
Dec 8, 2006
Messages
8,834
Location
New Jersey
 
 
Simply unplug the AFM for diagnostic purposes. If the AFM is not faulty, there should be no change in ECU logic.
 
Joined
Feb 19, 2017
Messages
65
Location
B'ham, AL
Well, we got snowed out today. Had a few minutes to throw a meter on my truck when I got home. It appears that I do not have 12v at pin 3 with the key on, I used pin 1 for the ground. I got 12v at pin 2 with and without the key on. I still get 12v at the efi fuse. So what does that mean? Bad ecu or damaged wire to pin 3? I will take a closer look at the wiring under the fuse box when the snow lets up. I failed to mention that the truck did sit for a few months until I got all of the parts to complete the head gasket job. All removed parts were kept inside the garage if any of this matters.

Thanks,

Keith
 
Joined
Dec 8, 2006
Messages
8,834
Location
New Jersey
 
 
That means that:
1. The ECU is not triggering the EFI relay
2. The ECU is triggering the EFI relay but it's not making it to the relay.
The signal from the ECU (connector E5 pin 3) goes through connector EB1 which should be somewhat close to the fusebox.
 
Top Bottom