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OBD1 ford 5.0 fuel injection electrical issues I need an expert

Dirtracer 619

Well-Known Member
I have chased this problem as far as I can go when running at temp it will randomly miss and pop and some times shuts completely down so then i kill all power and turn it back on and it starts right back up

some times it runs like a raped ape then all of a sudden mis and pop I cannot race like this, its embarrassing and I need to race before I get to old.

so I am in Ramona if there is anyone that knows how to properly test the sensors and diagnose my problem please contact me.

PS if I need to travel to get it done I will it is very important to me

Thanks all for looking
 

sdsocalloco

Member
"I need to race before I get to old." I love it!! I feel the same way, haha.

Have you tried pulling the trouble codes? I know ODB1 is more limited than OBD2 but it should point you in the right direction if it is a sensor. I think I have a Ford OBD1 code reader. I can swing over and scan it sometime in the next few days. Also in Ramona.
 

green787

Well-Known Member
OBD1 got us to the moon... When the computer failed we pulled it out and plugged in another one.... It's a series of switch closures that won't stop your car from running, but it runs better when all the conditions are met...
The problem is you are stuck with one computer and don't have a pile of them to go through like at the wrecking yards....
I would take out the computer board and look for loose solder joints, or evidence of heat failure.... re-solder any questionable points on the board and make sure it is inserted properly in the card cage... Make sure you have the proper +5 - 5 voltage and if the rectifier is working.... Then read the trouble codes and see what's wrong....
 

Dirtracer 619

Well-Known Member
Thanks so i did a test and got codes, 15, 67 and 85
as near as i can tell 15 is a read only memory failure

it also can be that when I shut off the batteries it loses power so there is a 15 power interruption to computer

then 67 something to do with air conditioning

I also took the computer out took cover off blew it out with some canned air and took off the protective foam incase this was causing the computer to overheat. so

not 100% sure what to do next SDSOCALLOCO you are more than welcome to come by
pm me and I can send you my number etc

Green787 thanks for input board was bolted down and tight it is a old computer except for the chip everything looked ok to me whats more truck started back up after i was done so thats a positive haha what ever ideas come my way I will try it and let you know PS truck was tuned at JBA
 

manicmechanic

Well-Known Member
Just a thought may have already been eliminated.
Alternators have a large electro magnetic field, that can raise hell with engine controllers when its screwed up.
Try disconnecting it and running on battery only.
 

sdsocalloco

Member
Edit:
You can dismiss codes 67 and 85.

Code 15 could be ROM failure or KAM failure. If you loose power to the computer it is the KAM failure (keep alive memory). If it is indicating a code 15 ROM failure, I hear this is pretty common with a chipped computer. The way you tell is the ROM error is noted in the KOEO test and the KAM error is noted in continuous memory (CM) part of the test. I put a crappy description of how to tell the difference between the two codes below. Try to see if code 15 is a KOEO code or a CM code.

Could try removing the chip, clearing the codes, and rerunning the tests to see if the ROM error side of the code15 (assuming that is showing up as code15) clears up. Even if it does, code 15 will continue if no 'keep alive memory' power is run. You may want to consider running a fused line from the line side of your disconnect switch to your computer. Someone correct me if i am mistaken, but this could allow the computer to log pending codes while the engine is running that are otherwise cleared when power is removed from the computer...at lease this helps with OBD2 setups.



How To Count “Check Engine” Light Blinks
When the “Check Engine” light blinks during the test you will get several different blinks, the separation time between blinks is used to indicate what information is being displayed.Turn key to RUN.You will hear some relays engage and the fuel pumps prime the system. This is the EEC beginning the test.The fuel pumps will stop and the EEC will now begin giving codes.You may catch a brief flickering of the light. This is a rapid code read that is used by the code readers you can purchase. Do not worry all those rapid flashes just flicker by. You should now be given blinks at a slower pace of 2 & 4 second pauses.First digit of first KOEO code (1/2 second between blinks)2 second pauseSecond digit of first KOEO code (1/2 second between blinks)4 second pause Next KOEO codeOnce all KOEO codes are read the EEC will repeat them6 second pauseSingle Separator Blink (this indicates the change from KOEO codes to CM codes)6 second pauseCodes from Continues Memory (uses same 1/2, 2, and 4 second timing as KOEO codes and also repeats them)If nothing has been recorded by the EEC since last battery disconnect you will see
 
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sdsocalloco

Member
I think this is going to end up being a solder connection in the computer or a loose pin/plug in the harness that is intermittently losing connection. These get loose after being disconnected a few times. Ford has a "pin tension" test in their wiring troubleshooting workflow.

Super happy to help track it down. Maybe this weekend or top of next week?
Andy
858-583-2289
 

green787

Well-Known Member
With a wiring diagram and a simple 12V test probe, you can remove the computer and hook the test lead to +pos and then touch the appropriate connections in the computer connector with the probe end, to see if they get to ground through the various sensors on the engine...If it does the test light will light.... You might have to have the car running in the case of oil pressure sensors which is the first place I would look.....
Most of the devices just allow voltage to pass to ground through them...which trips a relay..... So those are really just a bunch of ground points that complete a circuit and latch a micro relay inside the computer.... and sometimes outside the computer through the larger relays positioned around the engine compartment....
 

burninfuel

Well-Known Member
Main issues with all ecu is a bad ground to the ecu, do several and see if goes away.
ls engines, ecotec, hondas are ground problems
 

Dirtracer 619

Well-Known Member
So what we have found in the last couple days, I have an Aeromotive 700 fuel pump and found when we connect the wires to it, we drop from 12.67 to 11.4V
I am wondering if that is normal or maybe there is some internal resistance, will call the tech guys tuesday
 

Dirtracer 619

Well-Known Member
did some testing and I guess thats about normal for a voltage drop under load so will keep looking
 

dzrt performance

Well-Known Member
So what we have found in the last couple days, I have an Aeromotive 700 fuel pump and found when we connect the wires to it, we drop from 12.67 to 11.4V
I am wondering if that is normal or maybe there is some internal resistance, will call the tech guys tuesday
no that isn't normal and low battery voltage will wreak havoc on an EFI system.
possibly the wiring to your pump is under size, need to know more about your wiring. a relay with proper size wire may fix this for you
 

Dirtracer 619

Well-Known Member
See thats the thing. The battery is 13.6v the alternator puts out 14.4v you disconnect the fuel pump wires and they match the battery hook it up and it drops to 11. 4 but that means the pump is running and the voltage is down in the 11's. Also we ran around the block and fuel pressure was 40-41 except when i let off and just cruised then it dropped about 4 -5 psi Then would pick right back up when i stepped on it. So I'm thinking it might be something else. Which is why I'm here haha cause I'm somewhat stumped

The codes were nothing that matters 15, 67 & 85 on both tests

So i have a test plan
1. Have an additional computer. That i can put my chip in,
2. Disconnect the fuel pump wires, and run temporary harness with larger wires
3 go run it. See how it goes...


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_

Well-Known Member
While you may not be fixing all your problems, you are on the right track to fixing a definite fuel delivery / fuel pump issue.

1st, you should see no more than a 1-volt drop to any electrical component on the vehicle when that component is operating. This 1-volt drop is the sum of both the +12V and the GND. If you are seeing more than a 1-volt drop, there are several possible root causes. The most common are:

1) Wire size is to small for the load demand of the fuel pump under normal operating conditions.
2) Fuel Pump under excessive load, a result of in-adequate fuel line size or possible plugged filter(s), (pre- and post- filters.)

RE: Proper Wire size,
Identify the Fuel Pump manufacture's current draw specs for your fuel pump, and use this value to confirm proper wire size requirements for the fuel pump based on fuel pump current draw and total length of wire from fuel pump fuse/breaker to fuel pump, plus the length of the fuel pump GND wire to chassis ground. You can either PM me the total length and current draw and I'll respond with proper wire size, or you can find on-line calculators to calculate the proper wire size.
 

Dirtracer 619

Well-Known Member
Hi all, i thought i would post up where i am at on my electrical popping issues.
I replaced the old stock 1991 distributor with an MSD pro billet distributor and when i took out the old one i noticed the lower
Bushing had some play in it. Maybe scattering the spark. Not sure but new never hurts. And also new plug wires even though they were not old.

Now the motor hasn't shut down and the popping is 99% gone. I do get a pop every once in a while but only like one. For the most part she starts right up and runs great. The last two tests in the desert were good,
So i am signed up,and ready to go race the MORE. Duel in the desert on the 28th

Lets hope we have a good time and the ol truck does the entire race without issue and this old driver can bring her home!


Thanks everyone who gave ideas for me to check out I did each and every one i could. I think they all helped.
Will post up after the race.
Later


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Dirtracer 619

Well-Known Member
Im back!,

Well the popping is still there when, when hard on the gas then let off for a corner or big holes then you stand on it and getting popping threw the air cleaner,
We did notice if you keep the gas on a little it does not pop as bad. And when cruising fast there is none.

I think my next step is to look at the fuel injectors maybe have them checked for flow, one other area i need to look at is my exhaust, i have stock shorty headers. They may have a mis match to the exhaust ports.

Grasping at straws here!

On a good point we did manage to get a 3rd place in our 1450 race at MORE,s Duel in the Desert. Our first podium!!


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green787

Well-Known Member
Im back!,

Well the popping is still there when, when hard on the gas then let off for a corner or big holes then you stand on it and getting popping threw the air cleaner,
We did notice if you keep the gas on a little it does not pop as bad. And when cruising fast there is none.

I think my next step is to look at the fuel injectors maybe have them checked for flow, one other area i need to look at is my exhaust, i have stock shorty headers. They may have a mis match to the exhaust ports.

Grasping at straws here!

On a good point we did manage to get a 3rd place in our 1450 race at MORE,s Duel in the Desert. Our first podium!!


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You have a lose wire somewhere... The engine is not timed properly.... There are vacuum lines disconnected.... You have fuel delivery issues at full throttle.....
These are the things I would check.... If your truck idles the fuel injectors are working... The headers can't possibly have anything to do with it...
Just my humble opinion....
Bring it to Duarte and I'll tune it for you....
 

Dirtracer 619

Well-Known Member
I could use some new eyes on it Im down in ramona though
Tuned twice JBA speed shop, ran perfect both times on the dyno
After multiple runs could not reproduce. But that makes sense
It takes off fine, just has a just on/off/on problem

On a side note we run 36# injectors but stock rails and cross tube
70 mm Maf and throttle body

I thought stock rails should handle up to 400 hp
Maybe not. But gage was consistent pressure around 40 psi


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dzrt performance

Well-Known Member
had a car just the other day with similar issue...nobody could figure it out, to a dyno twice.....ran it hard, seemd to work ok on the dyno. but once out in the rough one cylinder would miss horribly.

everything possible was replaced. plugs, injectors, coil packs and so forth to no avail. got a break and finally was able to prove it to a particular cylinder.

in the end. the connection to the coil pack was faulty. to the naked eye....it looked fine. you could measure power and ground at the coil, tested continuity back to the ecu, everything looked fine.

what happened is the OEM style metripak pins had lost "tension" on the mating surface from be plugged and unplugged countless times over the years. once the G's and vibration in the dirt came into play, it was all over.

bottom line is I would recommend going through each and every connection in your harness and cleaning (rubbing alcohol and compressed air) every pin, or even better simply replacing them.

OEM style pins, regardless of chevy or ford or whoever.....simply were not designed for the harsh environment that they are now being used in. and sure, they work for a while. but at the end of the day, the don't last like higher quality stuff does. same goes for your ecu. sure, the same level of technology (or even lower level) took us to the moon....but hey....sails and oars got us across the oceans once too and was the predominate technology of the day .for your racing use.....I would strip out all that OEM stuff and step up and get a modern workable engine management system and good quality wiring for it.
 

Dirtracer 619

Well-Known Member
End of story

Well from all everyones help and i tried everything suggested
We have finally got her running great. And in the mean time lots of new parts for the ole heap

The last two races we ended up with a third and a fifth so far!
So thanks again for everyone that chimed in
Team 1453


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