This has been some what a saga for me but I think sharing it with you all might be helpful.
Cruiser Moab 2024
Drove out to the event and about 5 miles out my CEL comes on. Read the code and it was a P1071 system lean back one.
Reset the code and monitored it at the event. The LTFT was just under the threshold by 2%.
Started the drive home and things got worse. Monitored MPG and it was all over the map, power was ok at times and other times it was crap. long cranks to get the engine to fire was becoming increasingly more often.
Got the truck home and parked it for the winter.
Lead up to Cruise Moab 2025
Got another mouse infestation and got an early start on prepping for the event.
Started the truck and more of the same crappy performance and a CEL.
Replace the injectors, a little bit better but not great.
I had other things to contend with like installing a winch, repairing chewed wires as so fourth.
So I was working around the truck and when I could I'd take it for a drive and swap items out.
Swapped out, open circuit relay, Fuel pump relay, fuel pump resistor, fusible links, Ignition switch. Nothing is helping and the drive to Moab 2025 starts in 4 days.
Now I swap in a Denso Fuel pump. And the truck shows some promise on the first drive. I pull it into the garage for a few last things and go to back it out of the garage and it wont start. endless cranking and it won't start. It's dead!
I grab my timing light and confirm there is spark, so it's a fuel problem.
Spend the next two days with my EWD and I just can't get my head around the problem and with the deadline looming for Moab it just wasn't going to happen. Called a few people and cancelled my plans.
Took a couple of days away from the truck to clear my head. The main issue was that I had voltage to the fuel pump but when turning the key to the run position it would drop to 0v. This is an issue with amperage and the cause is a bad connection.
After thinking about the problem and working through the diagram my new working theory was that multiple relays were contributing to the problem. The power distribution in our 80s is basically 4 22amp relays P# 90987-02004.
So I order 4 relays and waited.
Relays came in, got installed and and the truck fired right up on a short crank. The truck is 30 years old and has 335,000 miles.
So now for the second half of the story.
Ordering that relay in the united states will get you a 90987-02004-83. This in not what came from the factory! The best I can tell is that the factory part went for around 56.00 and this new part is like 10.00. I went through Amayama and they were 24.00 each. It was a little over 115.00 with shipping for the same relays that lasted 30 years.
attached is one of the factory relays and an o'reily one that I bought. The factory -83 has the same cap as the o'reily and a similar price point.
The 4 relays are MAIN Power, Tail light, EFI and Open circuit. You might consider changing them also.
I have found a source that claims they can provide Japanese relays and on the surface they do look the same. I ordered a sample to see what they have. If it checks out I'll stock then in a qty of 4 to help with costs and wait times.
Looking at the pictures if the internals of the two relays I think it will be obvious if the sample isn't an authentic Japaneses relay.
Cruiser Moab 2024
Drove out to the event and about 5 miles out my CEL comes on. Read the code and it was a P1071 system lean back one.
Reset the code and monitored it at the event. The LTFT was just under the threshold by 2%.
Started the drive home and things got worse. Monitored MPG and it was all over the map, power was ok at times and other times it was crap. long cranks to get the engine to fire was becoming increasingly more often.
Got the truck home and parked it for the winter.
Lead up to Cruise Moab 2025
Got another mouse infestation and got an early start on prepping for the event.
Started the truck and more of the same crappy performance and a CEL.
Replace the injectors, a little bit better but not great.
I had other things to contend with like installing a winch, repairing chewed wires as so fourth.
So I was working around the truck and when I could I'd take it for a drive and swap items out.
Swapped out, open circuit relay, Fuel pump relay, fuel pump resistor, fusible links, Ignition switch. Nothing is helping and the drive to Moab 2025 starts in 4 days.
Now I swap in a Denso Fuel pump. And the truck shows some promise on the first drive. I pull it into the garage for a few last things and go to back it out of the garage and it wont start. endless cranking and it won't start. It's dead!
I grab my timing light and confirm there is spark, so it's a fuel problem.
Spend the next two days with my EWD and I just can't get my head around the problem and with the deadline looming for Moab it just wasn't going to happen. Called a few people and cancelled my plans.
Took a couple of days away from the truck to clear my head. The main issue was that I had voltage to the fuel pump but when turning the key to the run position it would drop to 0v. This is an issue with amperage and the cause is a bad connection.
After thinking about the problem and working through the diagram my new working theory was that multiple relays were contributing to the problem. The power distribution in our 80s is basically 4 22amp relays P# 90987-02004.
So I order 4 relays and waited.
Relays came in, got installed and and the truck fired right up on a short crank. The truck is 30 years old and has 335,000 miles.
So now for the second half of the story.
Ordering that relay in the united states will get you a 90987-02004-83. This in not what came from the factory! The best I can tell is that the factory part went for around 56.00 and this new part is like 10.00. I went through Amayama and they were 24.00 each. It was a little over 115.00 with shipping for the same relays that lasted 30 years.
attached is one of the factory relays and an o'reily one that I bought. The factory -83 has the same cap as the o'reily and a similar price point.
The 4 relays are MAIN Power, Tail light, EFI and Open circuit. You might consider changing them also.
I have found a source that claims they can provide Japanese relays and on the surface they do look the same. I ordered a sample to see what they have. If it checks out I'll stock then in a qty of 4 to help with costs and wait times.
Looking at the pictures if the internals of the two relays I think it will be obvious if the sample isn't an authentic Japaneses relay.
